WO2025232307A1 - Communication method and apparatus - Google Patents

Abstract

Provided in the present application are a communication method and apparatus. In the present method, before a first access network device switches from a first mode to a second mode, a first terminal which does not accept a service of the second mode is triggered to change a serving access network device, such that the first terminal can continue service transmission. Alternatively, the first access network device releases the first terminal to an idle state, such that service transmission of the first terminal can be interrupted in a normal manner, thereby avoiding failure of the service transmission of the first terminal.

Description

Communication methods and devices

This application claims priority to Chinese patent application filed on May 9, 2024, with application number 202410587642.X and entitled "Communication Method and Apparatus", the entire contents of which are incorporated herein by reference.

Technical Field

This application relates to the field of communication technology, and in particular to a communication method and apparatus.

Background Technology

When a satellite is providing services to a terminal, it operates in normal mode when it is simultaneously connected to both the terminal and the core network. When the satellite is not simultaneously connected to both the terminal and the core network, it operates in store-and-forward (S&F/SF) mode. SF mode can be used in scenarios where the satellite cannot always be connected to a ground gateway station. In such scenarios, the satellite cannot connect to both the terminal and the core network at the same time and needs to cache the data arriving from either the terminal or the core network and forward it at a later time.

However, if the satellite providing services to the terminal undergoes a mode switch, it may cause the terminal's service transmission to fail.

Summary of the Invention

This application provides a communication method and apparatus that enables the terminal to function correctly when the satellite providing services to the terminal undergoes a mode switch, thereby preventing terminal service transmission failure.

Firstly, a communication method is provided. This method can be executed by a first access network device, by a module (e.g., processor, chip, or chip system) applied to the first access network device, or by a logical node, logical module, or software capable of implementing all or part of the functions of the first access network device. For ease of description, the following description will take the execution of this method by the first access network device as an example.

The method includes: before the first access network device switches from a first mode to a second mode, the first access network device sends first information to a first terminal served by the first access network device, the first information triggering the first terminal to switch to accessing the second access network device, or releasing the first terminal to an idle state; wherein, the first mode refers to the access network device simultaneously connecting the terminal and the core network device, the second mode refers to the access network device not simultaneously connecting the terminal and the core network device, the first terminal is a terminal that does not accept the service of the second mode, and the second access network device operates in the first mode; the first access network device switches from the first mode to the second mode.

Based on the method described in the first aspect, before the first access network device switches from the first mode to the second mode, it triggers the first terminal, which does not accept the service of the second mode, to switch to the serving access network device, so that the first terminal can continue to transmit services. Alternatively, the first access network device releases the first terminal to an idle state, which can normally interrupt the transmission of the first terminal's services and avoid the failure of the first terminal's service transmission.

Optionally, before sending the first information to the first terminal, the communication method may further include: the first access network device sending second information, the second information indicating that the operating mode of the first access network device changes from the first mode to the second mode. This allows the operating modes of the first access network device to be aligned with those of the first terminal, avoiding mismatches between their operating modes.

Optionally, before sending the first information to the first terminal, the communication method may further include: the first access network device receiving third information from the first terminal or a core network device serving the first terminal, the third information indicating that the first terminal is a terminal that does not accept the second mode of service. This enables the first access network device to know whether the first terminal accepts the second mode, thereby determining whether it is necessary to replace the serving access network device for the first terminal and avoiding unexpected service interruption of the first terminal.

Optionally, when the third information originates from the first terminal, the third information is included in the service information and/or capability information. The service information indicates that the service currently being performed by the first terminal does not accept the second mode of service, and the capability information indicates that the first terminal does not have the capability to accept the second mode of service. It is understood that the service information can be carried in the radio resource control (RRC) protocol, and can be a separate reporting message, decoupled from existing signaling, or it can reuse existing signaling, such as the capability information of the first terminal triggered when accessing the network, thus saving overhead.

Optionally, the third information may also indicate the identifier of the first terminal. The identifier of the first terminal may be a symbol such as letters and numbers used to uniquely identify the first terminal, such as the UE S1 application protocol identity (UE S1AP ID), international mobile subscriber identity (IMSI), subscription permanent identifier (SUPI), cell radio network temporary identifier (C-RNTI), etc.

Secondly, a communication method is provided. This method can be executed by a first terminal, by a module applied to the first terminal (such as a processor, chip, or chip system), or by a logical node, logical module, or software capable of implementing all or part of the functions of the first terminal. For ease of description, the following description will take the execution of this method by the first terminal as an example.

The method includes: sending third information to a first access network device, the third information indicating that the first terminal is a terminal that does not accept the service of the second mode, the first access network device serving the first terminal, the second mode referring to the access network device not simultaneously connecting the terminal and the core network device; receiving first information from the first access network device, the first information triggering the first terminal to switch to accessing the second access network device, or releasing the first terminal to an idle state, the second access network device operating in the first mode, the first mode referring to simultaneously connecting the terminal and the core network device; and according to the first information, accessing the second access network device or entering an idle state.

Optionally, entering the idle state based on the first information may include: performing cell reselection if the first information indicates that the first terminal's Radio Resource Control (RRC) connection is being released.

Optionally, the communication method may further include: receiving second information from a first access network device, the second information indicating that the operating mode of the first access network device is changed from a first mode to a second mode.

Optionally, the third information is included in the service information and/or capability information, whereby the service information indicates that the service currently being performed by the first terminal does not accept the service of the second mode, and the capability information indicates that the first terminal does not have the capability to accept the service of the second mode.

It is understood that the technical effects of the method in the second aspect mentioned above can also be referred to the relevant introduction in the first aspect mentioned above, and will not be repeated here.

Thirdly, a communication method is provided. This method can be executed by a first terminal, by a module applied to the first terminal (such as a processor, chip, or chip system), or by a logical node, logical module, or software capable of implementing all or part of the functions of the first terminal. For ease of description, the following description will take the execution of this method by the first terminal as an example.

The method includes: when a first terminal that does not accept the service of the second mode is camped in the cell of the first access network device, obtaining second information, the second information indicating that the operating mode of the first access network device is changed from the first mode to the second mode, wherein the first mode refers to the access network device simultaneously connecting the terminal and the core network device, and the second mode refers to the access network device not simultaneously connecting the terminal and the core network device; reselecting to the second access network device, or continuing to camp in the cell of the first access network device without entering the connected state, the second access network device operating in the first mode.

Based on the third approach, if the first terminal in the idle state does not accept the service of the second mode, cell reselection will occur, and it will access the second access network device operating in the first mode. Alternatively, it may continue to camp on the cell of the first access network device without entering the connected state. That is, the first terminal considers the cell of the first access network device it is currently camping on as an acceptable cell and will not initiate entry into the connected state. This avoids a mismatch between the operating modes of the first access network device and the first terminal. Alternatively, the first terminal may always be in a cell search state (any cell selection), which is beneficial for quickly camping on the cell of the second access network device when a suitable second access network device is available.

