WO2025223020A1 - Communication method and apparatuses, storage medium, and computer program product - Google Patents

Abstract

The present application provides a communication method and apparatuses, a storage medium, and a computer program product, which are used for improving the throughput of a communication system. In the present application, a terminal apparatus acquires first information. The first information is used for determining an area where a second communication apparatus provides a service. The terminal apparatus switches from a first communication apparatus to the second communication apparatus when the first information indicates that the area where the second communication apparatus provides the service comprises a first area, and the first area comprises an area where the terminal apparatus is located. Since the terminal apparatus determines, on the basis of the first information, whether it is necessary to switch to the second communication apparatus, the master communication apparatus therefore does not need to issue a switching instruction to the terminal apparatus during this process, allowing the solution to reduce signaling overhead.

Description

A communication method, apparatus, storage medium, and computer program product

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese Patent Application No. 202410516629.5, filed on April 26, 2024, entitled "A Communication Method, Apparatus, Storage Medium and Computer Program Product", the entire contents of which are incorporated herein by reference.

Technical Field

This application relates to the field of communication technology, and in particular to a communication method, apparatus, storage medium, and computer program product.

Background Technology

Currently, the 5G New Radio (NR) technology is evolving from revision (R) 18 to revision (R19). Simultaneously, NR technology has moved from the standardization phase to the commercial deployment phase. The NR standard protocol is a wireless communication technology designed for terrestrial cellular network scenarios, providing users with ultra-low latency, ultra-reliability, ultra-high speed, and massive connectivity wireless communication services. Compared to terrestrial communication, non-terrestrial networks (NTN) communication features large coverage areas and flexible networking, achieving seamless global network coverage. NTN communication utilizes equipment such as drones, high-altitude platforms, and satellites to provide data transmission and voice communication services to user equipment (UE). Improving communication performance is currently a pressing issue that needs to be addressed.

Summary of the Invention

This application provides a communication method, apparatus, storage medium, and computer program product for determining whether to switch to a second communication device based on first information. This communication device switching scheme can save signaling overhead, reduce resource overhead, and thereby improve communication performance.

In one possible implementation, the terminal device can communicate with multiple communication devices. For example, the terminal device may establish a radio resource control (RRC) connection with one communication device but not with other communication devices. The communication device with which the terminal device has an RRC connection can be called the primary communication device, and the communication devices without an RRC connection can be called secondary communication devices. The primary communication device and one or more secondary communication devices can send the same or different data to the same terminal device on the same resources. This scheme can improve the performance and/or throughput of the communication system. In this scenario, the terminal device may need to switch to a secondary satellite device. If the primary communication device needs to make a judgment and issue a switching command every time a secondary satellite device switches, it will result in high signaling overhead, thereby increasing the load on the primary communication device.

To address the aforementioned problems, this application provides a solution in which the terminal device can determine whether to switch communication devices based on first information. For example, the first information can be used to determine the area served by the second communication device. If the terminal device determines, based on the first information, that the area served by the second communication device includes the area where the terminal device is located, it can then switch from the first communication device to the second communication device. In this solution, the terminal device determines whether to switch communication devices based on the first information, eliminating the need for the primary communication device to issue a switching command to the terminal device. This solution can save signaling overhead, reduce resource consumption, and thereby improve communication performance.

On the other hand, the second and third communication devices can improve communication performance by sending data to the same terminal device on the same resources (e.g., the same time-domain and/or frequency-domain resources). For example, sending different data to the same terminal device on the same resources (e.g., the same time-domain and/or frequency-domain resources) can improve data transmission efficiency and increase the throughput of the communication system. Furthermore, sending the same data to the same terminal device on the same resources (e.g., the same time-domain and/or frequency-domain resources) can improve the reliability of data transmission.

Firstly, this application provides a communication method that can be executed by a terminal device. The terminal device may include a terminal equipment or a chip system within the terminal equipment.

The terminal device acquires first information. The first information is used to determine the area where the second communication device provides services. If the first information indicates that the area where the second communication device provides services includes a first area, the terminal device switches from the first communication device to the second communication device, where the first area includes the area where the terminal device is located.

Since the terminal device determines whether to switch to the second communication device based on the first information, the main communication device does not need to issue a switching command to the terminal device during this process. This scheme can save signaling overhead, reduce resource overhead, and thus improve communication performance.

In one possible implementation, if the first information indicates that the area served by the second communication device does not include the first area, the terminal device determines that it does not need to switch to the second communication device. The terminal device can continue to communicate with the first communication device, or continue to determine whether the area served by the next candidate auxiliary communication device includes the first area.

In one possible implementation, the terminal device establishes an RRC connection with the third communication device, but does not establish an RRC connection with the second communication device or the first communication device.

In this example, the third communication device can be considered the primary communication device, and the first and second communication devices can be considered two secondary communication devices. The primary and secondary communication devices can send data to the terminal device, either individually or jointly. For example, the primary and secondary communication devices can send data to the terminal device on the same resources (e.g., the same time-domain and/or frequency-domain resources), and the data sent by the primary and secondary communication devices can be the same or different. This scheme can improve the performance and/or throughput of the communication system. The data and resources sent by the secondary communication devices to the terminal device can be notified by the primary communication device, by other devices, or determined by the secondary communication device according to preset rules. The primary and secondary communication devices can also send data to the terminal device on different resources (e.g., different time-domain and different frequency-domain resources).

In one possible implementation, the terminal device receives first data and second data, the first data comes from a second communication device, the second data comes from a third communication device, the first data occupies a first resource, and the second data occupies a first resource.

The first data and the second data can be the same or different. For example, the first resource may include/be a time-domain resource or a frequency-domain resource. As another example, the first resource may include/be a time-domain resource and a frequency-domain resource. For example, if the second communication device and the third communication device send data to the same terminal device on the same resources (e.g., the same time-domain resources and/or frequency-domain resources), communication performance can be improved. For example, if the second communication device and the third communication device send different data to the same terminal device on the same resources (e.g., the same time-domain resources and/or frequency-domain resources), data transmission efficiency can be improved, increasing the throughput of the communication system. As another example, if the second communication device and the third communication device send the same data to the same terminal device on the same resources (e.g., the same time-domain resources and/or frequency-domain resources), data transmission reliability can be improved.

In one possible implementation, the first information includes at least one of the following: information associated with the location of the second communication device; time information (e.g., current time); information associated with the Doppler signal of the second communication device; and information associated with the timing advance (TA) of the second communication device. This information is readily available to the terminal device, thereby reducing the complexity of the solution. For example, the terminal device can determine whether to switch to the auxiliary communication device based on the time information. This solution reduces the hardware requirements of the terminal device and is applicable to terminal devices with weaker capabilities (e.g., no positioning function).

In one possible implementation, the information associated with the position of the second communication device includes: the elevation angle corresponding to the second communication device; and/or, the orbital angle corresponding to the second communication device. For example, the elevation angle corresponding to the second communication device includes the angle between a line originating from the terminal device and directed toward the second communication device and the projection of that line onto a horizontal plane. For example, the orbital angle corresponding to the second communication device includes: the angle between a line connecting a point on the orbit of the second communication device and the center of the orbit of the second communication device, and the angle between a reference point on the orbit of the second communication device and the center of the orbit of the second communication device.

In one possible implementation, the information associated with the Doppler of the signal from the second communication device includes: the corresponding Doppler of the second communication device; and/or, the Doppler rate of the second communication device.

In one possible implementation, the information associated with the TA of the second communication device includes at least one of the following: the TA corresponding to the second communication device; the rate of change of the TA corresponding to the second communication device; and the rate of change of the rate of change of the TA corresponding to the second communication device.

In one possible implementation, if the first information satisfies a first condition, the terminal device determines that the area where the first information instructs the second communication device to provide services includes the first area. In another possible implementation, if the first information does not satisfy the first condition, the terminal device determines that the area where the first information instructs the second communication device to provide services does not include the first area.

For example, the first condition includes at least one of the following: the elevation angle corresponding to the second communication device belongs to the first elevation angle range; the orbital angle corresponding to the second communication device belongs to the first orbital angle range; the time indicated by the time information belongs to the time period during which the second communication device provides services to the first area; the Doppler corresponding to the second communication device belongs to the first Doppler range; the Doppler rate corresponding to the second communication device belongs to the first Doppler rate range; the TA corresponding to the second communication device belongs to the first TA range; the TA change rate corresponding to the second communication device belongs to the first TA change rate range; and the change rate of the TA change rate corresponding to the second communication device belongs to the second TA change rate range.

As can be seen from the above implementation methods, the terminal device can determine whether to switch to an auxiliary communication device based on a comparison of the first information with some parameter ranges or time periods. The first information is relatively easy for the terminal device to obtain, thus reducing the complexity of the solution. For example, the terminal device can determine whether to switch to an auxiliary communication device based on time information. This solution reduces the hardware requirements of the terminal device and is applicable to terminal devices with weaker capabilities (e.g., without positioning functionality).

In one possible implementation, the terminal device receives first configuration information. The first configuration information includes information indicating at least one of the following: a first elevation angle range, a first orbital angle range, a time period during which the second communication device provides service to the first area, a first Doppler range, a first Doppler rate range, a first TA range, a first TA rate of change range, and a second TA rate of change range.

In one possible implementation, the first configuration information further includes: ephemeris information of the second communication device, and/or location information of a ground reference point. The location information of the ground reference point is used to determine the elevation angle corresponding to the second communication device. The ephemeris information can assist the terminal device in determining whether to switch to the auxiliary communication device. The ground reference point can be a relatively central point in a region. When the terminal device calculates the elevation angle corresponding to the second communication device based on the ground reference point, it is not necessary to determine the location information of the terminal device. This scheme can reduce the hardware requirements of the terminal device and can be applied to terminal devices with weaker capabilities (e.g., without positioning functions).

In one possible implementation, the first configuration information further indicates that the first communication device has a higher priority than the second communication device, and the second communication device is the highest priority communication device to be switched after the first communication device. In this scheme, the priority of the third communication device can be set according to the order in which each communication device provides services to the first area, or it can refer to other information, such as the signal quality of each communication device, to set its priority. The terminal device can sequentially determine whether each candidate auxiliary communication device can be successfully switched based on the priority information of each candidate auxiliary communication device indicated by the first configuration information. This scheme allows the terminal device to determine the target auxiliary communication device as quickly as possible, thereby improving the efficiency of the communication system.

In one possible implementation, the terminal device acquires second information to determine the area where the first communication device provides service now or after a first duration. Before switching from the first communication device to the second communication device, the terminal device further determines that the area where the first communication device, indicated by the second information, provides service does not include the first area. In another possible implementation, if the area where the first communication device, indicated by the second information, provides service includes the first area, the terminal device can determine that it is not necessary to switch the secondary communication device from the first communication device to another communication device.

In this scheme, the terminal device needs to determine whether to switch the auxiliary communication device from the first communication device to another communication device when it is determined that the first communication device is currently or about to be unable to provide service to the first area. This scheme can maximize the time that the first communication device provides service to the terminal device, thereby reducing the frequency of switching auxiliary communication devices and saving resource costs.

In one possible implementation, the second information includes at least one of the following: information associated with the location of the first communication device; time information (e.g., current time or time after a first duration); information associated with the Doppler signal of the first communication device; and information associated with the TA of the first communication device.

In one possible implementation, the information associated with the position of the first communication device includes at least one of the following: the elevation angle corresponding to the first communication device; and the orbital angle corresponding to the first communication device. For example, the elevation angle corresponding to the first communication device includes the angle between a line originating from the terminal device and directed toward the first communication device and the projection of that line onto a horizontal plane. For example, the orbital angle corresponding to the first communication device includes the angle between a line connecting a point on the orbit of the first communication device and the center of the orbit of the first communication device, and the angle between a reference point on the orbit of the first communication device and the center of the orbit of the first communication device.

In one possible implementation, the information associated with the Doppler of the signal from the first communication device includes at least one of the following: the corresponding Doppler of the first communication device; and the corresponding Doppler rate of the first communication device.

In one possible implementation, the information associated with the TA of the first communication device includes at least one of the following: the TA corresponding to the first communication device; the rate of change of the TA corresponding to the first communication device; and the rate of change of the rate of change of the TA corresponding to the first communication device.

The second information terminal device is relatively easy to obtain, thus reducing the complexity of the solution. For example, the terminal device can determine whether to switch to the auxiliary communication device based on time information. This solution can reduce the hardware capability requirements of the terminal device and can be applied to terminal devices with weaker capabilities (such as those without positioning functions).

In one possible implementation, if the second information fails to meet the second condition, the terminal device determines that the area served by the first communication device indicated by the second information does not include the first area. The second condition includes at least one of the following: the elevation angle corresponding to the first communication device belongs to a second elevation angle range; the orbital angle corresponding to the first communication device belongs to a second orbital angle range; the time indicated by the time information belongs to the time period during which the first communication device provides service to the first area; the Doppler effect corresponding to the first communication device belongs to a second Doppler range; the Doppler rate corresponding to the first communication device belongs to a second Doppler rate range; the TA corresponding to the first communication device belongs to a second TA range; the TA change rate corresponding to the first communication device belongs to a third TA change rate range; and the change rate of the TA change rate corresponding to the first communication device belongs to a fourth TA change rate range.

In one possible implementation, the inability of the second information to satisfy the second condition may include at least one of the following: the elevation angle corresponding to the first communication device indicated by the second information does not belong to the second elevation angle range; the orbital angle corresponding to the first communication device indicated by the second information does not belong to the second orbital angle range; the time indicated by the time information in the second information does not belong to the time period during which the first communication device provides service to the first area; the Doppler frequency corresponding to the first communication device indicated by the second information does not belong to the second Doppler frequency range; the Doppler rate corresponding to the first communication device indicated by the second information does not belong to the second Doppler rate range; the TA frequency corresponding to the first communication device indicated by the second information does not belong to the second TA frequency range; the TA frequency change rate corresponding to the first communication device indicated by the second information does not belong to the third TA frequency change rate range; and the TA frequency change rate corresponding to the first communication device indicated by the second information does not belong to the fourth TA frequency change rate range.

In another possible implementation, if the second information satisfies the second condition, the terminal device determines that the area served by the first communication device indicated by the second information includes the first area. In this case, the terminal device can determine that there is no need to switch the auxiliary communication device from the first communication device to another communication device.

In one possible implementation, the terminal device switches from the first communication device to the second communication device by: the terminal device ceasing to receive synchronization signals from the first communication device. This can save on the terminal device's resource and power consumption.

In one possible implementation, the terminal device switches from the first communication device to the second communication device, including/compromising that the terminal device receives a synchronization signal from the second communication device, the synchronization signal being used for timing synchronization between the terminal device and the second communication device. In this way, the terminal device can transmit data with the second communication device.

In one possible implementation, the terminal device can transmit data with the first communication device before switching from the first communication device. For example, before switching from the first communication device to the second communication device, the terminal device receives a synchronization signal from the first communication device, which is used for timing synchronization between the terminal device and the first communication device. The terminal device receives data from the first communication device on a second resource, and also receives data from a third communication device on the second resource. This can improve communication throughput. The data sent to the terminal device by the third communication device and the first communication device can be the same or different. The resources occupied by the third communication device and the first communication device for sending data to the terminal device can be the same (same time-domain resources and/or frequency-domain resources) or different (different time-domain resources and different frequency-domain resources).

Secondly, this application provides a communication method that can be executed by a third communication device. The third communication device may include a network device or a chip system within a network device. For example, the third communication device may include a satellite device or a chip (or chip system) within a satellite device. As another example, the third communication device may include a ground station or a chip (or chip system) within a ground station. The ground station may, for example, include network equipment (e.g., access network equipment) deployed on the ground.

The third communication device acquires third information, which is used to determine the area where the second communication device provides services. If the third information indicates that the area where the second communication device provides services includes a first area, the third communication device determines that the terminal device is switching from the first communication device to the second communication device, where the first area includes the area where the terminal device is located.

Since the terminal device determines whether to switch to the second communication device based on the first information, and the third communication device determines whether the terminal device should switch to the second communication device based on the third information, during this process, the third communication device and the terminal device each determine whether the terminal device should switch to the second communication device based on the information used to determine the area provided by the second communication device. During this process, there is no need for the main communication device to issue a switching command to the terminal device, and this scheme can save signaling overhead.

In one possible implementation, if the third communication device determines that the terminal device does not need to switch to the second communication device when the third information indicates that the area where the second communication device provides services does not include the first area.

In one possible implementation, the terminal device establishes an RRC connection with the third communication device, but does not establish an RRC connection with the second communication device, nor with the first communication device. Related details and beneficial effects can be found in the description of the possible implementations of the first aspect, and will not be repeated here.

In one possible implementation, the third communication device sends second data to the terminal device using the first resource, and the first resource is also used by the second communication device to send first data to the terminal device. Related details and beneficial effects can be found in the description of possible implementations of the first aspect, and will not be repeated here.

In one possible implementation, the third information includes at least one of the following: information associated with the location of the second communication device; time information (e.g., current time); information associated with the Doppler signal of the second communication device; and information associated with the TA of the second communication device. The contents of the third information can be found in the description of the possible implementations of the first aspect above, and will not be repeated here.

In one possible implementation, if the third information satisfies the first condition, the third communication device determines that the area in which the third information instructs the second communication device to provide services includes the first area. In another possible implementation, if the third information does not satisfy the first condition, the third communication device determines that the area in which the third information instructs the second communication device to provide services does not include the first area. The content of the first condition can be found in the description of the possible implementations of the first aspect above, and will not be repeated here.

The third information satisfies the first condition including at least one of the following: the elevation angle corresponding to the second communication device indicated by the third information belongs to the first elevation angle range; the orbital angle corresponding to the second communication device indicated by the third information belongs to the first orbital angle range; the time indicated by the time information in the third information belongs to the time period during which the second communication device provides service to the first area; the Doppler corresponding to the second communication device indicated by the third information belongs to the first Doppler range; the Doppler rate corresponding to the second communication device indicated by the third information belongs to the first Doppler rate range; the TA corresponding to the second communication device indicated by the third information belongs to the first TA range; the TA change rate corresponding to the second communication device indicated by the third information belongs to the first TA change rate range; and the change rate of the TA change rate corresponding to the second communication device indicated by the third information belongs to the second TA change rate range.

In one possible implementation, the third communication device sends first configuration information. The details and benefits of the first configuration information can be found in the description of the possible implementations of the first aspect, and will not be repeated here.

In one possible implementation, the third communication device sends second configuration information to the second communication device. The second configuration information includes information indicating at least one of the following: a first elevation angle range, a first orbital angle range, a time period during which the second communication device provides services to the first region, a first Doppler range, a first Doppler rate range, a first TA range, a first TA rate of change range, and a second TA rate of change range.

In one possible implementation, the second configuration information can be associated with the first region. For example, the second configuration information may also include information for indicating the first region.

In one possible implementation, the second configuration information is used by the second communication device to determine the timing for sending a synchronization signal to the first region. For example, when the second communication device determines that one or more of the second configuration information is satisfied, it can begin sending a synchronization signal to the first region (or periodically send a synchronization signal to the first region with a second duration as the period). Alternatively, when the second communication device determines that one or more of the second configuration information cannot be satisfied, it can stop sending a synchronization signal to the first region (or stop periodically sending a synchronization signal to the first region with a second duration as the period; or, for example, the second communication device can periodically send a synchronization signal to the first region with a third duration as the period, where the third duration can be longer than the second duration). It can be seen that in these schemes, with the assistance of the second configuration information, the third communication device can control the number and frequency of synchronization signals sent to the first region, avoiding the need for continuously sending synchronization signals to the first region at a high frequency, thus saving resource overhead.

In one possible implementation, the third communication device acquires sixth information, which is used to determine the area where the first communication device provides service now or after a first duration. Before the terminal device switches to the second communication device, the third communication device determines that the area provided by the first communication device indicated by the sixth information does not include the first area. In another possible implementation, if the area provided by the first communication device indicated by the sixth information includes the first area, the third communication device can determine that the terminal device does not need to switch the auxiliary communication device from the first communication device to another communication device. In this scheme, the third communication device needs to determine that the terminal device needs to switch the auxiliary communication device from the first communication device to another communication device when it determines that the first communication device is currently or will soon be unable to provide service to the first area. This scheme can maximize the time that the first communication device provides service to the terminal device, thereby reducing the frequency of auxiliary communication device switching and saving resource costs.

In one possible implementation, the sixth information includes at least one of the following: information associated with the location of the first communication device; time information (e.g., current time or time after a first duration); information associated with the Doppler signal of the first communication device; and information associated with the TA of the first communication device. The contents of the sixth information can be found in the description of the possible implementations of the first aspect above, and will not be repeated here.

In one possible implementation, if the sixth information fails to satisfy the second condition, the third communication device determines that the area served by the first communication device indicated by the sixth information does not include the first area. In another possible implementation, if the sixth information satisfies the second condition, the third communication device determines that the area served by the first communication device indicated by the sixth information includes the first area. In this case, the third communication device determines that the terminal device does not need to switch the auxiliary communication device from the first communication device to another communication device. The contents of the second condition can be found in the description of the possible implementations of the first aspect above, and will not be repeated here.

In one possible implementation, the sixth information failing to satisfy the second condition includes at least one of the following: the elevation angle corresponding to the first communication device indicated by the sixth information does not belong to the second elevation angle range; the orbital angle corresponding to the first communication device indicated by the sixth information does not belong to the second orbital angle range; the time indicated by the time information in the sixth information does not belong to the time period during which the first communication device provides service to the first area; the Doppler corresponding to the first communication device indicated by the sixth information does not belong to the second Doppler range; the Doppler rate corresponding to the first communication device indicated by the sixth information does not belong to the second Doppler rate range; the TA corresponding to the first communication device indicated by the sixth information does not belong to the second TA range; the TA change rate corresponding to the first communication device indicated by the sixth information does not belong to the third TA change rate range; and the change rate of the TA change rate corresponding to the first communication device indicated by the sixth information does not belong to the fourth TA change rate range.

Thirdly, this application provides a communication method that can be executed by a second communication device. The second communication device may include a network device or a chip system within the network device. For example, the second communication device may include a satellite device or a chip (or chip system) within the satellite device. As another example, the second communication device may include a ground station or a chip (or chip system) within the ground station. The ground station may, for example, include network equipment (e.g., access network equipment) deployed on the ground.

The second communication device acquires fourth information, which is used to determine the area where the second communication device provides services. If the fourth information indicates that the area where the second communication device provides services includes the first area, the second communication device sends a synchronization signal to the first area. Sending the synchronization signal to the first area may include: the second communication device starting to send the synchronization signal to the first area, or the second communication device periodically sending the synchronization signal to the first area for a second duration (which may be a shorter duration).

Since the second communication device can determine whether to send a synchronization signal to the first area based on the fourth information, this scheme can prevent the second communication device from continuously sending synchronization signals to the first area at a high frequency, thereby saving resource consumption, reducing interference in the communication system, and reducing the complexity of the scheme on the second communication device side.

