WO2025167465A1 - Communication method and apparatus - Google Patents

Abstract

Embodiments of the present application relate to the field of communications, and provide a communication method and apparatus, which are used for reducing the complexity of terminal device implementation. In the method, a terminal device can determine, on the basis of received timing information, system frame timing of a neighboring cell of the terminal device, i.e., a first cell. In this way, the terminal device can acquire the system frame timing of the neighboring cell (comprising the first cell) of the terminal device, so that subsequently, before the terminal device achieves synchronization with the first cell, the terminal device can use the system frame timing to determine a reference time point of ephemeris information of the first cell. After the terminal device has determined the reference time point of the ephemeris information of the first cell, the ephemeris information of the first cell can be used for completing Doppler frequency offset correction, timing advance adjustment, etc., so that the complexity of terminal device implementation can be reduced. Moreover, the terminal device can use the ephemeris information of the first cell to access the first cell, so that handover is successfully completed, thereby ensuring service continuity of the terminal device.

Description

Communication method and device

This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on February 6, 2024, with application number 202410171656.3 and application name “Communication Method and Device”, the entire contents of which are incorporated by reference into this application.

Technical Field

The present application relates to the field of communications, and in particular to a communication method and device.

Background Art

Currently, satellite ephemeris information can be used to provide terminal devices with information related to the satellite's location. For example, a satellite can provide satellite ephemeris information to a terminal device via dedicated system information (SI) or radio resource control (RRC) signaling. Satellite ephemeris information can include an epoch time field, which can indicate a system frame number (SFN) and subframe number, i.e., the epoch time. The satellite ephemeris information is referenced to the epoch time. The SFN and subframe number indicated by the epoch time field are referenced to the system frame timing of the cell providing the epoch time.

Neighboring cells of the serving cell where a terminal device is located can provide the terminal device with its ephemeris information. After the terminal device synchronizes with the neighboring cell, it can use the ephemeris information of the neighboring cell. This increases the complexity of terminal device implementation. Therefore, how to reduce the complexity of terminal device implementation is an urgent problem to be solved.

Summary of the Invention

The embodiments of the present application provide a communication method and apparatus to reduce the complexity of implementing a terminal device.

To achieve the above objectives, the present invention adopts the following technical solutions:

In a first aspect, a communication method is provided. The method can be performed by a terminal device, or by a module (e.g., a processor, chip, or chip system) applied to the terminal device, or by a logical node, logic module, or software that implements all or part of the terminal device's functions. The method includes receiving timing information and determining the system frame timing of a first cell based on the timing information. The first cell is a neighboring cell of the terminal device.

Based on the method described in the first aspect, it can be known that the terminal device can determine the neighboring area of the terminal device based on the received timing information, or in other words, the neighboring area of the service cell where the terminal device is located, that is, the system frame timing of the first cell. In this way, the terminal device can obtain the system frame timing of the neighboring area of the terminal device (including the first cell), so that the terminal device can use the system frame timing to determine the reference time point of the ephemeris information of the first cell before synchronizing with the first cell. After the terminal device determines the reference time point of the ephemeris information of the first cell, it can use the ephemeris information of the first cell to complete Doppler frequency offset correction and timing advance adjustment, etc., so that the complexity of the terminal device implementation can be reduced. At the same time, the terminal device can use the ephemeris information of the first cell and the system frame timing to access the first cell, so as to avoid the problem that the terminal device does not know the system frame timing of the first cell, resulting in the inability to use the ephemeris information provided by the first cell to access the first cell, resulting in a handover failure. In addition, the availability problem of the ephemeris information provided by the target cell during the handover process can be solved, so that the handover is completed normally, the business continuity of the terminal device is guaranteed, and the impact on the mobility performance of the terminal device is reduced.

In one possible design scheme, the timing information includes relative timing information or absolute timing information; determining the system frame timing of the first cell based on the timing information includes: determining the system frame timing of the first cell based on the system frame timing and relative timing information of the second cell; or determining the system frame timing of the first cell based on the absolute timing information. The second cell is a service cell of the terminal device. It can be understood that the system frame timing of the second cell is a parameter known to the terminal device, and the terminal device can deduce the system frame timing of the first cell based on the system frame timing of the second cell and the system frame timing of the second cell, thereby achieving flexibility; or, the system frame timing of the first cell can be directly determined based on the absolute timing information, which is simple to implement and reduces computational overhead.

In one possible design scheme, the relative timing information indicates a first deviation value between the system frame number SFN of the first system frame in the first cell and the SFN of the second system frame in the second cell; and/or a second deviation value between the boundary of the first time unit of the first cell and the boundary of the second time unit of the second cell, so as to be applicable to different scenarios. For example, the boundary of the first system frame and the boundary of the second system frame can be at the same time domain position; or, the boundary of the first system frame and the boundary of the second system frame can be at different time domain positions, such as the first system frame and the second system frame can be the two system frames with the closest time domain distance, etc., without limitation.

Optionally, the first deviation value is the SFN of the first system frame minus the SFN of the second system frame; or, the first deviation value is the SFN of the second system frame minus the SFN of the first system frame. The first deviation value can be a positive value or a negative value, or can be 0, which is flexible and not limited.

Optionally, the second deviation value is the time of the boundary of the first time unit - the time of the boundary of the second time unit; or, the second deviation value is the time of the boundary of the second time unit - the time of the boundary of the first time unit. The second deviation value can be a positive value or a negative value, or it can also be 0, which is flexible and not limited.

Optionally, the time unit includes at least one of the following: a system frame, a subframe, a time slot, or a symbol; the time unit includes a first time unit and a second time unit to meet different application scenarios.

In one possible design scheme, the absolute timing information indicates the time of the starting boundary of the third system frame in the first cell, or the time of the ending boundary of the third system frame in the first cell. In this way, the terminal device can directly determine the time or occupied time domain position of each system frame in the first cell based on the time of the starting boundary of the third system frame and the duration of each system frame, or directly based on the time of the ending boundary of the third system frame and the duration of each system frame.

In one possible design scheme, the timing information is provided to the terminal device by the first cell. For example, the network device to which the first cell belongs can send it to the network device to which the second cell belongs, and the network device to which the second cell belongs then forwards it to the terminal device. In this way, the terminal device can obtain real-time timing information, thereby improving the accuracy of the timing information and the reliability of communication.

Alternatively, the timing information is provided to the terminal device by the second cell. For example, the timing information of one or more neighboring cells (such as including the first cell) of the second cell can be predefined or preconfigured. When the terminal device needs to access the first cell, the network device to which the second cell belongs can directly send the timing information to the terminal device to reduce signaling overhead; or, the network devices to which each adjacent cell belongs can exchange their respective timing information. For example, the network device to which the first cell belongs can send the timing information to the network device to which the second cell belongs, and the network device to which the second cell belongs can store the timing information for subsequent use. When the terminal device needs to access the first cell, the network device to which the second cell belongs can directly provide the timing information to the terminal device, thereby achieving flexibility and no limitation.

In one possible design, the method described in the first aspect further includes: receiving ephemeris information of a first cell. The ephemeris information of the first cell is provided by the first cell to the terminal device, and the ephemeris information of the first cell includes first time information, and the first time information is based on the system frame timing of the first cell.

In one possible design, the system frame timing of the first cell is used for the terminal device to use the ephemeris information of the first cell.

The terminal device can subsequently determine the reference time point of the ephemeris information of the first cell based on the predetermined system frame timing of the first cell, and use the ephemeris information of the first cell to access the first cell. At the same time, the available ephemeris information of the first cell is provided to the terminal device, which is conducive to the terminal device completing synchronization with the first cell as soon as possible, avoiding the terminal device from blindly searching the first cell, reducing unnecessary power consumption and overhead of the terminal device, shortening the switching delay, and improving mobility performance. In addition, during the switching process, the ephemeris information provided by the first cell is usually more effective or accurate. The use of this ephemeris information by the terminal device is conducive to improving the precision or accuracy of subsequent operations such as timing synchronization and Doppler frequency offset compensation, thereby improving the performance of the terminal device accessing the target cell.

For example, optionally, the first cell is accessed according to the system frame timing of the first cell and the ephemeris information of the first cell.

Optionally, accessing the first cell based on the system frame timing of the first cell and the ephemeris information of the first cell includes: determining location information of the first network device based on the system frame timing of the first cell and the ephemeris information of the first cell, and pre-compensating a Doppler frequency offset and/or adjusting a timing advance (TA) based on the location information. The first network device is a network device to which the first cell belongs.

In one possible design, the first cell is one of at least one candidate cell of the terminal device. Optionally, the method of the first aspect further includes: receiving a radio resource control (RRC) reconfiguration message, and determining the first cell among the at least one candidate cell as the target cell based on a handover condition. The RRC reconfiguration message is used to indicate the handover condition to the terminal device, and the RRC reconfiguration message is from a network device to which the second cell belongs.

That is, the terminal device can determine the first cell that meets the conditions among at least one candidate cell as the target cell based on the conditions for executing the switching, and initiate a random access process to the first cell. In other words, the switching method can be conditional switching, so as to avoid the possibility of being unable to switch due to deterioration of channel conditions, reduce the possibility of radio link failure, and improve robustness.

In one possible design, the first cell is a target cell for handover by the terminal device. Optionally, the method described in the first aspect further includes: receiving an RRC reconfiguration message. The RRC reconfiguration message is used to instruct the terminal device to handover to the first cell, and the RRC reconfiguration message is from a network device to which the second cell belongs.

That is, the terminal device can directly switch to the first cell according to the instructions of the RRC reconfiguration message. In other words, the switching method can be a normal switching method. Compared with the conditional switching method, the terminal device does not need to determine the target cell in at least one candidate cell, which is simple to implement and reduces overhead.

In one possible design scheme, the RRC reconfiguration message includes the ephemeris information of the first cell, or the ephemeris information of the first cell can be carried in the RRC reconfiguration message, that is, carried in an existing information element to reduce the difficulty of implementation, or can also be carried in a new information element to improve the implementation flexibility, without limitation.

In a second aspect, a communication method is provided. The method can be executed by a network device, or by a module applied to the network device (such as a processor, chip, or chip system, etc.), or by a logical node, logic module or software that can realize all or part of the network device functions (such as a centralized unit (CU), distributed unit (DU) or radio unit (RU), etc.). The method includes: obtaining timing information and sending the timing information to the terminal device. The timing information is used by the terminal device to determine the system frame timing of the first cell, and the first cell is a neighboring cell of the terminal device.

It can be understood that the network device can be a network device belonging to the first cell, recorded as the first network device; or the network device can be a network device belonging to the second cell, recorded as the second network device. When the network device is the first network device, the first network device can send the timing information to the terminal device through forwarding by the second network device; when the network device is the second network device, the second network device can directly send the timing information to the terminal device, such as the second network device can send the timing information to the terminal device based on the predefined or preconfigured timing information of the first cell, or the second network device can forward the timing information, for example, the second network device can receive the timing information from the first network device and forward the timing information to the terminal device, without limitation.

In one possible design, the timing information includes relative timing information or absolute timing information.

In one possible design, the relative timing information indicates a first offset between a system frame number (SFN) of a first system frame in a first cell and an SFN of a second system frame in a second cell; and/or a second offset between a boundary of a first time unit in the first cell and a boundary of a second time unit in the second cell, where the second cell is a serving cell for the terminal device.

Optionally, the first offset value is the SFN of the first system frame minus the SFN of the second system frame; or, the first offset value is the SFN of the second system frame minus the SFN of the first system frame.

Optionally, the second deviation value is the time of the boundary of the first time unit minus the time of the boundary of the second time unit; or, the second deviation value is the time of the boundary of the second time unit minus the time of the boundary of the first time unit.

Optionally, the time unit includes at least one of the following: a system frame, a subframe, a time slot, or a symbol; the time unit includes a first time unit and a second time unit.

In one possible design, the absolute timing information indicates the time of the start boundary of the third system frame in the first cell, or the time of the end boundary of the third system frame in the first cell.

In one possible design, the timing information is provided to the terminal device by a first cell, or the timing information is provided to the terminal device by a second cell, where the second cell is a serving cell of the terminal device.

In one possible design, the method described in the second aspect further includes: obtaining ephemeris information of the first cell and sending the ephemeris information of the first cell to the terminal device. The ephemeris information of the first cell is provided by the first cell to the terminal device, and the ephemeris information of the first cell includes first time information, and the first time information is referenced to the system frame timing of the first cell.