Fourthly, a communication method is provided. This method can be executed by a first terminal, by a module applied to the first terminal (such as a processor, chip, or chip system), or by a logical node, logical module, or software capable of implementing all or part of the functions of the first terminal. For ease of description, the following description will take the execution of this method by the first terminal as an example.

The method includes: receiving second information from a first access network device, the second information indicating that the operating mode of the first access network device changes from a first mode to a second mode, wherein the first access network device serves a first terminal, the first mode refers to the access network device simultaneously connecting the terminal and the core network device, and the second mode refers to the access network device not simultaneously connecting the terminal and the core network device; when the first terminal accepts the service of the second mode, disabling a timer or increasing the timer's duration, the timer being used to determine whether the service transmission of the first terminal is successful within the timer duration.

Based on the method in the fourth aspect, it is known that in the second mode, since the first access network device does not connect to the first terminal and the core network device at the same time, it is unable to transmit real-time services. Therefore, it is necessary to turn off the timer or increase the timer duration to avoid errors due to the short timer duration in the second mode, so that the first terminal can successfully transmit data in the second mode.

Fifthly, a communication method is provided. This method can be executed by a first access network device, by a module (e.g., processor, chip, or chip system) applied to the first access network device, or by a logical node, logical module, or software capable of implementing all or part of the functions of the first access network device. For ease of description, the following description will use the execution of this method by the first access network device as an example.

The method includes: when a first access network device determines that it is about to disconnect from a first terminal, and when it determines that a third access network device serving the first terminal after the first access network device is operating in a second mode, the first access network device sends a first indication message to the first terminal, the first indication message indicating that the first terminal does not enter an idle state and the first network device is operating in the first mode; wherein, the first mode refers to the access network device simultaneously connecting to the terminal and the core network device, and the second mode refers to the access network device not simultaneously connecting to the terminal and the core network device.

Based on the method in the fifth aspect, when the first access network device is about to disconnect from the first terminal, according to the fact that the third access network device serving the first terminal after the first access network device is working in the second mode, it is determined not to release the first terminal to the idle state, so that the first access network device and the first terminal can align to the next working mode, the third access network device can work correctly, and the first terminal's service transmission failure is avoided.

Optionally, the communication method may further include: the first access network device instructing the first terminal that the third access network device is operating in a second mode.

Optionally, the communication method may further include: when the first access network device provides services to the first terminal, the first access network device sends second indication information to the core network device serving the first terminal, the second indication information instructing the first access network device to serve the first terminal, and/or the first access network device to operate in a first mode for the first terminal. This allows the core network device to send downlink data to the first access network device after obtaining information that the first terminal is in a normal connection state, thereby achieving real-time data transmission and improving data transmission efficiency.

Optionally, the communication method may further include: a first access network device receiving downlink data sent by a core network device according to a second instruction.

Optionally, the communication method may further include: if the first access network device determines that it is about to disconnect from the first terminal or has already disconnected, the first access network device sends a third indication message to the core network device serving the first terminal. The third indication message indicates that the first access network device will not serve the first terminal, and/or the first access network device will operate in a second mode for the first terminal. By instructing the first access network device to serve the first terminal through the second indication message, and/or having the first access network device operate in the first mode for the first terminal, the core network device can determine how to send downlink data from the first terminal, thereby improving data transmission efficiency.

Optionally, the communication method may further include: when the first access network device determines that it is about to disconnect from the first terminal or has already disconnected, the first access network device sends the context information of the first terminal to the core network device serving the first terminal. After the first access network device disconnects from the first terminal, when the first terminal accesses a new access network device, it needs to perform initial authentication through the context information of the first terminal, which can ensure that the first terminal successfully accesses the new access network device and avoid service transmission failure.

Optionally, the first access network device sends the context information of the first terminal to the core network device, including: the first access network device receiving a request message from the core network device, the request message being used to request the context of the first terminal; and the first access network device sending the context information of the first terminal to the core network device according to the request message. Thus, the core network device can send downlink data to the new access network device providing services to the first terminal. When the new access network device provides services to the first terminal, it sends the downlink data to the first terminal, enabling the new access network device to operate correctly.

Sixthly, a communication method is provided. This method can be executed by a first terminal, by a module applied to the first terminal (such as a processor, chip, or chip system), or by a logical node, logical module, or software capable of implementing all or part of the functions of the first terminal. For ease of description, the following description will take the execution of the method by the first terminal as an example.

The method includes: receiving second information from a first access network device, the second information indicating that the operating mode of the first access network device is changed from a second mode to a first mode, wherein the first access network device serves a first terminal, the second mode means that the access network device does not connect the terminal and the core network device at the same time, and the first mode means that the access network device connects the terminal and the core network device at the same time; starting a timer or shortening the timer duration, the timer being used to determine whether the service transmission of the first terminal is successful within the timer duration.

Based on the method in the sixth aspect, the first terminal obtains information that the working mode of the first access network device has changed from the second mode to the first mode, so that the working mode of the first terminal and the first access network device are aligned, avoiding mismatch between the working modes of the first terminal and the first access network device, and ensuring the accuracy of determining whether the service has been successfully transmitted in the first mode by starting a timer or shortening the timer duration.

Seventhly, a communication method is provided. This method can be executed by a first terminal, by a module applied to the first terminal (e.g., a processor, chip, or chip system), or by a logical node, logical module, or software capable of implementing all or part of the functions of the first terminal. For ease of description, the following description will use the example of the method being executed by the first terminal.

The method includes: during the process of the first terminal waiting for the service of the third access network device, obtaining second information, the second information indicating that the working mode of the first access network device is changed from the second mode to the first mode, the first mode means that the access network device connects to the terminal and the core network device at the same time, the second mode means that the access network device does not connect to the terminal and the core network device at the same time, the third access network device works in the second mode; and accessing the first network device.

Based on the method in the seventh aspect, it is known that for a first terminal that is not connected to the first network device and is waiting for the service of the third access network device, it can connect to the first network device after it learns that the first network device has changed to the first mode, thus ensuring that the first terminal can transmit services normally.

Eighthly, a communication method is provided. This method can be executed by a first terminal, by a module applied to the first terminal (e.g., a processor, chip, or chip system), or by a logical node, logical module, or software capable of implementing all or part of the functions of the first terminal. For ease of description, the following description assumes the method is executed by the first terminal.

The method includes: when a first terminal that does not accept the service of the second mode is camped in the cell of the first access network device and is not allowed to enter the connected state, obtaining second information, the second information indicating that the working mode of the first access network device is changed from the second mode to the first mode, wherein the first mode refers to the access network device simultaneously connecting the terminal and the core network device, and the second mode refers to the access network device not simultaneously connecting the terminal and the core network device; and determining that the first terminal is allowed to enter the connected state in the cell of the first access network device.