In one possible implementation, the terminal device establishes an RRC connection with the third communication device, but does not establish an RRC connection with the second communication device, nor with the first communication device. Related details and beneficial effects can be found in the description of the possible implementations of the first aspect, and will not be repeated here.

In one possible implementation, the second communication device transmits first data to the terminal device using the first resource, and the first resource is also used by the third communication device to transmit second data to the terminal device. Related details and beneficial effects can be found in the description of possible implementations of the first aspect, and will not be repeated here.

In one possible implementation, the fourth information includes at least one of the following: information associated with the location of the second communication device; time information; information associated with the Doppler signal of the second communication device; and information associated with the TA of the second communication device. The contents of the fourth information can be found in the description of the possible implementations of the first aspect above, and will not be repeated here.

In one possible implementation, the second communication device sends a synchronization signal to the first region when the fourth information satisfies the first condition. The details and benefits of the first condition can be found in the description of the possible implementations of the first aspect, and will not be repeated here.

The fourth information satisfies the first condition including at least one of the following: the elevation angle corresponding to the second communication device indicated by the fourth information belongs to the first elevation angle range; the orbital angle corresponding to the second communication device indicated by the fourth information belongs to the first orbital angle range; the time indicated by the time information in the fourth information belongs to the time period during which the second communication device provides service to the first area; the Doppler corresponding to the second communication device indicated by the fourth information belongs to the first Doppler range; the Doppler rate corresponding to the second communication device indicated by the fourth information belongs to the first Doppler rate range; the TA corresponding to the second communication device indicated by the fourth information belongs to the first TA range; the TA change rate corresponding to the second communication device indicated by the fourth information belongs to the first TA change rate range; and the change rate of the TA change rate corresponding to the second communication device indicated by the fourth information belongs to the second TA change rate range.

In another possible implementation, if the fourth information does not meet the first condition, the second communication device determines that the area where the fourth information indicates the second communication device to provide services does not include the first area. It may not start sending a synchronization signal to the first area, or it may periodically send a synchronization signal to the first area with a third duration (the third duration is a relatively long duration, for example, the third duration is longer than the second duration).

In one possible implementation, the second communication device acquires fifth information, which is used to determine the area where the second communication device provides services. If the fifth information indicates that the area where the second communication device provides services does not include the first area, the second communication device determines to stop sending synchronization signals to the first area. This saves resource overhead.

In another possible implementation, if the fifth information indicates that the area where the second communication device provides service includes the first area, the second communication device can continuously send a synchronization signal to the first area, or periodically send a synchronization signal to the first area for a second duration (which can be a shorter duration). This extends the service time for the terminal device, reduces the frequency of switching between auxiliary communication devices, and thus saves resource overhead.

In one possible implementation, if the fifth information does not meet the first condition, the second communication device determines to stop sending the synchronization signal to the first area. If the fifth information meets the first condition, the second communication device may continuously send the synchronization signal to the first area, or periodically send the synchronization signal to the first area with a second duration (which may be a shorter duration).

In one possible implementation, after the second communication device determines to stop sending synchronization signals to the first area, it further includes at least one of the following: the second communication device stops sending synchronization signals to the first area; the second communication device stops periodically sending synchronization signals to the first area with a second duration; the second communication device periodically sends synchronization signals to the first area with a third duration, the third duration being longer than the second duration. This can save resource consumption.

In one possible implementation, the fifth information includes at least one of the following: information associated with the location of the second communication device; time information (e.g., current time); information associated with the Doppler signal of the second communication device; and information associated with the TA of the second communication device. The contents of the fifth information can be found in the relevant descriptions of the possible implementations of the first aspect described above, and will not be repeated here.

In one possible implementation, the fifth information not satisfying the first condition includes at least one of the following: the elevation angle corresponding to the second communication device indicated by the fifth information is not within the first elevation angle range; the orbital angle corresponding to the second communication device indicated by the fifth information is not within the first orbital angle range; the time indicated by the time information in the fifth information is not within the time period during which the second communication device provides service to the first area; the Doppler corresponding to the second communication device indicated by the fifth information is not within the first Doppler range; the Doppler rate corresponding to the second communication device indicated by the fifth information is not within the first Doppler rate range; the TA corresponding to the second communication device indicated by the fifth information is not within the first TA range; the TA change rate corresponding to the second communication device indicated by the fifth information is not within the first TA change rate range; and the change rate of the TA change rate corresponding to the second communication device indicated by the fifth information is not within the second TA change rate range.

In one possible implementation, the second communication device receives second configuration information. The details and benefits of the second configuration information can be found in the description of possible implementations in the second aspect, and will not be repeated here.

Fourthly, a communication device is provided, which can be the aforementioned terminal device, third communication device, or second communication device. The communication device may include a communication unit and a processing unit to perform any one of the first to third aspects, or any possible implementation of the first to third aspects. The communication unit is used to perform functions related to transmission and reception. The communication unit may be referred to as a transceiver unit. Optionally, the communication unit includes a receiving unit and a transmitting unit. In one design, the communication device is a communication chip, the processing unit may be one or more processors or processor cores, and the communication unit may be the input/output circuit, input/output interface, or antenna port of the communication chip.

In another design, the communication unit can be a transmitter and a receiver, or the communication unit can be a transmitter and a receiver.

Optionally, the communication device may also include modules that can be used to perform any one of the first to third aspects described above, or to perform any possible implementation of the first to third aspects.

Fifthly, a communication device is provided, which may be the aforementioned terminal device, a third communication device, or a second communication device. The communication device may include a processor and a memory to execute any one of the first to third aspects, or to execute any possible implementation of the first to third aspects. Optionally, it may also include a transceiver, the memory for storing computer programs or instructions, and the processor for retrieving and executing the computer programs or instructions from the memory. When the processor executes the computer programs or instructions in the memory, the communication device executes any one of the first to third aspects, or to execute any possible implementation of the first to third aspects.

Optionally, there may be one or more processors and one or more memories.

Optionally, the memory can be integrated with the processor, or the memory can be set up separately from the processor.

Optionally, the transceiver may include a transmitter and a receiver.

In a sixth aspect, a communication device is provided, which may be the aforementioned terminal device, a third communication device, or a second communication device. The communication device may include a processor to execute any one of the first to third aspects, or to execute any possible implementation of the first to third aspects. The processor is coupled to a memory. Optionally, the communication device further includes a memory. Optionally, the communication device further includes a communication interface, and the processor is coupled to the communication interface.

In one implementation, when the communication device is a terminal device, a third communication device, or a second communication device, the communication interface can be a transceiver or an input/output interface. Optionally, the transceiver can be a transceiver circuit. Optionally, the input/output interface can be an input/output circuit.

In another implementation, when the communication device is a chip or chip system, the communication interface can be an input/output interface, interface circuit, output circuit, input circuit, pin, or related circuit on the chip or chip system. The processor can also be manifested as a processing circuit or logic circuit.

Seventhly, a system is provided, which includes the aforementioned terminal device.

In one possible implementation, the system may further include a third communication device, a second communication device, and a first communication device.

Eighthly, a computer program product is provided, comprising: a computer program (also referred to as code or instructions) that, when executed, causes a computer to perform any one of the first to third aspects described above, or to perform any possible implementation of the first to third aspects.

Ninth aspect, a computer-readable storage medium is provided that stores a computer program (also referred to as code or instructions) that, when run on a computer, causes the computer to perform any one of the first to third aspects described above, or to perform any possible implementation of the first to third aspects.

A tenth aspect provides a processing apparatus, comprising: an interface circuit and a processing circuit. The interface circuit may include an input circuit and an output circuit. The processing circuit is configured to receive signals through the input circuit and transmit signals through the output circuit, thereby enabling any one of the first to third aspects, or any possible implementation thereof, to be implemented.

In specific implementation, the aforementioned processing device can be a chip, the input circuit can be an input pin, the output circuit can be an output pin, and the processing circuit can be a transistor, gate circuit, flip-flop, and various logic circuits, etc. The input signal received by the input circuit can be received and input by, for example, but not limited to, a receiver, and the signal output by the output circuit can be, for example, but not limited to, output to a transmitter and transmitted by the transmitter. Furthermore, the input circuit and the output circuit can be the same circuit, which is used as the input circuit and output circuit at different times. This application does not limit the specific implementation method of the processor and various circuits.

In one implementation, the communication device is a terminal device, a third communication device, or a second communication device. The interface circuit can be an RF processing chip in the terminal device, the third communication device, or the second communication device, and the processing circuit can be a baseband processing chip in the terminal device, the third communication device, or the second communication device.

In another implementation, the communication device can be a component of a terminal device, a third communication device, or a second communication device, such as an integrated circuit product like a system-on-a-chip (SoC) or a communication chip. The interface circuit can be an input/output interface, interface circuit, output circuit, input circuit, pins, or related circuits on the chip or chip system. The processing circuit can be the logic circuit on the chip.

Attached Figure Description

Figure 1A is a schematic diagram of a network architecture of a communication system applicable to an embodiment of this application;

Figure 1B is a schematic diagram of the network architecture of another communication system applicable to the embodiments of this application;

Figure 1C is a schematic diagram of the network architecture of another communication system applicable to the embodiments of this application;

Figure 1D is a schematic diagram of the network architecture of another communication system applicable to the embodiments of this application;

Figure 1E is a schematic diagram of the network architecture of another communication system applicable to the embodiments of this application;

Figure 1F is a schematic diagram of the network architecture of another communication system applicable to the embodiments of this application;

Figure 1G is a schematic diagram of the network architecture of another communication system applicable to the embodiments of this application;

Figure 2 is a possible flowchart of a communication method provided in an embodiment of this application;

Figure 3 is a schematic diagram of an elevation angle provided in an embodiment of this application;

Figure 4 is a schematic diagram of a track angle provided in an embodiment of this application;

Figure 5 is a schematic diagram of Doppler and Doppler rate of change corresponding to a communication device provided in an embodiment of this application;

Figure 6 is a schematic diagram of the arrival of information transmitted by multiple communication devices to a terminal device according to an embodiment of this application;

Figure 7 is a schematic flowchart of a possible method for a terminal device to acquire data according to an embodiment of this application;

Figure 8 is a possible flowchart of another communication method provided in an embodiment of this application;

Figure 9 is a schematic diagram of a communication device provided in an embodiment of this application;

Figure 10 is a schematic diagram of another structure of the communication device provided in an embodiment of this application;

Figure 11 is a schematic diagram of another structure of the communication device provided in the embodiment of this application.

Detailed Implementation

The terms and nouns used in the embodiments of this application are described below.

(1) Resources.

The resources in the embodiments of this application may include, for example, time-domain resources and/or frequency-domain resources.

(1.1) Time domain resources.

Time-domain resources may include at least one of the following: radio frames, subframes, slots, mini slots, or symbols (e.g., orthogonal frequency division multiplexing (OFDM), such as discrete fourier transform (DFT) extended OFDM (DFT-spread OFDM, DFT-S-OFDM), orthogonal time-frequency and space (OTFS)).

A time-domain element may include a radio frame, a subframe, a slot, a mini slot, or an OFDM symbol. A time-domain element may also include resources aggregated from multiple radio frames, subframes, slots, mini slots, or OFDM symbols. Specifically, a radio frame may include multiple subframes, a subframe may include one or more slots, and a slot may include at least one symbol. Alternatively, a radio frame may include multiple slots, and a slot may include at least one symbol. It should be noted that, in this embodiment, an OFDM symbol may also be simply referred to as a symbol.

Depending on the subcarrier spacing, the length of each symbol can vary, and therefore the time slot length can also vary. For example, a time slot with a subcarrier spacing of 15 kHz has a length of 0.5 ms, a time slot with a subcarrier spacing of 60 kHz has a length of 0.125 ms, and so on.

In this embodiment of the application, the time domain unit can also be replaced by: time domain resource unit or time domain unit, etc.

(1.2) Frequency domain resources.

In the frequency domain, frequency domain resources can include one or more frequency domain units. A frequency domain unit can be a resource block (RB), a physical resource block (PRB), a subcarrier, a resource block group (RBG), a predefined subband, a precoding resource block group (PRG), a resource pool, a bandwidth part (BWP), a resource element (RE) (also called a resource unit or resource particle), a carrier, or a serving cell. PRBs and RBs can be interchanged. Optionally, a resource pool can include one or more resources, which can include at least one of time-domain resources, frequency-domain resources, code-domain resources, or spatial-domain resources. The number and size of resources included in the resource pool can be predetermined or configured by signaling.

Subcarrier or RE refers to the smallest frequency domain unit on a specific symbol in a multicarrier system. Subcarrier spacing (SCS) is the interval between the center or peak positions of two adjacent subcarriers in the frequency domain in an OFDM system. In 5G NR, various subcarrier spacings are introduced, and different carriers can have different subcarrier spacings. The baseline is 15kHz, which can be 15kHz × 2n, where n is an integer from 3.75, 7.5 up to 480kHz. In the embodiments of this application, RE can refer to a resource unit of time-frequency resources, for example, it can be considered as the smallest time-frequency resource unit. In this application, subcarrier and RE are interchangeable and have the same content.

A subchannel is the smallest unit of frequency domain resources occupied by a physical cross-channel shared channel. A subchannel can include one or more resource blocks (RBs). The bandwidth of a wireless communication system in the frequency domain can include multiple RBs. For example, in the various possible bandwidths of an LTE system, the number of physical resource blocks (PRBs) included can be 6, 15, 25, 50, etc. In the frequency domain, an RB can include several subcarriers. For example, in an LTE system, an RB includes 12 subcarriers, where the spacing between each subcarrier can be 15kHz. Of course, other subcarrier spacings can also be used, such as 3.75kHz, 30kHz, 60kHz, or 120kHz subcarrier spacings, which are not limited here.

A frequency domain unit may include a RE, an RB, a channel, a subchannel, a carrier, or a bandwidth part (BWP). A frequency domain unit may also include resources aggregated from multiple REs, multiple RBs, multiple subchannels, multiple carriers, or multiple BWPs. In the embodiments of this application, a channel can be equivalently replaced by a resource block set (RB set), and the frequency domain bandwidth of an RB set can be 20 MHz.

In this embodiment, the frequency domain unit can also be replaced by: frequency domain resource unit or frequency unit, etc.

A frequency domain resource set may include one or more frequency domain elements. A frequency domain resource set may also be called a frequency domain resource collection, frequency domain resource group, etc. For example, a frequency domain resource set may include a resource block set (RBset), an RB, a subchannel, a resource pool, a carrier, and a BWP.

(2) Reference signal.

The reference signal in the embodiments of this application may include at least one of the following: positioning reference signal (PRS), sounding reference signal (SRS), channel state information reference signal (CSI-RS), demodulation reference signal (DMRS), phase-tracking reference signals (PTRS), or synchronization signal and physical sidelink broadcast channel block (SSB).

The technical solutions of this application embodiment can be applied to various communication systems, such as terrestrial communication systems, NTN communication systems, and satellite communication systems. Satellite communication systems can be integrated with mobile communication systems. For example, mobile communication systems can be 4th Generation (4G) communication systems (e.g., Long Term Evolution (LTE) systems), Worldwide Interoperability for Microwave Access (WiMAX) communication systems, 5th Generation (5G) communication systems (e.g., New Radio (NR) systems), and future mobile communication systems. Mobile communication systems can also be vehicle-to-everything (V2X) systems and Internet of Things (IoT) systems.

(3) Region.

Region (e.g., the first region involved in the embodiments of this application): Unless otherwise specified, "region" in the following embodiments of this application refers to a geographical region. A region is fixed relative to the Earth, or it can be understood as a geographical region that is fixed relative to the Earth. For example, a region may have at least one of the following attributes: shape, outline, size, radius, area, geographical location, etc.

The term "region" can also have an altitude attribute, meaning a region can be understood as a geographical area at a given altitude or altitude range. By default, a region can refer to a geographical area on the ground with an altitude of 0 kilometers (km) or an altitude around 0 km (e.g., within the range of [-2, 2] km), or a geographical area with a certain average altitude. Additionally, it can refer to geographical areas at other specific altitudes or altitude ranges, such as a geographical area with an altitude of 10 km, or a geographical area with an altitude around 10 km (e.g., within the range of [7, 13] km).

In one possible implementation, the aforementioned region fixed relative to the Earth can also be referred to as a "wave position," "geographical region," etc. Of course, other names are also possible, and this application does not specifically limit the name of the region fixed relative to the Earth.

Different regions may have the same or different shapes, outlines, sizes, radii, and areas. Different regions may be geographically different. Different regions may or may not overlap.

In one possible implementation, "region fixed relative to the Earth" can be understood as follows: the region's outline, size, or geographical location remains unchanged; for example, the region's outline, size, or geographical location does not change over time. Alternatively, "region fixed relative to the Earth" can be understood as follows: the region's outline and the points within it can be described using a fixed Earth coordinate system, or the coordinates of each point on the region's outline in the fixed Earth coordinate system remain constant.

In one possible implementation, the shape of the region can be a regular hexagon, or other shapes such as a regular pentagon, a circle, an ellipse, etc. Alternatively, the shape of the region can also be irregular, without limitation.

For example, the shape of a region can be defined by a protocol or by a network device. Regions defined by different network devices can have the same or different shapes. The same network device can also define multiple region shapes. Similarly, the size, radius, and area of a region can also be defined by a protocol or by a network device. Regions defined by different network devices can have the same or different sizes, radii, or areas. The same network device can also define multiple region sizes, multiple region radii, or multiple region areas.

In one possible implementation, the Earth's surface can be divided into multiple regions, and these regions can be indexed (e.g., numbered). Terminal devices and network devices can agree on the numbering method for these regions (e.g., starting from 1 or 0) and the correspondence between regions and indexes. Alternatively, the protocol can define the numbering method for these regions and the correspondence between regions and indexes. Based on the region indexes, information such as the region's geographical location can be determined.

Optionally, the multiple regions can completely cover the Earth's surface, such that any location on the Earth's surface belongs to a certain region; or, the multiple regions can also cover part of the geographical location on Earth, for example, the multiple regions may not cover the Earth's South Pole and/or North Pole, that is, the South Pole and/or North Pole may not exist in the region.

Optionally, the method of dividing the network into multiple zones can be defined by a protocol or by the network device. Different network devices can define the same or different division methods. The same network device can also define multiple division methods.

As a first possible method of partitioning, the Earth's surface can be divided using a latitude and longitude grid with a granularity, for example, a latitude and longitude grid with a granularity of 1 degree. If only this discretization method is used, the globe can be divided into 360×360＝129600 regions. Terminal devices and network devices can define the indexes of these 129600 regions as 0,1,…,129599, or they can also define them as 1,2,…,129600.

Optionally, when introducing the altitude attribute of a geographic region, multiple grids can be defined to divide the Earth's surface. For example, a grid at an altitude of 0 km or within the range of [-2, 2] km can be divided into 1-degree latitude and longitude grids, generating 129,600 regions. At an altitude of 10 km or within the range of [7, 13] km, further division using 1-degree latitude and longitude grids generates another 129,600 regions. When indexing these regions, the index range needs to be expanded. For example, the total index could be 0, 1, ..., 129,599, 129,600, 129,601, ..., 259,199, where the first 129,600 indices represent the region index at an altitude of 0 km or within the range of [-2, 2] km, and the last 129,600 indices represent the region index at an altitude of 10 km or within the range of [7, 13] km.

For example, the granularity of the latitude and longitude grid can be determined based on the type of network device. For instance, a relatively small granularity can be used for discretization when the network device is a LEO satellite, and a relatively large granularity can be used when the network device is a geosynchronous orbit (GEO) satellite.

As a second possible method of division, the Earth's surface can be divided using latitude and longitude grids of various granularities. For example, a portion of the Earth's surface or a portion of its administrative region can be divided using a latitude and longitude grid with a granularity of 1 degree, while another portion of the surface or administrative region can be divided using a latitude and longitude grid with a granularity of 2 degrees.

Alternatively, by introducing the altitude attribute of a geographic region, the Earth's surface can be divided using a latitude and longitude grid with a granularity of 1 degree at an altitude of 0 km, and the Earth's surface can be divided using a latitude and longitude grid with a granularity of 2 degrees at an altitude of 10 km.

As a third possible method of division, the Earth's surface can be divided by administrative regions. For example, a township-level administrative region could be considered as a region.

As a fourth possible division method, for GEO satellites, the projection of one of the GEO satellite's beams onto the ground can be considered as a region. Since GEO satellites are stationary relative to the Earth, the projection of the GEO satellite's beams onto the ground can be considered fixed relative to the Earth.

In practical applications, the Earth's surface can be divided using a combination of different methods. For example, a portion of the Earth's surface or a part of its administrative region can be divided using a latitude and longitude grid with a granularity of 1, while another portion of the surface or administrative region can be divided according to its administrative region.

In one possible implementation, when the Earth's surface is divided into multiple regions, different levels of region division can be applied to the same surface area. For example, for a given surface area, a first level of region division can be performed using a 10-degree granularity latitude and longitude grid, a second level using a 6-degree granularity grid, and a third level using a 1-degree granularity grid. In this case, within the surface area, the number of regions at the first level is greater than the number at the second level, and the number of regions at the second level is greater than the number at the third level. Furthermore, in this scenario, each level of region can be individually numbered.

Figure 1A exemplarily illustrates an architecture diagram of a communication system 1000 applicable to an embodiment of this application. As shown in Figure 1A, the communication system includes a wireless access network 100 and a core network 200. Optionally, the communication system 1000 may also include an Internet 300. The wireless access network 100 may include at least one wireless access network device (110a and 110b in Figure 1A) and at least one terminal device (120a-120j in Figure 1A). The terminal device is wirelessly connected to the wireless access network device, and the wireless access network device is wirelessly or wiredly connected to the core network. The core network device and the wireless access network device may be independent and different physical devices, or the functions of the core network device and the logical functions of the wireless access network device may be integrated on the same physical device, or a single physical device may integrate some of the functions of the core network device and some of the functions of the wireless access network device. Terminal devices and wireless access network devices may be interconnected via wired or wireless means. Figure 1A is just a schematic diagram. The communication system may also include other network devices, such as wireless relay devices and wireless backhaul devices, which are not shown in Figure 1A.