It is understood that the network device may be a first network device or a second network device. When the network device is the first network device, the first network device may send the ephemeris information of the first cell to the terminal device through forwarding by the second network device; when the network device is the second network device, the second network device may receive the ephemeris information of the first cell from the first network device and forward the ephemeris information of the first cell to the terminal device, without limitation.

In one possible design, the system frame timing of the first cell is used for the terminal device to use the ephemeris information of the first cell.

In one possible design scheme, the first cell is one of at least one candidate cell of the terminal device.

Optionally, the network device may be a second network device, and the method according to the second aspect further includes: sending an RRC reconfiguration message to the terminal device, wherein the RRC reconfiguration message is used to indicate a condition for the terminal device to perform a handover.

In one possible design scheme, the first cell is the target cell for switching of the terminal device.

Optionally, the network device may be a second network device, and the method described in the second aspect further includes: sending an RRC reconfiguration message to the terminal device, wherein the RRC reconfiguration message is used to instruct the terminal device to switch to the first cell.

In one possible design, the RRC reconfiguration message includes ephemeris information of the first cell.

The technical effects of the communication device described in the second aspect can refer to the technical effects of the communication method described in the first aspect, and will not be repeated here.

In a third aspect, a communication device is provided. The communication device may be a terminal device, a module (e.g., a processor, chip, or chip system) applied to the terminal device, or a logical node, logic module, or software that implements all or part of the terminal device's functions. The communication device includes: a module for executing the method described in the first aspect, such as a transceiver module and a processing module.

The transceiver module is configured to receive timing information, and the processing module is configured to determine the system frame timing of a first cell based on the timing information. The first cell is a neighboring cell of the terminal device.

In one possible design, the timing information includes relative timing information or absolute timing information. The processing module is further configured to determine the system frame timing of the first cell based on the system frame timing and relative timing information of the second cell; or to determine the system frame timing of the first cell based on the absolute timing information. The second cell is a serving cell of the terminal device.

In one possible design scheme, the relative timing information indicates a first deviation value between the system frame number SFN of the first system frame in the first cell and the SFN of the second system frame in the second cell; and/or a second deviation value between the boundary of the first time unit of the first cell and the boundary of the second time unit of the second cell.

Optionally, the first offset value is the SFN of the first system frame minus the SFN of the second system frame; or, the first offset value is the SFN of the second system frame minus the SFN of the first system frame.

Optionally, the second deviation value is the time of the boundary of the first time unit minus the time of the boundary of the second time unit; or, the second deviation value is the time of the boundary of the second time unit minus the time of the boundary of the first time unit.

In one possible design, the absolute timing information indicates the time of the start boundary of the third system frame in the first cell, or the time of the end boundary of the third system frame in the first cell.

In one possible design scheme, the timing information is provided to the terminal device by the first cell; or, the timing information is provided to the terminal device by the second cell.

In one possible design, the transceiver module is further configured to receive ephemeris information of the first cell, wherein the ephemeris information of the first cell is provided by the first cell to the terminal device and includes first time information, and the first time information is based on the system frame timing of the first cell.

In one possible design, the system frame timing of the first cell is used for the terminal device to use the ephemeris information of the first cell.

Optionally, the processing module is further configured to access the first cell according to the system frame timing of the first cell and the ephemeris information of the first cell.

Optionally, the processing module is further configured to determine location information of the first network device based on the system frame timing of the first cell and the ephemeris information of the first cell, and pre-compensate the Doppler frequency offset and/or adjust the timing advance TA based on the location information. The first network device is a network device to which the first cell belongs;

In one possible design scheme, the first cell is one of at least one candidate cell of the terminal device.

Optionally, the transceiver module is further configured to receive a radio resource control (RRC) reconfiguration message. The processing module is further configured to determine, based on a handover condition, a first cell among the at least one candidate cell as a target cell. The RRC reconfiguration message is used to indicate a handover condition to the terminal device, and the RRC reconfiguration message is from a network device to which the second cell belongs.

In one possible design scheme, the first cell is the target cell for switching of the terminal device.

Optionally, the transceiver module is further configured to receive an RRC reconfiguration message, wherein the RRC reconfiguration message is used to instruct the terminal device to switch to the first cell, and the RRC reconfiguration message comes from a network device to which the second cell belongs.

In one possible design, the RRC reconfiguration message includes ephemeris information of the first cell.

Optionally, the transceiver module may include a sending module and a receiving module, wherein the sending module is used to implement the sending function of the communication device described in the third aspect, and the receiving module is used to implement the receiving function of the communication device described in the third aspect.

Optionally, the communication device described in the third aspect may further include a storage module, wherein the storage module stores a program or instruction. When the processing module executes the program or instruction, the communication device may execute the communication method described in the first aspect.

It should be noted that the communication device described in the third aspect can be a terminal device, a chip (system) or other parts or components in the terminal device, or a device including a terminal device, and this application does not limit this.

In addition, the technical effects of the communication device described in the third aspect can refer to the technical effects of the communication method described in the first aspect, and will not be repeated here.

In a fourth aspect, a communication device is provided. The communication device may be a network device, or a module applied to a network device (e.g., a processor, chip, or chip system), or a logical node, logic module, or software (e.g., a CU, DU, or RU) that can implement all or part of the network device functions. The communication device includes: a module for executing the method described in the second aspect, such as a transceiver module and a processing module.

The processing module is configured to obtain timing information, and the transceiver module is configured to send the timing information to the terminal device. The timing information is used by the terminal device to determine the system frame timing of the first cell, which is a neighboring cell of the terminal device.

In one possible design, the timing information includes relative timing information or absolute timing information.

In one possible design, the relative timing information indicates a first offset between a system frame number (SFN) of a first system frame in a first cell and an SFN of a second system frame in a second cell; and/or a second offset between a boundary of a first time unit in the first cell and a boundary of a second time unit in the second cell, where the second cell is a serving cell for the terminal device.

Optionally, the first offset value is the SFN of the first system frame minus the SFN of the second system frame; or, the first offset value is the SFN of the second system frame minus the SFN of the first system frame.

Optionally, the second deviation value is the time of the boundary of the first time unit minus the time of the boundary of the second time unit; or, the second deviation value is the time of the boundary of the second time unit minus the time of the boundary of the first time unit.

Optionally, the second deviation value is the time of the boundary of the first time unit minus the time of the boundary of the second time unit; or, the second deviation value is the time of the boundary of the second time unit minus the time of the boundary of the first time unit.

Optionally, the time unit includes at least one of the following: a system frame, a subframe, a time slot, or a symbol; the time unit includes a first time unit and a second time unit.

In one possible design, the absolute timing information indicates the time of the start boundary of the third system frame in the first cell, or the time of the end boundary of the third system frame in the first cell.

In one possible design, the timing information is provided to the terminal device by a first cell, or the timing information is provided to the terminal device by a second cell, where the second cell is a serving cell of the terminal device.

In one possible design, the processing module is further configured to obtain ephemeris information of the first cell. The transceiver module is further configured to send the ephemeris information of the first cell to the terminal device. The ephemeris information of the first cell is provided by the first cell to the terminal device, and the ephemeris information of the first cell includes first time information, which is referenced to the system frame timing of the first cell.

In one possible design, the system frame timing of the first cell is used for the terminal device to use the ephemeris information of the first cell.

In one possible design scheme, the first cell is one of at least one candidate cell of the terminal device.

Optionally, the transceiver module is further configured to send an RRC reconfiguration message to the terminal device, wherein the RRC reconfiguration message is used to indicate a condition for the terminal device to perform a handover.

In one possible design scheme, the first cell is the target cell for switching of the terminal device.

Optionally, the transceiver module is further configured to send an RRC reconfiguration message to the terminal device, wherein the RRC reconfiguration message is used to instruct the terminal device to switch to the first cell.

In one possible design, the RRC reconfiguration message includes ephemeris information of the first cell.

Optionally, the transceiver module may include a sending module and a receiving module, wherein the sending module is used to implement the sending function of the communication device described in the fourth aspect, and the receiving module is used to implement the receiving function of the communication device described in the fourth aspect.

Optionally, the communication device described in the fourth aspect may further include a storage module, wherein the storage module stores a program or instruction. When the processing module executes the program or instruction, the communication device may execute the method described in the second aspect.

It can be understood that the communication device described in the fourth aspect can be a network device, a chip (system) or other parts or components in the network device, or a device that includes a network device. This application does not limit this.

In addition, the technical effects of the communication device described in the fourth aspect can refer to the technical effects of the method described in the second aspect, and will not be repeated here.

In a fifth aspect, a communication device is provided, comprising: a processor configured to execute the communication method described in the first aspect or the second aspect.

In one possible design solution, the communication device described in the fifth aspect may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be used for the communication device described in the fifth aspect to communicate with other communication devices.

In one possible design, the communication device described in the fifth aspect may further include a memory. The memory may be integrated with the processor or provided separately. The memory may be used to store computer programs and/or data involved in the communication method described in the first aspect or the second aspect.

In an embodiment of the present application, the communication device described in the fifth aspect may be the network device described in any one of the first aspect or the second aspect, or the chip (system) or other parts or components in the network device, or a device including the network device; or, the communication device may be the terminal device described in any one of the first aspect or the second aspect above, or the chip (system) or other parts or components in the terminal device, or a device including the terminal device.

In addition, the technical effects of the communication device described in the fifth aspect can refer to the technical effects of the communication method described in the first aspect or the second aspect, and will not be repeated here.

In a sixth aspect, a communication device is provided, comprising: a processor coupled to a memory, the processor configured to execute a computer program stored in the memory, so that the communication device performs the communication method described in the first aspect or the second aspect.

In one possible design solution, the communication device described in the sixth aspect may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be used for the communication device described in the sixth aspect to communicate with other communication devices.

In an embodiment of the present application, the communication device described in the sixth aspect may be the network device described in any one of the first aspect or the second aspect, or a chip (system) or other parts or components in the network device, or a device including the network device; or, the communication device may be the terminal device described in any one of the first aspect or the second aspect above, or a chip (system) or other parts or components in the terminal device, or a device including the terminal device.

In addition, the technical effects of the communication device described in the sixth aspect can refer to the technical effects of the communication method described in the first aspect or the second aspect, and will not be repeated here.

In the seventh aspect, a communication device is provided, comprising: a processor and a memory; the memory is used to store a computer program, and when the processor executes the computer program, the communication device executes the communication method described in the first aspect or the second aspect.

In one possible design solution, the communication device described in the seventh aspect may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be used for the communication device described in the seventh aspect to communicate with other communication devices.

In an embodiment of the present application, the communication device described in the seventh aspect may be the network device described in any one of the first aspect or the second aspect, or the chip (system) or other parts or components in the network device, or a device including the network device; or, the communication device may be the terminal device described in any one of the first aspect or the second aspect above, or the chip (system) or other parts or components in the terminal device, or a device including the terminal device.

In addition, the technical effects of the communication device described in the seventh aspect can refer to the technical effects of the communication method described in the first aspect or the second aspect, and will not be repeated here.

In an eighth aspect, a communication device is provided, comprising: a processor; the processor is configured to be coupled to a memory, and after reading a computer program in the memory, execute the communication method as described in the first aspect or the second aspect according to the computer program.

In one possible design solution, the communication device described in the eighth aspect may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be used for the communication device described in the eighth aspect to communicate with other communication devices.

In an embodiment of the present application, the communication device described in the eighth aspect may be the network device described in any one of the first aspect or the second aspect, or the chip (system) or other parts or components in the network device, or a device including the network device; or, the communication device may be the terminal device described in any one of the first aspect or the second aspect above, or the chip (system) or other parts or components in the terminal device, or a device including the terminal device.

In addition, the technical effects of the communication device described in the eighth aspect can refer to the technical effects of the communication method described in the first aspect or the second aspect, and will not be repeated here.

In a ninth aspect, a communication system is provided, comprising the terminal device described in the above aspect and the network device described in the above aspect, wherein the terminal device is configured to execute the communication method described in the first aspect, and the network device is configured to execute the communication method described in the second aspect.

In a tenth aspect, a communication chip is provided, in which instructions are stored. When the chip is run on a communication device, the communication method described in the first aspect or the second aspect is implemented.

In an eleventh aspect, a computer-readable storage medium is provided, comprising: a computer program or instructions; when the computer program or instructions are run on a computer, the communication method described in any one of the first aspect or the second aspect is executed.