Based on the method in the eighth aspect, since the first terminal does not accept the service of the second mode, it is not allowed to access the first access network device operating in the second mode. When the first terminal obtains the information that the first access network device has switched to the first mode according to the second information, the first terminal determines to change the cell where it is camped on the first access network device to a suitable cell, so that it can access the first access network device normally. This allows the idle first terminal to subsequently initiate entry into the connected state, ensuring the normal operation of the service transmission process.

Ninthly, a communication device is provided. The communication device includes a processor configured to perform the method of any one of the embodiments of the first to fourth aspects, or to perform the method of any one of the embodiments of the fifth to eighth aspects.

In one possible implementation, the communication device described in the ninth aspect may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver can be used for communication between the communication device described in the ninth aspect and other communication devices.

In one possible implementation, the communication device described in the ninth aspect may further include a memory. This memory may be integrated with the processor or disposed separately. The memory may be used to store computer programs and/or data involved in the methods of any of the embodiments of the first to fourth aspects, or computer programs and/or data involved in the methods of any of the embodiments of the fifth to eighth aspects.

Furthermore, the technical effects of the communication device described in the ninth aspect can be referenced from the technical effects of any of the embodiments in the first to fourth aspects, or from the technical effects of any of the embodiments in the fifth to eighth aspects, which will not be repeated here.

A tenth aspect provides a communication device. The communication device includes a processor coupled to a memory, the processor being configured to execute a computer program or instructions stored in the memory, such that the communication device performs a method according to any one of the embodiments of the first to fourth aspects, or performs a method according to any one of the embodiments of the fifth to eighth aspects.

In one possible implementation, the communication device may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver can be used for communication between the communication device and other communication devices.

In one possible implementation, the communication device further includes the memory for storing the aforementioned computer program or instructions. Optionally, the memory and processor are integrated together.

Furthermore, the technical effects of the communication device described in the tenth aspect can be referred to the technical effects of any of the embodiments in the first to fourth aspects, or the technical effects of any of the embodiments in the fifth to eighth aspects, which will not be repeated here.

Eleventhly, a communication device is provided. This communication device is used to implement the method of any one of the embodiments of the first to fourth aspects.

In a twelfth aspect, a communication device is provided. This communication device is used to implement the method of any one of the embodiments of the fifth to eighth aspects.

In a thirteenth aspect, a communication system is provided. The communication system includes: a first access network device for performing the method described in any one of the embodiments of the first or fifth aspect; and a first terminal for performing the method described in any one of the embodiments of the second to fourth or sixth to eighth aspects.

In a fourteenth aspect, a computer-readable storage medium is provided, comprising: a computer program or instructions; when the computer program or instructions are executed, causing the method of any of the embodiments of the first to fourth aspects described above to be implemented, or causing the method of any of the embodiments of the fifth to eighth aspects described above to be implemented.

In a fifteenth aspect, a computer program product is provided, comprising a computer program or instructions that, when executed, cause the method of any of the embodiments of the first to fourth aspects described above to be implemented, or cause the method of any of the embodiments of the fifth to eighth aspects described above to be implemented.

Attached Figure Description

Figure 1 is a schematic diagram of a system architecture 100 provided in an embodiment of this application;

Figure 2 is a schematic diagram of a system architecture 200 provided in an embodiment of this application;

Figure 3 is a schematic diagram of a system architecture 300 provided in an embodiment of this application;

Figure 4 is a schematic diagram of a system architecture 400 provided in an embodiment of this application;

Figure 5 is a schematic diagram of an SF scenario provided in an embodiment of this application;

Figure 6 is a schematic diagram of mode conversion provided in an embodiment of this application;

Figure 7 is a schematic diagram of the communication system provided in an embodiment of this application;

Figure 8 is a schematic diagram of the communication system provided in an embodiment of this application;

Figure 9 is a schematic diagram of the O-RAN architecture provided in an embodiment of this application;

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

Figure 11 is a schematic diagram of the second flow of the communication method provided in the embodiment of this application;

Figure 12 is a schematic diagram of the communication method provided in the embodiment of this application.

Figure 13 is a schematic diagram of the communication method provided in the embodiment of this application;

Figure 14 is a schematic diagram of the communication method provided in the embodiment of this application.

Figure 15 is a schematic diagram of the communication device provided in an embodiment of this application;

Figure 16 is a schematic diagram of the structure of the communication device provided in the embodiment of this application.

Detailed Implementation

1. Non-terrestrial networks (NTN)

In a broad sense, base stations/sites in NTN include various types of aerial base stations, such as low Earth orbit (LEO), middle Earth orbit (MEO), geosynchronous Earth orbit (GEO), high altitude platform station (HAPS) systems, and unmanned aerial vehicles (UAVs). From the perspective of the 3rd Generation Partnership Project (3GPP), base stations/sites in NTN mainly include GEO, MEO, LEO, and HAPS.

Satellites are generally categorized into GEO, MEO, and LEO, primarily based on their orbital altitude. LEO satellites, or "low-Earth orbit satellites," orbit at altitudes of approximately 160–2,000 km. The vast majority of Earth observation satellites, geodetic satellites, space stations, and some new communication satellite systems use LEO satellites. MEO satellites, or "medium-Earth orbit satellites," orbit at altitudes of 2,000–35,786 km and are commonly used for television relay and navigation. GEO satellites, or "high-Earth orbit satellites," orbit at an altitude of approximately 35,786 km. Satellites in this orbit are unaffected by the Earth's rotation and are commonly used for remote sensing and satellite phones.

2. Satellite Network Architecture

The following introduces five radio access network (RAN) architectures based on NTN, which can be divided into pass-through architecture and regeneration architecture. The pass-through architecture will be introduced first.

Architecture 1: Transparent architecture.

Figure 1 is a schematic diagram of a system architecture 100 provided in an embodiment of this application. As shown in Figure 1, during communication between the user equipment (UE) and the base station (gNB), the satellite communicates with the NTN gateway through the New Radio (NR) system air interface (Uu interface), the gNB communicates with the 5G core network (5G CN) through the next generation (NG) interface, and the 5G CN communicates with the data network through the N6 interface. The network communication segment between the UE and the gNB (or ng-eNB, not shown in the figure) is called a remote radio unit (RRU), and the NG-RAN node is used to ensure normal communication between the UE and the 5G CN. The satellite can act as an L1 relay for radio frequency filtering, frequency conversion, and amplification, regenerating the physical layer signal so that the physical layer signal is invisible to the protocol layers above the physical layer. The NTN gateway station can support all the necessary functions for forwarding NR-Uu interface signals, forwarding NR-Uu interface signals (from the UE) relayed by the satellite to the gNB, or forwarding NR-Uu interface signals from the gNB to the satellite. This architecture can be called a "transparent architecture" or "transparent satellite architecture." In this architecture, the satellite can be understood as the RRU of the ground gNB. The satellite only provides simple physical signal coverage. However, this radio frequency extension function needs to be achieved through the NTN gateway station and the microwave link between the satellite and the NTN gateway station to reach the satellite. In this process, no protocol layer processing or logical interface is established.

The following describes four regenerative architectures.