The network devices involved in the embodiments of this application include, for example, radio access network (RAN) devices. RAN devices can be base stations, evolved NodeBs (eNodeBs), transmission reception points (TRPs), transmission points (TPs), next-generation NodeBs (gNBs) in 5G mobile communication systems, base stations in future mobile communication systems, or access nodes in WiFi systems; they can also be modules or units that perform some of the functions of a base station, for example, they can be central units (CUs), distributed units (DUs), or radio units (RUs). The CU (Radio Control Unit) performs the functions of the Radio Resource Control Protocol (RRC) and Packet Data Convergence Protocol (PDCP) of the base station, and can also perform the functions of the Service Data Adaptation Protocol (SDAP). The DU (Radio Access Unit) performs the functions of the Radio Link Control (RANC) and Medium Access Control (MAC) layers of the base station, and can also perform some or all of the physical layer functions. For specific descriptions of the above protocol layers, please refer to the relevant technical specifications of the 3rd Generation Partnership Project (3GPP). The CU and DU can be set up separately or included in the same network element, such as in the baseband unit (BBU). The RU (Radio Receiver Unit) can be included in radio frequency equipment or radio frequency units, such as in the remote radio unit (RRU), active antenna unit (AAU), or remote radio head (RRH). In different systems, CU, DU, or RU may have different names, but those skilled in the art will understand their meanings. For example, in an open radio access network (ORAN) system, CU can also be called open CU (open-CU, O-CU), DU can also be called open DU (open-DU, O-DU), and RU can also be called open RU (open-RU, O-RU). In this application, any unit among CU (or CU control plane (CU-CP), CU user plane (CU-UP), DU, and RU) can be implemented through software modules, hardware modules, or a combination of software and hardware modules. CU-CP can also be called open CU-CP (open-CU-CP, O-CU-CP), and CU-UP can also be called open CU-UP (open-CU-UP, O-CU-UP).

Figure 1B illustrates an exemplary O-RAN system architecture provided by an embodiment of this application. The O-RAN system in the embodiments provided by this application may include components other than those shown in Figure 1B. As shown in Figure 1B, the access network device (RAN, for example, an eNB, gNB, or next-generation access network device) communicates with the core network (CN) via a backhaul link and with the user equipment (UE) via an air interface. For example, the baseband unit (BBU) in the access network device communicates with the core network via a backhaul link, and the radio unit (RU) in the access network device communicates with at least one UE via an air interface. The BBU communicates with at least one RU via a fronthaul link; the BBU and RU may or may not be co-located. The BBU includes at least one control unit (CU) and at least one distributed unit (DU), which can communicate via at least one midhaul link. In the embodiments of this application, the third communication device can configure information of the auxiliary communication device to the terminal device (e.g., UE), and can also send signaling to the terminal device for activating or deactivating one or more communication devices. The sending of these signaling messages can be sent to the terminal device by the CU and/or DU in the third communication device.

Figure 1C exemplarily illustrates a schematic diagram of an O-RAN system architecture provided in an embodiment of this application. As shown in Figure 1C, O-RAN may include O-CU-CP, O-CU-UP, O-DU, and O-RU. The system architecture may also include an open cloud (O-cloud), a service management and orchestration framework, an open eNB (O-eNB), a near-real-time (RT) RAN Intelligent Controller (RIC), and a non-real-time RIC. The non-RT RIC can monitor, configure, manage, and control radio resources of at least one of multiple O-CU-CP, O-CU-UP, DU, or O-eNB. As shown in Figure 1C, the interfaces defined by 3GPP include, for example, E1, F1 (e.g., F1-c, F1-u), NG (e.g., NG-c, NG-u), Xn (e.g., Xn-c, Xn-u), and X2 (e.g., X2-c, X2-u). For example, the O-RAN communication system also includes interfaces such as O1, O2, E2, A1, and Open Fronthaul (FH) interfaces (e.g., Open-FH Control (M)-plane, and Open-FH Control, User, and Synchronization (CUS)-plane). The names of the interfaces and the connection methods of the units shown in Figure 1C are just examples. In practical applications, the O-RAN system may include more or fewer interfaces, or more or fewer units.

Wireless access network equipment can be a macro base station (as shown in Figure 1A, 110a), a micro base station or an indoor station (as shown in Figure 1A, 110b), or a relay node or donor node, etc. The embodiments of this application do not limit the specific technology or equipment form used in the wireless access network equipment. For ease of description, a base station is used as an example of wireless access network equipment in the following description.

Terminal devices can also be referred to as user equipment (UE), mobile stations, mobile terminal devices, etc. Terminal devices can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, smart cities, etc. Terminal devices can be mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicles, drones, helicopters, airplanes, ships, robots, robotic arms, smart home devices, sensors, etc. The embodiments of this application do not limit the specific technologies or device forms used in the terminal devices.

The aforementioned terminal devices can establish connections with the operator's network through interfaces provided by the operator's network (such as N1), and use data and/or voice services provided by the operator's network. The terminal devices can also access the Domain Name System (DNS) through the operator's network, and use operator services deployed on the DNS, and/or services provided by third parties. These third parties can be service providers outside of the operator's network and the terminal devices, and can provide other data and/or voice services to the terminal devices. The specific form of these third parties can be determined based on the actual application scenario and is not limited here.

Terminal devices can also be referred to as user equipment (UE), mobile stations, mobile terminal devices, etc. Terminal devices can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, smart cities, etc. Terminal devices can be mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicles, drones, helicopters, airplanes, ships, robots, robotic arms, smart home devices, roadside units (RSUs), etc. The embodiments of this application do not limit the specific technologies or device forms used in the terminal devices.

Base stations and terminal equipment can be fixed or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; on water; or in the air on aircraft, balloons, and satellites. The embodiments of this application do not limit the application scenarios of the base stations and terminal equipment.

The roles of base stations and terminal devices can be relative. For example, the helicopter or drone 120i in Figure 1A can be configured as a mobile base station. For terminal devices 120j that access the wireless access network 100 through 120i, terminal device 120i is a base station; however, for base station 110a, 120i is a terminal device, meaning that 110a and 120i communicate via a wireless air interface protocol. Of course, 110a and 120i can also communicate via a base station-to-base station interface protocol. In this case, relative to 110a, 120i is also a base station. Therefore, both base stations and terminal devices can be collectively referred to as communication devices. 110a and 110b in Figure 1A can be called communication devices with base station functions, and 120a-120j in Figure 1A can be called communication devices with terminal device functions.

Communication between base stations and terminal devices, between base stations, and between terminal devices can be conducted using licensed spectrum, unlicensed spectrum, or both simultaneously. Communication can be conducted using spectrum below 6 GHz, spectrum above 6 GHz, or both simultaneously. The embodiments of this application do not limit the spectrum resources used for wireless communication.

In the embodiments of this application, the functions of the base station can be executed by modules (such as chips) within the base station, or by a control subsystem that includes base station functions. This control subsystem, including base station functions, can be a control center in the aforementioned application scenarios such as smart grids, industrial control, intelligent transportation, and smart cities. Similarly, the functions of the terminal device can be executed by modules (such as chips or modems) within the terminal device, or by a device that includes terminal device functions.

In this application, the base station sends downlink signals or downlink information to the terminal device, with the downlink information carried on the downlink channel; the terminal device sends uplink signals or uplink information to the base station, with the uplink information carried on the uplink channel. In order to communicate with the base station, the terminal device needs to establish a radio connection with a cell controlled by the base station. The cell with which the terminal device has established a radio connection is called the serving cell of the terminal device. When the terminal device communicates with this serving cell, it is also subject to interference from signals from neighboring cells.

The core network involved in this application embodiment may include network devices that process and forward user signaling and data. For example, it includes core network devices such as access and mobility management functions (AMF), session management functions (SMF), user plane gateways, and location management devices. The user plane gateway can be a server with functions such as mobility management, routing, and forwarding of user plane data, generally located on the network side, such as a serving gateway (SGW), packet data network gateway (PGW), or user plane function (UPF). AMF and SMF are equivalent to the mobility management entity (MME) in a long-term evolution (LTE) system. AMF is mainly responsible for admission aspects, and SMF is mainly responsible for session management. Of course, the core network may also include other network elements, which are not listed here.

Figure 1A is only a schematic diagram. The wireless communication system may also include other devices, such as core network devices, wireless relay devices and/or wireless backhaul devices, which are not shown in Figure 1A.

Figures 1D and 1E exemplarily illustrate network architecture diagrams of several communication systems applicable to embodiments of this application. The communication system may include satellites, network devices, and terminal devices, etc. The communication system may also include gateways and core network devices. Figures 1D and 1E exemplarily illustrate a converged network architecture of NTN and terrestrial networks. A description is provided below with reference to the accompanying drawings.

The satellite can be a highly elliptical orbit (HEO) satellite, a GEO satellite, a medium earth orbit (MEO) satellite, or a low earth orbit (LEO) satellite. This application does not limit the satellite's operating mode; for example, the satellite can operate in transparent mode or regenerative mode. Figure 1D illustrates the satellite operating in transparent mode, and Figure 1E illustrates the satellite operating in regenerative mode.

When a satellite operates in transparent mode, it provides transparent relay forwarding functionality. A gateway possesses the functions of a network device (such as a base station) or some of the functions of a network device (such as a base station); in this case, the gateway can be considered a network device (such as a base station). Alternatively, the network device (such as a base station) can be deployed separately from the gateway. In this case, the feeder link latency includes both the latency from the satellite to the gateway and the latency from the gateway to the gNB. The transparent mode discussed later assumes that the gateway and gNB are located together or close to each other. For cases where the gateway and gNB are far apart, the feeder link latency is simply the sum of the latency from the satellite to the gateway and the latency from the gateway to the gNB.

When a satellite is operating in regenerative mode, it has data processing capabilities and functions as a network device (such as a base station) or partially functions as a network device (such as a base station). In this case, the satellite can be regarded as a network device (such as a base station).

Satellites can communicate wirelessly with terminals via broadcast communication signals and navigation signals. Optionally, each satellite can provide communication, navigation, and positioning services to terminal devices through multiple beams. For example, each satellite uses multiple beams to cover the service area, and the relationship between different beams can be one or more of time-division, frequency-division, and space-division.

A gateway (also known as a ground station, earth station, or gateway) is a network device used to connect satellites and ground-based devices (such as ground base stations). One or more satellites can connect to one or more ground-based network devices (such as ground base stations) through one or more gateways; this is not a limitation. The link between a satellite and a terminal is called a service link, and the link between a satellite and a gateway is called a feeder link. Network devices can be deployed separately from gateways; therefore, the latency of the feeder link can include both the latency from the satellite to the gateway and the latency from the gateway to the network device.

The network devices in this application embodiment may include network devices deployed on satellites (such as satellite base stations), network devices deployed on gateways, or network devices deployed on the ground (such as ground base stations). For example, the network devices may be radio access network (RAN) nodes, RAN nodes in O-RAN systems, etc., as shown in Figures 1A, 1B, and 1C. Related details are as described above and will not be repeated here.

A core network (CN) device is a ground-based device that can communicate with NTN devices within an NTN system. For example, a CN can be the CN shown in Figures 1A, 1B, and 1C; relevant details are described above and will not be repeated here.

The terminal can be the terminal involved in Figures 1A, 1B and 1C. For relevant details, please refer to the above description and we will not repeat them here.

The embodiments of this application can also be applied to other communication system architectures, such as air-to-ground (ATG) communication systems, which include at least one network device and at least one high-altitude terminal. High-altitude terminals include, for example, high-altitude aircraft and onboard terminals. The satellites in Figures 1D and 1E can also be replaced with other relay devices, such as high-altitude platform stations (HAPS) or other NTN devices. The communication system shown in Figure 1D or 1E is merely an example and does not limit the communication systems to which the methods provided in the embodiments of this application are applicable.

It is understood that the embodiments of this application can also be applied to air-to-ground (ATG) communication systems. As an example, please refer to Figure 1F, which is a schematic diagram of the network architecture of another communication system to which the embodiments of this application are applicable. The communication system includes at least one network device and at least one high-altitude terminal device. The high-altitude terminal device includes, for example, high-altitude aircraft and onboard terminal devices.

Figure 1G exemplarily illustrates another possible communication system architecture applicable to embodiments of this application. As shown in Figure 1G, the communication system includes a first communication device, a second communication device, a third communication device, and a terminal device. This application embodiment uses the third communication device as the primary communication device and the first and second communication devices as secondary communication devices. In Figure 1G, the third communication device is used as the primary satellite device, the first communication device as secondary satellite device #1, and the second communication device as secondary satellite device #2. The terminal device can establish an RRC connection with the primary satellite device but does not establish an RRC connection with the secondary satellite device.

In this embodiment, the primary satellite device and the secondary satellite device #1 can communicate with the terminal device, for example, the primary satellite device and the secondary satellite device #1 send data to the terminal device on the same resources. The terminal device can determine whether it needs to switch from the secondary satellite device #1 to the secondary satellite device #2 based on first information. When the terminal device determines that it needs to switch to the secondary satellite device #2, the secondary satellite device #1 switches to the secondary satellite device #2. Afterwards, the primary satellite device and the secondary satellite device #2 can communicate with the terminal device (the terminal device stops communicating with the secondary satellite device #1, for example, stops maintaining downlink timing synchronization with the secondary satellite device #1), for example, the primary satellite device and the secondary satellite device #2 send data to the terminal device on the same resources.

In this embodiment, the primary satellite device and the secondary satellite device (e.g., secondary satellite device #1 or secondary satellite device #2) have the capability to transmit data to the terminal device on the same resources (e.g., the same time-domain resources and/or frequency-domain resources) (for understanding, this capability can be referred to as the first capability). The term "same resources" in this embodiment can be replaced with "same time-domain resources," "same frequency-domain resources," or "same frequency-domain resources and the same time-domain resources." Descriptions of "same resources" in other locations are provided here and will not be repeated.

In practical applications, the primary satellite device and the secondary satellite device can use this first capability, that is, to send data to the terminal device on the same resources (e.g., the same time-domain resources and/or frequency-domain resources), or in other words, the primary satellite device and the secondary satellite device jointly transmit data to the terminal device. Alternatively, the primary satellite device and the secondary satellite device may not use this first capability, for example, the two data transmissions sent by the primary satellite device and the secondary satellite device to the terminal device may occupy different resources (e.g., the time-domain resources and frequency-domain resources occupied by the two data transmissions may be different); or the primary satellite device and the secondary satellite device may not need to jointly transmit data to the terminal device; or the terminal device may communicate with a single satellite device (the primary satellite device or the secondary satellite device).

As shown in Figure 1G, the terminal device can be the terminal or its internal chip system involved in Figures 1A, 1B, 1C, 1D, 1E, or 1F. The first communication device in this embodiment can be a satellite or its internal chip system as shown in Figures 1D, 1E, or 1F, or it can be a network device (e.g., access network equipment, ground station, etc.) or its internal chip system as shown in Figures 1A, 1B, 1C, 1D, 1E, or 1F. The second communication device in this embodiment can be a satellite or its internal chip system as shown in Figures 1D, 1E, or 1F, or it can be a network device (e.g., access network equipment, ground station, etc.) or its internal chip system as shown in Figures 1A, 1B, 1C, 1D, 1E, or 1F. The third communication device in this application embodiment can be a satellite or a chip system inside a satellite as shown in Figure 1D, Figure 1E or Figure 1F, or it can be a network device (e.g., access network device, ground station, etc.) or a chip system inside a network device as shown in Figure 1A, Figure 1B, Figure 1C, Figure 1D, Figure 1E or Figure 1F.

The communication device in this application embodiment can also be replaced by a cell or a transmission reception point (TRP). For example, the third communication device can also be replaced by a cell, a third cell, or a primary cell. The first communication device can be replaced by a cell, a first cell, or a secondary cell. The second communication device can be replaced by a cell, a second cell, or a secondary cell. The secondary communication device involved in this application embodiment can also be replaced by a secondary cell. When the third communication device is the third cell, the second communication device is the second cell, and the first communication device is the first cell, any two of the third cell, the second cell, and the first cell can belong to cells within the coverage area of different network devices, or belong to cells within the coverage area of the same network device. This application embodiment does not impose any restrictions on this. When the third communication device is the third cell and the second communication device is the second cell (or, the third communication device is the third cell and the first communication device is the first cell), and the second communication device and the third communication device send data to the terminal device on the same resources (the same time domain resources and/or frequency domain resources), this scheme can also be called multi-cell joint transmission.

In the embodiments of this application, any two of the third communication device, the second communication device, and the first communication device can be of the same type or different types.

For example, the third communication device is a third satellite device (e.g., a primary satellite device), the second communication device is a second satellite device (e.g., auxiliary satellite device #2), and the first communication device is a first satellite device (e.g., auxiliary satellite device #1). The satellite devices (e.g., the first, second, and third satellite devices) in this embodiment can be satellites or internal chip systems within satellites as shown in Figures 1D, 1E, or 1F. When the second and third communication devices transmit data to the terminal device on the same resources (the same time-domain and/or frequency-domain resources), this scheme can also be called multi-satellite joint transmission. When the second and third communication devices transmit data to the terminal device on the same resources (the same time-domain and/or frequency-domain resources), and the difference between the downlink timings corresponding to the signals transmitted by the two communication devices is less than a first threshold, this transmission method can also be called multi-satellite joint quasi-synchronous transmission. In this embodiment, the first threshold can be the cyclic prefix (CP) duration, or other set values, or a value calculated based on the CP duration (e.g., the CP duration plus or minus a value, or, for example, the CP duration multiplied by a value). When the second and third communication devices transmit data to the terminal device on the same resources (the same time-domain resources and/or frequency-domain resources), and the difference between the downlink timings corresponding to the signals transmitted by the two communication devices is equal to a first threshold, this transmission method can also be called multi-satellite joint quasi-synchronous (or asynchronous) transmission. When the second and third communication devices transmit data to the terminal device on the same resources (the same time-domain resources and/or frequency-domain resources), and the difference between the downlink timings corresponding to the signals transmitted by the two communication devices is greater than a first threshold, this transmission method can also be called multi-satellite joint asynchronous transmission. In the embodiments of this application, when any one of the third, second, and first communication devices is a satellite device, the operating mode of the satellite device can be a transparent transmission mode or a regeneration mode. The operating modes of any two of the third, second, and first communication devices can be the same or different.

For example, the third communication device is a network device (such as access network equipment, ground station, etc.), and the second and first communication devices are satellite devices. Alternatively, the third communication device is a satellite device, and the second and first communication devices are network devices (such as access network equipment, ground station, etc.). Or, the third, second, and third communication devices are three network devices (such as access network equipment, ground station, etc.).

Based on the content shown in at least one of Figures 1A, 1B, 1C, 1D, 1E, 1F, and 1G, as well as the other content mentioned above, Figure 2 exemplarily illustrates a possible flowchart of a communication method provided by an embodiment of this application. For ease of understanding, Figure 2 uses the interaction of a terminal device, a first communication device, a second communication device, and a third communication device as an example. Examples of the terminal device, the first communication device, the second communication device, and the third communication device can be found in the description of Figure 1G above, and will not be repeated here.

For example, the first communication device is a first satellite device (or first auxiliary communication device, first auxiliary satellite device, auxiliary satellite device #1), the second communication device is a second satellite device (or second auxiliary communication device, second auxiliary satellite device, auxiliary satellite device #2), and the third communication device is a third satellite device (or a primary satellite device). Figure 2 provides an example of a terminal device switching auxiliary communication devices. In the scheme provided by this application embodiment, the terminal device can communicate with one or more auxiliary communication devices, and the terminal device can switch from one or more auxiliary communication devices to one or more auxiliary communication devices. This application embodiment uses the example of the terminal device switching from one auxiliary communication device (first communication device) to another auxiliary communication device (second communication device) as an example. The switching process for other auxiliary communication devices can also refer to the process of the terminal device switching from the first communication device to the second communication device, and will not be repeated here. In this application embodiment, the terminal device can establish an RRC connection with the primary communication device, but does not need to establish an RRC connection with the auxiliary communication device. The terminal device can communicate with the primary communication device (e.g., send uplink or downlink data), and the terminal device can also communicate with the auxiliary communication devices (e.g., send uplink or downlink data).

The following description is provided in conjunction with the accompanying diagram.

Step 201: The terminal device obtains the first information and determines to switch from the first communication device to the second communication device based on the first information.

In this application embodiment, the first information may include/be replaced with: information for determining the area where the second communication device provides services, or information for determining whether the area where the second communication device provides services includes the first area.

For example, the first information includes/is at least one of the following: information associated with the location of the second communication device (e.g., the elevation angle and/or orbital angle of the second communication device), first time information (e.g., current time information), information associated with the Doppler of the signal of the second communication device (e.g., the Doppler and Doppler rate corresponding to the second communication device), and information associated with the TA of the second communication device (e.g., at least one of the TA, the rate of change of TA, and the rate of change of the rate of change of TA corresponding to the second communication device). The first region includes/is the region where the terminal device is located.

The following describes two implementation methods for how a terminal device determines whether to switch communication devices based on first information, using implementation methods A1 and A2 as examples. In implementation method A1, the terminal device can determine whether to switch to the second communication device based on the first information (e.g., information about the second communication device). In implementation method A2, the terminal device can determine whether to switch to the second communication device based on both the first information (e.g., information about the second communication device) and the second information (e.g., information about the first communication device).

In implementation method A1, the terminal device can determine whether it needs to switch to the second communication device based on the first information (e.g., information of the second communication device).

In implementation A1, when determining whether to switch communication devices, the terminal device may not need to consider information from other communication devices (e.g., second information). For example, the terminal device can determine whether the area served by the second communication device includes the first area based on the first information. For example, if the first information indicates that the area served by the second communication device includes/is the first area, the terminal device determines that it needs to switch to the second communication device (or switch the auxiliary communication device from the first communication device to the second communication device). Alternatively, if the first information indicates that the area served by the second communication device does not include the first area, the terminal device determines that it does not need to switch the auxiliary communication device. Since the terminal device can determine whether to switch communication devices based on the first information, this scheme does not require other communication devices (e.g., a third communication device) to issue switching instructions, thereby saving signaling overhead.

There are several ways for a terminal device to determine whether the area served by the second communication device includes the first area based on the first information. For example, if the first information meets the first condition, the terminal device determines that the area served by the second communication device includes the first area. Alternatively, the terminal device can determine that, if the first information meets the first condition, the area served by the second communication device includes the first area.

The first condition includes, for example, one or more of the following: the elevation angle corresponding to the second communication device belongs to the first elevation angle range (Implementation A1.1); the orbital angle corresponding to the second communication device belongs to the first orbital angle range (Implementation A1.2); the time indicated by the first time information (e.g., the current time) belongs to the time period during which the second communication device provides services to the first area (Implementation A1.3); the Doppler corresponding to the second communication device belongs to the first Doppler range (Implementation A1.4); the Doppler rate corresponding to the second communication device belongs to the first Doppler rate range (Implementation A1.5); the TA corresponding to the second communication device belongs to the first TA range (Implementation A1.6); the TA change rate corresponding to the second communication device belongs to the first change rate range (Implementation A1.7); the change rate of the TA change rate corresponding to the second communication device belongs to the second change rate range (Implementation A1.8).

In implementation method A1.1, taking the first information including/as the elevation angle corresponding to the second communication device as an example, the first condition includes: the elevation angle corresponding to the second communication device belongs to the first elevation angle range.

The elevation angle in this embodiment can be formed by two lines. The elevation angle can be replaced by a "direction angle". For example, the elevation angle corresponding to the second communication device can be formed by the angle between the line passing through the second communication device and the projection of the line on a plane. For example, the elevation angle can include: the angle between the line originating from the terminal device (or ground reference point) and the projection of the line on the horizontal plane.