In a twelfth aspect, a computer program product is provided, comprising a computer program or instructions, which, when executed on a computer, enables the communication method described in any one of the first aspect or the second aspect to be executed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a terrestrial quasi-stationary NTN cell;

FIG2 is a schematic diagram of a terrestrial mobile NTN cell;

FIG3 is a schematic diagram of the architecture of a communication system according to an embodiment of the present application;

FIG4 is a second schematic diagram of the architecture of the communication system provided in an embodiment of the present application;

FIG5 is a flow chart of a communication method according to an embodiment of the present application;

FIG6 is a first schematic diagram of timing information provided in an embodiment of the present application;

FIG7 is a second schematic diagram of timing information provided in an embodiment of the present application;

FIG8 is a third schematic diagram of timing information provided in an embodiment of the present application;

FIG9 is a fourth schematic diagram of timing information provided in an embodiment of the present application;

FIG10 is a second flow chart of the communication method provided in an embodiment of the present application;

FIG11 is a third flow chart of the communication method provided in an embodiment of the present application;

FIG12 is a first structural diagram of a communication device provided in an embodiment of the present application;

FIG13 is a second structural diagram of a communication device provided in an embodiment of the present application.

DETAILED DESCRIPTION

For ease of understanding, the technical terms involved in the embodiments of this application are first introduced below.

1. Non-terrestrial network (NTN)

Currently, New Radio (NR) technology is evolving from Release 18 to Release 19. NR has also moved from standardization to commercial deployment. The NR standard protocol was originally developed as a wireless communication technology designed for terrestrial cellular network scenarios, providing users with ultra-low latency, ultra-reliability, ultra-high speeds, and a vast array of connections. However, cellular networks cannot provide seamless global coverage. For example, in areas without terrestrial base stations, such as ocean surfaces, polar regions, and rainforests, voice and data services cannot be provided in these areas.

NTN is a general term for networks involving flying objects, including satellite communication networks, high-altitude platform stations (HAPS), and air-to-ground networks. Key use cases for NTN include areas with poor land coverage, maritime communications, public safety needs, inter-aircraft communications, and railways, aiming to provide mobile broadband services to users. HAPS are carried on airborne platforms, primarily aircraft, balloons, and airships, and serve as mobile communication base stations, providing mobile services using the same frequency bands as terrestrial mobile networks.

Compared to terrestrial communications, NTN communications boasts a wider coverage area and flexible networking, enabling seamless global network coverage. The NTN network not only complements existing terrestrial networks but can also be considered an independent communications system providing users with global high-speed network access. Currently, research institutes, communications organizations, and telecommunications companies worldwide are participating in the research and development of NTN communication technologies and standards, striving to build a unified network for space, air, and ground communications.

NTN communications utilizes drones, high-altitude platforms, satellites, and other equipment to form networks and provide data transmission, voice communication, and other services to user equipment (UE). High-altitude platform equipment typically operates at an altitude of 8 to 50 km above the ground. Satellite communication networks rely on spaceborne platforms. Satellite communication systems can be categorized into three types based on the satellite's orbital altitude: geostationary earth orbit (GEO) satellite communication systems, also known as synchronous orbit satellite systems; medium earth orbit (MEO) satellite communication systems; and low earth orbit (LEO) satellite communication systems.

The area covered by NTN signals or the area where NTN cells can provide services is called an NTN cell. Based on the mobility of NTN cells in the ground coverage area, NTN cells can be divided into the following three categories: earth-fixed NTN cells, quasi-earth-fixed NTN cells, and earth-moving NTN cells.

The coverage area of a terrestrial NTN cell is fixed to a certain area on the ground, i.e., continuous fixed-point coverage. It is understood that NTN cells provided by GEO satellites are of this type, without limitation.

The coverage area of a terrestrial quasi-stationary NTN cell is fixed to a specific area on the ground for a period of time, and then changes to another area on the ground after a period of time. This means that the coverage area is fixed within a period of time. For example, as shown in Figure 1, the satellite moves along its direction of travel. At time t1-t2, the NTN cell provided by the satellite is cell #1. The coverage area of the satellite at time t1-t2 is area 1, and t2 > t1. It is understood that LEO satellites and MEO satellites can also provide this type of NTN cell, without limitation.

The coverage area of a terrestrial mobile NTN cell slides across the ground. For example, as shown in Figure 2, as the satellite moves in the direction of travel, at time t1, the satellite provides NTN cell #1, and the satellite's coverage area at t1 is Area 1. At time t2, the satellite provides NTN cell #1, and the satellite's coverage area at t2 is Area 2. At time t3, the satellite provides NTN cell #1, and the satellite's coverage area at t3 is Area 3. In other words, as the satellite continues to move, its coverage area changes at every moment, such as Area 1 → Area 2 → Area 3, with t3 > t2 > t1. Areas 1, 2, and 3 may or may not overlap, and there is no limitation on this. It is understood that LEO and MEO satellites can also provide this type of NTN cell, and there is no limitation on this.

2. Satellite ephemeris information

Satellite ephemeris information, also known as satellite ephemeris information, can be used to provide terminal devices with information related to the satellite's location. In NTN scenarios, terminal devices need to use satellite location information to perform certain time and frequency maintenance and measurement operations. For example, based on the satellite and terminal positions, the terminal device can calculate the propagation delay between them and further calculate timing advance (TA) parameters for TA maintenance. For another example, the UE can compensate for Doppler frequency offset caused by satellite operation based on the satellite's position and motion, etc. (without limitation).

Satellite ephemeris information can include but is not limited to the following two formats:

Format 1: Satellite ephemeris information may include the position vector and velocity vector of the satellite at the reference time of the ephemeris information. For example, in the Earth-centered Earth-fixed (ECEF) coordinate system, the velocity vector and position vector of the satellite in the X-axis, Y-axis, and Z-axis directions.

Format 2: Satellite ephemeris information may include orbital parameter information.

The orbital parameters may include the semi-major axis, eccentricity, inclination, longitude of ascending node, argument of periapsis, mean anomaly, or other orbital parameters, without limitation. These orbital parameters can determine the satellite's orbit. It is understood that the orbital parameters may also be referred to as the six numbers, or any other possible names, without limitation.

Both Format 1 and Format 2 use the epoch time as the reference time point. For example, in Format 1, the satellite's velocity and position can be the satellite's velocity and position at the epoch time; in Format 2, the orbital parameters (such as inclination and mean anomaly) can be the parameter values at the epoch time.

The epoch time can be information about a point in time. The network can provide the epoch time in the following ways: (1) The satellite provides satellite ephemeris information to the terminal device through system information (SI) or radio resource control (RRC) dedicated signaling. The satellite ephemeris information can include or provide an epoch time field. The epoch time field can indicate a system frame number (SFN) and subframe number, which is the epoch time.

Alternatively, (2) for the above-mentioned method of providing the satellite's ephemeris information to the terminal device through system information, if the satellite ephemeris information does not contain or does not provide the epoch time field, the end point of the system information window (SI window) in which the system information containing the ephemeris information is sent is used as the epoch time by default.

If the satellite ephemeris information includes an epoch time field, or if the satellite provides the epoch time field, the SFN and subframe number indicated by this field are referenced to the system frame timing of the cell providing the epoch time. A cell can provide the ephemeris information of its own satellites to terminals in the cell, as well as the ephemeris information of satellites in other cells, such as neighboring cells.

For example, cell #a sends ephemeris information #1 of satellite #1 of cell #a and ephemeris information #2 of satellite #2 of cell 2 to terminal device #1 (terminal device within cell #a). Both satellite ephemeris information #1 and satellite ephemeris information #2 contain their own epoch time fields. At this time, the SFN and subframe indicated by these two epoch time fields are determined according to the system frame timing of cell #a.

Currently, the neighboring cell of the serving cell where the terminal device is located can provide the terminal device with the ephemeris information of the neighboring cell. For example, if the neighboring cell of the serving cell where the terminal device is located is cell #1, cell #1 can provide the terminal device with the ephemeris information of cell #1. The epoch time of this ephemeris information is referenced to the timing of cell #1. In other words, when the terminal device uses this ephemeris information, it must first synchronize with cell #1 and determine the system frame timing of cell #1 before determining the reference time point of the ephemeris information. Only after the terminal device determines the reference time point of the ephemeris information can it use this ephemeris information to calculate the current satellite position for subsequent operations.

However, due to the influence of Doppler frequency deviation caused by satellite movement, the terminal device needs to correct/compensate for the Doppler frequency deviation before it can synchronize with the satellite (such as the satellite belonging to cell #1 mentioned above). This increases the implementation complexity of the terminal device, resulting in greater complexity in the implementation of the terminal device.

For example, when the serving cell of a terminal device can no longer provide services to the terminal device, for example, due to the movement of the terminal device or network equipment, the signal quality of the serving cell currently accessed by the terminal device may deteriorate, and the quality of the serving cell is insufficient to support the terminal device to perform services in the cell, the terminal device needs to switch to a cell with better signal quality, such as a target cell, to obtain services. During the handover process, the target cell may provide the terminal device with its ephemeris information.

However, before the terminal device is synchronized with the target cell, the terminal device does not obtain the system frame timing of the target cell, and thus cannot determine the reference time point of the target cell's ephemeris information, and thus cannot use the target cell's ephemeris information to calculate the position of the satellite (the satellite belonging to the target cell). As a result, the terminal device cannot use the Doppler frequency deviation pre-compensation method based on parameters such as the terminal device's position, the satellite's position, and the relative motion of the terminal device and the satellite. At this time, the terminal device needs to correct/compensate the Doppler frequency deviation by itself for subsequent synchronization and access to the target cell, resulting in greater implementation complexity of the terminal device.

Based on the above introduction, how to reduce the complexity of terminal device implementation is an urgent problem to be solved.

In summary, in response to the above technical problems, this embodiment proposes the following technical solutions to reduce the complexity of implementing the terminal device.

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

The technical solutions of the embodiments of the present application can be applied to various communication systems, such as wireless fidelity (WiFi) systems, vehicle to everything (V2X) communication systems, device-to-device (D2D) communication systems, 4G, such as long-term evolution (LTE) systems, world-wide interoperability for microwave access (WiMAX) communication systems, 5G, such as new radio (NR) systems, and future communication systems.

This application will present various aspects, embodiments, or features in the context of systems that may include multiple devices, components, modules, etc. It should be understood and appreciated that each system may include additional devices, components, modules, etc., and/or may not include all of the devices, components, modules, etc. discussed in conjunction with the figures. Furthermore, combinations of these aspects may also be used.

Additionally, in the embodiments of this application, words such as "exemplary" and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "exemplary" should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of the word "exemplary" is intended to present concepts in a concrete manner.

In the embodiments of the present application, "information", "signal", "message", "channel" and "signaling" can sometimes be used interchangeably. It should be noted that when the distinction between them is not emphasized, the meanings they intend to express are matched. "of", "corresponding, relevant" and "corresponding" can sometimes be used interchangeably. It should be noted that when the distinction between them is not emphasized, the meanings they intend to express are matched. In addition, the "/" mentioned in the present application can be used to represent an "or" relationship. It can be understood that in the present application, "indication" can include direct indication, indirect indication, explicit indication and implicit indication. When describing a certain indication information as being used to indicate A, it can be understood that the indication information carries A, directly indicates A, or indirectly indicates A.

In the embodiment of the present application, the information indicated by the indication information is referred to as information to be indicated. In the specific implementation process, there are many ways to indicate the information to be indicated, such as but not limited to, the information to be indicated can be directly indicated, such as the information to be indicated itself or the index of the information to be indicated, etc., or the information to be indicated can be indirectly indicated by indicating other information, wherein there is an association relationship between the other information and the information to be indicated. It is also possible to indicate only a part of the information to be indicated, while the other parts of the information to be indicated are known or agreed in advance. For example, the indication of specific information can also be achieved with the help of the arrangement order of each piece of information agreed in advance (such as specified in the protocol), thereby reducing the indication overhead to a certain extent.

The information to be indicated can be sent as a whole or divided into multiple sub-information and sent separately. The transmission period and/or transmission timing of these sub-information can be the same or different. The specific transmission method is not limited in this application. The transmission period and/or transmission timing of these sub-information can be predefined, for example, according to a protocol, or can be configured by the transmitting device through sending configuration information to the receiving device.

The network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Ordinary technicians in this field will know that with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

To facilitate understanding of the embodiments of the present application, a communication system applicable to the embodiments of the present application is first described in detail using the communication system shown in Figure 3 as an example. For example, Figure 3 is a schematic diagram of the architecture of a communication system applicable to the communication method provided in the embodiments of the present application.