Architecture 2: Regenerated satellites without inter-satellite links, but with base station processing capabilities.

Figure 2 is a schematic diagram of a system architecture 200 provided in an embodiment of this application. As shown in Figure 2, the satellite can act as a base station. For example, the satellite communicates with the UE via the NR-Uu interface. Simultaneously, the satellite communicates with the 5G CN via the NG interface, and the 5G CN communicates with the data network via the N6 interface. During the communication between the satellite and the 5G CN, the NTN gateway station connects network segments using different protocols to ensure normal communication. In the satellite-NTN gateway station network segment, the NG interface is an interface deployed in the satellite radio interface (SRI), and the NG-RAN node ensures normal communication between the UE and the 5G CN. The NTN gateway station is a transmission network layer node that supports all necessary transmission protocols and connects network segments using different protocols to ensure normal communication. This architecture can be called a "regenerative architecture." In this architecture, the satellite, as a base station, has all the protocol layer processing functions of a base station and can directly process signals from the UE or directly send signals to the UE.

Architecture 3: Regenerated satellites with inter-satellite links and base station processing capabilities.

Figure 3 is a schematic diagram of a system architecture 300 provided in an embodiment of this application. As shown in Figure 3, satellite 1 and satellite 2 can act as base stations. For example, satellite 1 communicates with the UE via the NR-Uu interface and with another satellite 2, which also acts as a base station, via the Xn interface. The Xn interface can be deployed on an inter-satellite link (ISL). Simultaneously, satellite 1 and satellite 2 communicate with the 5GCN via the NG interface. The 5G CN communicates with the data network via the N6 interface. During the communication between satellite 1 and satellite 2 and the 5G CN, the NTN gateway station connects network segments using different protocols to ensure normal communication. In the satellite-NTN gateway station network segment, the NG interface is an interface deployed in the satellite radio interface (SRI), and the NG-RAN node ensures normal communication between the UE and the 5G CN. The NTN gateway station is a transport network layer node that supports all necessary transport protocols and connects network segments using different protocols to ensure normal communication. In Architecture 3, a satellite can also be viewed as a base station. The difference between Architecture 3 and Architecture 2 is that this scenario has ISL (Inter-Satellite Link), which allows the establishment of Xn interfaces between satellites. Furthermore, when Satellite 1 and the NTN gateway station are not visible to each other, data from Satellite 1 can be transmitted back to the ground via Satellite 2. Architecture 3 is the most promising architecture for the future.

Architecture 4: Regenerative satellite with DU processing capabilities for base stations.

Figure 4 is a schematic diagram of a system architecture 400 provided in an embodiment of this application. As shown in Figure 4, during communication between the UE and the central unit (CU) of the base station (gNB), the satellite acts as the distributed unit (DU) of the base station (gNB). The satellite communicates with the NTN gateway through the F1 interface, the gNB-CU communicates with the 5G CN through the NG interface, and the 5G CN communicates with the data network through the N6 interface. The NG-RAN node is used to ensure the normal operation of communication between the UE and the 5G CN. In this architecture, the satellite has some base station functions, namely the gNB-DU function, directly processing signals from the UE or directly transmitting signals to the UE.

Architecture 5: Satellites with integrated access and backhaul (IAB) capabilities.

In this scenario, the satellite can act as an IAB node, similar to architecture 4. However, the difference is that in architecture 5, in addition to deploying DU, a mobile terminal (MT) module is also deployed on the satellite. The MT uses the air interface between the satellite and the ground base station for backhaul, eliminating the need to establish a separate microwave backhaul link between the satellite and the NTN gateway station.

3. Store and forward (S&F/SF) technology

Within 3GPP, NTN-related topics include NR NTN and Internet of Things (IoT) NTN. They use essentially the same architecture, with some differences in characteristics. IoT NTN is based on Long Term Evolution (LTE), and its base station is an eNB. In Release 19, IoT NTN will study SF technology based on a regenerable satellite architecture. The need for SF is to address scenarios where the number of satellites and ground gateway stations is very small, making it impossible to maintain a constant connection between ground gateway stations and satellites. In such scenarios, when satellites cover the UE, the UE may not be able to connect to the gateway station and therefore cannot communicate with the core network. Conversely, when satellites can connect to the gateway station and thus the core network, there may be no UE below. In such scenarios, normal real-time services cannot be completed.

Figure 5 is a schematic diagram of an SF scenario provided by an embodiment of this application. As shown in Figure 5, in the SF scenario that needs to be studied in R19, for some non-real-time IoT services (such as sensor data reporting), communication between the satellite and the UE can be carried out first when there is no gateway satellite covering the UE. When the satellite covers the NTN gateway, the satellite becomes a gateway satellite, and then communication between the satellite and the core network is carried out in a relay manner. This requires the satellite to have a certain storage and processing capacity to cache the data arriving from the UE or the core network and forward it at a later time. Therefore, in this scenario, the satellite is a regenerator satellite, i.e., an eNB, which can also be extended to a gNB.

The discussion on SF (Short-Side) mode in Release 19 concludes that the satellite must indicate to the UE that it is operating in SF mode, not normal mode. In scenarios where the UE is far from the gateway station, the satellite will not simultaneously cover both the UE and the CN (Network Application Clusters), and will always operate in SF mode. In scenarios where the UE is close to the gateway station, the satellite will always simultaneously cover both the UE and the CN, and will always operate in normal mode. However, it does not currently consider that if the distance between the UE and the gateway station is moderate, the satellite may sometimes only cover the gateway station, sometimes both the UE and the gateway station, and sometimes only the UE. If the satellite currently providing service to the UE undergoes a mode switch, it may lead to data transmission failure for the UE or prevent it from accessing a new satellite.

Figure 6 is a schematic diagram of mode conversion provided in an embodiment of this application. As shown in Figure 6, the possible mode conversions of the satellite include the conversion from normal mode to SF mode as shown in Figure 6(a), and the conversion from SF mode to normal mode as shown in Figure 6(b). As shown in Figure 6(a), if the UE can only receive services in normal mode, but the satellite switches from normal mode to SF mode while providing services to the UE, it will cause a sudden increase in service latency, resulting in UE service transmission failure. As shown in Figure 6(b), the satellite switches from SF mode to normal mode while providing services to the UE. At this time, the satellite is working in normal mode. When the satellite leaves the UE but can still connect to the CN, the UE will be released to the idle state, causing the base station connected to the UE during initial access to be unable to connect to the CN, and the UE cannot perform initial authentication, which may result in the UE being unable to successfully access the next SF satellite.

To address the aforementioned technical problems, the embodiments of this application propose the following technical solutions.

The technical solutions in this application will now be described with reference to the accompanying drawings.