The elevation angle in this embodiment can range from [0°, 90°]. For example, when the line of sight is above the horizontal line, the angle between the line of sight and the horizontal line in the vertical plane is called the elevation angle. For another example, the elevation angle includes the angle between the communication device (e.g., a satellite device) and the horizon where the terminal device is located. The elevation angle can also be used to describe the position of the communication device (e.g., a satellite device) above the terminal device (or ground reference point) at a certain moment; for example, an elevation angle of 90° can indicate that the communication device (e.g., a satellite device) is directly above the terminal device (or ground reference point). Because the elevation angle is related to the position of the terminal device (or ground reference point), the elevation angle of the same communication device (e.g., a satellite device) will be different for different terminal devices (or ground reference points) on the ground. Furthermore, the elevation angle changes continuously as the communication device (e.g., a satellite device) moves in its orbit.

There are several methods for a terminal device to obtain the elevation angle corresponding to the second communication device. For example, the terminal device can determine the elevation angle based on the ephemeris information of the second communication device. For instance, the terminal device can determine the position of the second communication device based on its ephemeris information, and then calculate the elevation angle of the second communication device based on the position of the second communication device and the position of the terminal device. If the second communication device is a satellite device, its ephemeris information may include, for example, the satellite device's velocity information, its trajectory information, its position information, and the time information corresponding to its position.

For example, the terminal device acquires the position of a ground reference point. The ground reference point can be a point within an area, such as a point relatively close to (or located in) the central area of an area. The ground reference point can be reused from ground reference points used in cell reselection or conditional handover (CHO) measurement procedures. The position of this ground reference point can be pre-configured on the terminal device side, or it can be sent to the terminal device by other communication devices (e.g., a third communication device), or the position can be determined by the terminal device according to preset rules. For instance, the terminal device determines the position of the second communication device based on its ephemeris information, and then calculates the elevation angle based on the position of the second communication device and the position of the ground reference point. This elevation angle is the elevation angle of the second communication device. When two terminal devices within an area calculate the elevation angle of the second communication device, they can both calculate the corresponding elevation angle based on the position of the second communication device and the position of the ground reference point. In this case, the elevation angles calculated by two different terminal devices within the area may be equal.

Figure 3 illustrates a possible elevation angle provided by an embodiment of this application. As shown in Figure 3, the terminal device is located at the origin of the coordinate system. The three coordinate axes of this coordinate system are represented as the x-axis, y-axis, and z-axis, and any two of the three axes are perpendicular to each other. Figure 3 illustrates an example with the first communication device as auxiliary satellite device #1, the second communication device as auxiliary satellite device #2, and the third communication device as the primary satellite device. The communication system may also include other satellite devices, which are not shown in Figure 3. The orbits of any two of the first, second, and third communication devices can be the same orbit or different orbits; Figure 3 shows one possible example.

Please refer to Figure 3. Line #13 is the line originating from the terminal device and projected towards the second communication device. In Figure 3, line #14 represents the projection of line #13 onto the horizontal plane. _θ2 is the angle between line #13 and its projection onto the horizontal plane (line #14). _θ2 is the elevation angle corresponding to the second communication device. Similarly, line #11 is the line originating from the terminal device and projected towards the first communication device. In Figure 3, line #12 represents the projection of line #11 onto the horizontal plane. _θ1 is the angle between line #11 and its projection onto the horizontal plane (line #12). _θ1 is the elevation angle corresponding to the first communication device.

The elevation angle shown in Figure 3 is illustrated using the location of the terminal device as the origin of the coordinate system. In practical applications, the origin of the coordinate system for calculating the elevation angle can be replaced by the location of a ground reference point. The elevation angle shown in Figure 3 is one possible example; in practical applications, other angles can also be used to represent the elevation angle. For example, the elevation angle corresponding to the first communication device is _θ1 , and the elevation angle corresponding to the second communication device can be the supplementary or complementary angle of _θ2 . Alternatively, the elevation angle corresponding to the first communication device can be the supplementary or complementary angle of _θ1 , and the elevation angle corresponding to the second communication device can be _θ2 . Again, the elevation angle corresponding to the first communication device can be the supplementary or complementary angle of _θ1 , and the elevation angle corresponding to the second communication device can be the supplementary or complementary angle of _θ2 .

In implementation A1.1, the terminal device can obtain a first elevation angle range, and then determine whether the area where the second communication device provides services includes the first area based on whether the elevation angle of the second communication device is within the first elevation angle range. For example, when the elevation angle of the second communication device is within the first elevation angle range, the terminal device determines that the area where the first information indicates the second communication device provides services includes the first area. As another example, when the elevation angle of the second communication device is not within the first elevation angle range, the terminal device determines that the area where the first information indicates the second communication device provides services does not include the first area.

The terminal device can acquire information indicating the first elevation angle range and determine the first elevation angle range based on the information indicating the first elevation angle range. The information indicating the first elevation angle range can be pre-configured, protocol-defined, or indicated by other communication devices (e.g., a third communication device).

The information used to indicate the first elevation angle range can be either elevation angle values or index values related to the first elevation angle range. The following examples illustrate the specific forms of information used to indicate the first elevation angle range.

Example 1: The information used to indicate the first elevation angle range includes two elevation angle values. These two elevation angle values are used to indicate the two boundaries of the first elevation angle range. For example, if the elevation angle range is [50°, 90°], the information indicating the elevation angle range includes elevation angle values of 50° and 90°.

In this application embodiment, "°" is used as a symbol to represent angle. In this application embodiment, the symbol "[]" representing an angle range can be replaced with "()". For example, [50°, 90°] can be replaced with (50°, 90°), where 50° and 90° can be considered the boundaries of the elevation angle range. [50°, 90°] indicates that the elevation angle range includes 50° and 90°. (50°, 90°) indicates that the elevation angle range does not include 50° and 90°.

Example 2: The information used to indicate the first elevation angle range may include an elevation angle value. This elevation angle value is the minimum elevation angle value within the first elevation angle range. The maximum elevation angle value within the first elevation angle range is a predefined value, such as 90°. For example, if the information used to indicate the first elevation angle range is an elevation angle value of 50°, then the first elevation angle range is [50°, 90°]. This maximum elevation angle value may be pre-configured on the terminal device side or agreed upon by a protocol, or sent to the terminal device by other communication devices (e.g., a third communication device).

Example 3: The information used to indicate the first elevation angle range may include an elevation angle value. This elevation angle value may indicate the two boundaries of the first elevation angle range, for example, the elevation angle value is 60°. The range before and after this elevation angle value within 30° (i.e., [30°, 90°]) constitutes the first elevation angle range, where 30° is an example and can be replaced with other preset angle values. This preset angle value may be pre-configured on the terminal device side or agreed upon by a protocol, or sent to the terminal device by other communication devices (e.g., a third communication device).

Example 4: The information used to indicate the first elevation angle range may include an index value. This index value is associated with the first elevation angle range, and the terminal device can use the index value to find the elevation angle range associated with the index value, thereby determining the first elevation angle range.

In one possible implementation, the terminal device can obtain information about multiple communication devices (or auxiliary communication devices, or candidate auxiliary communication devices, or auxiliary communication devices to be switched over). These auxiliary communication devices can be designated as auxiliary communication devices to be switched over, and the second communication device belongs to this group of auxiliary communication devices. In another possible implementation, these auxiliary communication devices can have priorities; for example, the first communication device has a higher priority than the second communication device, and the second communication device is the highest priority communication device to be switched over after the first communication device. The second communication device can be the highest priority among these candidate auxiliary communication devices. Therefore, when the terminal device needs to switch auxiliary communication devices (e.g., the terminal device determines that the first communication device is currently or will soon be unable to provide service to the terminal device), it can determine whether the second communication device can provide service to the terminal device based on priority (e.g., determining whether the area where the second communication device provides service includes the first area based on first information). The priority information of these auxiliary communication devices (e.g., priority information can be indicated in the form of a list of auxiliary communication devices) can be pre-configured on the terminal device side or notified to the terminal device by other communication devices (e.g., a third communication device). In another possible implementation, the terminal device can identify multiple auxiliary communication devices that can provide services to the terminal device, and then select the communication device with the best or better quality as the target auxiliary communication device to be switched based on the signal quality of these auxiliary communication devices.

The following table exemplifies an example of information about a communication device (or secondary communication device, or candidate secondary communication device, or secondary communication device to be switched to) acquired by a terminal device. As shown in Table 1, the information of a communication device (or secondary communication device, or candidate secondary communication device, or secondary communication device to be switched to) may include the index of the communication device, the ephemeris information of the communication device, and information indicating the elevation angle range corresponding to the communication device. Table 1 illustrates an example where the information indicating the elevation angle range corresponding to the communication device includes two boundary values of the elevation angle range. The elevation angle ranges corresponding to different communication devices may be the same or different. For example, if the second communication device is communication device #1, then the first elevation angle range is [elevation angle #3, elevation angle #4].

Table 1 Examples of information on candidate auxiliary communication devices

The following table exemplifies information about another type of communication device (or auxiliary communication device, or candidate auxiliary communication device, or auxiliary communication device to be switched to) using Table 2. Table 2 illustrates information indicating the elevation angle range corresponding to this communication device, including the minimum elevation angle within that range. For example, if the second communication device is communication device #1, then the first elevation angle range is [elevation angle #3, maximum elevation angle]. The maximum elevation angle can be a preset value, for example, 90 degrees. Other content in Table 2 is similar to that in Table 1 and will not be repeated.

Table 2 Examples of information about communication devices

The priority of each communication device (or candidate auxiliary communication device, or auxiliary communication device to be switched) acquired by the terminal device may be pre-configured, protocol-defined, or indicated by other communication devices (e.g., a third communication device). Other communication devices (e.g., a third communication device) may explicitly or implicitly indicate the priority of each communication device (or candidate auxiliary communication device, or auxiliary communication device to be switched).

For example, the priority of each communication device (or candidate auxiliary communication device, or auxiliary communication device to be switched) can be the sorting relationship of each auxiliary communication device to be switched in the list. For example, in Table 1, the priority of communication device #0 is higher than the priority of communication device #1, and the priority of communication device #1 is higher than the priority of communication device #2. When the terminal device determines that a communication device needs to be switched, it can first determine whether communication device #0 provides service to the first area. If it does not provide service, the terminal device can continue to determine whether communication device #1 provides service to the first area. If it provides service, the terminal device can switch to communication device #1; if it does not provide service, the terminal device can continue to determine whether communication device #2 provides service to the first area. In one possible implementation, the priority of each communication device (or candidate auxiliary communication device, or auxiliary communication device to be switched) may be determined based on the order in which each communication device provides services to the first area. For example, based on the movement pattern of each communication device, the communication device that provides services to the first area earliest (or the communication device whose elevation angle is earliest within the elevation angle range corresponding to the communication device) may have the highest priority; the communication device that provides services to the first area second (or the communication device whose elevation angle is second within the elevation angle range corresponding to the communication device) may have the second highest priority, and so on.

The terminal device can also acquire other information about the communication device (or candidate auxiliary communication device, or auxiliary communication device to be switched to), such as the communication device's identifier, downlink synchronization reference signal sequence information, downlink synchronization signal frequency, measurement timing configuration, polarization information, etc. One or more of this information may be pre-configured, protocol-defined, or indicated by other communication devices (e.g., a third communication device). This information can assist the terminal device in switching to the auxiliary communication device. For example, after determining that it needs to switch to the second communication device, the terminal device can more quickly search for the synchronization signal of the second communication device based on this information, thereby achieving timing synchronization (or downlink timing synchronization) with the second communication device more quickly.

In implementation method A1.2, taking the first information as the orbital angle corresponding to the second communication device as an example, the first condition includes: the orbital angle corresponding to the second communication device belongs to the range of the first orbital angle.

In this embodiment of the application, the angles used to describe the angle range of the orbital interval may include: the angle between a line passing through the communication device (e.g., a satellite device) and the center of the orbit of the communication device (e.g., a satellite device), and the angle between a reference point on the orbit of the communication device (e.g., a satellite device) and the center of the orbit of the communication device (e.g., a satellite device). For example, the angles in the first orbital angle range include: the angle between a line connecting a point on the orbit of the second communication device and the center of the orbit of the second communication device, and the angle between a reference point on the orbit of the second communication device and the center of the orbit of the second communication device.

In this application embodiment, the angle used to indicate the orbital interval can range from [0°, 360°]. In this application embodiment, the reference point for the orbits of different communication devices (e.g., satellite devices) can be different. The reference point in this application embodiment may include the intersection of the ascending orbit and the orbital plane of the communication device (e.g., satellite device), or the intersection of the ascending orbit and the ecliptic plane. The ecliptic plane can refer to the orbital plane of the Earth's revolution around the Sun. An ascending orbit can refer to a satellite's motion from the Earth's South Pole to the Earth's North Pole; conversely, a descending orbit can be referred to as a downward orbit.

There are several methods for a terminal device to obtain the orbital angle corresponding to the second communication device. For example, the terminal device can determine the orbital angle based on the ephemeris information of the second communication device. For instance, the terminal device can determine the position of the second communication device based on its ephemeris information, and then calculate the orbital angle of the second communication device based on its position and the position of its orbital center.

Figure 4 illustrates a possible orbital angle provided by an embodiment of this application. Figure 4 uses a first communication device as auxiliary satellite device #1 and a second communication device as auxiliary satellite device #2 as an example. The communication system may also include other satellite devices, not shown in Figure 3. The orbits of any two of the first and second communication devices can be the same orbit or different orbits; Figure 3 shows one possible example.

Please refer to Figure 4, which shows the orbital planes of the second communication device and the first communication device. Figure 4 uses the orbital centers of the two orbits as an example, but in practical applications, the orbital centers of different communication devices (e.g., satellite devices) may be different. Figure 4 exemplarily shows reference point #22 on the orbit of the first communication device and reference point #21 on the orbit of the second communication device.

As shown in Figure 4, the angle between the line connecting reference point #21 and the track center of the second communication device, and the line connecting the two track centers of the second communication device, is _r2 . _r2 can be, for example, the track angle corresponding to the second communication device. Similarly, the angle between the line connecting reference point #22 and the track center of the first communication device, and the line connecting the two track centers of the first communication device, is _r1 . _r1 can be, for example, the track angle corresponding to the first communication device.

In implementation method A1.2, the terminal device can acquire a first orbital angle range, and then determine whether the area where the second communication device provides services includes the first area based on whether the orbital angle of the second communication device is within the first orbital angle range. For example, when the orbital angle of the second communication device is within the first orbital angle range, the terminal device determines that the area where the first information indicates the second communication device provides services includes the first area. As another example, when the orbital angle of the second communication device is not within the first orbital angle range, the terminal device determines that the area where the first information indicates the second communication device provides services does not include the first area.

The terminal device can acquire information indicating a first track angle range and determine the first track angle range based on the information indicating the first track angle range. The information indicating the first track angle range can be pre-configured, protocol-defined, or indicated by other communication devices (e.g., a third communication device).

The information used to indicate the first track angle range can be track angle values or index values related to the first track angle range. The following examples illustrate the specific forms of information used to indicate the first track angle range.

Example 1: The information used to indicate the first track angle range includes two track angle values. These two track angle values are used to indicate the two boundaries of the first track angle range. For example, if the track angle range is [50°, 130°], the information indicating the track angle range includes track angle values of 50° and 130°.

Example 2: The information used to indicate the first track angle range may include a track angle value. For example, the track angle value could be the minimum or maximum value within the first track angle range, with another boundary value defined by the protocol or pre-configured. Alternatively, the track angle value could indicate the two boundaries of the first track angle range. For instance, the track angle value could be 90°. The first track angle range is defined by a 40° range before and after the track angle value (i.e., [50°, 130°]), where 40° is an example and can be replaced by other preset angle values. These preset angle values can be pre-configured on the terminal device side, agreed upon by the protocol, or sent to the terminal device by other communication devices (e.g., a third communication device).

Example 3: The information used to indicate the first track angle range may include an index value. This index value is associated with the first track angle range, and the terminal device can use the index value to find the track angle range associated with the index value, thereby determining the first track angle range.

In one possible implementation, the terminal device can acquire information about multiple communication devices (or auxiliary communication devices, or candidate auxiliary communication devices, or auxiliary communication devices to be switched over), which can serve as auxiliary communication devices to be switched over, and the second communication device belongs to these multiple auxiliary communication devices. Based on the information from these communication devices, the terminal device determines whether the communication device provides service to the first area.

The following table 3 illustrates an example of information about a communication device (or auxiliary communication device, or candidate auxiliary communication device, or auxiliary communication device to be switched to) acquired by a terminal device. As shown in Table 3, the information of a communication device (or auxiliary communication device, or candidate auxiliary communication device, or auxiliary communication device to be switched to) may include the index of the communication device, the ephemeris information of the communication device, and information indicating the orbital angle range corresponding to the communication device. Table 3 illustrates an example where the information indicating the orbital angle range corresponding to the communication device includes two boundary values of the orbital angle range. The orbital angle ranges corresponding to different communication devices may be the same or different. For example, if the second communication device is communication device #1, then the first orbital angle range is [orbital angle #3, orbital angle #4].

Table 3 Examples of information on candidate auxiliary communication devices

The terminal device can obtain information about multiple communication devices (or auxiliary communication devices, or candidate auxiliary communication devices, or auxiliary communication devices to be switched to), including priority information for each communication device. For details, please refer to the relevant description in Implementation A1.1 above, which will not be repeated here. Table 3 illustrates part of the information about the communication devices obtained by the terminal device. The terminal device can also obtain other information about the communication devices (or candidate auxiliary communication devices, or auxiliary communication devices to be switched to), for details, please refer to the relevant description in Implementation A1.1 above, which will not be repeated here.

In implementation method A1.3, taking the first information as time information as an example, the first condition includes: the time indicated by the time information in the first information (e.g., the current time) belongs to the time period during which the second communication device provides services to the first area.

The terminal device can obtain the time period during which the second communication device provides services to the first area. If the terminal device determines that the time indicated by the time information in the first information (e.g., the current time) belongs to the time period during which the second communication device provides services to the first area, then the terminal device can determine that the area served by the second communication device includes the first area. If the terminal device determines that the time indicated by the time information in the first information (e.g., the current time) does not belong to the time period during which the second communication device provides services to the first area, then the terminal device can determine that the area served by the second communication device does not include the first area.

Information regarding the time period during which the second communication device provides services to the first area may be pre-configured on the terminal device side, defined by a protocol, or sent by other communication devices (such as a third communication device).

In one possible implementation, the terminal device can acquire information about multiple communication devices (or auxiliary communication devices, or candidate auxiliary communication devices, or auxiliary communication devices to be switched over), which can serve as auxiliary communication devices to be switched over, and the second communication device belongs to these multiple auxiliary communication devices. Based on the information from these communication devices, the terminal device determines whether the communication device provides service to the first area.

Table 4 below illustrates an example of information about a communication device (or secondary communication device, or candidate secondary communication device, or secondary communication device to be switched to) obtained by a terminal device. As shown in Table 4, the information of a communication device (or secondary communication device, or candidate secondary communication device, or secondary communication device to be switched to) may include the index of the communication device, the ephemeris information of the communication device, and the time period during which the communication device provides service to the first area. The time periods during which different communication devices provide service to the first area may be the same or different. For example, if the second communication device is communication device #1, then the time period during which the second communication device provides service to the first area is [t2, t3].

Table 4 Examples of information on candidate auxiliary communication devices

In one possible implementation, as shown in the example provided in Table 4, t1 is equal to t2, and t3 is equal to t4. The terminal device can use communication device #0 as its auxiliary communication device at time t0, switch from communication device #0 to communication device #1 at time t1 (or around time t1) (using communication device #1 as its auxiliary communication device, and communication device #0 no longer serving as an auxiliary communication device for the terminal device), and switch from communication device #1 to communication device #2 at time t3 (or around time t3) (using communication device #2 as its auxiliary communication device, and communication device #1 no longer serving as an auxiliary communication device for the terminal device).

The terminal device can obtain information about multiple communication devices (also called auxiliary communication devices, candidate auxiliary communication devices, or auxiliary communication devices to be switched to), including priority information of each communication device. For details, please refer to the relevant description in Implementation A1.1 above, which will not be repeated here. Table 4 illustrates part of the information about the communication devices obtained by the terminal device. The terminal device can also obtain other information about the communication devices (or candidate auxiliary communication devices, or auxiliary communication devices to be switched to), for details, please refer to the relevant description in Implementation A1.1 above, which will not be repeated here.

In implementation method A1.4, taking the first information as the Doppler corresponding to the second communication device as an example, the first condition includes: the Doppler corresponding to the second communication device belongs to the first Doppler range.

Figure 5 illustrates a schematic diagram of Doppler and Doppler rate corresponding to the signal of a communication device. In Figure 5, the horizontal axis represents longitude, the vertical axis represents latitude, and the dashed lines represent Doppler contour maps. That is, the Doppler values of the signal received by the communication device at two locations located on the same dashed line are equal, while the Doppler values of the signal received by the communication device at two locations located on different dashed lines are unequal. In Figure 5, the solid lines represent Doppler rate of change contour maps. That is, the Doppler rate of change of the signal received by the communication device at two locations located on the same dashed line is equal, while the Doppler rate of change of the signal received by the communication device at two locations located on different dashed lines is unequal.

As shown in Figure 5, the distance between the communication device and the terminal device affects the Doppler value of the signal received by the terminal device from the communication device. For example, the Doppler values of the signals received from the same communication device at wave positions #1 and #2 are different. On the other hand, as the communication device moves, the Doppler value of the signal received at wave position #1 also shifts. That is, as the communication device moves, the Doppler value of the signal received from the communication device in the same area also changes.

In this embodiment, a communication device can correspond to a Doppler range. For example, a second communication device can correspond to a first Doppler range. When the Doppler signal of the second communication device corresponds to the first Doppler range, the terminal device determines that the area served by the second communication device includes the first area. Conversely, when the Doppler signal of the second communication device does not correspond to the first Doppler range, the terminal device determines that the area served by the second communication device does not include the first area.

There are several ways for a terminal device to obtain the Doppler signal corresponding to the second communication device. For example, the terminal device receives a signal from the second communication device and obtains the Doppler signal corresponding to the second communication device based on that signal. Another example is that the terminal device obtains the position and/or velocity information of the second communication device (e.g., determining the position and/or velocity information of the second communication device based on its ephemeris information) and the position of the terminal device, and then determines the Doppler signal corresponding to the second communication device based on this information. Yet another example is that the terminal device calculates the Doppler signal corresponding to the second communication device based on the motion relationship between the second communication device and the terminal device (e.g., determined based on the ephemeris information of the second communication device). For example, the terminal device receives a reference signal from the second communication device (e.g., demodulation reference signal (DMRS), phase tracking reference signal (PTRS), synchronization signal and PBCH block (SSB), channel state information reference signal (CSI-RS), etc.), and obtains the Doppler corresponding to the signal of the second communication device by detecting the reference signal.

The terminal device can obtain the first Doppler range by referring to the aforementioned implementation method for obtaining the first elevation angle range, which is similar and will not be repeated here.