As shown in FIG3 , the communication system mainly includes: network equipment and terminal equipment.

Among them, there may be multiple network devices, such as a first network device (such as the network device to which the first cell described below belongs), a second network device (such as the network device to which the second cell described below belongs), etc. The network device may be a device with wireless transceiver functions, or it may be a chip or chip system provided in the device, located in the access network (AN) of the communication system, for providing access services to the terminal. For example, the network device may be called a radio access network device (RAN), and may specifically be an access network device of the next generation mobile communication system, such as an access network device of the 6th generation (6G) mobile communication system, such as a 6G base station, or in the next generation mobile communication system, the network device may also have other naming methods, which are all covered within the scope of protection of the embodiments of the present application, and the embodiments of the present application do not impose any limitations on this. Alternatively, the network device may also include a 5th generation (5G) mobile communication system, such as a next generation NodeB (gNB) in a new radio (NR) system, or one or a group of (including multiple antenna panels) antenna panels of a base station in 5G, or it may also be a network node constituting a gNB, a transmission point (TRP or transmission point, TP) or a transmission measurement function (TMF), such as a central unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU), an RSU with base station function, or a wired access gateway, etc. Alternatively, network devices may also include: access points (APs) in wireless fidelity (WiFi) systems, wireless relay nodes, wireless backhaul nodes, various forms of macro base stations, micro base stations (also called small stations), relay stations, access points, wearable devices, vehicle-mounted devices, and the like.

The CU and DU may be configured separately or in the same network element, such as a baseband unit (BBU). The RU may be included in a radio frequency device or radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH). It is understood that the network device may be a CU node, a DU node, or a device including a CU node and a DU node. Furthermore, the CU may be classified as a network device in the access network RAN, or as a network device in the core network CN, without limitation herein.

The terminal device may be one or more, such as a first terminal device, a second terminal device, a third terminal device, etc. The terminal device may be a terminal device with transceiver functions, or may be a chip or chip system provided in the terminal device. The terminal device may also be referred to as user equipment (UE), access terminal device, subscriber unit (subscriber unit), user station, mobile station (MS), mobile station, remote station, remote terminal device, mobile device, user terminal device, terminal device, wireless communication device, user agent, or user device. The terminal device in this embodiment can be a mobile phone, a cellular phone, a smart phone, a tablet computer, a wireless data card, a personal digital assistant (PDA), a wireless modem, a handheld device (handset), a laptop computer, a machine type communication (MTC) terminal device, a computer with wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a smart home device (for example, a refrigerator, a TV, etc.), or a computer. The terminal device of this embodiment may also be an on-board module, on-board module, on-board component, on-board chip or on-board unit built into the vehicle as one or more components or units. The terminal device may also be other devices with terminal device functions. For example, the terminal device may be a device that functions as a terminal device in D2D communication.

The embodiments of this application do not limit the form of the terminal device. The device used to implement the functions of the terminal device can be the terminal device; it can also be a device that supports the terminal device to implement the functions, such as a chip system. The device can be installed in the terminal device or used in conjunction with the terminal device. In the embodiments of this application, the chip system can be composed of a chip or include a chip and other discrete devices.

Optionally, the communication system may also include a core network (CN). CN is mainly responsible for maintaining the subscription data of the mobile network and providing functions such as session management, mobility management, policy management and security authentication for the terminal. CN may include the following network functions: user plane function (UPF), authentication server function (AUSF), access and mobility management function (AMF), session management function (SMF), network slice selection function (NSSF), network exposure function (NEF), network function repository function (NRF), policy control function (PCF), unified data management (UNDM), and so on. management (UDM), application function (AF), network slice-specific and SNPN authentication and authorization function (NSSAAF), location management function (LMF), network data analytics function (NWDAF), short message service function (SMSF), security anchor functionality (SEAF), etc.

Taking UPF and AMF as examples, UPF is mainly responsible for user data processing (forwarding, receiving, billing, etc.). For example, UPF can receive user data from the data network (DN) and forward the user data to the terminal through the access network equipment. UPF can also receive user data from the terminal through the access network equipment and forward the user data to the DN. DN refers to the operator network that provides data transmission services to users. For example, the Internet Protocol (IP) Multimedia Service (IMS), the Internet, etc. DN can be an operator's external network or a network controlled by the operator, used to provide business services to terminal devices. AMF is mainly responsible for access and mobility management in mobile networks. For example, user location update, user registration network, user switching, etc. For a detailed introduction to other network element functions, please refer to the existing protocols and will not be repeated here.

It is understood that the embodiments of the present application are also applicable to the 4th generation (4G) mobile communication long-term evolution (LTE) system, or any other possible system, without limitation. For example, in the 4G LTE system, the core network element may be a mobility management entity (MME), and the network device may be an evolved NodeB (eNB).

In this communication system, a terminal device can determine the neighboring cell of the terminal device based on the received timing information, or in other words, the neighboring cell of the serving cell where the terminal device is located, that is, the system frame timing of the first cell. In this way, the terminal device can obtain the system frame timing of the neighboring cell of the terminal device (including the first cell), so that the terminal device can use the system frame timing to determine the reference time point of the ephemeris information of the first cell before synchronizing with the first cell. After the terminal device determines the reference time point of the ephemeris information of the first cell, it can use the ephemeris information of the first cell to complete Doppler frequency offset correction and timing advance adjustment, etc., thereby reducing the complexity of the terminal device implementation. At the same time, the terminal device can use the ephemeris information of the first cell and the system frame timing to access the first cell, so as to avoid the problem that the terminal device does not know the system frame timing of the first cell, resulting in the inability to access the first cell using the ephemeris information provided by the first cell, which causes a handover failure. This can solve the problem of the availability of the ephemeris information provided by the target cell during the handover process, so that the handover is completed normally, ensuring the service continuity of the terminal device and reducing the impact on the mobility performance of the terminal device.

It can be understood that FIG3 is a simplified schematic diagram for ease of understanding, and the communication system may also include other network devices and/or other terminal devices, which are not shown in FIG3 .

Exemplarily, Figure 4 is a second architectural diagram of a communication system applicable to the communication method provided in this embodiment. As shown in (a) and (b) in Figure 4, the communication system is a satellite communication system, which mainly includes: terminal equipment, gateway stations (gateway, GW, also known as ground stations, signal gateway stations) and satellites (also known as satellite base stations, such as the first network device and the second network device described below).

The link between the satellite and the terminal device is called a service link, the link between the satellite and the gateway is called a feeder link, and the link between satellites is called an inter-satellite link. Satellites can be divided into transparent mode and regenerative mode based on their operating mode. Figure 4 (a) illustrates the NTN transparent payload architecture scenario. In this scenario, the satellite operates in transparent mode, performing only signal forwarding and lacking data processing capabilities. The gNB is located on the ground, and the satellite is connected to the gNB via a ground-based gateway. Signals between the UE and the gNB are transmitted via the satellite, while data processing functions remain at the gNB. Figure 4 (b) illustrates the NTN regenerative payload architecture scenario. In this scenario, the satellite operates in regenerative mode, assuming all or part of the base station functionality, i.e., it can perform data processing. Specifically, there are two configurations: a complete base station located on the satellite, and a base station DU located on the satellite. In these scenarios, the satellite can be considered a base station. Furthermore, base stations can be connected to the core network. Multiple satellites collaborate to provide services to terminal devices in overlapping coverage areas.

For ease of understanding, the communication method provided in the embodiment of the present application will be specifically described below with reference to Figures 5 to 11.

5 is a flow chart of a communication method according to an embodiment of the present application. The method can be applied to the communication between the network device (mainly involving the first device and the second network device) and the terminal device in the above communication system.

Specifically, as shown in FIG5 , the process of the communication method is as follows:

S501: A network device sends timing information, and a terminal device receives the timing information accordingly.

S502: The terminal device determines the system frame timing of the first cell based on the timing information.

Based on the above step S501:

The timing information can be used by the terminal device to determine the system frame timing of the first cell.

The first cell may be a neighboring cell of the terminal device, or in other words, the first cell may be a cell adjacent to the serving cell (i.e., the second cell described below) where the terminal device is located. The system frame timing of the first cell may be the time domain position of the system frame within the first cell, or in other words, the arrangement of the system frames within the first cell in the time domain.

In one possible design, the timing information may include relative timing information or absolute timing information.

The following two methods are used as examples to describe timing information in detail.

Mode 1: The timing information may include relative timing information.

The relative timing information may indicate a first deviation value between the system frame number SFN of the first system frame in the first cell and the SFN of the second system frame in the second cell; and/or a second deviation value between the boundary of the first time unit of the first cell and the boundary of the second time unit of the second cell.

The following three cases are used as examples to describe relative timing information in detail.

Case 1: The relative timing information may indicate a first offset value.

The boundary of the first system frame and the boundary of the second system frame may be at the same time domain position, that is, the boundary of the first system frame and the boundary of the second system frame may be aligned in the time domain/time. For example, the starting (or initial) boundary of the first system frame may be aligned in the time domain with the starting boundary of the second system frame; or, the starting boundary of the first system frame may be aligned in the time domain with the ending (or terminating) boundary of the second system frame; or, the ending boundary of the first system frame may be aligned in the time domain with the starting boundary of the second system frame; or, the ending boundary of the first system frame may be aligned in the time domain with the ending boundary of the second system frame, etc., without limitation.

It is understood that the duration of each system frame can be fixed, for example, 10 ms, and each system frame is arranged sequentially based on the size of the SFN. Therefore, the time domain offset between the first system frame and the second system frame can be equal to the offset between the SFN of the first system frame and the SFN of the second system frame. The SFN value can be 0-1023, or any other possible value, without limitation.

Optionally, the first offset value may be the SFN of the first system frame minus the SFN of the second system frame; or, the first offset value may be the SFN of the second system frame minus the SFN of the first system frame. It should be understood that in case 1, the SFN of the first system frame and the SFN of the second system frame may be the same or different, that is, the first offset value may be a positive value, a negative value, or 0, without limitation.

For example, taking the case where the first offset value is represented by the SFN of the first system frame minus the SFN of the second system frame, and the start boundary of the first system frame is aligned with the start boundary of the second system frame in the time domain, as shown in FIG6 , the difference between the SFNs corresponding to the two time-aligned system frames of cell #1 (i.e., the first cell) and cell #2 (i.e., the second cell) is 6. Taking the system frame #6 corresponding to SFN #6 in cell #1 and the system frame #0 corresponding to SFN #0 in cell #2 as examples, the first offset value #1 = SFN #6 in cell #1 - SFN #0 in cell #2 = 6 - 0 = 6. That is, the relative timing information can indicate that the first offset value #1 is equal to 6.

Case 2: The relative timing information may indicate a first offset value and a second offset value.

Among them, the boundary of the first system frame and the boundary of the second system frame may not be in the same time domain position, that is, the boundary of the first system frame and the boundary of the second system frame are not aligned in the time domain/time, and the SFN of the first system frame and the SFN of the second system frame may be different. Exemplarily, the first system frame and the second system frame may be the two system frames with the closest time domain distance, such as the starting boundaries of the first system frame and the second system frame are the closest in the time domain, or the ending boundaries of the first system frame and the second system frame are the closest in the time domain, etc., without limitation. It can be understood that the first system frame and the second system frame may not be the two system frames with the closest time domain distance, without limitation. For ease of understanding, in Case 2, the embodiment of the present application takes the first system frame and the second system frame as the two system frames with the closest time domain distance as an example for introduction, and will not be elaborated subsequently.

In case 2, the relative timing information needs to indicate a first offset value. For the introduction to the first offset value, refer to the introduction to case 1 above and will not be repeated here. The relative timing information also needs to indicate a second offset value, which can be the second offset value between the boundary of the first time unit of the first cell and the boundary of the second time unit of the second cell.

The first time unit and the second time unit can be the two time units with the closest time domain distance, such as the starting boundaries of the first time unit and the second time unit are the closest in time domain, or the ending boundaries of the first system frame and the second system frame are the closest in time domain, etc., without limitation. It is understood that the first time unit and the second time unit may also not be the two time units with the closest time domain distance, without limitation. For ease of understanding, in Case 2, the embodiment of the present application is described as an example in which the first time unit and the second time unit are the two time units with the closest time domain distance, and no further explanation is given later.

Optionally, the second deviation value may be the time of the boundary of the first time unit minus the time of the boundary of the second time unit; or the second deviation value may be the time of the boundary of the second time unit minus the time of the boundary of the first time unit. The second deviation value may be positive, negative, or 0, without limitation.