The technical solutions of this application embodiment can be applied to various communication systems, such as wireless network (Wi-Fi) systems, vehicle to everything (V2X) communication systems, device-to-device (D2D) communication systems, machine-to-machine (M2M) communication systems, machine-type communication (MTC) systems, IoT communication systems, vehicle-to-everything (V2M) communication systems, fourth-generation (4G) mobile communication systems such as LTE systems, LTE frequency division duplex (FDD) systems, LTE time division duplex (TDD) systems, fifth-generation (5G) mobile communication systems such as NR systems, and communication systems evolved after 5G, such as 6G.

In the embodiments of this application, "instruction" can include direct and indirect instructions, as well as explicit and implicit instructions. The information indicated by a certain piece of information (such as the first instruction information, second instruction information, or third instruction information below) is called the information to be instructed. In the specific implementation process, there are many ways to indicate the information to be instructed, such as, but not limited to, directly indicating the information to be instructed, such as the information to be instructed itself or its index. It can also indirectly indicate the information to be instructed by indicating other information, where there is a correlation between the other information and the information to be instructed. It can also indicate only a part of the information to be instructed, while the other parts are known or pre-agreed upon. For example, the instruction of specific information can be achieved by using a pre-agreed (e.g., protocol-defined) arrangement order of various pieces of information, thereby reducing instruction overhead to some extent. At the same time, common parts of various pieces of information can be identified and indicated uniformly to reduce the instruction overhead caused by individually indicating the same information.

Furthermore, the specific instruction method can also be any existing instruction method, such as, but not limited to, the above-mentioned instruction methods and their various combinations. As described above, for example, when multiple pieces of information of the same type need to be indicated, the instruction methods for different pieces of information may differ. In the specific implementation process, the required instruction method can be selected according to specific needs. This application embodiment does not limit the selected instruction method. Therefore, the instruction methods involved in this application embodiment should be understood to cover various methods that enable the party to be instructed to obtain the information to be indicated.

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

"Predefined" or "pre-configured" can be achieved by pre-saving corresponding codes, tables, or other means that can be used to indicate relevant information in the device. This application does not limit the specific implementation method. "Saving" can refer to saving in one or more memories. These memories can be separate installations or integrated into the encoder, decoder, processor, or communication device. Alternatively, some memories can be separately installed, while others are integrated into the decoder, processor, or communication device. The type of memory can be any form of storage medium, and this application does not limit this.

The “protocol” mentioned in the embodiments of this application may refer to a protocol family in the field of communication, a standard protocol with a similar protocol family frame structure, or a related protocol applied to future communication systems. The embodiments of this application do not specifically limit this.

In the embodiments of this application, descriptions such as "when," "under the circumstances," "if," and "if" all refer to the device making corresponding processing under certain objective circumstances, and are not limited to a specific time. They do not require the device to make a judgment action during implementation, nor do they imply any other limitations.

In the description of the embodiments of this application, unless otherwise stated, "/" indicates that the objects before and after are in an "or" relationship. For example, A/B can represent A or B. "And/or" in the embodiments of this application is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and/or B can represent: A alone, A and B simultaneously, and B alone, where A and B can be singular or plural. Furthermore, in the description of the embodiments of this application, unless otherwise stated, "multiple" refers to two or more. "At least one of the following" or similar expressions refer 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 represent: a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, and c can be single or multiple. Furthermore, to facilitate a clear description of the technical solutions in the embodiments of this application, the terms "first" and "second" are used in the embodiments of this application to distinguish identical or similar items with substantially the same function and effect. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that "first" and "second" are not necessarily different. Meanwhile, in the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is being used as an example, illustration, or explanation. Any embodiment or implementation described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or implementations. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner for ease of understanding.

The network architecture and business scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

To facilitate understanding of the embodiments of this application, the communication system applicable to the embodiments of this application will be described in detail first using the communication system shown in FIG7 as an example. For example, FIG7 is a schematic diagram of the architecture of a communication system to which the method provided in the embodiments of this application is applicable.

As shown in Figure 7, the communication system mainly includes a first terminal and a first access network device. The first access network device serves the first terminal and can be a non-terrestrial network device, such as an eNB in a regenerable architecture. If the first terminal does not accept the service of the second mode, the first access network device sends first information to the first terminal before switching from the first mode to the second mode. Based on this first information, the first terminal either accesses the second access network device or enters an idle state. The first mode refers to the access network device simultaneously connecting the terminal and the core network device, while the second mode refers to the access network device not simultaneously connecting the terminal and the core network device. The second access network device operates in the first mode. The first mode can be a normal mode, and the second mode can be an SF mode, as described above. This ensures that the first terminal can function correctly when the first access network device serves the first terminal and the mode switches, preventing service transmission failures.

In one possible scenario, this communication system can be applied to 5G or future 6G communication systems. For example, as shown in Figure 8, the communication system 10 includes a RAN 100, a core network (CN) 200, and an Internet 300. RAN 100 includes at least one RAN node (as shown in Figure 8, 110a and 110b, collectively referred to as 110) and at least one terminal (as shown in Figure 8, 120a-120j, collectively referred to as 120). RAN 100 may also include other RAN nodes, such as wireless relay equipment and/or wireless backhaul equipment (not shown in Figure 8). Terminal 120 is wirelessly connected to RAN node 110. RAN node 110 is wirelessly or wired connected to core network 200. The core network equipment in core network 200 and RAN node 110 in RAN 100 can be different physical devices, or they can be the same physical device integrating core network logical functions and wireless access network logical functions.

RAN 100 can be a 3GPP-related cellular system, such as a 4G or 5G mobile communication system, or a future-oriented evolution system (such as a 6G mobile communication system). RAN 100 can also be an open access network (open RAN, O-RAN, or ORAN), a cloud radio access network (CRAN), or a Wi-Fi system. RAN 100 can also be a communication system that integrates two or more of the above systems.

RAN node 110, sometimes referred to as access network equipment, RAN entity, or access node, constitutes part of the communication system and is used to help terminals achieve wireless access. Multiple RAN nodes 110 in communication system 10 can be of the same type or different types. In some scenarios, the roles of RAN node 110 and terminal 120 are relative. For example, network element 120i in Figure 8 can be a helicopter or drone, which can be configured as a mobile base station. For terminals 120j accessing RAN 100 through network element 120i, network element 120i is a base station; but for base station 110a, network element 120i is a terminal. RAN node 110 and terminal 120 are sometimes both referred to as communication devices. For example, network elements 110a and 110b in Figure 8 can be understood as communication devices with base station functions, and network elements 120a-120j can be understood as communication devices with terminal functions.

In one possible scenario, the RAN node can be a base station, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next-generation NodeB (gNB), a next-generation base station in a 6G mobile communication system, a base station in a future mobile communication system, or an access point (AP) in a Wi-Fi system. The RAN node can be a macro base station (as shown in Figure 8, 110a), a micro base station or indoor station (as shown in Figure 8, 110b), a relay node or donor node, or a radio controller in a CRAN scenario. Optionally, the RAN node can also be a server, wearable device, vehicle, or in-vehicle equipment. For example, the access network equipment in vehicle-to-everything (V2X) technology can be a roadside unit (RSU). All or part of the functions of the RAN node in this application can also be implemented through software functions running on hardware, or through virtualization functions instantiated on a platform (e.g., a cloud platform). The RAN node in this application can also be a logical node, logical module, or software that can implement all or part of the functions of the RAN node.