Table 5 below illustrates an example of information about a communication device (or secondary communication device, or candidate secondary communication device, or secondary communication device to be switched to) acquired by a terminal device. As shown in Table 5, the information of a communication device (or secondary communication device, or candidate secondary communication device, or secondary communication device to be switched to) may include the index of the communication device, the ephemeris information of the communication device, and the Doppler range corresponding to the communication device. The Doppler ranges corresponding to different communication devices may be the same or different. For example, if the second communication device is communication device #1, then the Doppler range corresponding to the second communication device (i.e., the first Doppler range) is [Doppler3, Doppler4].

Table 5 Examples of information on candidate auxiliary communication devices

The terminal device can obtain information about multiple communication devices (or auxiliary communication devices, or candidate auxiliary communication devices, or auxiliary communication devices to be switched to), including priority information for each communication device. For details, please refer to the relevant description in Implementation A1.1 above, which will not be repeated here. Table 5 illustrates part of the information about the communication devices obtained by the terminal device. The terminal device can also obtain other information about the communication devices (or candidate auxiliary communication devices, or auxiliary communication devices to be switched to), for details, please refer to the relevant description in Implementation A1.1 above, which will not be repeated here.

In implementation method A1.5, taking the first information as the Doppler rate corresponding to the second communication device as an example, the first condition includes: the Doppler rate corresponding to the second communication device belongs to the first Doppler rate range.

The Doppler rate corresponding to the second communication device determined by the terminal device can be the rate of change of Doppler values over a period of time. For details on the rate of change of Doppler values, please refer to Figure 5 above; it will not be repeated here. The term "Doppler rate" can be replaced with "rate of change of Doppler values." There are several ways for the terminal device to obtain the Doppler rate corresponding to the second communication device. For example, the terminal device may acquire two Doppler values sequentially and then calculate the rate of change of Doppler values over that period. For instance, the terminal device may divide the difference between the two Doppler values by the duration of that period to obtain the Doppler rate. Another example is that the terminal device may acquire the motion trajectory and/or speed information of the second communication device (e.g., determining the motion trajectory and/or speed information of the second communication device based on its ephemeris information) and the position of the terminal device, and then determine the Doppler rate corresponding to the second communication device based on this information.

In this embodiment, a communication device can correspond to a Doppler rate range. For example, a second communication device can correspond to a first Doppler rate range. When the Doppler rate corresponding to the signal of the second communication device belongs to the first Doppler rate range, the terminal device determines that the area provided by the second communication device includes the first area. Conversely, when the Doppler rate corresponding to the signal of the second communication device does not belong to the first Doppler rate range, the terminal device determines that the area provided by the second communication device does not include the first area.

The method by which the terminal device obtains the first Doppler rate range can refer to the aforementioned implementation method for obtaining the first elevation angle range, and is similar, so it will not be described again.

Table 6 below illustrates an example of information about a communication device (or secondary communication device, or candidate secondary communication device, or secondary communication device to be switched to) acquired by a terminal device. As shown in Table 6, the information of a communication device (or secondary communication device, or candidate secondary communication device, or secondary communication device to be switched to) may include the index of the communication device, the ephemeris information of the communication device, and the Doppler rate range corresponding to the communication device. The Doppler rate ranges corresponding to different communication devices may be the same or different. For example, if the second communication device is communication device #1, then the Doppler rate range corresponding to the second communication device (i.e., the first Doppler rate range) is [Doppler_rate3, Doppler_rate4].

Table 6 Examples of information on candidate auxiliary communication devices

The terminal device can obtain information about multiple communication devices (or auxiliary communication devices, or candidate auxiliary communication devices, or auxiliary communication devices to be switched to), including priority information for each communication device. For details, please refer to the relevant description in Implementation A1.1 above, which will not be repeated here. Table 6 illustrates part of the information about the communication devices obtained by the terminal device. The terminal device can also obtain other information about the communication devices (or candidate auxiliary communication devices, or auxiliary communication devices to be switched to), for details, please refer to the relevant description in Implementation A1.1 above, which will not be repeated here.

In implementation method A1.6, taking the first information as the TA corresponding to the second communication device as an example, the first condition includes: the TA corresponding to the second communication device belongs to the range of the first TA.

There are several ways for a terminal device to obtain the TA corresponding to a second communication device. For example, the terminal device can obtain the TA of the second communication device from signaling received from other communication devices. Alternatively, the terminal device can receive a signal from the second communication device and obtain the TA corresponding to that signal. Another example is that the terminal device can obtain the location of the second communication device (e.g., determine the location of the second communication device based on its ephemeris information) and the location of the terminal device, and then determine the TA corresponding to the second communication device based on these two location information. Yet another example is that the terminal device can calculate the TA corresponding to the second communication device based on the motion relationship between the second communication device and the terminal device (e.g., determined based on the ephemeris information of the second communication device).

In this embodiment, a communication device can correspond to a TA range. For example, a second communication device can correspond to a first TA range. When the TA corresponding to the signal of the second communication device belongs to the first TA range, the terminal device determines that the area served by the second communication device includes the first area. Conversely, when the TA corresponding to the signal of the second communication device does not belong to the first TA range, the terminal device determines that the area served by the second communication device does not include the first area.

The method by which the terminal device obtains the first TA range can refer to the aforementioned implementation method for obtaining the first elevation angle range, and is similar, so it will not be described again.

In implementation method A1.7, taking the first information as the TA change rate corresponding to the second communication device as an example, the first condition includes: the TA change rate corresponding to the second communication device belongs to the range of the first TA change rate.

The rate of change of the transfer signal (TA) corresponding to the second communication device, determined by the terminal device, can be the rate of change of the TA over a period of time. There are several ways for the terminal device to obtain the rate of change of the TA corresponding to the second communication device. For example, the terminal device may acquire two TA values sequentially and then calculate the rate of change of the TA over that period. Alternatively, the terminal device may divide the difference between the two TA values by the duration of that period to obtain the rate of change of the TA. The terminal device may also acquire the position and/or speed information of the second communication device (e.g., determining the position and/or speed information of the second communication device based on its ephemeris information) and the position of the terminal device, and then determine the rate of change of the TA corresponding to the second communication device based on this information.

In this embodiment, a communication device can correspond to a TA change rate range. For example, a second communication device can correspond to a first TA change rate range. When the TA change rate corresponding to the signal of the second communication device belongs to the first TA change rate range, the terminal device determines that the area provided by the second communication device includes the first area. Conversely, when the TA change rate corresponding to the signal of the second communication device does not belong to the first TA change rate range, the terminal device determines that the area provided by the second communication device does not include the first area.

The method by which the terminal device obtains the first TA change rate range can refer to the aforementioned implementation method for obtaining the first elevation angle range, and is similar, so it will not be described again.

In implementation method A1.8, taking the first information as the rate of change of the TA change rate corresponding to the second communication device as an example, the first condition includes: the rate of change of the TA change rate corresponding to the second communication device belongs to the range of the second TA change rate.

The rate of change of the TA corresponding to the second communication device, as determined by the terminal device, can be the rate of change of the TA over a period of time. There are several ways for the terminal device to obtain the rate of change of the TA corresponding to the second communication device. For example, the terminal device may acquire two TA rates of change sequentially and then calculate the rate of change of the TA over that period. Alternatively, the terminal device may divide the difference between the two TA rates of change by the duration of that period to obtain the rate of change of the TA. Another example is that the terminal device may acquire the motion trajectory and/or speed information of the second communication device (e.g., determining the motion trajectory and/or speed information of the second communication device based on its ephemeris information) and the terminal device's position, and then determine the rate of change of the TA corresponding to the second communication device based on this information.

In this embodiment, a communication device can correspond to a range of TA change rates. For example, a second communication device can correspond to a second TA change rate range. When the TA change rate corresponding to the signal of the second communication device falls within the second TA change rate range, the terminal device determines that the area served by the second communication device includes the first area. Conversely, when the TA change rate corresponding to the signal of the second communication device does not fall within the second TA change rate range, the terminal device determines that the area served by the second communication device does not include the first area.

The method by which the terminal device obtains the second TA rate of change range can refer to the aforementioned implementation method for obtaining the first elevation angle range, and is similar, so it will not be described again.

Implementation methods A1.1, A1.2, A1.3, A1.4, A1.5, A1.6, A1.7, and A1.8 can be used in combination. For example, the first condition can also be multiple items. When all items in the first condition are satisfied, it is determined that the first information satisfies the first condition; otherwise, it is determined that the first condition is not satisfied. For example, the first condition is that the elevation angle corresponding to the second communication device belongs to the first elevation angle range, and the orbital angle corresponding to the second communication device belongs to the first orbital angle range. When the elevation angle indicated by the first information belongs to the first elevation angle range, and the orbital angle indicated by the first information belongs to the first orbital angle range, the terminal device determines that the first information satisfies the first condition. When the elevation angle indicated by the first information does not belong to the first elevation angle range, and/or, the orbital angle indicated by the first information does not belong to the first orbital angle range, the terminal device determines that the first information does not satisfy the first condition. Other examples are similar and will not be described in detail.

In implementation method A2, the terminal device can determine whether it is necessary to switch to the second communication device based on the first information (information of the second communication device) and the second information (information of the first communication device).

In one possible implementation, the terminal device can acquire second information. The second information may include/are for determining the area where the first communication device provides services. The second information may include/are for determining the area where the first communication device currently and/or will soon (e.g., after a first duration) provide services, or for determining whether the area where the first communication device provides services currently and/or will soon (e.g., after a first duration) include the first area. For example, the terminal device can determine whether the area where the first communication device provides services includes the first area based on whether the second information satisfies a first condition. As another example, the terminal device can determine the motion pattern of the second communication device based on ephemeris information, and then, based on the motion pattern and the second information, infer whether the area where the first communication device provides services after a first duration includes the first area.

In this application's embodiments, "about to" can refer to an upcoming moment, or to a time after a certain duration, such as a time after a first duration. The value of the first duration can be preset, defined by a protocol, or indicated by another communication device to the terminal device. The value of the first duration can be a positive number, for example, the first duration is 5 minutes.

For example, the second information includes/is at least one of the following: information associated with the position of the first communication device (e.g., the elevation angle and/or orbital angle of the first communication device), time information (e.g., current time information), information associated with the Doppler of the signal of the first communication device (e.g., the Doppler and Doppler rate corresponding to the first communication device), and information associated with the TA of the first communication device (e.g., at least one of the TA, the rate of change of TA, and the rate of change of the rate of change of TA corresponding to the first communication device).

In this embodiment, the second information and the first information can be two separate pieces of information, or they can be the same piece of information (for example, the first information and the second information can be the current time). The types of the first information and the second information can be the same or different. For example, the first information is the elevation angle corresponding to the second communication device, and the second information is the elevation angle, orbital angle, or current time of the first communication device.

For example, the terminal device can determine, based on the second information, whether the area currently and/or in the future (e.g., after a first duration) still includes the first region. If the second information indicates that the area currently and/or in the future (e.g., after a first duration) does not include the first region, the terminal device determines that it needs to switch to the secondary communication device. If the terminal device determines, based on the first information, that the area served by the second communication device includes/is the first region, the terminal device can determine that the target secondary communication device to be switched to is the second communication device. The terminal device can then switch from the first communication device to the second communication device (or switch the secondary communication device from the first communication device to the second communication device). In embodiment A2, the specific implementation of the terminal device determining that the area served by the second communication device includes/is the first region can be found in one or more of the aforementioned embodiments A1.1, A1.2, A1.3, A1.4, A1.5, A1.6, A1.7, and A1.8, and will not be repeated here.

In another possible implementation, if the second information indicates that the area served by the first communication device will still include the first area in the future (e.g., after the first duration), the terminal device can determine that there is no need to switch to the auxiliary communication device, that is, it can continue to communicate with the first communication device.

In another possible implementation, if the second information indicates that the area served by the first communication device still includes the first region, the terminal device can determine that switching to the secondary communication device is not yet necessary. Alternatively, if the second information indicates that the area served by the first communication device still includes the first region, the terminal device, in conjunction with the second information, determines whether the first communication device will still include the first region in the future (e.g., after the first duration). For example, if the first communication device will still include the first region in the future (e.g., after the first duration), the terminal device can determine that switching to the secondary communication device is not yet necessary. If the first communication device will not include the first region in the future (e.g., after the first duration), the terminal device can determine that switching to the secondary communication device is necessary. If the terminal device determines, based on the first information, that the area served by the second communication device includes/is the first region, the terminal device can determine that the target secondary communication device to be switched to is the second communication device. The terminal device can then switch from the first communication device to the second communication device (or switch the secondary communication device from the first communication device to the second communication device).

In this embodiment, the terminal device can search for the next available secondary communication device when the first communication device is currently unable to provide service, or when the first communication device is about to become unavailable, and then switch to the secondary communication device. This approach can extend the usage time of the secondary communication device as much as possible, thereby reducing the number of secondary communication device switches and avoiding overly frequent switches, thus saving resource consumption.

In one possible implementation, the second information can be used to indicate the area currently being served by the first communication device. For example, the second information may include/be at least one of the following: the elevation angle, orbital angle, Doppler, Doppler rate, TA, rate of change of TA, rate of change of the rate of change of TA, and the current time. For example, the terminal device can obtain the second information based on the location information of both the terminal device and the first communication device. Alternatively, the terminal device can determine the second information based on signals received from the first communication device. Alternatively, the terminal device can determine the second information based on information received from other communication devices (e.g., a third communication device). The method by which the terminal device obtains the second information can refer to the aforementioned method of obtaining the first information.

In another possible implementation, the second information can be used to indicate the area where the first communication device will provide service in the future (e.g., after the first duration). For example, the second information may include/be for at least one of the following: the elevation angle, orbital angle, Doppler, Doppler rate, TA, rate of change of TA, rate of change of the rate of change of TA, and the current time of the first communication device in the future (e.g., after the first duration). For example, the terminal device may infer the second information in the future (e.g., after the first duration) based on the ephemeris information (and/or motion trajectory) of the first communication device and the location information (and/or motion trajectory) of the terminal device. For example, based on the current elevation angle (or orbital angle, or Doppler, or Doppler rate, or TA, or TA rate of change, or rate of change of TA rate of change) of the first communication device and the ephemeris information of the first communication device, the terminal device predicts the future (e.g., after a first duration) elevation angle (or orbital angle, or Doppler, or Doppler rate, or TA, or TA rate of change, or rate of change of TA rate of change) of the first communication device. The elevation angle of the first communication device indicated by the second information can be understood as the future (e.g., after a first duration) elevation angle (or orbital angle, or Doppler, or Doppler rate, or TA, or TA rate of change, or rate of change of TA rate of change) of the first communication device.

There are several ways for the terminal device to determine whether the area currently or soon (e.g., after a first duration) of service provided by the first communication device includes the first region, based on the second information. When the second information is used to determine the area currently being provided by the first communication device, the terminal device can determine the area currently being provided by the first communication device based on the second information, or it can infer the area to be provided by the first communication device in the future (e.g., after a first duration) based on the second information and the ephemeris information of the first communication device. When the second information is used to determine the area to be provided by the first communication device in the future (e.g., after a first duration), the terminal device can determine the area to be provided by the first communication device in the future (e.g., after a first duration) based on the second information.

For example, if the second information fails to meet the second condition, the terminal device determines that the area served by the first communication device indicated by the second information does not include the first area. As another example, if the second information meets the second condition, the terminal device determines that the area served by the first communication device indicated by the second information includes the first area.

For example, the second condition may include one or more of the following:

The elevation angle corresponding to the first communication device falls within the range of the second elevation angle;

The orbital angle corresponding to the first communication device falls within the range of the second orbital angle.

The time indicated by the time information belongs to the time period during which the first communication device provides services to the first area;

The Doppler range corresponding to the first communication device belongs to the second Doppler range;

The Doppler rate corresponding to the first communication device falls within the range of the second Doppler rate.

The TA corresponding to the first communication device belongs to the range of the second TA;

The TA change rate corresponding to the first communication device falls within the range of the third TA change rate.

The rate of change of the TA corresponding to the first communication device falls within the range of the fourth TA rate of change.

For example, the second condition is that the elevation angle corresponding to the first communication device belongs to the second elevation angle range. If the elevation angle indicated by the second information (which may be the current elevation angle of the first communication device or the elevation angle of the first communication device after a first duration) does not belong to the second elevation angle range, the terminal device determines that the second information cannot satisfy the second condition. If the elevation angle indicated by the second information (which may be the current elevation angle of the first communication device or the elevation angle of the first communication device after a first duration) belongs to the second elevation angle range, the terminal device determines that the second information satisfies the second condition.

For another example, the second condition is that the orbital angle corresponding to the first communication device belongs to the range of the second orbital angle. If the orbital angle indicated by the second information (which may be the current orbital angle of the first communication device or the orbital angle of the first communication device after a first duration) does not belong to the range of the second orbital angle, the terminal device determines that the second information cannot satisfy the second condition. If the orbital angle indicated by the second information (which may be the current orbital angle of the first communication device or the orbital angle of the first communication device after a first duration) belongs to the range of the second orbital angle, the terminal device determines that the second information satisfies the second condition.

For another example, the second condition is that the time indicated by the second information (which could be the current time or a time after the first duration) falls within the time period during which the first communication device provides service to the first area. If the time indicated by the second information (which could be the current time or a time after the first duration) does not fall within the time period during which the first communication device provides service to the first area, then the terminal device determines that the second information does not satisfy the second condition. If the time indicated by the second information (which could be the current time or a time after the first duration) falls within the time period during which the first communication device provides service to the first area, then the terminal device determines that the second information satisfies the second condition.

For another example, the second condition is that the Doppler signal corresponding to the first communication device belongs to the second Doppler range. If the Doppler signal indicated by the second information (which could be the current Doppler signal of the first communication device or the Doppler signal of the first communication device after a first duration) does not belong to the second Doppler range, the terminal device determines that the second information cannot satisfy the second condition. If the Doppler signal indicated by the second information (which could be the current Doppler signal of the first communication device or the Doppler signal of the first communication device after a first duration) belongs to the second Doppler range, the terminal device determines that the second information satisfies the second condition.

The second condition can also include multiple conditions. If all conditions are met, the second information is determined to satisfy the first condition; otherwise, it is determined not to satisfy the second condition. For example, the second condition could be that the elevation angle corresponding to the first communication device belongs to a second elevation angle range, and the orbital angle corresponding to the first communication device belongs to a second orbital angle range. When the elevation angle indicated by the second information (which could be the current elevation angle of the first communication device or the elevation angle of the first communication device after a first duration) does not belong to the second elevation angle range, and/or, the orbital angle indicated by the second information (which could be the current orbital angle of the first communication device or the orbital angle of the first communication device after a first duration) does not belong to the second orbital angle range, the terminal device determines that the second information does not satisfy the second condition. When the elevation angle indicated by the second information (which could be the current elevation angle of the first communication device or the elevation angle of the first communication device after a first duration) belongs to the second elevation angle range, and the orbital angle indicated by the second information (which could be the current orbital angle of the first communication device or the orbital angle of the first communication device after a first duration) belongs to the second orbital angle range, the terminal device determines that the second information satisfies the second condition.

Examples of other conditions can be found in the aforementioned examples, as well as in the aforementioned content regarding the terminal device's determination of whether the first information meets the first condition, which will not be repeated here.

Step 202: The second communication device sends a synchronization signal.

Correspondingly, the terminal device receives the synchronization signal.

In step 202, "the terminal device receives a synchronization signal" and "the terminal device switches from the first communication device to the second communication device" can be interchanged. Switching from the first communication device to the second communication device can include/be replaced by: the terminal device selecting the second communication device as the auxiliary communication device, and the first communication device no longer serving as the auxiliary communication device. Alternatively, switching from the first communication device to the second communication device can include/be replaced by: the terminal device establishing downlink timing synchronization with the second communication device, and the terminal device no longer maintaining the downlink timing synchronization of the first communication device (or not establishing downlink timing synchronization with the first communication device). Alternatively, switching from the first communication device to the second communication device can include/be replaced by: the terminal device detecting the synchronization signal of the second communication device, and the terminal device no longer detecting the synchronization signal of the first communication device.

Step 202 can also be replaced by: the terminal device switching from the first communication device to the second communication device when the first information indicates that the area where the second communication device provides services includes the first area.

Alternatively, step 202 can also be replaced by: the terminal device switching from the first communication device to the second communication device when the first information indicates that the area where the second communication device provides services includes the first area, and the second information indicates that the area where the first communication device provides services currently and/or after the first duration does not include the first area.

In one possible implementation, when the second communication device determines that the terminal device needs to switch from the auxiliary communication device to the second communication device, the second communication device sends a synchronization signal to the area where the terminal device is located. In other words, the second communication device begins periodically sending the synchronization signal to the first area (the area where the terminal device is located) at a shorter duration (e.g., a second duration). Further, when the second communication device subsequently determines that the terminal device will no longer use the second communication device as the auxiliary communication device, the second communication device can stop periodically sending the synchronization signal to the first area (the area where the terminal device is located) at a shorter duration (e.g., the second duration). (For example, the second communication device can stop sending the synchronization signal to the first area altogether, or periodically send the synchronization signal to the first area at a longer duration (e.g., a third duration, the third duration being longer than the second duration). Because in this implementation, the second communication device does not continuously periodically send the synchronization signal to the first area at a shorter duration (e.g., the second duration), resource consumption can be saved, and interference in the communication system can be reduced.

Step 203: The third communication device sends the second data to the terminal device from the first resource.

Step 204: The second communication device sends the first data to the terminal device from the first resource.

Correspondingly, the terminal device receives first data and second data on the first resource.

In this embodiment, a primary communication device (e.g., a third communication device) and one or more secondary communication devices (e.g., a second communication device) can transmit data to a terminal device on the same resources (time-domain resources and/or frequency-domain resources). The data transmitted to the terminal device by any two of the primary and secondary communication devices can be the same or different. This embodiment uses the example of a third communication device and a second communication device transmitting data to the terminal device on the same resources.

In steps 203 and 204, since the resources for the first data and the second data are the same, the terminal device receives superimposed data of the first data and the second data. The first data comes from the second communication device, and the second data comes from the third communication device. The first resource is used by the second communication device to send the first data, and the first data occupies the first resource. The first resource is also used by the third communication device to send the second data, and the second data occupies the first resource. The first data and the second data can be the same data or different data. Alternatively, the first data and the second data can carry the same information or different information.

In one possible implementation, the first resource may include time-domain resources and frequency-domain resources, with the first data and the second data having the same time-domain resources and the same frequency-domain resources. In another possible implementation, the first resource may include time-domain resources, where the first data and the second data have the same time-domain resources, and their frequency-domain resources may be the same or different. In yet another possible implementation, the first resource may include frequency-domain resources, where the first data and the second data have the same frequency-domain resources, and their time-domain resources may be the same or different.

Step 205: The terminal device acquires the first data and the second data.

In step 205, the terminal device obtains the first data and the second data from the superimposed signal corresponding to the received first data and the second data.