Exemplarily, the second deviation value can be: the time of the starting boundary of the first time unit - the time of the starting boundary of the second time unit; or, the time of the starting boundary of the second time unit - the time of the starting boundary of the first time unit; or, the time of the ending boundary of the first time unit - the time of the ending boundary of the second time unit; or, the time of the ending boundary of the second time unit - the time of the ending boundary of the first time unit; or, the time of the starting boundary of the first time unit - the time of the ending boundary of the second time unit; or, the time of the ending boundary of the second time unit - the time of the starting boundary of the first time unit; or, the time of the ending boundary of the first time unit - the time of the starting boundary of the second time unit; or, the time of the starting boundary of the second time unit - the time of the ending boundary of the first time unit, etc., without limitation.

Optionally, the time unit may include at least one of the following: a system frame, a subframe, a time slot, or a symbol. The time unit may include the first time unit and the second time unit.

It is understood that a system frame may consist of 10 subframes, each subframe may have a fixed duration, such as 1 ms; the number of time slots contained in a subframe may depend on the subcarrier space (SCS); and a time slot may consist of 14 orthogonal frequency division multiplexing (OFDM) symbols. Based on the relationship between the system frame, subframe, time slot, and symbol, the second offset value may be characterized by one or more of the above.

It should be understood that if the first time unit includes a of the above-mentioned system frames, subframes, time slots, or symbols, the second time unit also needs to include a of the above-mentioned system frames, subframes, time slots, or symbols, and the unit types corresponding to the a contained in the first time unit can be the same as or one-to-one corresponding to the unit types contained in the second time unit, without limitation.

For example, the first offset value is represented by the SFN of the first system frame minus the SFN of the second system frame, and the second offset value is represented by the time of the starting boundary of the first time unit minus the time of the starting boundary of the second time unit. As shown in FIG7 , the first system frame is the system frame #7 corresponding to the SFN #7 in the cell #1 (i.e., the first cell), the first time unit is the system frame #7 corresponding to the SFN #7 in the cell #1, and the starting boundary of the system frame #7 in the cell #1 is The time of the boundary is t1; the second system frame is the system frame #2 corresponding to SFN #2 in cell #2 (i.e., the second cell), the second time unit is the system frame #2 corresponding to SFN #2 in cell #2, and the time of the starting boundary of the system frame #2 in cell #2 is t2, then the first offset value #2 = SFN #7 in cell #1 - SFN #2 in cell #2 = 7 - 2 = 5, and the second offset value #1 = t1 - t2, that is, the relative timing information can indicate that the first offset value #2 is equal to 5, and the second offset value #1 is equal to t1 - t2.

It can be understood that the above introduction is based on the system frame as an example of the unit type of the first time unit and the second time unit. The implementation principles of subframes, time slots and symbols are similar to the implementation principles of the above-mentioned system frames. You can refer to them for understanding and will not elaborate on them.

Case 3: The relative timing information may indicate a second offset value.

That is, the first offset value in the above case 1 and case 2 is 0, or the first offset value does not exist. For example, the SFN of the first system frame and the SFN of the second system frame may be the same, and there is no limitation.

Exemplarily, the first offset value is represented by the SFN of the first system frame minus the SFN of the second system frame, and the second offset value is represented by the time of the starting boundary of the first time unit minus the time of the starting boundary of the second time unit. As shown in Figure 8, it is assumed that the first system frame is the system frame #0 corresponding to SFN #0 in cell #1 (i.e., the first cell), the first time unit is the system frame #0 corresponding to SFN #0 in cell #1, and the time of the starting boundary of the system frame #0 in cell #1 is t3; the second system frame is the system frame #0 corresponding to SFN #0 in cell #2 (i.e., the second cell), the second time unit is the system frame #0 corresponding to SFN #0 in cell #2, and the time of the starting boundary of the system frame #0 in cell #2 is t4, then the first offset value #3 = SFN #0 in cell #1 - SFN #0 in cell #2 = 0, and the second offset value #2 = t3-t4. That is, the relative timing information can indicate that the second offset value #2 is equal to t3-t4.

Mode 2: The timing information may include absolute timing information.

The absolute timing information may indicate the time of the start boundary of the third system frame within the first cell, or the time of the end boundary of the third system frame within the first cell. For example, the start boundary of the third system frame within the first cell may be 10:50:30 (10 milliseconds) on January 30, 2024, or the start boundary of the third system frame within the first cell may be 10:50:30 (20 milliseconds) on January 30, 2024, without limitation. The third system frame may be any system frame within the first cell, without limitation. It is understood that the absolute timing information may be timed using a timing method such as the Global Positioning System (GPS) or Universal Time Coordinated (UTC). Alternatively, the timing information may be a Gregorian calendar date, such as the cumulative time since 00:00:00 on January 1, 1900. The timing information may also use any other possible timing method, without limitation.

For example, as shown in FIG9 , taking the third system frame as system frame #0 corresponding to SFN #0 in cell #1 (i.e., the first cell), assuming that the time of the start boundary of system frame #0 corresponding to SFN #0 in cell #1 is T1, such as T1 = 10:50:30:10 milliseconds on January 30, 2024, then the absolute timing information may indicate that the time of the start boundary of system frame #0 corresponding to SFN #0 in cell #1 is 10:50:30:10 milliseconds on January 30, 2024; for another example, assuming that the time of the end boundary of system frame #0 corresponding to SFN #0 in cell #1 is T2, such as T2 = 10:50:30:20 milliseconds on January 30, 2024, then the absolute timing information may indicate that the time of the end boundary of system frame #0 corresponding to SFN #0 in cell #1 is 10:50:30:20 milliseconds on January 30, 2024. It can be understood that the time of the end boundary of the system frame #0 corresponding to SFN #0 in the cell #1 is the same as the time of the start boundary of the system frame #1 corresponding to SFN #1 in the cell #1, that is, the time of the start boundary of the system frame #1 corresponding to SFN #1 in the cell #1 is T2 = 10:50:30 20 milliseconds on January 30, 2024.

It is understandable that the timing information may also be represented in any other possible form without limitation.

It is understood that before the network device sends the timing information, the network device may first obtain the timing information. The following specifically introduces the implementation process of the network device needing to obtain the timing information first.

In combination with the above-mentioned situation 1 and situation 2, in a possible design scheme, the timing information can be provided to the terminal device by the first cell; or, the timing information can be provided to the terminal device by the second cell.

That is, the timing information can be provided to the terminal device by the network device to which the first cell belongs (referred to as the first network device), or the timing information can be provided to the terminal device by the network device to which the second cell belongs (referred to as the second network device). The following two examples are used as examples for detailed introduction.

Example 1: The above network device is a first network device.

In this example, the first network device may generate timing information, which may then be forwarded to the terminal device via the second network device.

Example 2: The above network device is the second network device.

In this example, the second network device can receive timing information from the first network device and forward it to the terminal device; alternatively, the timing information of one or more neighboring cells of the second cell (such as including the first cell) can be predefined or preconfigured, and the second network device can obtain the timing information of the first cell based on the predefined or preconfigured information for subsequent forwarding to the terminal device. For example, when the terminal device needs to access the first cell, the second network device can send the timing information to the terminal device. It is understandable that the second network device can also obtain timing information through any other possible means, without limitation.

It can be understood that the naming of the above timing information is only an example, and the timing information can also be called time information, timing-related information, etc., without limitation.

The following introduces the specific implementation of network devices sending timing information.

As can be seen from the above description, the timing information can be provided by the first network device to the terminal device, or the timing information can be provided by the second network device to the terminal device. The following describes in detail the implementation process of the network device sending the timing information.

(1) Based on the above example 1, the network device may be a first network device, which may send the timing information to the terminal device. For example, the first network device may send the timing information to a second network device, which may forward the timing information to the terminal device.

It is understood that the timing information sent by the first network device to the second network device may not be sent directly from the first network device to the second network device. For example, the first network device may forward the timing information via other core network elements, such as the AMF and MME. It is understood that the above-mentioned AMF and MME are merely examples, and the core network element may also be any other possible network element without limitation. For example, the first network device may send the timing information to the AMF, and the AMF may forward the timing information to the second network device.

For another example, the CU of the first network device may obtain timing information and send the timing information to the DU of the first network device. The DU of the first network device may forward the timing information to the DU of the second network device. The DU of the second network device may then forward the timing information to the CU of the second network device, and so on.

It is understandable that the first network device may also send the timing information to the second network device in any other possible manner without limitation.

Similarly, the second network device forwards the timing information to the terminal device. This can be done by the CU of the second network device sending the timing information to the DU of the second network device, which then forwards the timing information to the terminal device. It is understood that the second network device can also send the timing information to the terminal device in any other possible manner, without limitation.

(2) Based on Example 2 above, the network device may be a second network device. When the second network device receives timing information from the first network device, the second network device may forward the received timing information to the terminal device. When the second network device can obtain the timing information of the first network device according to a predefined or preconfigured method, the second network device may directly send the timing information to the terminal device.

It can be understood that in this example, the implementation principle of the second network device forwarding the timing information to the terminal device can be referred to the relevant introduction of the above example 1 and will not be repeated here.

Based on the above step S502:

The terminal device can determine the system frame timing of the first cell based on the timing information, so that it can subsequently use the system frame timing to access the first cell, so as to avoid the problem that the terminal device does not know the system frame timing of the first cell, resulting in the inability to use the ephemeris information provided by the first cell to access the first cell, resulting in switching failure.

The following describes the above methods 1 and 2 as examples.

Based on the above-mentioned method 1: the terminal device can determine the system frame timing of the first cell according to the system frame timing and relative timing information of the second cell.

It is understood that the second cell may be the serving cell of the terminal device, or in other words, the second cell may be the serving cell before the handover. At this point, the terminal device has already achieved downlink synchronization with the second cell, and the system frame timing of the second cell may be a known parameter of the terminal device. The terminal device can determine the system frame timing of the first cell based on the system frame timing and relative timing information of the second cell. This is described in detail below.

(1) Based on the above situation 1: the relative timing information may indicate a first deviation value.

In this case, the terminal device can derive/calculate the system frame timing of the first cell based on the system frame timing of the second cell and the first deviation value.

For example, as shown in FIG6 , it is assumed that the system frame timing of cell #2 is: the time of the starting boundary of system frame #0 corresponding to SFN #0 in cell #2 is ta, the time of the starting boundary of system frame #1 corresponding to SFN #1 in cell #2 is ta+10 ms, ..., the time of the starting boundary of system frame #n corresponding to SFN #n in cell #2 is ta+(n×10) ms, and so on.

Based on the above, first offset value #1 = SFN #6 in cell #1 - SFN #0 in cell #2 = 6 - 0 = 6. Therefore, the start or end boundary time of system frame #6 corresponding to SFN #6 in cell #1 is the same as that of system frame #0 corresponding to SFN #0 in cell #2. That is, the start boundary time of system frame #6 corresponding to SFN #6 in cell #1 can be ta. A terminal device can derive the time of each system frame in cell #1 based on the duration of each system frame. For example, the start boundary time of system frame #5 corresponding to SFN #5 in cell #1 can be ta-10ms, the start boundary time of system frame #7 corresponding to SFN #7 in cell #1 can be ta+10ms, and so on. In this way, the terminal device can derive the system frame timing of cell #1.

(2) Based on the above situation 2: the relative timing information may indicate a first offset value and a second offset value.

In this case, the terminal device can derive/calculate the system frame timing of the first cell based on the system frame timing of the second cell, the first offset value, and the second offset value.

For example, as shown in Figure 7, it is assumed that the system frame timing of cell #2 is: the time of the starting boundary of system frame #0 corresponding to SFN #0 in cell #2 is tb, the time of the starting boundary of system frame #1 corresponding to SFN #1 in cell #2 is tb+10ms, the time of the starting boundary of system frame #2 corresponding to SFN #2 in cell #2 is tb+20ms,..., the time of the starting boundary of system frame #n corresponding to SFN #n in cell #2 is tb+(n×10)ms, and so on.

Based on the above, first offset value #2 = SFN #7 in cell #1 - SFN #2 in cell #2 = 7 - 2 = 5. Assuming second offset value #1 = 5ms, the start boundary of system frame #7 corresponding to SFN #7 in cell #1 can be tb + 25ms. The terminal device can derive the timing of other system frames in cell #1 based on the duration of each system frame. For example, the start boundary of system frame #6 corresponding to SFN #6 in cell #1 can be tb + 15ms, and the start boundary of system frame #8 corresponding to SFN #8 in cell #1 can be tb + 35ms, and so on. In this way, the terminal device can derive the system frame timing of cell #1.