In another possible scenario, multiple RAN nodes collaborate to assist the terminal in achieving wireless access, with different RAN nodes each implementing some of the base station's functions. For example, RAN nodes can be CUs, DUs, CUs (control plane, CP), CUs (user plane, UP), or radio units (RUs). CUs and DUs can be set up separately or included in the same network element, such as a baseband unit (BBU). RUs can be included in radio frequency equipment or radio frequency units, such as RRUs, active antenna units (AAUs), or remote radio heads (RRHs).

In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU can also be called O-CU (open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules.

It is understood that the RAN node mentioned above can be a newly defined name, and RAN nodes can also be described in different ways, such as access node, network device, wireless access node, etc., without limitation. Unless otherwise specified in this application, network device will be used as the term.

Terminals can also be called terminal devices, user equipment (UE), mobile stations, mobile terminals, etc. Terminals can be widely used in various scenarios, such as device-to-device (D2D), V2X communication, machine-type communication (MTC), Internet of Things (IoT), point-of-sale (POS) machines, customer-premises equipment (CPE), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables (e.g., smartwatches, smart bracelets, pedometers, smart glasses), smart transportation, and smart cities. The terminal can be a mobile phone, tablet computer, computer with wireless transceiver capabilities, wearable device, vehicle device (e.g., vehicle assembly, vehicle module, vehicle chip, on-board unit (OBU) or telematics box (T-BOX)), drone, helicopter, airplane, ship, robot, robotic arm, smart home device, satellite terminal, etc. The embodiments of this application do not limit the device form of the terminal.

In another possible scenario, this communication system can be applied to an O-RAN architecture. For example, Figure 9 is a schematic diagram of an O-RAN architecture provided in an embodiment of this application. As shown in Figure 9, the intelligent controller (RIC) communicates with the eNB through the E2 interface. The RIC controls the eNB to send relevant information to the terminal. The relevant information here may include the first information mentioned above, which will not be elaborated here.

In this communication system, before the first access network device switches from the first mode to the second mode, it triggers the first terminal, which does not accept the service of the second mode, to switch to the serving access network device, so that the first terminal can continue to transmit services. Alternatively, the first access network device releases the first terminal to an idle state, which can normally interrupt the service transmission of the first terminal and avoid the service transmission failure of the first terminal.

The embodiments of this application do not limit the device form of the network device. The apparatus used to implement the function of the network device can be the network device itself, or it can be an apparatus capable of supporting the network device in implementing the function, such as a chip system. This apparatus can be installed in the network device, or used in conjunction with the network device. In the embodiments of this application, the chip system can be composed of chips, or it can include chips and other discrete components.

The interaction process between various network elements/devices in the above-described communication system will be specifically described below with reference to Figure 10 and through method embodiments. The communication method provided in this application embodiment can be applied to the above-described communication system and specifically applied to various scenarios/processes mentioned in the above-described communication system, which will be described in detail below.

Figure 10 is a schematic flowchart of a communication method provided in an embodiment of this application. This communication method is applicable to the above-mentioned communication system and mainly involves the interaction between a first terminal and a first access network device.

As shown in Figure 10, the flow of this communication method is as follows:

S1001, the first terminal sends third information to the first access network device, and the first access network device receives the third information accordingly.

The third piece of information indicates that the first terminal does not accept the service of the second mode. The second mode refers to the access network device not simultaneously connecting the terminal and the core network device. The second mode can be SF mode, or any possible mode in the scenario where the access network device does not simultaneously connect the terminal and the core network device. The first terminal does not accept the service of the second mode, that is, the access network device operating in the second mode restricts the access of the first terminal, and the first terminal cannot access the access network device operating in the second mode. The first terminal can access the access network device operating in the first mode, where the first mode refers to the access network device simultaneously connecting the terminal and the core network device. That is, the first mode can be normal mode, or any possible mode in the scenario where the access network device simultaneously connects the terminal and the core network device.

This allows the first access network device to know whether the first terminal accepts the second mode, thereby determining whether it is necessary to replace the service access network device for the first terminal.

When the third information originates from the first terminal, it is contained within service information and/or capability information. The service information indicates that the first terminal's current service does not accept the second mode of service. This service information can be carried in the Radio Resource Control (RRC) protocol and can be a separate reporting message. For example, a UE in RRC-connected state sends an RRC message to the eNB indicating whether its current service accepts SF mode service. Alternatively, existing signaling can be reused, such as the capability information of the first terminal triggered when accessing the network. This capability information indicates that the first terminal does not have the capability to accept the second mode of service.

Optionally, the third information may also indicate the identifier of the first terminal. The identifier of the first terminal may be a symbol such as letters or numbers used to uniquely identify the first terminal, such as UE S1AP ID, IMSI, SUPI, C-RNTI, etc.

Optionally, the first access network device receives third information from the first terminal or the core network device serving the first terminal. That is, the first access network device can also obtain third information through the core network device serving the first terminal. It can be understood that the interaction between the first access network device or the first terminal and the core network device can be implemented through the mobility management entity of the control plane function. The mobility management entity can be an entity/network element with mobility management and connection management functions, such as the mobile management entity (MME) in a 4G network or the access and mobility management function (AMF) in a 5G network. The core network device can determine whether the currently active service accepts the second mode service based on the type of service currently being performed by the first terminal. For example, the CN obtains the type of service being performed by the UE, and based on the subscription information, determines whether the currently active service accepts the SF mode. Therefore, the MME network element in the CN indicates to the eNB whether the UE accepts the SF service, carrying the UE's identifier (such as UE S1AP ID, IMSI, SUPI, etc.).

S1002, before the first access network device switches from the first mode to the second mode, the first access network device sends first information to the first terminal served by the first access network device, and correspondingly, the first terminal receives the first information from the first access network device.

The first information triggers the first terminal to switch to access the second access network device, or releases the first terminal to an idle state, wherein the second access network device operates in the first mode.

It is understandable that if the first access network device switches from the first mode to the second mode, the first terminal will fail to transmit its services because it does not accept the services of the second mode. Therefore, by sending the first information to the first terminal through the first access network device to trigger the first terminal to switch to accessing the second access network device, the first terminal can continue to transmit services. Alternatively, the first access network device can release the first terminal to an idle state, which can normally interrupt the transmission of the first terminal's services and avoid the failure of the first terminal's service transmission.

The first information can be carried in a handover command (HO command) message to trigger the first terminal to switch to the second access network device, that is, to trigger the first terminal to switch to the cell of the second access network device. The message can carry the cell identifier under the second access network device; or, the first information can be carried in an RRC release message to instruct the first access network device to release the first terminal to the idle state.