As can be seen from the scheme provided in Figure 2, the terminal device can switch the auxiliary satellite device based on the first information (or the first information and the second information). During this process, no other communication device (such as a third communication device) needs to issue a switching command, so this scheme can save signaling overhead.

In the scheme provided in Figure 2, following step 201, another possible implementation includes the first information indicating that the area served by the second communication device does not include the first area. In this case, the terminal device can continue to detect whether the area served by other communication devices includes the first area. For example, if the area served by the fourth communication device includes the first area, the terminal device can switch from the first communication device to the fourth communication device.

In the scheme provided in Figure 2, for example, the difference between the downlink timing corresponding to the third communication device and the timing (or downlink timing) corresponding to the second communication device can be less than, equal to, or greater than the first threshold. Similarly, the difference between the timing (or downlink timing) corresponding to the second data and the downlink timing corresponding to the first data can be less than, equal to, or greater than the first threshold.

In this application embodiment, the timing can be replaced by downlink timing, downlink synchronization timing, time synchronization, or downlink time synchronization. Downlink timing is also known as downlink timing. Downlink timing is used to enable the terminal device to determine the frame boundaries, subframe boundaries, time slot boundaries, symbol boundaries, or receive window positions of frames transmitted by the communication device. For example, the difference between the downlink timing corresponding to the third communication device and the downlink timing corresponding to the second communication device can also be replaced by/include: the downlink timing difference between the third and second communication devices, the difference in frame boundaries of downlink frames from the third and second communication devices, downlink timing difference, synchronization position difference, time difference, downlink time difference, and the time difference of the received signal, etc. As another example, the difference between the downlink timing corresponding to the third and second communication devices can also be replaced by/include: the downlink timing difference when the terminal receives data from the third and second communication devices respectively, the difference in frame boundaries of downlink frames from the third and second communication devices respectively, downlink timing difference, synchronization position difference, time difference, downlink time difference, and the time difference of the received signal, etc. For example, the difference between the downlink timing corresponding to the third communication device and the downlink timing corresponding to the second communication device can also be replaced by/included as: the time difference of the frame boundary of the same frame number of the two downlink signals received by the terminal device from the third communication device and the second communication device respectively, the time difference of the time slot boundary of the same time slot number, or the time difference of the symbol boundary of the same symbol index number.

The difference between the downlink timing corresponding to the third communication device and the downlink timing corresponding to the second communication device may be a variable, which may be related to the difference in data transmission delay between the third and second communication devices. This difference may or may not be equal to the difference in data transmission delay between the third and second communication devices.

Figure 6 exemplarily illustrates a schematic diagram of the arrival of information transmitted by multiple communication devices to a terminal device according to an embodiment of this application. As shown in Figure 6, the data sent by the third communication device to the terminal device includes S1 and S2. The data sent by the second communication device to the terminal device includes S3. The arrival time of the data sent by the third communication device to the terminal device is _t0 , and the arrival time of the data sent by the second communication device to the terminal device is ( _t0 + _t1 ). _t1 is the time difference between the arrival times of the data sent by the third and second communication devices to the terminal device. _t1 can also be understood as the difference between the downlink timing corresponding to the third communication device and the downlink timing corresponding to the second communication device. _t1 may be less than or equal to a first threshold, or it may be greater than the first threshold.

When the difference between the downlink timing corresponding to the third communication device and the downlink timing corresponding to the second communication device exceeds a first threshold, the terminal device may require a more complex solution to eliminate interference between signals. To reduce the complexity of data acquisition on the terminal device side, embodiments of this application provide a data processing method. Referring to Figure 6 as an example, Figure 7 exemplarily illustrates a possible flowchart of a terminal device data acquisition method provided by an embodiment of this application. Referring to Figure 7, the process may include the following steps.

(1) The second data sent by the third communication device arrives at the terminal device through the channel corresponding to the third communication device, and the first data sent by the second communication device arrives at the terminal device through the channel corresponding to the second communication device. The first data and the second data occupy the same resources. The terminal device receives the superimposed signal corresponding to the first data and the second data. The terminal device decodes the second data (e.g., S1 and S2) from the received signal.

(2) The terminal device obtains the second data affected by the channel based on the second data and the influence of the channel on the signal. For example, the terminal device reconstructs the signal according to the decoding results of signals S1 and S2 to obtain S1 and S2 affected by the channel. The S1 and S2 affected by the channel are, for example, (S1*h1+S2*h2). Where h1 and h2 represent the influence of the channel on the signal.

(3) The terminal device removes the second data affected by the channel from the superimposed signal corresponding to the first data and the second data received, and then obtains the first data from the obtained data (e.g., S3). For example, the terminal device uses the superimposed signal of the two received communication devices to subtract the recovered (S1*h1+S2*h2) to obtain the first data. This process can be understood as a successive interference cancellation (SIC) signal processing method.

In the above example, the terminal device can also decode the first data in step (1) and then obtain the second data in step (3). The scheme is similar to the above and will not be described again.

The above method can eliminate interference between signals transmitted from multiple communication devices to the terminal device. Furthermore, this interference cancellation method can better extract the data transmitted by each communication device from the received superimposed signals.

Based on the content shown in Figures 1A, 1B, 1C, 1D, 1E, 1F or 1G, 2, 3, 4, 5, 6, and 7, and the other content mentioned above, Figure 8 exemplarily illustrates a possible flowchart of a communication method provided by an embodiment of this application. For ease of understanding, Figure 8 uses the interaction of a terminal device, a first communication device, a second communication device, and a third communication device as an example. For a description of the terminal device, the first communication device, the second communication device, and the third communication device, please refer to the relevant description in Figure 2 above, which will not be repeated here.

Step 801: The terminal device establishes an RRC connection with the third communication device.

In this embodiment of the application, during the process of establishing an RRC connection between the terminal device and the third communication device, the terminal device may first receive a synchronization signal (e.g., a synchronization signal) from the third communication device, then synchronize with the third communication device, and then establish an RRC connection with the third communication device.

In this embodiment, the terminal device can maintain synchronization with multiple communication devices, but it can establish an RRC connection with a third communication device without establishing RRC connections with other communication devices. For example, the terminal device receives the synchronization signal from the third communication device and then establishes an RRC connection with it. The terminal device receives the synchronization signal from the second communication device but does not establish an RRC connection with it. The communication device that establishes an RRC connection with the terminal device can also be called the primary communication device (e.g., the primary satellite device); other communication devices that do not establish an RRC connection with the terminal device, but whose downlink synchronization is maintained by the terminal device, can be called secondary communication devices (e.g., secondary satellite devices). Since the terminal device only establishes an RRC connection with the third communication device, this scheme can reduce the complexity of the scheme on the terminal device side. Furthermore, since the terminal device can synchronize with multiple communication devices, it can decode data sent from multiple communication devices on the same resources and then recover the data sent by each of the multiple communication devices.

Step 802: The third communication device sends the first configuration information to the terminal device.

Correspondingly, the terminal device receives the first configuration information.

The first configuration information includes information about one or more communication devices. For example, the first configuration information may include information about a second communication device. For example, the first configuration information includes information indicating at least one of the following: a first elevation angle range, a first orbital angle range, a time period during which the second communication device provides service to the first area, a first Doppler range, a first Doppler rate range, a first TA range, a first TA rate of change range, and a second TA rate of change range. This information can assist the terminal device in determining whether the second communication device is currently providing service to the first area. For example, this information can assist the terminal device in determining whether the first information meets a first condition (see the description of the embodiment provided in Figure 2 above, which will not be repeated here), thereby providing a basis for whether to switch to an auxiliary communication device.

In another possible implementation, the first configuration information further includes at least one of the following: ephemeris information of the second communication device and position information of a ground reference point. The position information of the ground reference point in the first configuration information is used to determine the elevation angle corresponding to the second communication device. This information can help the terminal device to search for the synchronization signal of the second communication device more quickly, thereby improving communication efficiency.

For example, the first configuration information may include information about the first communication device. For instance, the first configuration information includes information indicating at least one of the following: a second elevation angle range, a second orbital angle range, a time period during which the first communication device provides service to the first area, a second Doppler range, a second Doppler rate range, a second TA range, a third TA rate of change range, and a fourth TA rate of change range. This information can assist the terminal device in determining whether the first communication device is currently or will be providing service to the first area in the future (e.g., after a first duration). For example, this information can assist the terminal device in determining whether the second information meets the second condition (see the description of the embodiment provided in Figure 2 above, which will not be repeated here), thereby providing a basis for whether to switch to the auxiliary communication device.

In another possible implementation, the first configuration information further includes at least one of the following: ephemeris information of the first communication device and location information of a ground reference point. The location information of the ground reference point in the first configuration information is used to determine the elevation angle corresponding to the first communication device. The ground reference point used to determine the elevation angle corresponding to the first communication device in the first configuration information and the ground reference point used to determine the elevation angle corresponding to the second communication device in the first configuration information can be the same or two different ground reference points. This information can assist the terminal device in more quickly searching for the synchronization signal of the second communication device, thereby improving communication efficiency.

In another possible implementation, the first configuration information may further include information on the priority of each communication device (or candidate auxiliary communication device, or auxiliary communication device to be switched). The first configuration information may indicate the priority of each communication device explicitly or implicitly. For example, the first configuration information may include priority information for a first communication device, a second communication device, and a fourth communication device. The first configuration information indicates that the first communication device has a higher priority than the second communication device, and the second communication device has a higher priority than the fourth communication device. When the terminal device determines that it needs to switch the auxiliary communication device from the first communication device to another communication device, the terminal device may select the candidate auxiliary communication device with the highest priority, i.e., the second communication device, based on the priority of the candidate auxiliary communication devices indicated by the first configuration information. If the terminal device determines that the area served by the second communication device includes the first area, the terminal device switches the auxiliary communication device from the first communication device to the second communication device. If the terminal device determines that the area served by the second communication device does not include the first area, or the second communication device is currently unavailable, the terminal device continues to determine whether the area served by the fourth communication device includes the first area. Similarly, if the area served by the fourth communication device includes the first area, the terminal device switches the auxiliary communication device from the first communication device to the fourth communication device. The relevant solutions can be found in the priority description in Figure 2 above, and will not be repeated here.

In another possible implementation, the first configuration information may further include other information about the communication devices (e.g., the second communication device and/or the first communication device), such as the identifier of the communication device, downlink synchronization reference signal sequence information, downlink synchronization signal frequency, measurement timing configuration, polarization information, etc. This information can assist the terminal device in receiving the synchronization signals from these communication devices, thereby accelerating the synchronization signal search process and improving communication efficiency.

Step 802 may be omitted, and the relevant content in the first configuration information may be pre-configured on the terminal device side or pre-defined by the protocol.

Step 803: The first communication device sends a synchronization signal.

Correspondingly, the terminal device receives a synchronization signal from the first communication device.

The synchronization signal of the first communication device can be used for timing synchronization between the terminal device and the first communication device.

The terminal device can establish an RRC connection with the main communication device, i.e., the third communication device. The terminal device can choose not to establish an RRC connection with the auxiliary communication device (i.e., the first communication device).

Step 803 may also be omitted. When the first communication device and the third communication device need to transmit data to the terminal device on the same resources (e.g., the same time domain and/or the same frequency domain resources), and when the downlink timing of the two data sets is greater than or equal to the first threshold, step 803 may be executed so that the terminal device can synchronize its downlink timing with both the first and third communication devices, thereby recovering the individual signals from the received superimposed signals. Alternatively, when the downlink timing of the two data sets is less than or equal to the first threshold, step 803 may also be omitted, and the terminal device can synchronize its downlink timing with the third communication device, thereby receiving signals.

Step 804: The third communication device sends data to the terminal device on the second resource, and the first communication device sends data to the terminal device on the second resource.

Correspondingly, the terminal device receives data on the second resource. The data received by the terminal device on the second resource is the superimposed data sent by the third communication device and the first communication device. The second resource can be a time-domain resource, a frequency-domain resource, or a combination of both.

Step 804 is an example. Step 804 may also be omitted. During the period when the terminal device uses the first communication device as an auxiliary communication device, the first communication device may not send data jointly with the third communication device, the first communication device may not send data to the terminal device, or the first communication device may send data to the terminal device alone, or the third communication device may send data to the terminal device alone.

Step 805: The terminal device obtains the first information and determines, based on the first information, that it needs to switch from the first communication device to the second communication device.

In step 805, the terminal device can determine, based on the first information and the first configuration information, that it needs to switch from the first communication device to the second communication device. For example, if the terminal device determines that the first information meets the first condition, it can determine that it needs to switch from the auxiliary communication device to the second communication device. Alternatively, if the terminal device determines that the first information meets the first condition and the second information does not meet the second condition, it can determine that it needs to switch from the auxiliary communication device to the second communication device. Yet another example, if the terminal device determines that the first information does not meet the first condition or the second information meets the second condition, it can determine that it does not need to switch from the auxiliary communication device to the second communication device.

The content of step 805 can be found in the relevant description of step 201 above, and will not be repeated here.

Step 806: The third communication device obtains third information and determines, based on the third information, that the terminal device needs to switch from the first communication device to the second communication device.

The implementation method by which the third communication device determines whether the terminal device needs to switch to the auxiliary communication device is similar to the scheme executed on the terminal device side, and can be found in the descriptions of the aforementioned implementation methods A1 and A2. For example, the third communication device determines whether the terminal device needs to switch to the second communication device based on the content of the third information. For instance, if the third communication device determines that the third information meets the first condition, it can determine that the terminal device needs to switch from the auxiliary communication device to the second communication device. As another example, the third communication device determines whether the terminal device needs to switch to the second communication device based on the content of the third information and the sixth information. For instance, if the third communication device determines that the third information meets the first condition and the sixth information does not meet the second condition, it can determine that the terminal device needs to switch from the auxiliary communication device to the second communication device.

For example, if the third communication device determines that the third information does not meet the first condition or the sixth information meets the second condition, the terminal device may determine that it does not need to switch the auxiliary communication device to the second communication device.

The third information may include/can be replaced by: information for determining the area where the second communication device provides services, or information for determining whether the area where the second communication device provides services includes the first area. For example, the third information includes/is: information associated with the location of the second communication device (e.g., the elevation angle and/or orbital angle of the second communication device), first time information (e.g., current time information), information associated with the Doppler of the signal of the second communication device (e.g., the Doppler and Doppler rate corresponding to the second communication device), and at least one of the following: information associated with the TA of the second communication device (e.g., at least one of the TA, the rate of change of TA, and the rate of change of the rate of change of TA corresponding to the second communication device).

For example, the third communication device can obtain the third information based on the location information of the terminal device and the location information of the second communication device. Alternatively, the third communication device can determine the third information based on a signal received from the second communication device. Or, the third communication device can receive the third information from the terminal device or other devices. As another example, the method by which the third communication device obtains the third information can be found in the aforementioned description of the method by which the terminal device obtains the first information, and will not be repeated here.

The third information acquired by the third communication device may be the same type as or different from the first information acquired by the terminal device. For example, the first information may include time information, which the terminal device uses to determine whether to switch to the second communication device; the third information may also include time information, which the third communication device uses to determine whether to switch to the second communication device. As another example, the first information may include the elevation angle of the second communication device, which the terminal device uses to determine whether to switch to the second communication device; the third information may include time information, which the third communication device uses to determine whether to switch to the second communication device.

The method by which the third communication device determines that the third information satisfies the first condition is similar to the method by which the terminal device determines that the first information satisfies the first condition. The content of the first condition is as described above and will not be repeated here.

For example, the third information satisfying the first condition includes at least one of the following: the elevation angle corresponding to the second communication device indicated by the third information belongs to the first elevation angle range; the orbital angle corresponding to the second communication device indicated by the third information belongs to the first orbital angle range; the time indicated by the time information in the third information belongs to the time period during which the second communication device provides service to the first area; the Doppler corresponding to the second communication device indicated by the third information belongs to the first Doppler range; the Doppler rate corresponding to the second communication device indicated by the third information belongs to the first Doppler rate range; the TA corresponding to the second communication device indicated by the third information belongs to the first TA range; the TA change rate corresponding to the second communication device indicated by the third information belongs to the first TA change rate range; and the change rate of the TA change rate corresponding to the second communication device indicated by the third information belongs to the second TA change rate range.

The sixth information may include/be replaced by: information for determining the area where the first communication device provides services currently and/or in the future (e.g., after the first duration), or information for determining whether the area where the first communication device provides services currently and/or in the future (e.g., after the first duration) includes the first area. The sixth information may be inferred by the third communication device based on the current information of the first communication device and in combination with the ephemeris information of the first communication device. The relevant scheme can be referred to the aforementioned method of the terminal device obtaining the second information, which is similar and will not be repeated here.

For example, the sixth information includes/is at least one of the following: information associated with the position of the first communication device (e.g., the elevation angle and/or orbital angle of the first communication device), first time information (e.g., current time information), information associated with the Doppler of the signal of the first communication device (e.g., the Doppler and Doppler rate corresponding to the first communication device), and information associated with the TA of the first communication device (e.g., at least one of the TA, the rate of change of TA, and the rate of change of the rate of change of TA corresponding to the first communication device).

For example, the third communication device can obtain the sixth information based on the location information of the terminal device and the location information of the first communication device. Alternatively, the third communication device can determine the sixth information based on a signal received from the first communication device. Or, the third communication device can receive the sixth information from the terminal device or other devices. As another example, the method by which the third communication device obtains the sixth information can be found in the aforementioned description of how the terminal device obtains the second information, and will not be repeated here.

The sixth information acquired by the third communication device may be the same type as or different from the second information acquired by the terminal device. For example, the second information may include time information; the sixth information may also include time information. As another example, the second information may include the elevation angle of the first communication device; the sixth information may include time information.

The method by which the third communication device determines that the sixth information cannot satisfy the second condition is similar to the method described above for determining that the second information cannot satisfy the second condition. The content of the second condition is as described above and will not be repeated here.

For example, the sixth information may fail to meet the second condition if at least one of the following is true: the elevation angle (current or after the first duration) of the first communication device indicated by the sixth information does not fall within the first elevation angle range; the orbital angle (current or after the first duration) of the first communication device indicated by the sixth information does not fall within the first orbital angle range; the time indicated by the time information in the sixth information (current or after the first duration) does not fall within the time period during which the first communication device provides service to the first area; the Doppler (current or after the first duration) of the first communication device indicated by the sixth information does not fall within the first Doppler range; the Doppler rate (current or after the first duration) of the first communication device indicated by the sixth information does not fall within the first Doppler rate range; the TA (current or after the first duration) of the first communication device indicated by the sixth information does not fall within the first TA range; the TA change rate (current or after the first duration) of the first communication device indicated by the sixth information does not fall within the first TA change rate range; and the rate of change of the TA change rate (current or after the first duration) of the first communication device indicated by the sixth information does not fall within the second TA change rate range.

The content of step 806 can be found in the scheme of the terminal device determining the need to switch to the auxiliary communication device in step 201 above. It is similar and will not be repeated here.

In another possible implementation, the third communication device may receive signaling from other communication devices (e.g., terminal devices) to notify the third communication device that the terminal device has switched to the second communication device.

Step 807: The third communication device sends the second configuration information to the second communication device.

Correspondingly, the second communication device receives the second configuration information.

In one possible implementation, the second configuration information includes, for example, information indicating at least one of the following: a first elevation angle range, a first orbital angle range, a time period during which the second communication device provides service to the first region, a first Doppler range, a first Doppler rate range, a first TA range, a first TA rate of change range, and a second TA rate of change range. The second configuration information also includes information indicating the first region.

The second configuration information can be associated with the first area. For example, the second configuration information also includes information for indicating the first area. Information for indicating the first area includes: wave position information within the first area, and/or, the location information of the terminal device. The location information of the terminal device may include, for example, the coordinates of the terminal device's location in a coordinate system, or the administrative location of the terminal device, such as its street number. A wave position can be understood as a defined location area on the ground; wave position information may include, for example, information for identifying the wave position, such as a wave position identifier. For details regarding wave positions and areas, please refer to the foregoing description, which will not be repeated here.

In one possible implementation, the second configuration information is used by the second communication device to determine the timing for sending a synchronization signal to the first region. For example, when the second communication device determines that one or more of the second configuration information is satisfied, it can begin sending a synchronization signal to the first region (or periodically send a synchronization signal to the first region with a second duration as the period). Alternatively, when the second communication device determines that one or more of the second configuration information cannot be satisfied, it can stop sending a synchronization signal to the first region (or stop periodically sending a synchronization signal to the first region with a second duration as the period; or, for example, the second communication device can periodically send a synchronization signal to the first region with a third duration as the period, where the third duration can be longer than the second duration). It can be seen that in these schemes, with the assistance of the second configuration information, the second communication device can control the number and frequency of synchronization signals sent to the first region, avoiding the need for continuously sending synchronization signals to the first region at a high frequency, thus saving resource overhead.

Step 808: The second communication device acquires fourth information, and if the fourth information indicates that the area where the second communication device provides services includes the first area, it sends a synchronization signal to the first area.

Correspondingly, the terminal device receives a synchronization signal from the second communication device.

Step 808 can also be replaced by: the second communication device acquiring fourth information, and if the fourth information indicates that the area served by the second communication device includes the first area, determining that the terminal device needs to switch to the second communication device. If the second communication device determines that the terminal device needs to switch to the second communication device, it sends a synchronization signal to the first area, or begins periodically sending a synchronization signal to the first area with a second duration.

The implementation method of the second communication device determining whether the terminal device needs to switch to the auxiliary communication device is similar to the scheme executed on the terminal device side, and can be found in the descriptions of the aforementioned implementation methods A1 and A2. For example, the second communication device determines whether the terminal device needs to switch to the second communication device based on the content of the fourth information. For example, if the second communication device determines that the fourth information meets the first condition, it may send a synchronization signal to the first area, or start periodically sending a synchronization signal to the first area with a second duration (or determine that the terminal device needs to switch the auxiliary communication device to the second communication device). As another example, the second communication device determines whether the terminal device needs to switch to the second communication device based on the content of the fourth and sixth information. For example, if the second communication device determines that the fourth information meets the first condition and the seventh information does not meet the second condition, it may send a synchronization signal to the first area, or start periodically sending a synchronization signal to the first area with a second duration (or determine that the terminal device needs to switch the auxiliary communication device to the second communication device).

For example, if the second communication device determines that the fourth information does not meet the first condition or the seventh information meets the second condition, it can determine that the terminal device does not need to switch the auxiliary communication device to the second communication device, and may not send a synchronization signal to the first area, or may not periodically send a synchronization signal to the first area with a second duration (for example, it may periodically send a synchronization signal to the first area with a third duration).

The fourth information may include/be replaced by: information for determining the area where the second communication device provides services, or information for determining whether the area where the second communication device provides services includes the first area.

For example, the fourth information includes/is at least one of the following: information associated with the position of the second communication device (e.g., the elevation angle and/or orbital angle of the second communication device), first time information (e.g., current time information), information associated with the Doppler of the signal of the second communication device (e.g., the Doppler and Doppler rate corresponding to the second communication device), and information associated with the TA of the second communication device (e.g., at least one of the TA, the rate of change of TA, and the rate of change of the rate of change of TA corresponding to the second communication device).