(3) Based on the above situation 3: the relative timing information may indicate a second offset value.

In this case, the terminal device can deduce/calculate the system frame timing of the first cell based on the system frame timing of the second cell and the second offset value.

For example, as shown in FIG8 , it is assumed that the time of the starting boundary of the system frame #0 corresponding to SFN #0 in cell #2 is tc, the time of the starting boundary of the system frame #1 corresponding to SFN #1 in cell #2 is tc+10ms, ..., the time of the starting boundary of the system frame #n corresponding to SFN #n in cell #2 is tc+(n×10)ms, and so on.

Assuming second offset value #2 = 1ms, the time of the starting boundary of system frame #0 corresponding to SFN #0 in cell #1 can be tc + 1ms. The terminal device can derive the time of each system frame in cell #1 based on the duration of each system frame. For example, the time of the starting boundary of system frame #1 corresponding to SFN #1 in cell #1 can be tc + 11ms, the time of the starting boundary of system frame #2 corresponding to SFN #2 in cell #1 can be tc + 21ms, and so on. In this way, the terminal device can derive the system frame timing of cell #1.

Based on the above method 2: the terminal device can determine the system frame timing of the first cell based on the absolute timing information.

That is to say, the terminal device can directly derive/calculate the system frame timing of the first cell based on the time of the starting boundary of the third system frame in the first cell, or the time of the ending boundary of the third system frame in the first cell.

For example, as shown in Figure 9, assuming that the starting boundary time of system frame #0 corresponding to SFN #0 in cell #1 is 10:50:30:10 milliseconds on January 30, 2024, the terminal device can deduce the respective times of other system frames in cell #1 based on the duration of each system frame. For example, the starting boundary time of system frame #1 corresponding to SFN #1 in cell #1 can be 10:50:30:20 milliseconds on January 30, 2024, and the starting boundary time of system frame #2 corresponding to SFN #2 in cell #1 can be 10:50:30:30 milliseconds on January 30, 2024, and so on. In this way, the terminal device can deduce the system frame timing of cell #1.

In combination with the above-mentioned method 1 or method 2, the terminal device can determine the system frame timing of the first cell, so that the terminal device can subsequently use the system frame timing to access the first cell.

In summary, the terminal device can determine the neighboring area of the terminal device based on the received timing information, or in other words, the neighboring area of the service cell where the terminal device is located, that is, the system frame timing of the first cell. In this way, the terminal device can obtain the system frame timing of the neighboring area of the terminal device (including the first cell), so that the terminal device can subsequently use the system frame timing to determine the reference time point of the ephemeris information of the first cell before synchronizing with the first cell. After the terminal device determines the reference time point of the ephemeris information of the first cell, it can use the ephemeris information of the first cell to complete Doppler frequency deviation correction and timing advance adjustment, etc., so that the complexity of the terminal device implementation can be reduced. At the same time, the terminal device can use the ephemeris information of the first cell and the system frame timing to access the first cell, so as to avoid the problem that the terminal device does not know the system frame timing of the first cell, resulting in the inability to use the ephemeris information provided by the first cell to access the first cell, resulting in a handover failure. In addition, the availability problem of the ephemeris information provided by the target cell during the handover process can be solved, so that the handover is completed normally, the business continuity of the terminal device is guaranteed, and the impact on the mobility performance of the terminal device is reduced.

In combination with the above embodiment, in a possible design solution, the above method may further include:

The network device sends the ephemeris information of the first cell to the terminal device. Correspondingly, the terminal device receives the ephemeris information of the first cell.

It can be understood that before the network device sends the ephemeris information of the first cell to the terminal device, the network device may also obtain the ephemeris information of the first cell.

The ephemeris information of the first cell may be provided by the first cell to the terminal device, and the ephemeris information of the first cell may also be referred to as the ephemeris information of the first network device, or any other possible name, without limitation. When the network device is a first network device, the first network device may send the ephemeris information of the first cell to the terminal device through forwarding by a second network device; when the network device is a second network device, the second network device may receive the ephemeris information of the first cell from the first network device and forward the ephemeris information of the first cell to the terminal device, without limitation.

The ephemeris information of the first cell may include first time information, which may indicate a reference time point of the ephemeris information of the first cell. That is, the ephemeris-related information indicated by the ephemeris information of the first cell, such as the speed and location of the first network device, is the speed and location corresponding to the reference time point. It is understood that the first time information may be the epoch time field mentioned above, denoted as epoch time field #1. Epoch time field #1 may indicate SFN #a and subframe number #b. Subframe #b corresponding to subframe number #b may be a subframe in system frame #a corresponding to SFN #a. It is understood that the value of a may be 0-1023, or any other possible value, without limitation; the value of b may be 0-9, or any other possible value, without limitation.

In one possible design, the system frame timing of the first cell may be used by the terminal device to utilize the ephemeris information of the first cell. It is understood that, after receiving the ephemeris information of the first cell, the terminal device may use the system frame timing to determine a reference time point for the ephemeris information of the first cell. After determining the reference time point for the ephemeris information, the terminal device may use the ephemeris information to calculate the current satellite position for subsequent synchronization operations.

Exemplarily, the first time information can be based on the system frame timing of the first cell. For example, the epoch time field #1 can be based on the system frame timing of the first cell. That is, the time of system frame #a and the time of subframe #b are based on the system frame timing. The terminal device can determine the time of system frame #a and the time of subframe #b, that is, the epoch time, based on the system frame timing of the first cell.

Taking the system frame timing of the first cell shown in the above-mentioned case 1, that is, the starting boundary time of system frame #5 corresponding to SFN #5 in cell #1 can be ta-10ms, the starting boundary time of system frame #6 corresponding to SFN #6 in cell #1 can be ta, and the starting boundary time of system frame #7 corresponding to SFN #7 in cell #1 can be ta+10ms, as an example, assuming a=8 and b=2, then the starting boundary time of system frame #a can be ta+20ms. The terminal device can deduce the time of subframe #b based on the duration of each subframe, that is, the starting boundary time of subframe #b can be ta+23ms. In this case, the epoch time is ta+23ms. It can be understood that the relevant introduction to the ephemeris information of the first cell can refer to the relevant introduction in the above-mentioned technical terminology section and will not be repeated here.

It should be understood that the timing information of the first cell can be provided to the terminal device only when the first cell provides the terminal device with the ephemeris information of the first cell. In this way, resource overhead can be reduced and on-demand provision can be achieved without limitation.

Optionally, the above method may further include:

The terminal device accesses the first cell according to the system frame timing of the first cell and the ephemeris information of the first cell.

Exemplarily, the terminal device may determine the location information of the first network device based on the system frame timing of the first cell and the ephemeris information of the first cell. The first network device may be a network device to which the first cell belongs.

The terminal device can pre-compensate the Doppler frequency offset and/or adjust the timing advance (TA) based on the location information.

In combination with the above introduction, after the terminal device determines the epoch time, the terminal device can calculate the location information of the first network device at the current moment, such as the current position, etc., based on the epoch time and the ephemeris-related information indicated by the ephemeris information of the first cell, without limitation.

The terminal device can compensate for the Doppler frequency shift caused by the movement of the first network device based on the current position of the first network device, the current position of the terminal device, and the relative movement between the first network device and the terminal device; and/or the terminal device can calculate the propagation delay between the first network device and the terminal device based on the current position of the first network device and the current position of the terminal device, and then calculate TA-related parameters for use in maintaining the TA. In this way, after the terminal device pre-compensates for the Doppler frequency shift and/or adjusts the TA, it can access the first cell.

It should be understood that the terminal device can obtain its own location information through the global navigation satellite system (GNSS) or GPS, or the terminal device can obtain its own location information in any other possible implementation method without limitation.

It can be understood that the specific implementation process of the terminal device pre-compensating the Doppler frequency offset according to the location information, the terminal device adjusting the TA according to the location information, and the terminal device accessing the first cell according to the system frame timing of the first cell and the ephemeris information of the first cell can refer to the existing technology and will not be repeated.

As can be seen from the above description, when a terminal device switches from the second cell to the first cell, that is, the serving cell quality of the second cell is insufficient to support the terminal device to perform services in the cell, the terminal device needs to change the serving cell, that is, the first cell. The following two scenarios are used as examples to specifically describe the first cell.

Scenario 1: Normal switching.

In this scenario, the switching of the terminal device is controlled by the source network device, that is, the source network device (i.e., the second network device) instructs the terminal device to switch to which cell by sending a switching command (such as the RRC reconfiguration message described below). After receiving the switching command, the terminal device accesses the target cell according to the content contained in the switching command.

That is, the first cell may be the target cell for the terminal device to perform switching. The network device instructs the terminal device to switch to the first cell by sending a switching command, and the terminal device accesses the first cell according to the content contained in the switching command.

Exemplarily, the network device sends an RRC reconfiguration message to the terminal device, and correspondingly, the terminal device receives the RRC reconfiguration message.

The RRC reconfiguration message may be from a network device to which the second cell belongs, that is, the network device in this step is a source network device, that is, the aforementioned second network device. The second network device may send an RRC reconfiguration message to the terminal device, and the terminal device may receive the RRC reconfiguration message from the second network device. The RRC reconfiguration message may be used to instruct the terminal device to switch to the first cell, and the terminal device may determine to switch to the first cell based on the RRC reconfiguration message.

It should be understood that the complete implementation process of scenario 1 can refer to the relevant introduction of scenario a below and will not be repeated here.

Scenario 2: Conditional switching.

In this scenario, the source network device (i.e., the second network device) configures handover conditions for the terminal device. The terminal device then evaluates whether the handover conditions are met and, if so, proactively accesses the target cell. In other words, the first cell can be one of at least one candidate cell for the terminal device. Based on the handover conditions, the terminal device can determine the first cell among the at least one candidate cell as the target cell.

Exemplarily, the network device sends an RRC reconfiguration message to the terminal device, and correspondingly, the terminal device receives the RRC reconfiguration message.

The terminal device determines the first cell among at least one candidate cell as the target cell according to the conditions for performing the handover.

The RRC reconfiguration message may be from a network device to which the second cell belongs, that is, the network device in this step is a source network device, that is, the aforementioned second network device. The second network device may send an RRC reconfiguration message to the terminal device, and the terminal device receives the RRC reconfiguration message from the second network device. The RRC reconfiguration message may be used to indicate a condition for the terminal device to perform a handover, and the terminal device may determine a first cell among at least one candidate cell as a target cell based on the condition for performing the handover.

It is understood that the condition for executing the handover may be that the signal quality of the cell meets the preset condition, and the signal quality may include: reference signal receiving power (RSRP), signal to interference plus noise ratio (SINR), or reference signal receiving quality (RSRQ), or any other parameter that may be used to characterize signal quality or strength, without limitation. Exemplarily, the signal quality of the cell meeting the preset condition may include at least one of the following: the RSRP of the cell is greater than the first value; the SINR of the cell is greater than the second value; or the RSRQ of the cell is greater than the third value, etc., without limitation. The condition for executing the handover may also include any other possible conditions, without limitation.

It should be understood that the complete implementation process of scenario 2 can refer to the relevant introduction of scenario b below and will not be repeated here.

Based on the above scenarios 1 and 2, in one possible design scheme, the RRC reconfiguration message may include the ephemeris information of the above-mentioned first cell, or in other words, the ephemeris information of the first cell may be carried in the RRC reconfiguration message, that is, carried in an existing information element, to reduce the difficulty of implementation. The second network device may send the ephemeris information of the first cell to the terminal device via the RRC reconfiguration message; alternatively, the ephemeris information of the first cell may also be carried in a new information element to improve the flexibility of implementation, without limitation. The above-mentioned timing information may also be carried in the RRC reconfiguration message, that is, carried in an existing information element, to reduce the difficulty of implementation. Alternatively, the above-mentioned timing information may also be carried in a new information element to improve the flexibility of implementation, without limitation.

The above describes the overall process of the communication method. The following uses the following scenario as an example to specifically introduce the communication method.