Optionally, before the first access network device sends the first information to the first terminal served by the first access network device, the communication method may further include: the first access network device sending second information, the second information indicating that the operating mode of the first access network device changes from the first mode to the second mode. The first access network device sending the second information to the first terminal may occur after or before the first terminal sending the third information to the first access network device.

The second information can be carried in a broadcast message, such as in a system information block (SIB). The first access network device indicates a change in its operating mode from the first mode to the second mode via a broadcast message. For example, the eNB changes the broadcast S&F indication to true and triggers the UE to read system information updates. Alternatively, the eNB can send a short message to the UE to trigger the UE to read system information updates, so that the UE receives the information that the eNB's operating mode has changed to S&F mode. Optionally, the second information indicates that the first access network device's operating mode will change from the first mode to the second mode. That is, the first access network device broadcasts a message in advance that it will switch operating modes, but its operating mode remains the first mode. This ensures that the first access network device and the first terminal are aligned in their operating modes, avoiding mismatches between the operating modes of the first access network device and the first terminal.

S1003, the first terminal connects to the second access network device or enters an idle state based on the first information.

If a second access network device operating in the first mode is available to provide services to the terminal, the first access network device instructs the first terminal to access the second access network device via the first information. If the first access network device does not detect a second access network device that can provide services to the terminal, the first access network device releases the first terminal to an idle state.

Optionally, S1003 may include: performing cell reselection when the first information indicates the release of the first terminal's Radio Resource Control (RRC) connection. After the first access network device releases the first terminal to an idle state, and the first terminal is in an idle state, cell reselection is performed, and the cell reselection process follows the S, R criteria.

In one possible implementation, the communication method may further include: if a first terminal that does not accept the service of the second mode is camped in the cell of the first access network device, the first terminal obtains the second information and reselects to the second access network device, or continues to camp in the cell of the first access network device without entering the connected state.

In other words, when the first terminal in an idle state obtains information that the first access network device has changed from the first mode to the second mode, it performs cell reselection. Alternatively, the first terminal can always be in any cell selection state, which is beneficial for quickly camping on the cell of the second access network device when a suitable second access network device is available.

If no suitable second access network device is available, meaning no access network device operating in the first mode can provide service to the first terminal (i.e., no suitable cell is available), the first terminal can continue to camp on the cell of the first access network device without entering the connected state. In other words, the first terminal considers the current cell of the first access network device to be an acceptable cell and remains camped there, but will not initiate entry into the connected state. An acceptable cell is used when the terminal cannot find a cell within the same public land mobile network (PLMN). In this case, the terminal can camp on a cell in a different PLMN (called an acceptable cell). When camped on an acceptable cell, the terminal can only make emergency calls but cannot initiate normal service requests. In this embodiment, the situation where the first terminal, which does not accept the second mode service, camps on the cell of the first access network device operating in the second mode is also considered an acceptable cell. This allows the first terminal to choose a cell to camp on, reducing the need for frequent cell searches and saving power.

S1004, the first access network device switches from the first mode to the second mode.

After determining whether all first terminals that do not accept the second mode are switched to access the second access network device or released to an idle state, the first access network device switches from the first mode to the second mode. For example, the eNB disconnects the S1 interface from the MME and disconnects the power supply link, thus the eNB operates in SF mode.

It is understandable that the execution order of S1003 and S1004 is not limited; S1003 can be executed before or after S1004.

In another possible implementation, the communication method further includes: if the first terminal accepts the service of the second mode, after receiving the second information from the first access network device, the first terminal disables a timer or increases the timer's duration. The timer is used to determine whether the first terminal's service transmission is successful within the time limit. The timer can be a non-access stratum (NAS) timer, started when the first terminal sends a NAS message, used to listen for a response message from the network side. If there is no response from the network side within the NAS timer's duration, the message transmission is considered to have failed, thus generating an error message. In the second mode, since the first access network device does not simultaneously connect the first terminal and the core network device, real-time services cannot be transmitted. After the first terminal sends a NAS message, it needs to wait until the first terminal reconnects to the first access network device to receive the NAS message. Therefore, the NAS timer needs to be disabled or its duration increased to avoid errors due to a short timer duration in the second mode, ensuring successful data transmission by the first terminal in the second mode.

The first terminal receives information from the first access network device that it has changed from the first mode to the second mode. Since the first terminal accepts the service of the second mode, the first terminal stops transmitting non-second mode services and starts transmitting second mode services. Non-second mode services can be real-time transmission services, while second mode services can be non-real-time transmission services, such as sensor data reporting services.

Optionally, the communication method may further include: the first access network device instructing the first terminal that the access network device serving the first terminal after the first access network device is operating in a first mode or a second mode. Specifically, this can be indicated via SIB broadcast. For example, satellite 1 may broadcast via SIB instructing the UE to access a list of satellites after satellite 1, and may also indicate whether multiple satellites in the satellite list, such as satellite 2 and satellite 3, are operating in SF mode.

In summary, before the first access network device switches from the first mode to the second mode, it triggers the first terminal, which does not accept the service of the second mode, to switch to the serving access network device, allowing the first terminal to continue transmitting services. Alternatively, the first access network device releases the first terminal to an idle state, which can normally interrupt the service transmission of the first terminal and avoid service transmission failure.

Figure 11 is a schematic flowchart of another communication method provided in an embodiment of this application. This communication method is applicable to the above-mentioned communication system and mainly involves the interaction between a first terminal and a first access network device.

As shown in Figure 11, the flow of this communication method is as follows:

S1101, the first access network device sends the second information to the first terminal, and correspondingly, the first terminal receives the second information from the first access network device.

The first access network device operates in the first mode. The descriptions of the first and second modes in S1001 are not repeated here. The second information is similar to that in S1002, both used to indicate a change in the operating mode of the first access network device. This second information can also be carried in a broadcast message; for example, the eNB changes the broadcast S&F indication to false. The difference is that in S1002, the instruction to change the first access network device's operating mode from the first mode to the second mode is sent before the mode change; in S1101, the second information indicates that the first access network device's operating mode is changed from the second mode to the first mode. Compared to the first access network device operating in the second mode, the first terminal's transmission performance is better when the first access network device is operating in the first mode, therefore the second information is sent after the mode change to the first mode. The description of the second information in S1002 is also not repeated here.

Optionally, the communication method may further include: S1100, the first access network device switches from the second mode to the first mode. That is, after the first access network device switches to the first mode, the interaction between the first access network device and the first terminal in S1101 is performed.

S1102, the first terminal starts the timer or shortens the timer duration.

The timer is used to determine whether the service transmission of the first terminal is successful within the specified time period.

The timer description can be found in S1004 and will not be repeated here. Shorten the timer's duration to the value for service transmission in the first mode, for example, shorten it to the normal value of the NAS timer used for transmitting non-SF services, and then begin transmitting non-SF services. This ensures the accuracy of determining whether service transmission was successful in the first mode.