For example, the second communication device can obtain the fourth information based on the location information of the terminal device and the location information of the second communication device. Alternatively, the second communication device can determine the fourth information based on information received from other communication devices (such as the third communication device). Or, the second communication device can receive the fourth information from the terminal device or other devices. As another example, the method by which the second communication device obtains the fourth information can be found in the aforementioned description of the method by which the terminal device obtains the first information, and will not be repeated here.

The fourth information acquired by the second communication device may be the same type as or different from the first information acquired by the terminal device. For example, the first information may include time information, which the terminal device uses to determine whether to switch to the second communication device; the fourth information may also include time information, which the second communication device uses to determine whether to switch to the second communication device. As another example, the first information may include the elevation angle of the second communication device, which the terminal device uses to determine whether to switch to the second communication device; the fourth information may include time information, which the second communication device uses to determine whether to switch to the second communication device.

The method by which the second communication device determines that the fourth information satisfies the first condition is similar to the method by which the terminal device determines that the first information satisfies the first condition. The content of the first condition can be found in the foregoing description and will not be repeated here.

For example, the fourth information satisfying the first condition includes at least one of the following: the elevation angle corresponding to the second communication device indicated by the fourth information belongs to the first elevation angle range; the orbital angle corresponding to the second communication device indicated by the fourth information belongs to the first orbital angle range; the time indicated by the time information in the fourth information belongs to the time period during which the second communication device provides service to the first area; the Doppler corresponding to the second communication device indicated by the fourth information belongs to the first Doppler range; the Doppler rate corresponding to the second communication device indicated by the fourth information belongs to the first Doppler rate range; the TA corresponding to the second communication device indicated by the fourth information belongs to the first TA range; the TA change rate corresponding to the second communication device indicated by the fourth information belongs to the first TA change rate range; and the change rate of the TA change rate corresponding to the second communication device indicated by the fourth information belongs to the second TA change rate range.

The seventh information may include/be replaced by: information for determining the area where the first communication device provides services currently and/or in the future (e.g., after a first duration), or information for determining whether the area where the first communication device provides services currently and/or in the future (e.g., after a first duration) includes the first area. The seventh information may be inferred by the second communication device based on the current information of the first communication device and in conjunction with the ephemeris information of the first communication device. Similar schemes can be found in the aforementioned method for the terminal device to obtain the second information, and will not be elaborated further.

For example, the seventh information includes/is at least one of the following: information associated with the position of the first communication device (e.g., the elevation angle and/or orbital angle of the first communication device), first time information (e.g., current time information), information associated with the Doppler of the signal of the first communication device (e.g., the Doppler corresponding to the first communication device and the Doppler rate), and information associated with the TA of the first communication device (e.g., at least one of the TA corresponding to the first communication device, the rate of change of TA, and the rate of change of the rate of change of TA).

For example, the second communication device can obtain the seventh information based on the location information of the terminal device and the location information of the first communication device. Alternatively, the second communication device can determine the seventh information based on information received from other communication devices (such as the third communication device). Or, the second communication device can receive the seventh information from the terminal device or other devices. For further examples, the method by which the second communication device obtains the seventh information can be found in the aforementioned description of how the terminal device obtains the second information, and will not be repeated here.

The type of the seventh information acquired by the second communication device may be the same as or different from the type of the second information acquired by the terminal device. For example, the second information may include time information; the seventh information may also include time information. As another example, the second information may include the elevation angle of the first communication device; the seventh information may include time information.

The method by which the second communication device determines that the seventh information cannot satisfy the second condition is similar to the method described above for determining that the second information cannot satisfy the second condition. The content of the second condition is as described above and will not be repeated here.

For example, the seventh information failing to meet the second condition includes at least one of the following: the elevation angle (current or after the first duration) corresponding to the first communication device indicated by the seventh information does not belong to the first elevation angle range; the orbital angle (current or after the first duration) corresponding to the first communication device indicated by the seventh information does not belong to the first orbital angle range; the time indicated by the time information in the seventh information (current or after the first duration) does not belong to the time period during which the first communication device provides service to the first area; the Doppler (current or after the first duration) corresponding to the first communication device indicated by the seventh information does not belong to the first Doppler range; the Doppler rate (current or after the first duration) corresponding to the first communication device indicated by the seventh information does not belong to the first Doppler rate range; the TA (current or after the first duration) corresponding to the first communication device indicated by the seventh information does not belong to the first TA range; the TA change rate (current or after the first duration) corresponding to the first communication device indicated by the seventh information does not belong to the first TA change rate range; and the change rate of the TA change rate (current or after the first duration) corresponding to the first communication device indicated by the seventh information does not belong to the second TA change rate range.

The content of step 808 can be found in the scheme of the terminal device determining the need to switch to the auxiliary communication device in step 201 above. It is similar and will not be repeated here.

Steps 808, 806, and 805 may not have a sequential relationship; they may be executed simultaneously or not simultaneously. Figure 8 shows one possible example. In actual applications, steps 808 or 806 may be executed before step 805, or step 805 may be executed between steps 808 and 806, or step 806 may be executed after step 808, etc.

In one possible implementation, in step 808, when the second communication device sends a synchronization signal to the first area, the terminal device can begin receiving the synchronization signal from the second communication device. In another possible implementation, when the second communication device sends a synchronization signal to the first area, and the terminal device determines that it needs to switch to the second communication device, the terminal device can begin receiving the synchronization signal from the second communication device. This saves power on the terminal device.

In another possible implementation, the second communication device may receive signaling from other communication devices (e.g., a third communication device) to notify the second communication device to begin sending a synchronization signal to the first area, or to periodically send a synchronization signal to the first area for a second duration. In yet another possible implementation, the second communication device may receive signaling from other communication devices (e.g., a third communication device) to notify the second communication device to stop sending a synchronization signal to the first area, or to stop periodically sending a synchronization signal to the first area for a second duration, or to begin periodically sending a synchronization signal to the first area for a third duration.

Step 809: The terminal device switches to the second communication device.

Step 809 may include the terminal device switching from the first communication device to the second communication device. Step 809 may be replaced by at least one of the following: stopping receiving synchronization signals from the first communication device; receiving synchronization signals from the second communication device, wherein the synchronization signals from the second communication device are used for timing synchronization between the terminal device and the second communication device.

The content of step 809 can be found in the description of step 202 above, and will not be repeated here.

Step 810: The third communication device sends the second data to the terminal device from the first resource.

The content of step 810 can be found in the description of step 203 above, and will not be repeated here.

Step 811: The second communication device sends the first data to the terminal device from the first resource.

Correspondingly, the terminal device receives first data and second data on the first resource.

The content of step 811 can be found in the description of step 204 above, and will not be repeated here.

Step 812: The terminal device acquires the first data and the second data.

The content of step 812 can be found in the description of step 205 above, and will not be repeated here.

Step 813: The second communication device obtains the fifth information. If the fifth information indicates that the area where the second communication device provides services does not include the first area, then: stop sending synchronization signals to the first area or stop periodically sending synchronization signals to the first area for a second duration.

Step 813 can also be replaced by: the second communication device acquiring the fifth information, and if the fifth information indicates that the area served by the second communication device does not include the first area, determining that the terminal device needs to switch from the second communication device to another auxiliary communication device. If the second communication device determines that the terminal device needs to switch from the second communication device to another auxiliary communication device, it stops sending synchronization signals to the first area, or stops periodically sending synchronization signals to the first area with a second duration.

The second communication device's cessation of periodically sending synchronization signals to the first area with a second duration can be replaced by periodically sending synchronization signals to the first area with a third duration, where the third duration is longer than the second duration.

The implementation method by which the second communication device determines whether the terminal device needs to switch to an auxiliary communication device is similar to the scheme executed on the terminal device side, as described in the aforementioned implementation method A1. For example, the second communication device determines whether the terminal device needs to switch from the second communication device to another auxiliary communication device based on the content of the fifth information. For example, if the second communication device determines that the fifth information does not meet the first condition, it stops sending synchronization signals to the first area or stops periodically sending synchronization signals to the first area with a second duration. Alternatively, if the second communication device determines that the fifth information meets the first condition, it can determine that the terminal device does not need to switch the auxiliary communication device from the second communication device to another communication device, and can continue to periodically send synchronization signals to the first area with a second duration.

The fifth piece of information may include/be replaced by: information for determining the area where the second communication device provides services, or information for determining whether the area where the second communication device provides services includes the first area.

For example, the fifth information includes/is at least one of the following: information associated with the position of the second communication device (e.g., the elevation angle and/or orbital angle of the second communication device), first time information (e.g., current time information), information associated with the Doppler of the signal of the second communication device (e.g., the Doppler corresponding to the second communication device, the Doppler rate), and information associated with the TA of the second communication device (e.g., at least one of the TA corresponding to the second communication device, the rate of change of TA, and the rate of change of the rate of change of TA).

For example, the second communication device can obtain the fifth information based on the location information of the terminal device and the location information of the second communication device. Alternatively, the second communication device can determine the fifth information based on information received from other communication devices (such as the third communication device). Or, the second communication device can receive the fifth information from the terminal device or other devices. As another example, the method by which the second communication device obtains the fifth information can be found in the aforementioned description of the method by which the terminal device obtains the first information, and will not be repeated here.

The fifth piece of information acquired by the second communication device may be the same type as or different from the first piece of information acquired by the terminal device. For example, the first piece of information may include time information, which the terminal device uses to determine whether to switch to the second communication device; the fifth piece of information may also include time information, which the second communication device uses to determine whether to switch to the second communication device. As another example, the first piece of information may include the elevation angle of the second communication device, which the terminal device uses to determine whether to switch to the second communication device; the fifth piece of information may include time information, which the second communication device uses to determine whether to switch to the second communication device.

For example, the fifth information not satisfying the first condition includes at least one of the following: the elevation angle corresponding to the second communication device indicated by the fifth information does not belong to the first elevation angle range; the orbital angle corresponding to the second communication device indicated by the fifth information does not belong to the first orbital angle range; the time indicated by the time information in the fifth information does not belong to the time period during which the second communication device provides service to the first area; the Doppler corresponding to the second communication device indicated by the fifth information does not belong to the first Doppler range; the Doppler rate corresponding to the second communication device indicated by the fifth information does not belong to the first Doppler rate range; the TA corresponding to the second communication device indicated by the fifth information does not belong to the first TA range; the TA change rate corresponding to the second communication device indicated by the fifth information does not belong to the first TA change rate range; and the change rate of the TA change rate corresponding to the second communication device indicated by the fifth information does not belong to the second TA change rate range.

The content of the first condition can be found in the relevant description of the embodiment provided in Figure 2 above, and will not be repeated here.

This application embodiment uses a second communication device as an example to describe the process of a third communication device sending second configuration information to the second communication device, the second communication device sending data to the terminal device, and the second communication device determining to stop sending synchronization signals to the first area or to stop periodically sending synchronization signals to the first area for a second duration. Similarly, for other auxiliary communication devices, such as the first communication device, a similar process to that of the second communication device can be performed. For example, the third communication device can send configuration information (which can be similar to the second configuration information) to the first communication device, the first communication device can send data to the terminal device (e.g., the aforementioned step 804), and the first communication device can also determine to stop sending synchronization signals to the first area or to stop periodically sending synchronization signals to the first area for a duration (e.g., the second duration) (this step can refer to the scheme on the second communication device side in the aforementioned step 813, which is similar and will not be described again).

The above scheme describes the process by which a terminal device switches its auxiliary communication device from the first communication device to the second communication device. Subsequent terminal devices may switch the auxiliary communication device from the second communication device to other communication devices, with similar schemes, which will not be elaborated further. As shown in Figure 8, the second communication device can determine the transmission time and frequency of the synchronization signal based on certain information. For example, if the elevation angle corresponding to the second communication device is within the first elevation angle range, the second communication device can start (or periodically transmit the synchronization signal to the first area with a second duration). Conversely, if the elevation angle corresponding to the second communication device is not within the first elevation angle range, the second communication device can stop (or stop periodically transmitting the synchronization signal to the first area with a second duration) (for example, it can periodically transmit the synchronization signal to the first area with a third duration). This method allows the second communication device to avoid continuously transmitting the synchronization signal to the first area at a high frequency, thereby saving resource consumption and reducing signal interference in the communication system.

In another possible implementation, the first communication device may also perform the same scheme as the second communication device. For example, the first communication device may start sending a synchronization signal to the first area or start periodically sending a synchronization signal to the first area with a second duration if it determines that the terminal device needs to set the auxiliary communication device as the first communication device. The first communication device may also stop sending a synchronization signal to the first area or stop periodically sending a synchronization signal to the first area with a second duration if it determines that the terminal device needs to switch the auxiliary communication device from the first communication device to another communication device.

In this embodiment, the information that the third communication device needs to send (such as first configuration information, second configuration information, etc.) can be carried in at least one of the broadcast information of system information block (SIB) 1, other system information (OSI), and main system information block (MIB), and broadcast or multicast to the terminal device by the third communication device. This avoids scheduling different resources for different terminal devices to send the above signaling, thereby saving the signaling overhead of resource scheduling and reducing the complexity of system scheduling.

In another possible implementation, if the third communication device sends information (such as first configuration information, second configuration information, etc.) during the radio resource control (RRC) connection establishment phase and subsequent communication, this information can be carried in at least one of the following: RRC signaling (e.g., RRC setup message, RRC reconfiguration message, RRC resume message, etc.), downlink control information (DCI), group DCI, and media access control (MAC) control element (CE). This information can be indicated by signaling or by tables. Alternatively, the information that the third communication device needs to send (such as first configuration information, second configuration information, etc.) can be carried with data transmission or in a separately allocated physical downlink shared channel (PDSCH). The information that the third communication device needs to indicate (such as first configuration information, second configuration information, etc.) can be sent via unicast or multicast. In this way, this information corresponding to each/group of terminal devices can be flexibly controlled.

It is understood that, in order to achieve the functions described in the above embodiments, the third communication device, the second communication device, the first communication device, and the terminal device may include hardware structures and/or software modules corresponding to the execution of each function. Those skilled in the art should readily recognize that, based on the units and method steps of the various examples described in conjunction with the embodiments disclosed in this application, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application scenario and design constraints of the technical solution.

Based on the same concept, Figures 9, 10, and 11 are schematic diagrams of possible communication devices provided in embodiments of this application. These communication devices shown in Figures 9, 10, and 11 can be used to implement the functions of the terminal device, third communication device, or second communication device in the above method embodiments, and therefore can also achieve the beneficial effects of the above method embodiments. In the embodiments of this application, the communication device can be a terminal device as shown in Figures 1A, 1B, 1C, 1D, 1E, 1F, or 1G; it can also be a network device (such as a satellite device or a network device deployed on the ground) as shown in Figures 1A, 1B, 1C, 1D, 1E, 1F, or 1G; or it can be a chip (or chip system) applied to the terminal device or network device shown in Figures 1A, 1B, 1C, 1D, 1E, 1F, or 1G.

As shown in Figure 9, the communication device 1300 includes a processing unit 1310 and a transceiver unit 1320. The communication device 1300 is used to implement the functions of the terminal device, the third communication device, or the second communication device in the method embodiments shown in Figure 2 or Figure 8. The transceiver unit 1320 can also be referred to as a communication unit. The transceiver unit 1320 may include a sending unit and a receiving unit.

When the communication device 1300 is used to implement the function of the terminal device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the processing unit 1310 is used to acquire first information, and when the first information indicates that the area provided by the second communication device includes the first area, switch from the first communication device to the second communication device.

When the communication device 1300 is used to implement the function of the terminal device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the transceiver unit 1320 is used to receive first data and second data.

When the communication device 1300 is used to implement the function of the terminal device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the processing unit 1310 is used to determine, when the first information satisfies the first condition, that the area in which the first information indicates the second communication device to provide services includes the first area.

When the communication device 1300 is used to implement the function of the terminal device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the transceiver unit 1320 is used to receive first configuration information.

When the communication device 1300 is used to implement the function of the terminal device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the processing unit 1310 is used to obtain second information before switching from the first communication device to the second communication device, and determine that the area provided by the first communication device indicated by the second information does not include the first area.

When the communication device 1300 is used to implement the function of the terminal device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the processing unit 1310 is used to determine that the area provided by the first communication device indicated by the second information does not include the first area when the second information cannot meet the second condition.

When the communication device 1300 is used to implement the function of the terminal device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the processing unit 1310 is used to stop receiving the synchronization signal from the first communication device.

When the communication device 1300 is used to implement the function of the terminal device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the transceiver unit 1320 is used to receive a synchronization signal from the second communication device.

When the communication device 1300 is used to implement the function of the third communication device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the processing unit 1310 is used to obtain third information, and when the third information indicates that the area where the second communication device provides services includes the first area, it determines that the terminal device switches from the first communication device to the second communication device.

When the communication device 1300 is used to implement the function of the third communication device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the transceiver unit 1320 is used to send second data to the terminal device from the first resource, and the first resource is also used for the second communication device to send first data to the terminal device.

When the communication device 1300 is used to implement the function of the third communication device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the processing unit 1310 is used to determine, when the third information satisfies the first condition, that the area in which the third information indicates the second communication device to provide services includes the first area.

When the communication device 1300 is used to implement the function of the third communication device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the transceiver unit 1320 is used to send first configuration information.

When the communication device 1300 is used to implement the function of the third communication device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the transceiver unit 1320 is used to send second configuration information to the second communication device.

When the communication device 1300 is used to implement the function of the third communication device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the processing unit 1310 is used to obtain sixth information and determine that the area provided by the first communication device indicated by the sixth information does not include the first area.

When the communication device 1300 is used to implement the function of the third communication device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the processing unit 1310 is used to determine that the area provided by the first communication device indicated by the sixth information does not include the first area if the sixth information cannot satisfy the second condition.

When the communication device 1300 is used to implement the function of the second communication device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the processing unit 1310 is used to acquire fourth information, and when the fourth information indicates that the area where the second communication device provides services includes the first area, the transceiver unit 1320 is used to send a synchronization signal to the first area.

When the communication device 1300 is used to implement the function of the second communication device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the transceiver unit 1320 is used to send first data to the terminal device in the first resource.

When the communication device 1300 is used to implement the function of the second communication device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the processing unit 1310 is used to send a synchronization signal to the first area through the transceiver unit 1320 when the fourth information satisfies the first condition.

When the communication device 1300 is used to implement the function of the second communication device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the processing unit 1310 is used to obtain fifth information and determine to stop sending synchronization signals to the first area if the fifth information indicates that the area where the second communication device provides services does not include the first area.

When the communication device 1300 is used to implement the function of the second communication device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the processing unit 1310 is used to determine to stop sending the synchronization signal to the first area if the fifth information does not meet the first condition.

When the communication device 1300 is used to implement the function of the second communication device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the processing unit 1310 is used to stop sending synchronization signals to the first region; and to stop periodically sending synchronization signals to the first region with a second duration.

When the communication device 1300 is used to implement the function of the second communication device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the processing unit 1310 is used to periodically send a synchronization signal to the first region through the transceiver unit 1320 with a third duration as the period when the fifth information does not meet the first condition, and the third duration is longer than the second duration.

When the communication device 1300 is used to implement the function of the second communication device in the method embodiment shown in FIG2 or FIG8, in one possible implementation, the transceiver unit 1320 is used to receive the second configuration information.

For a more detailed description of the processing unit 1310 and the transceiver unit 1320 described above, please refer to the relevant descriptions in the method embodiments shown in Figure 2 or Figure 8.

As shown in Figure 10, the communication device 1400 includes a processor 1410 and an interface circuit 1420. The processor 1410 and the interface circuit 1420 are coupled to each other. It is understood that the interface circuit 1420 can be a transceiver or an input/output interface. The input/output interface is used for inputting and/or outputting information; output can be understood as sending, and input can be understood as receiving. Optionally, the communication device 1400 may also include a memory 1430 for storing instructions executed by the processor 1410, or storing input data required by the processor 1410 to execute instructions, or storing data generated after the processor 1410 executes instructions.

When the communication device 1400 is used to implement the method shown in FIG2 or FIG8, the processor 1410 is used to implement the function of the processing unit 1310, and the interface circuit 1420 is used to implement the function of the transceiver unit 1320.

Please refer to Figure 11. The communication device shown in Figure 11 can also be a schematic diagram of a possible baseband architecture. As shown in Figure 11, the communication device may include a processing system, which may include one or more processors. The processors can be used to execute processes, such as process #1...process #N shown in Figure 11.

A processing system can be implemented using a bus architecture, typically represented by a bus. A bus can include any number of interconnect buses and bridges, depending on the specific application and overall design constraints of the processing system. The bus communicatively couples various circuits together, including one or more processors (typically represented by a processor), memory, and computer-readable media (typically represented by computer-readable media, such as computer-readable media #1…computer-readable media #N shown in Figure 11). The bus can also link various other circuits, such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further. The bus interface provides the interface between the bus and transceivers, and between the bus and the interface.

The communication device may also include a transceiver (not shown in Figure 11), which may be replaced by interface circuitry or a communication interface, etc. The transceiver provides a communication interface or means for communicating with various other devices via a wireless transmission medium. The transceiver may be coupled to an antenna array, and the transceiver and antenna array may be used together for communication with a corresponding network type. At least one interface (e.g., a network interface and/or a user interface) provides a communication interface or means for communication via an internal bus or via an external transmission medium.

The processor is responsible for managing the bus and general processing, including executing software stored on a computer-readable medium. When the processor executes the software, it causes the processing system to perform the various functions described below for any particular device. Functions that can be implemented by the processor, memory, and computer-readable medium may include: encoding, decoding, rate matching, rate dematching, scrambling, descrambling, modulation, demodulation, layer mapping, fast Fourier transform (FFT), inverse fast Fourier transform (IFFT), inverse discrete Fourier transform (IDFT), precoding, resource element (RE) mapping, channel equalization, RE demapping, digital beamforming (BF), adding CP, removing CP, and one or more of the following.

The signaling involved in the embodiments of this application (such as first configuration information, second configuration information, first data, and second data) can be implemented by a processor, a memory, and a computer-readable medium. For example, the aforementioned signaling sent by a third communication device (such as a satellite device) to a terminal device is processed by the processor, memory, and computer-readable medium shown in FIG11 after processing the aforementioned parameters, and then sent to the terminal device.

When the communication device shown in FIG11 is used to implement the method shown in FIG2 or FIG8, the processor 1410 is used to implement the function of the processing unit 1310, and the interface circuit 1420 is used to implement the function of the transceiver unit 1320.

When the aforementioned communication device (e.g., the communication device shown in Figures 9, 10, or 11) is a chip applied to a terminal, the terminal chip implements the functions of the terminal device in the above method embodiments. The terminal chip receives information from a base station, which can be understood as the information being first received by other modules in the terminal (such as an RF module or antenna), and then sent to the terminal chip by these modules. The terminal chip sends information to the base station, which can be understood as the information being first sent to other modules in the terminal (such as an RF module or antenna), and then sent to the base station by these modules.