Scenario a: Taking normal switching as an example, Figure 10 is a flow chart of the communication method provided in an embodiment of the present application. As shown in Figure 10, the communication method is applicable to the above-mentioned communication system, mainly involving the interaction between the UE (such as the above-mentioned terminal device), the target base station (such as the above-mentioned first network, corresponding to the target cell, that is, the above-mentioned cell #1) and the source base station (such as the above-mentioned second network, corresponding to the source cell, that is, the above-mentioned cell #2). The target base station and the source base station can be satellites, such as the target base station can be satellite #1 and the source base station can be satellite #2.

The following describes in detail the method, which includes:

S1001: A source base station sends a handover request to a target base station. In response, the target base station receives the handover request from the source base station.

This step may also be: the source cell sends a handover request to the target cell, and the target cell receives the handover request from the source cell.

It can be understood that the handover request sent by the source base station to the target base station may not be sent directly by the source base station to the target base station, but may be forwarded through other network elements, such as AMF or MME and other core network elements. For example, the source base station may send a handover request to the AMF/MME, and the AMF/MME may forward the handover request to the target base station, without limitation.

S1002, the target base station performs admission control.

The target base station can determine whether to allow the terminal device to access based on the handover request. For example, the target base station can determine whether to accept the UE to be handed over to the target cell under this base station based on factors such as UE capabilities and network load. If the judgment result is allowed, the target base station sends a handover confirmation message to the source base station. The handover request confirmation includes the new cell-radio network temporary identifier (C-RNTI) and parameters such as the target base station security algorithm.

S1003: The target base station sends a handover request acknowledgment to the source base station. Correspondingly, the source base station receives the handover request acknowledgment from the target base station.

The handover request confirmation may include configuration information provided by the target cell/target base station for the UE, and the configuration information may include satellite ephemeris information of the target cell.

It can be understood that the handover request confirmation sent by the target base station to the source base station may not be sent directly by the target base station to the source base station, but may be forwarded through other network elements, such as AMF or MME and other core network elements. For example, the target base station may send a handover request confirmation to the AMF/MME, and the AMF/MME may forward the handover request confirmation to the source base station.

S1004: The source base station sends an RRC reconfiguration message to the UE. In response, the UE receives the RRC reconfiguration message from the source base station.

After receiving the handover confirmation message from the target base station, the source base station sends an RRC reconfiguration message (handover command) to the UE. The content included in the RRC reconfiguration message comes from the handover request confirmation in S1003. Specifically, the RRC reconfiguration message may include satellite ephemeris information of the target cell.

The RRC reconfiguration message may also include information about the target cell included in the handover command in the NR system and the configuration parameters required for the terminal device to access the target cell. For example, target cell information (such as the physical cell identifier (PCI) of the target cell and the corresponding frequency information of the target cell), the C-RNTI allocated by the target cell to the terminal device, and random access channel (RACH) resource information required to access the target cell (such as dedicated RACH resources and/or public RACH resources), etc., are not limited.

The RRC reconfiguration message is used to trigger the UE to perform handover, that is, to handover the UE from a source cell to a target cell, or in other words, to handover the UE from a source base station to a target base station.

S1005 , the source base station/target base station provides the timing information of the target cell to the UE.

It is understood that the timing information of the target cell can be relative timing information or absolute timing information. For a detailed description, please refer to the relevant description of step S501 above and will not be repeated here. The timing information of the target cell can be carried in the RRC reconfiguration message of step S1004, or can also be carried in other messages or signaling, without limitation. The timing information of the target cell can be provided to the UE only when the target cell provides the UE with the target cell ephemeris information. In this way, resource overhead can be reduced and provision can be achieved on demand.

For the specific implementation of the source base station or the target base station providing the timing information of the target cell to the UE, reference may be made to the relevant introduction in the above step S501 and will not be elaborated upon.

It should be understood that the embodiment of the present application does not limit the order of step S1005 and the above steps S1001 to S1004. That is, the network side (source base station/target base station) can provide the timing information of the target cell to the UE before triggering the handover process, or can also provide the timing information of the target cell to the UE during the handover process, without limitation.

S1006, the UE switches to the target cell.

The UE may use the timing information of the target cell to determine the system frame timing of the target cell. The specific implementation process of this process may refer to the relevant introduction of the above step S502 and will not be described in detail.

After the UE determines the system frame timing of the target cell, the UE can use the system frame timing to determine the reference time point of the ephemeris (i.e., the epoch time), and then use the calculated position information of the target base station (i.e., the above-mentioned satellite #1) to complete the Peller frequency offset pre-compensation and/or TA adjustment to achieve access to the target cell.

At step S1007, the UE sends an RRC reconfiguration complete message to the target base station. In response, the target base station receives the RRC reconfiguration complete message from the UE.

After the UE successfully accesses the target cell, it can send an RRC reconfiguration complete message to the target base station. After the target base station successfully receives the RRC reconfiguration complete message sent by the UE, it can be determined that the UE has successfully switched to the target cell and the handover process is successfully completed.

Scenario b: Taking conditional switching as an example, Figure 11 is a flow chart of the communication method provided in an embodiment of the present application. As shown in Figure 11, the communication method is applicable to the above-mentioned communication system, mainly involving the interaction between UE (such as the above-mentioned terminal device), candidate base station #1 (such as the above-mentioned first network, corresponding to candidate cell #1, that is, the above-mentioned cell #1), candidate base station #2 (the base station to which other candidate cells belong, corresponding to candidate cell #2) and source base station (such as the above-mentioned second network, corresponding to the source cell, that is, the above-mentioned cell #2), candidate base station #1, candidate base station #2 and source base station can be satellites, such as candidate base station #1 can be satellite #a, candidate base station #a can be satellite #b, and source base station can be satellite #c.

It can be understood that the communication system may also include one or more other candidate base stations (candidate cells), without limitation.

The following describes in detail the method, which includes:

S1101: The source base station sends a handover request to a candidate base station.

Exemplarily, the source base station may send a handover request to candidate base station #1 and candidate base station #2 respectively. Candidate base station #1 receives the handover request from the source base station. Candidate base station #2 receives the handover request from the source base station.

This step may also be: the source cell sends a handover request to candidate cell #1 and candidate cell #2 respectively. Candidate cell #1 receives the handover request from the source cell. Candidate cell #2 receives the handover request from the source cell.

The specific implementation process of this step is similar to the above step S1001, which can be used as a reference for understanding and will not be described in detail.

S1102: The candidate base station performs admission control.

Candidate base station #1 and candidate base station #2 can determine whether to allow the terminal device to access based on the handover request. If the decision is yes, a handover confirmation message is sent to the source base station. The handover confirmation message includes the new cell-radio network temporary identifier (C-RNTI) and the target base station's security-related algorithm, among other parameters.

S1103: The candidate base station sends a handover request confirmation to the source base station. Correspondingly, the source base station receives the handover request confirmation from each candidate base station.

Exemplarily, candidate base station #1 may send handover request confirmation #1 to the source base station, and the source base station receives handover request confirmation #1 from candidate base station #1. The handover request confirmation #1 may include configuration information provided by candidate cell #1/candidate base station #1 for the UE, and the configuration information may include satellite ephemeris information #1 of candidate cell #1.

Candidate base station #2 may send handover request confirmation #2 to the source base station, and the source base station receives handover request confirmation #2 from candidate base station #2. The handover request confirmation #2 may include configuration information provided by candidate cell #2/candidate base station #2 for the UE, and the configuration information may include satellite ephemeris information #2 of candidate cell #2.

S1104: The source base station sends an RRC reconfiguration message to the UE. Correspondingly, the UE receives the RRC reconfiguration message from the source base station.

After receiving the handover confirmation message from the target base station, the source base station sends an RRC reconfiguration message to the UE. This RRC reconfiguration message can be used to configure the UE for conditional handover. That is, the RRC reconfiguration message contains the conditions for the UE to perform handover. After receiving the configuration, the UE will evaluate whether the handover conditions are met for each candidate cell. The RRC reconfiguration message also includes the configuration information provided to the UE by candidate cell #1 and candidate cell #2 in step S1103 above, such as satellite ephemeris information #1 for candidate cell #1 and satellite ephemeris information #2 for candidate cell #2.

S1105. The UE sends an RRC reconfiguration complete message to the source base station.

After successfully receiving the RRC reconfiguration message, the UE may send an RRC reconfiguration complete message to the source cell for alignment with the source cell, which may indicate that the UE has successfully received or applied the configuration related to the conditional handover.

S1106: The source base station/candidate base station provides the timing information of the candidate cell to the UE.

The timing information of candidate cell #1 may be recorded as timing information #1, and the timing information of candidate cell #2 may be recorded as timing information #2. The source base station or candidate base station #1 may provide timing information #1 to the UE, and the source base station or candidate base station #2 may provide timing information #2 to the UE.

It should be understood that the embodiment of the present application does not limit the order of step S1106 and the above steps S1101-S1104. That is, the network side (source base station/candidate base station #1/candidate base station #2) can provide timing information #1 and timing information #2 to the UE before triggering the handover process, or can also provide timing information #1 and timing information #2 to the UE during the handover process, without limitation.

S1107: The UE selects a target cell and switches to the target cell.

The UE can evaluate the candidate cells based on the conditions configured in the source cell and select the candidate cell that meets the conditions as the handover object (ie, the target cell). For example, the UE selects the target cell as candidate cell #1, that is, candidate cell #1 is the target cell.

After the UE selects candidate cell #1 as the target cell, it uses the timing information to determine the system frame timing of target cell #1. The UE can use the system frame timing to determine the reference time point (i.e., epoch time) for ephemeris, and then use the calculated position information of candidate base station #1 (i.e., satellite #a, i.e., the target base station) to perform Pulser frequency offset pre-compensation and/or TA adjustment, thereby enabling access to target cell #1.

S1108: The UE sends an RRC reconfiguration complete message to the candidate base station #1. Correspondingly, the candidate base station #1 receives the RRC reconfiguration complete message from the UE.

After the UE successfully accesses the target cell #1, it can send an RRC reconfiguration complete message to the candidate base station #1. After the candidate base station #1 successfully receives the RRC reconfiguration complete message sent by the UE, it can be determined that the UE has successfully switched to the target cell #1 and the handover process is successfully completed.

It can be understood that the specific implementation principles of steps S1101-S1108 are similar to those of the above steps S1001-S1007, which can be used as a reference for understanding and will not be elaborated on.

In combination with the above scenarios a and b, the network provides the UE with information related to the candidate/target cell timing, so that the UE can determine the system frame timing of the target cell in advance during the handover process, and use the ephemeris information provided by the target cell normally to complete operations such as timing synchronization and Doppler frequency offset pre-compensation for the target cell, thereby completing the handover process. On the one hand, it solves the problem of the availability of the ephemeris information provided by the target cell during the handover process, so that the handover is completed normally and the service continuity of the UE is guaranteed; on the other hand, it provides the UE with available ephemeris information of the target cell, which is conducive to the UE completing synchronization with the target cell as soon as possible, avoiding the UE blindly searching for the target cell, reducing unnecessary UE power consumption and overhead, shortening the handover delay, and improving mobility performance; in addition, the ephemeris information provided by the target cell during the handover process is usually more valid or accurate. The UE's use of this ephemeris information is conducive to improving the precision or accuracy of operations such as TA adjustment, timing synchronization, and Doppler frequency offset compensation, thereby improving the performance of the UE accessing the target cell.

It can be understood that the above embodiment is introduced by taking the switching scenario as an example, and the embodiment of the present application can also be applied to other scenarios that are not switching, without limitation. For example, other scenarios also involve the terminal device needing to obtain the (system frame) timing of a certain cell, and the network can also adopt the implementation method of the embodiment of the present application to implement it, so that the terminal device can determine the timing of the relevant cell, such as the positioning scenario of the terminal device. In this scenario, the terminal device can receive a reference signal from the neighboring cell of the terminal device's service cell, or send a reference signal to the neighboring cell of the terminal device's service cell. The timing of sending the reference signal is based on the timing of the neighboring cell. Its implementation principle is similar to that of the above-mentioned switching scenario, which can be understood by reference and will not be elaborated.

The communication method provided in the embodiment of the present application is described in detail above in conjunction with Figures 5 to 11. The communication device for executing the communication method provided in the embodiment of the present application is described in detail below in conjunction with Figures 12 and 13.

Figure 12 is a structural diagram of a communication device according to an embodiment of the present application. As shown in Figure 12, the communication device 1200 includes a transceiver module 1201 and a processing module 1202. For ease of illustration, Figure 12 only shows the main components of the communication device 1200.

In some embodiments, the communication device 1200 may be applicable to the communication system shown in FIG. 3 or FIG. 4 to perform the functions of the above-mentioned terminal device.