When the aforementioned communication device (e.g., the communication device shown in Figures 9, 10, or 11) is a chip applied to a base station (e.g., a satellite base station), the base station chip implements the functions of the network device in the above method embodiments. The base station chip receives information from the terminal, which can be understood as the information being first received by other modules in the base station (such as radio frequency modules or antennas), and then sent to the base station chip by these modules. The base station chip sends information to the terminal, which can be understood as the information being sent down to other modules in the base station (such as radio frequency modules or antennas), and then sent to the terminal by these modules.

In this application, entity A sends information to entity B, either directly or indirectly through other entities. Similarly, entity B receives information from entity A, either directly or indirectly through other entities. Entities A and B can be RAN nodes or terminals, or modules within RAN nodes or terminals. Information transmission and reception can be between RAN nodes and terminals, such as between a base station and a terminal; between two RAN nodes, such as between a CU and a DU; or between different modules within a single device, such as between a terminal chip and other modules of the terminal, or between a base station chip and other modules of the base station.

It is understood that the processor in the embodiments of this application (e.g., processor 1410 in FIG. 10 and/or the processor in the processing system in FIG. 11) may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor may be a microprocessor or any conventional processor.

The method steps in the embodiments of this application can be implemented in hardware or in software instructions executable by a processor. The software instructions can consist of corresponding software modules, which can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disks, portable hard disks, compact disc read-only memory (CD-ROM), or any other form of storage medium well known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. The storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. Alternatively, the ASIC can reside in a base station or terminal. The processor and storage medium can also exist as discrete components in a base station or terminal.

In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer programs or instructions. When a computer program or instruction is loaded and executed on a computer, all or part of the processes or functions of the embodiments of this application are performed. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user equipment, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, a computer program or instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video optical disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or non-volatile storage medium, or may include both types of storage media.

In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and/or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

In this application, "at least one" means one or more, and "more than one" means two or more. "And/or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and/or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. In the textual description of this application, the character "/" generally indicates an "or" relationship between the preceding and following related objects; in the formulas of this application, the character "/" indicates a "division" relationship between the preceding and following related objects. "Including at least one of A, B, or C" can mean: including A; including B; including C; including A and B; including A and C; including B and C; including A, B, and C.

It is understood that the various numbers involved in the embodiments of this application (such as the numerical numbers "first" and "second", and the letter numbers "implementation A1", "implementation A1.1", "implementation C1", etc.) are only for the convenience of description and are not intended to limit the scope of the embodiments of this application. The order of the above-mentioned process numbers does not imply the order of execution; the execution order of each process should be determined by its function and internal logic.

Claims (60)

A communication method, characterized in that the method includes: Obtain first information, which is used to determine the area where the second communication device provides services; When the first information indicates that the area where the second communication device provides services includes the first area, the user switches from the first communication device to the second communication device, where the first area includes the area where the terminal device is located. Receive first data and second data, the first data comes from the second communication device and the second data comes from the third communication device, the first data occupies the first resource and the second data occupies the first resource. The method as described in claim 1, wherein obtaining the first information value further includes: If the area where the first information indicates that the second communication device provides services does not include the first area, it is determined that there is no need to switch to the second communication device. The method as described in claim 1 or 2, characterized in that the method further comprises at least one of the following: A radio resource control (RRC) connection is established with the third communication device, but no RRC connection is established with the second communication device, or no RRC connection is established with the first communication device. The method according to any one of claims 1-3, wherein the first data and the second data are the same or different. The method according to any one of claims 1-4, wherein the first information comprises at least one of the following: Information associated with the location of the second communication device; Time information; Information associated with the Doppler signal of the second communication device; Information associated with the timing advance (TA) of the second communication device. The method as described in claim 5, wherein the information associated with the position of the second communication device includes: the elevation angle corresponding to the second communication device; and/or, the orbital angle corresponding to the second communication device; The information associated with the Doppler of the signal from the second communication device includes: the corresponding Doppler of the second communication device; and/or, the Doppler rate of the second communication device; The information associated with the TA of the second communication device includes at least one of the following: the TA corresponding to the second communication device; the rate of change of the TA corresponding to the second communication device; and the rate of change of the rate of change of the TA corresponding to the second communication device. The method as described in claim 5, wherein the method further comprises: If the first information satisfies the first condition, it is determined that the area where the first information instructs the second communication device to provide services includes the first area; The first condition includes at least one of the following: The elevation angle corresponding to the second communication device belongs to the first elevation angle range; The orbital angle corresponding to the second communication device falls within the range of the first orbital angle. The time information indicates a time period during which the second communication device provides services to the first area; The Doppler range corresponding to the second communication device belongs to the first Doppler range; The Doppler rate corresponding to the second communication device falls within the first Doppler rate range; The TA corresponding to the second communication device belongs to the range of the first TA; The TA change rate corresponding to the second communication device falls within the range of the first TA change rate. The rate of change of the TA corresponding to the second communication device falls within the range of the second TA rate of change. The method as described in claim 7, wherein the method further comprises: If the first information does not meet the first condition, it is determined that the area where the first information indicates the second communication device to provide services does not include the first area. The method as described in claim 8, wherein the method further comprises: Receive the first configuration information; The first configuration information includes information for indicating at least one of the following: the first elevation angle range, the first orbital angle range, the time period during which the second communication device provides services to the first area, the first Doppler range, the first Doppler rate range, the first TA range, the first TA rate of change range, and the second TA rate of change range. The method as described in claim 9, wherein the first configuration information further includes: ephemeris information of the second communication device, and/or, location information of a ground reference point. The method as described in claim 9 or 10, wherein the first configuration information further indicates: The first communication device has a higher priority than the second communication device, and the second communication device is the highest priority communication device to be switched after the first communication device. The method according to any one of claims 1-11, characterized in that, before switching from the first communication device to the second communication device, it further includes: Obtain second information, which is used to determine the area where the first communication device provides services after the current time or after a first duration; It is determined that the area served by the first communication device indicated by the second information does not include the first area. The method as described in claim 12, wherein the second information includes at least one of the following: Information associated with the location of the first communication device; Time information; Information associated with the Doppler signal of the first communication device; Information associated with the TA of the first communication device. The method as described in claim 13, wherein the information associated with the position of the first communication device includes: the elevation angle corresponding to the first communication device; and/or, the orbital angle corresponding to the first communication device; The information associated with the Doppler of the signal from the first communication device includes: the corresponding Doppler of the first communication device; and/or, the Doppler rate of the first communication device. The information associated with the TA of the first communication device includes at least one of the following: the TA corresponding to the first communication device; the rate of change of the TA corresponding to the first communication device; or, the rate of change of the rate of change of the TA corresponding to the first communication device. The method as described in any one of claims 12-14, wherein determining that the area served by the first communication device indicated by the second information does not include the first area, comprises: If the second information fails to meet the second condition, it is determined that the area where the first communication device indicated by the second information provides services does not include the first area. The second condition includes at least one of the following: The elevation angle corresponding to the first communication device falls within the range of the second elevation angle. The orbital angle corresponding to the first communication device falls within the range of the second orbital angle. The time information indicates a time period during which the first communication device provides services to the first area; The Doppler range corresponding to the first communication device belongs to the second Doppler range; The Doppler rate corresponding to the first communication device falls within the second Doppler rate range; The TA corresponding to the first communication device belongs to the second TA range; the rate of change of the TA corresponding to the first communication device belongs to the third TA rate of change range; or, The rate of change of the TA corresponding to the first communication device falls within the range of the fourth TA rate of change. The method of claim 15, wherein the inability of the second information to satisfy the second condition may include at least one of the following: The elevation angle corresponding to the first communication device indicated by the second information does not fall within the range of the second elevation angle; The orbital angle corresponding to the first communication device indicated by the second information does not fall within the range of the second orbital angle; The time information in the second information does not indicate a time period during which the first communication device provides services to the first area; The Doppler signal indicated by the second information is not within the range of the second Doppler signal. The Doppler rate corresponding to the first communication device indicated by the second information does not fall within the range of the second Doppler rate; The TA corresponding to the first communication device indicated by the second information does not belong to the range of the second TA; The TA change rate corresponding to the first communication device indicated by the second information does not fall within the range of the third TA change rate; or, The rate of change of the TA corresponding to the first communication device indicated by the second information does not fall within the range of the fourth TA rate of change. The method according to any one of claims 12-16, characterized in that the method further comprises: If the second information satisfies the second condition, it is determined that the area where the first communication device indicated by the second information provides services includes the first area, and it is determined that there is no need to switch from the first communication device to another communication device. The method according to any one of claims 1-17, wherein the switching from the first communication device to the second communication device comprises: Stop receiving synchronization signals from the first communication device; Receive synchronization signals from the second communication device. The method as described in any one of claims 1-18, characterized in that, before switching from the first communication device to the second communication device, it further includes: Receive synchronization signals from the first communication device; Data is received from the first communication device on the second resource, and data is received from the third communication device on the second resource. A communication method, characterized in that the method is applicable to a third communication device, the method comprising: Obtain third information, which is used to determine the area where the second communication device provides services; If the third information indicates that the area where the second communication device provides services includes the first area, it is determined that the terminal device switches from the first communication device to the second communication device, and the first area includes the area where the terminal device is located. The first resource is used to send second data to the terminal device, and the first resource is also used for the second communication device to send the first data to the terminal device. The method as described in claim 20, characterized in that, after obtaining the third information, it further includes: If the third information indicates that the area where the second communication device provides services does not include the first area, it is determined that the terminal device does not need to switch to the second communication device. The method as described in claim 20 or 21, characterized in that the method further comprises at least one of the following: The terminal device establishes an RRC connection with the third communication device, but the terminal device does not establish an RRC connection with the second communication device, or the terminal device does not establish an RRC connection with the first communication device. The method according to any one of claims 20-22, wherein the first data and the second data are the same or different. The method according to any one of claims 20-23, wherein the third information includes at least one of the following: Information associated with the location of the second communication device; Time information; Information associated with the Doppler signal of the second communication device; Information associated with the timing advance (TA) of the second communication device. The method as described in claim 24, wherein the information associated with the position of the second communication device includes: the elevation angle corresponding to the second communication device; and/or, the orbital angle corresponding to the second communication device; The information associated with the Doppler of the signal from the second communication device includes: the corresponding Doppler of the second communication device; and/or, the Doppler rate of the second communication device; The information associated with the TA of the second communication device includes at least one of the following: the TA corresponding to the second communication device; the rate of change of the TA corresponding to the second communication device; and the rate of change of the rate of change of the TA corresponding to the second communication device. The method as described in claim 25, wherein the method further comprises: If the third information satisfies the first condition, it is determined that the area where the third information instructs the second communication device to provide services includes the first area; The first condition includes at least one of the following: The elevation angle corresponding to the second communication device belongs to the first elevation angle range; The orbital angle corresponding to the second communication device falls within the range of the first orbital angle. The time information indicates a time period during which the second communication device provides services to the first area; The Doppler range corresponding to the second communication device belongs to the first Doppler range; The Doppler rate corresponding to the second communication device falls within the first Doppler rate range; The TA corresponding to the second communication device belongs to the range of the first TA; The TA change rate corresponding to the second communication device falls within the range of the first TA change rate. The rate of change of the TA corresponding to the second communication device falls within the range of the second TA rate of change. The method as described in claim 26, characterized in that the method further comprises: If the third information does not meet the first condition, it is determined that the area where the third information indicates the second communication device to provide services does not include the first area. The method as described in claim 26 or 27, characterized in that the method further comprises: Send first configuration information, the first configuration information including information for indicating at least one of the following: the first elevation angle range, the first orbital angle range, the time period during which the second communication device provides services to the first area, the first Doppler range, the first Doppler rate range, the first TA range, the first TA rate of change range, and the second TA rate of change range. The method as described in claim 28, wherein the first configuration information further includes: ephemeris information of the second communication device, and/or, location information of a ground reference point. The method as described in claim 28 or 29, wherein the first configuration information further indicates: The first communication device has a higher priority than the second communication device, and the second communication device is the highest priority communication device to be switched after the first communication device. The method according to any one of claims 20-30, characterized in that the method further comprises: Send second configuration information to the second communication device, the second configuration information including information for indicating at least one of the following: the first elevation angle range, the first orbital angle range, the time period during which the second communication device provides services to the first area, the first Doppler range, the first Doppler rate range, the first TA range, the first TA rate of change range, and the second TA rate of change range. The method as described in claim 31, wherein the second configuration information further includes: information for indicating the first region. The method as described in any one of claims 20-32, characterized in that, before determining whether the terminal device switches from the first communication device to the second communication device, it further includes: Obtain the sixth information, which is used to determine the area where the first communication device provides services after the current time or after the first time period; The area where the first communication device indicated by the sixth information provides services does not include the first area. The method as described in claim 33, wherein the sixth information includes at least one of the following: Information associated with the location of the first communication device; Time information; Information associated with the Doppler signal of the first communication device; Information associated with the TA of the first communication device. The method as described in claim 34, wherein the information associated with the position of the first communication device includes: the elevation angle corresponding to the first communication device; and/or, the orbital angle corresponding to the first communication device; The information associated with the Doppler of the signal from the first communication device includes: the corresponding Doppler of the first communication device; and/or, the Doppler rate of the first communication device. The information associated with the TA of the first communication device includes at least one of the following: the TA corresponding to the first communication device; the rate of change of the TA corresponding to the first communication device; or, the rate of change of the rate of change of the TA corresponding to the first communication device. The method as described in any one of claims 33-35, wherein determining that the area served by the first communication device indicated by the sixth information does not include the first area, comprises: If the sixth information fails to meet the second condition, it is determined that the area where the first communication device indicated by the sixth information provides services does not include the first area. The second condition includes at least one of the following: The elevation angle corresponding to the first communication device falls within the range of the second elevation angle. The orbital angle corresponding to the first communication device falls within the range of the second orbital angle. The time information indicates a time period during which the first communication device provides services to the first area; The Doppler range corresponding to the first communication device belongs to the second Doppler range; The Doppler rate corresponding to the first communication device falls within the second Doppler rate range; The TA corresponding to the first communication device belongs to the second TA range; the rate of change of the TA corresponding to the first communication device belongs to the third TA rate of change range; or, The rate of change of the TA corresponding to the first communication device falls within the range of the fourth TA rate of change. The method as described in claim 36, wherein the sixth information failing to satisfy the second condition may include at least one of the following: The sixth information indicates that the elevation angle corresponding to the first communication device does not belong to the second elevation angle range; The orbital angle corresponding to the first communication device indicated by the sixth information does not belong to the range of the second orbital angle. The time information in the sixth piece of information indicates a time period that does not belong to the time period during which the first communication device provides services to the first area; The sixth information indicates that the Doppler corresponding to the first communication device does not belong to the second Doppler range; The sixth information indicates that the Doppler rate corresponding to the first communication device does not fall within the range of the second Doppler rate. The sixth information indicates that the TA corresponding to the first communication device does not belong to the range of the second TA; The TA change rate corresponding to the first communication device indicated by the sixth information does not fall within the range of the third TA change rate; or, The rate of change of the TA change rate corresponding to the first communication device indicated by the sixth information does not fall within the range of the fourth TA change rate. The method according to any one of claims 36-37, characterized in that the method further comprises: If the sixth information satisfies the second condition, it is determined that the area provided by the first communication device indicated by the sixth information includes the first area, and it is determined that the terminal device does not need to switch from the first communication device to another communication device. A communication method, characterized in that the method is applicable to a second communication device, the method comprising: Obtain fourth information, which is used to determine the area where the second communication device provides services; If the fourth information indicates that the area where the second communication device provides services includes the first area, a synchronization signal is sent to the first area; The first resource is used to send first data to the terminal device, and the first resource is also used for the third communication device to send second data to the terminal device. The method as described in claim 39, wherein the method further comprises at least one of the following: An RRC connection is established with the third communication device, but no RRC connection is established with the second communication device, or no RRC connection is established with the first communication device. The method according to any one of claims 39-40, wherein the first data and the second data are the same or different. The method according to any one of claims 39-41, wherein the fourth information includes at least one of the following: Information associated with the location of the second communication device; Time information; Information associated with the Doppler signal of the second communication device; Information associated with the timing advance (TA) of the second communication device. The method as described in claim 42, wherein the information associated with the position of the second communication device includes: the elevation angle corresponding to the second communication device; and/or, the orbital angle corresponding to the second communication device; The information associated with the Doppler of the signal from the second communication device includes: the corresponding Doppler of the second communication device; and/or, the Doppler rate of the second communication device; The information associated with the TA of the second communication device includes at least one of the following: the TA corresponding to the second communication device; the rate of change of the TA corresponding to the second communication device; and the rate of change of the rate of change of the TA corresponding to the second communication device. The method as described in claim 43, wherein sending a synchronization signal to the first region when the fourth information indicates that the region providing services by the second communication device includes the first region, comprises: If the fourth information satisfies the first condition, a synchronization signal is sent to the first region; The first condition includes at least one of the following: The elevation angle corresponding to the second communication device belongs to the first elevation angle range; The orbital angle corresponding to the second communication device falls within the range of the first orbital angle. The time information indicates a time period during which the second communication device provides services to the first area; The Doppler range corresponding to the second communication device belongs to the first Doppler range; The Doppler rate corresponding to the second communication device falls within the first Doppler rate range; The TA corresponding to the second communication device belongs to the range of the first TA; The TA change rate corresponding to the second communication device falls within the range of the first TA change rate. The rate of change of the TA corresponding to the second communication device falls within the range of the second TA rate of change. The method as described in claim 44, characterized in that the method further comprises: If the fourth information does not meet the first condition, it is determined that the area where the fourth information indicates the second communication device to provide services does not include the first area: Either do not send a synchronization signal to the first region, or periodically send a synchronization signal to the first region with a third duration. The method according to any one of claims 39-45, characterized in that the method further comprises: The fifth piece of information is obtained, which is used to determine the area where the second communication device provides services; If the fifth information indicates that the area where the second communication device provides services does not include the first area, it is determined to stop sending synchronization signals to the first area. The method as described in claim 46, characterized in that, after determining to stop sending synchronization signals to the first region, it further includes: Stop sending synchronization signals to the first area, or stop periodically sending synchronization signals to the first area with a second duration. and/or; A synchronization signal is periodically sent to the first region with a third duration, wherein the third duration is longer than the second duration. The method as described in any one of claims 46-47, wherein the fifth information comprises at least one of the following: Information associated with the location of the second communication device; Time information; Information associated with the Doppler signal of the second communication device; Information associated with the TA of the second communication device. The method as described in claim 48, wherein the information associated with the position of the second communication device includes: the elevation angle corresponding to the second communication device; and/or, the orbital angle corresponding to the second communication device; The information associated with the Doppler of the signal from the second communication device includes: the corresponding Doppler of the second communication device; and/or, the Doppler rate of the second communication device; The information associated with the TA of the second communication device includes at least one of the following: the TA corresponding to the second communication device; the rate of change of the TA corresponding to the second communication device; or, the rate of change of the rate of change of the TA corresponding to the second communication device. The method according to any one of claims 46-49, characterized in that the method further comprises: If the fifth information fails to meet the first condition, it is determined that the area where the fifth information indicates the second communication device to provide services does not include the first area; The first condition includes at least one of the following: The elevation angle corresponding to the second communication device belongs to the first elevation angle range; The orbital angle corresponding to the second communication device falls within the range of the first orbital angle. The time information indicates a time period during which the second communication device provides services to the first area; The Doppler range corresponding to the second communication device belongs to the first Doppler range; The Doppler rate corresponding to the second communication device falls within the first Doppler rate range; The TA corresponding to the second communication device belongs to the range of the first TA; The TA change rate corresponding to the second communication device falls within the range of the first TA change rate. The rate of change of the TA corresponding to the second communication device falls within the range of the second TA rate of change. The method as described in claim 50, wherein the inability of the fifth information to satisfy the first condition may include at least one of the following: The elevation angle corresponding to the second communication device indicated by the fifth information does not belong to the first elevation angle range; The orbital angle corresponding to the second communication device indicated by the fifth information does not belong to the first orbital angle range; The time information in the fifth piece of information indicates a time period that does not belong to the time period during which the second communication device provides services to the first area; The Doppler signal indicated by the fifth information is not within the range of the first Doppler. The Doppler rate corresponding to the second communication device indicated by the fifth information does not belong to the first Doppler rate range; The TA corresponding to the second communication device indicated by the fifth information does not belong to the range of the first TA; The TA change rate corresponding to the second communication device indicated by the fifth information does not fall within the range of the first TA change rate; or, The rate of change of the TA corresponding to the second communication device indicated by the fifth information does not fall within the range of the second TA rate of change. The method as described in any one of claims 50-51, characterized in that, after obtaining the fifth information, it further includes: If the fifth piece of information satisfies the first condition, it is determined that the area in which the fifth piece of information indicates the second communication device to provide services includes the first area. The method according to any one of claims 46-52, characterized in that, after obtaining the fifth information, it further includes: In the case where the fifth information indicates that the area where the second communication device provides services includes the first area: Continuously send a synchronization signal to the first area, or periodically send a synchronization signal to the first area with a second duration. The method according to any one of claims 39-53, characterized in that the method further comprises: Receive second configuration information, the second configuration information including information for indicating at least one of the following: the first elevation angle range, the first orbital angle range, the time period during which the second communication device provides services to the first area, the first Doppler range, the first Doppler rate range, the first TA range, the first TA rate of change range, and the second TA rate of change range. The method as described in claim 54, wherein the second configuration information further includes: information for indicating the first region. The method according to any one of claims 54-55, characterized in that the method further comprises: For at least one item in the second configuration information: If at least one of the conditions is met, a synchronization signal is initiated to be sent to the first region; and/or, If at least one of the requirements cannot be met, the transmission of synchronization signals to the first region shall be stopped. A communication device, characterized in that it includes a module for performing the method as described in any one of claims 1 to 19, or includes a module for performing the method as described in any one of claims 20 to 38, or includes a module for performing the method as described in any one of claims 39 to 56. A communication device, characterized in that it includes a processor and an interface circuit, the interface circuit being used to receive signals from other communication devices and transmit them to the processor or to send signals from the processor to other communication devices, the processor being used to implement the method as described in any one of claims 1 to 19, or the method as described in any one of claims 20 to 38, or the method as described in any one of claims 39 to 56, through logic circuits or execution code instructions. A computer-readable storage medium, characterized in that the storage medium stores a computer program or instructions that, when executed by a communication device, implement the method as described in any one of claims 1 to 19, or the method as described in any one of claims 20 to 38, or the method as described in any one of claims 39 to 56. A computer program product, characterized in that the computer program product stores a computer program, the computer program including program instructions, which, when executed by a computer, cause the method as described in any one of claims 1 to 19 to be implemented, or the method as described in any one of claims 20 to 38 to be implemented, or the method as described in any one of claims 39 to 56 to be implemented.