The transceiver module 1201 is configured to receive timing information, and the processing module 1202 is configured to determine the system frame timing of a first cell according to the timing information, wherein the first cell is a neighboring cell of the terminal device.

Optionally, the transceiver module 1201 may include a sending module (not shown in FIG12 ) and a receiving module (not shown in FIG12 ). The sending module is used to implement the sending function of the communication device 1200 , and the receiving module is used to implement the receiving function of the communication device 1200 .

Optionally, the communication device 1200 may further include a storage module (not shown in FIG12 ) storing a program or instruction. When the processing module 1202 executes the program or instruction, the communication device 1200 may perform the above-mentioned communication method.

It should be noted that the communication device 1200 can be a terminal device, a chip (system) or other parts or components in the terminal device, or a device including a terminal device, which is not limited in the embodiments of the present application.

In addition, the technical effects of the communication device 1200 can refer to the technical effects of the above-mentioned communication method, which will not be repeated here.

In some embodiments, the communication device 1200 may be applicable to the communication system shown in FIG. 3 or FIG. 4 to perform the functions of the aforementioned network device.

The processing module 1202 is configured to obtain timing information. The transceiver module 1201 is configured to send the timing information to the terminal device. The timing information is used by the terminal device to determine the system frame timing of the first cell, which is a neighboring cell of the terminal device.

Optionally, the transceiver module 1201 may include a sending module and a receiving module, wherein the sending module is used to implement the sending function of the communication device 1200 , and the receiving module is used to implement the receiving function of the communication device 1200 .

Optionally, the communication device 1200 may further include a storage module, wherein the storage module stores a program or instruction. When the processing module 1202 executes the program or instruction, the communication device 1200 may execute the above-mentioned communication method.

It should be noted that the communication device 1200 can be a network device, a chip (system) or other parts or components in the network device, or a device that includes a network device. This embodiment of the present application does not limit this.

In addition, the technical effects of the communication device 1200 can refer to the technical effects of the above-mentioned communication method, which will not be repeated here.

For example, FIG13 is a second structural diagram of a communication device provided in an embodiment of the present application. The communication device may be a terminal device or a network device, or may be a chip (system) or other component or assembly of a terminal device or a network device. As shown in FIG13 , the communication device 1300 may include a processor 1301. Optionally, the communication device 1300 may further include a memory 1302 and/or a transceiver 1303. The processor 1301 is coupled to the memory 1302 and the transceiver 1303, such as by a communication bus.

The following is a detailed introduction to the various components of the communication device 1300 with reference to FIG13:

The processor 1301 is the control center of the communication device 1300 and can be a single processor or a collective term for multiple processing elements. For example, the processor 1301 can be one or more central processing units (CPUs), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application, such as one or more microprocessors (digital signal processors, DSPs) or one or more field programmable gate arrays (FPGAs).

Optionally, the processor 1301 may execute various functions of the communication device 1300 , such as executing the communication method shown in FIG. 5 , by running or executing a software program stored in the memory 1302 and calling data stored in the memory 1302 .

In a specific implementation, as an embodiment, the processor 1301 may include one or more CPUs, such as CPU0 and CPU1 shown in FIG13 .

In a specific implementation, as an embodiment, the communication device 1300 may also include multiple processors, such as the processor 1301 and the processor 1304 shown in FIG13 . Each of these processors may be a single-core processor (single-CPU) or a multi-core processor (multi-CPU). The processor herein may refer to one or more devices, circuits, and/or processing cores for processing data (e.g., computer program instructions).

Among them, the memory 1302 is used to store the software program for executing the solution of this application, and the execution is controlled by the processor 1301. The specific implementation method can refer to the above method embodiment and will not be repeated here.

Alternatively, the memory 1302 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, a random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, an optical disc storage (including a compact disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but is not limited thereto. The memory 1302 may be integrated with the processor 1301 or exist independently and be coupled to the processor 1301 via an interface circuit (not shown in FIG. 13 ) of the communication device 1300. This embodiment of the present application does not specifically limit this.

Transceiver 1303 is used for communication with other communication devices. For example, if communication device 1300 is a terminal device, transceiver 1303 can be used to communicate with a network device or another terminal device. For another example, if communication device 1300 is a network device, transceiver 1303 can be used to communicate with a terminal device or another network device.

Optionally, the transceiver 1303 may include a receiver and a transmitter (not shown separately in FIG13 ), wherein the receiver is used to implement a receiving function, and the transmitter is used to implement a sending function.

Optionally, the transceiver 1303 can be integrated with the processor 1301, or can exist independently and be coupled to the processor 1301 through the interface circuit of the communication device 1300 (not shown in Figure 13). This embodiment of the present application does not specifically limit this.

It should be noted that the structure of the communication device 1300 shown in FIG13 does not constitute a limitation on the communication device. An actual communication device may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

In addition, the technical effects of the communication device 1300 can refer to the technical effects of the communication method described in the above method embodiment, and will not be repeated here.

An embodiment of the present application provides a communication system, which may include the terminal device in the above method embodiment and a network device.

It should be understood that in the embodiments of the present application, the terminal device and/or the network device can perform some or all of the steps in the embodiments. These steps or operations are only examples, and the embodiments of the present application can also perform other operations or variations of various operations. In addition, the various steps can be performed in the different orders presented in the embodiments, and it is possible that not all operations in the embodiments of the present application need to be performed. Moreover, the size of the sequence number of each step does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

It should be understood that the processor in the embodiments of the present application may be a central processing unit (CPU), but may also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

It should also be understood that the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), and direct rambus RAM (DR RAM).

The above embodiments can be implemented in whole or in part by software, hardware (such as circuits), firmware or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer program are loaded or executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (such as infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that contains one or more available media sets. The available medium can be a magnetic medium (for example, a floppy disk, a hard disk, a tape), an optical medium (for example, a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state drive.

It should be understood that the term "and/or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and/or B" can represent: A alone, A and B together, or B alone. A and B can be singular or plural. Furthermore, the character "/" as used herein generally indicates an "or" relationship between the associated objects, but it may also indicate an "and/or" relationship. For specific understanding, please refer to the context.

In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, and c can be single or plural.

It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage media include: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk, and other media that can store program codes.

The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims (34)

A communication method, comprising: receiving timing information; Determine the system frame timing of the first cell based on the timing information; wherein the first cell is a neighboring cell of the terminal device. The method according to claim 1, wherein the timing information comprises relative timing information or absolute timing information; The determining, according to the timing information, the system frame timing of the first cell includes: Determining the system frame timing of the first cell according to the system frame timing of the second cell and the relative timing information; wherein the second cell is a serving cell of the terminal device; Alternatively, the system frame timing of the first cell is determined based on the absolute timing information. The method according to claim 2 is characterized in that the relative timing information indicates a first offset value between a system frame number SFN of a first system frame in the first cell and an SFN of a second system frame in the second cell; and/or a second offset value between a boundary of a first time unit of the first cell and a boundary of a second time unit of the second cell. The method according to claim 3 is characterized in that the first offset value is the SFN of the first system frame minus the SFN of the second system frame; or, the first offset value is the SFN of the second system frame minus the SFN of the first system frame. The method according to claim 3 or 4 is characterized in that the second deviation value is the time of the boundary of the first time unit - the time of the boundary of the second time unit; or, the second deviation value is the time of the boundary of the second time unit - the time of the boundary of the first time unit. The method according to claim 5 is characterized in that the time unit includes at least one of the following: a system frame, a subframe, a time slot, or a symbol; and the time unit includes the first time unit and the second time unit. The method according to claim 2 is characterized in that the absolute timing information indicates the time of the starting boundary of the third system frame in the first cell, or the time of the ending boundary of the third system frame in the first cell. The method according to any one of claims 1-7 is characterized in that the timing information is provided by the first cell to the terminal device; or the timing information is provided by the second cell to the terminal device. The method according to any one of claims 1 to 8, further comprising: Receive the ephemeris information of the first cell; wherein the ephemeris information of the first cell is provided by the first cell to the terminal device, the ephemeris information of the first cell includes first time information, and the first time information is based on the system frame timing of the first cell. The method according to claim 9, further comprising: Access the first cell according to the system frame timing of the first cell and the ephemeris information of the first cell. The method according to claim 10, wherein accessing the first cell according to the system frame timing of the first cell and the ephemeris information of the first cell comprises: Determine location information of a first network device according to the system frame timing of the first cell and the ephemeris information of the first cell; wherein the first network device is a network device to which the first cell belongs; According to the position information, the Doppler frequency offset is pre-compensated and/or the timing advance TA is adjusted. The method according to any one of claims 1-11 is characterized in that the first cell is one of at least one candidate cell of the terminal device. The method according to claim 12, further comprising: Receiving a radio resource control (RRC) reconfiguration message; wherein the RRC reconfiguration message is used to indicate a condition for the terminal device to perform a handover, and the RRC reconfiguration message is from a network device to which the second cell belongs; According to the handover execution condition, a first cell among the at least one candidate cell is determined as a target cell. The method according to any one of claims 1-11 is characterized in that the first cell is a target cell for the terminal device to perform switching. The method according to claim 14, further comprising: Receive an RRC reconfiguration message; wherein, the RRC reconfiguration message is used to instruct the terminal device to switch to the first cell, and the RRC reconfiguration message is from a network device to which the second cell belongs. The method according to claim 13 or 15, characterized in that the RRC reconfiguration message includes ephemeris information of the first cell. A communication method, comprising: Acquire timing information; wherein the timing information is used by the terminal device to determine the system frame timing of a first cell, where the first cell is a neighboring cell of the terminal device; Sending the timing information to the terminal device. The method according to claim 17, wherein the timing information includes relative timing information or absolute timing information. The method according to claim 18 is characterized in that the relative timing information indicates a first deviation value between the system frame number SFN of the first system frame in the first cell and the SFN of the second system frame in the second cell; and/or a second deviation value between the boundary of the first time unit of the first cell and the boundary of the second time unit of the second cell; wherein the second cell is the service cell of the terminal device. The method according to claim 19 is characterized in that the first offset value is the SFN of the first system frame minus the SFN of the second system frame; or, the first offset value is the SFN of the second system frame minus the SFN of the first system frame. The method according to claim 19 or 20 is characterized in that the second deviation value is the time of the boundary of the first time unit minus the time of the boundary of the second time unit; or, the second deviation value is the time of the boundary of the second time unit minus the time of the boundary of the first time unit. The method according to claim 21 is characterized in that the time unit includes at least one of the following: a system frame, a subframe, a time slot, or a symbol; and the time unit includes the first time unit and the second time unit. The method according to claim 18 is characterized in that the absolute timing information indicates the time of the starting boundary of the third system frame in the first cell, or the time of the ending boundary of the third system frame in the first cell. The method according to any one of claims 17-23 is characterized in that the timing information is provided to the terminal device by the first cell; or the timing information is provided to the terminal device by the second cell; wherein the second cell is a serving cell of the terminal device. The method according to any one of claims 17 to 24, further comprising: Obtaining ephemeris information of the first cell; wherein the ephemeris information of the first cell is provided by the first cell to the terminal device, the ephemeris information of the first cell includes first time information, and the first time information is based on the system frame timing of the first cell as a reference; Send the ephemeris information of the first cell to the terminal device. The method according to any one of claims 17-25 is characterized in that the first cell is one of at least one candidate cell of the terminal device. The method according to claim 26, further comprising: Send an RRC reconfiguration message to the terminal device; wherein the RRC reconfiguration message is used to indicate the conditions for the terminal device to perform switching. The method according to any one of claims 17-25 is characterized in that the first cell is a target cell for the terminal device to perform switching. The method according to claim 28, further comprising: Send an RRC reconfiguration message to the terminal device; wherein the RRC reconfiguration message is used to instruct the terminal device to switch to the first cell. The method according to claim 27 or 29, wherein the RRC reconfiguration message includes ephemeris information of the first cell. A communication device, characterized in that the device comprises: a module for executing the method according to any one of claims 1 to 30. A communication device, characterized in that the communication device comprises: a processor; wherein the processor is used to execute the communication method according to any one of claims 1 to 30. A computer-readable storage medium, characterized in that the computer-readable storage medium includes a computer program or instructions, and when the computer program or instructions are run on a computer, the communication method according to any one of claims 1 to 30 is executed. A computer program product, characterized in that the computer program product comprises: a computer program or instructions, which, when the computer program or instructions are run on a computer, enables the communication method according to any one of claims 1 to 30 to be executed.