In one possible implementation, the communication method may further include: while the first terminal is waiting for service from the third access network device, acquiring second information, and accessing the first network device based on the second information, wherein the third access network device operates in a second mode. For a first terminal that is not connected to the first network device and is waiting for service from the third access network device, it can access the first network device after acquiring information that the first network device has changed to a first mode, ensuring that the first terminal can transmit services normally. For example, if the UE is not connected to satellite 1 operating in SF mode and is waiting for satellite 2 operating in SF mode, the UE can initiate access to satellite 1 after satellite 1's operating mode changes to normal mode.

In another possible implementation, the communication method may further include: when a first terminal that does not accept the second mode service is camped in the cell of the first access network device and is not allowed to enter the connected state, obtaining second information and determining, based on the second information, that the first terminal is allowed to enter the connected state in the cell of the first access network device. The situation where the first terminal that does not accept the second mode service is camped in the cell of the first access network device and is not allowed to enter the connected state is the same as the situation in S1003 where it continues to camp in the cell of the first access network device and does not enter the connected state. The first terminal that does not accept the second mode service being camped in the cell of the first access network device can be understood as being camped in an available cell. The available cell can be referred to in the description of S1003 and will not be repeated here. Since the first terminal does not accept the second mode service, it is not allowed to access the first access network device operating in the second mode. When the first terminal obtains information that the first access network device has switched to the first mode based on the second information, the first terminal determines to change the cell camped in the first access network device to a suitable cell, allowing normal access to the first access network device. This enables the idle first terminal to subsequently initiate entry into the connected state, ensuring the normal operation of the service transmission process.

S1103, if the first access network device determines that it is about to disconnect from the first terminal, and determines that the third access network device serving the first terminal after the first access network device is operating in the second mode, it sends a first instruction message to the first terminal.

The first indication information instructs the first terminal not to enter the idle state. The first access network device can determine whether the third access network device is operating in the second mode by using the ephemeris information and gateway location information of the third access network device. If the third access network device is operating in the second mode, it instructs the first terminal not to enter the idle state; that is, it does not release the first terminal to the idle state, but instead keeps the first terminal in the connected state and suspends access stratum (AS) operations. In this way, when the first access network device is about to disconnect from the first terminal, the first access network device and the first terminal can align their next operating modes, avoiding service transmission failures for the first terminal.

Optionally, the communication method may further include: the first access network device instructing the first terminal that the third access network device is operating in the second mode. Specifically, this can be done via SIB broadcast; for example, satellite 1 may broadcast an instruction to the UE via SIB to overwrite the UE's satellite list after satellite 1, specifically instructing the satellites (third access network devices) operating in SF mode within the satellite list.

Optionally, the communication method may further include: when the first access network device provides services to the first terminal, the first access network device sends a second indication information to the core network device serving the first terminal, the second indication information instructing the first access network device to serve the first terminal, and/or the first access network device to operate in a first mode for the first terminal.

The first access network device serving the first terminal, and the first access network device operating in the first mode for the first terminal, both indicate that the first terminal is being served by the first access network device and is in a connected state in the first mode, not in a connected state in the second mode. For example, a satellite (eNB) sends an indication message to the CN's MME network element indicating that it is currently covering the UE, or that the eNB is currently operating in normal mode for the UE, carrying the UE's identifier. In this case, the eNB still covers the UE, so the UE coverage indication information is true; the satellite is operating in normal mode instead of SF mode, so the SF indication information is false.

Specifically, the interaction between the first access network device or the first terminal and the core network device can be implemented through the mobility management entity of the control plane function. The mobility management entity can be referred to in the description of S1001, and will not be elaborated further. After obtaining information that the first terminal is in a normal connected state, the mobility management entity can send downlink data to the first access network device to achieve real-time data transmission and improve data transmission efficiency.

In addition, the core network equipment can also determine whether the first access network device serves the first terminal and/or whether the first access network device operates in the first mode for the first terminal by using the location of the first terminal and the ephemeris information of the first access network device. In other words, the core network equipment can determine the content specified by the second indication information on its own, saving signaling overhead.

Optionally, the communication method may further include: a first access network device receiving downlink data sent by a core network device according to second instruction information; and a mobility management entity sending downlink data to the first access network device after obtaining information that the first terminal is in a normal connected state.

For example, in SF mode, after the satellite (eNB) leaves the UE, the UE is not released to an idle state. The CN needs to distinguish whether the UE is in a normal connected state (the UE is being served by the eNB) or in a connected state in SF mode (the UE is not being served by the eNB) through an indication message. If the UE is in a normal connected state, the MME network element in the CN can send downlink data to the eNB currently serving the UE. If the UE is in a connected state in SF mode, the MME network element can send downlink data to the eNB that will subsequently serve the UE. Therefore, by instructing the first access network device to serve the first terminal through the second indication information, and/or by having the first access network device operate in the first mode for the first terminal, the core network device can determine how to send downlink data for the first terminal, thereby improving data transmission efficiency.

Optionally, the communication method may further include: when the first access network device determines that it is about to disconnect from the first terminal or has already disconnected, the first access network device sends a third indication message to the core network device serving the first terminal, the third indication message indicating that the first access network device does not serve the first terminal, and/or the first access network device operates in a second mode for the first terminal.

It is understood that the third indication information can be sent before or after S1103. If the first access network device determines that it has lost connection with the first terminal, the third indication information will be sent after S1103. The first access network device and the first terminal may be about to lose connection when the first terminal is at the cell edge of the first access network device.

The third indication information can be the opposite of the second indication information; that is, the value of the second indication information is inverted to obtain the third indication information. The fact that the first access network device does not serve the first terminal, or that the first access network device is operating in the second mode for the first terminal, both indicate that the first terminal is not being served by the first access network device, meaning the first terminal is in a connected state in the second mode. For example, before the satellite (eNB) leaves the UE (disconnects from the UE), or after it has left the UE, it sends an indication message to the CN's MME network element indicating that it is currently not covering the UE, or that the eNB is currently operating in SF mode for the UE, carrying the UE's identifier. In this case, if the eNB is not covering the UE, the indication information for UE coverage is false; if the satellite is operating in SF mode, the SF indication information is true. After obtaining the information that the first terminal is in a connected state in the second mode, the core network device can send downlink data to subsequent access network devices to achieve non-real-time data transmission and avoid data transmission failure.

In addition, the core network equipment can also determine, through the location of the first terminal and the ephemeris information of the first access network equipment, whether the first access network equipment is not serving the first terminal, and/or whether the first access network equipment is operating in the second mode for the first terminal. In other words, the core network equipment can independently determine the content specified by the third indication information, saving signaling overhead.

Optionally, the communication method may further include: when the first access network device determines that it is about to disconnect from the first terminal or has already disconnected, the first access network device sends the context information of the first terminal to the core network device serving the first terminal. The context information of the first terminal can be used for the initial authentication of the first terminal. By actively transferring the context information of the first terminal to the core network device, after the first access network device disconnects from the first terminal, when the first terminal accesses a new access network device, it needs to perform initial authentication through the context information of the first terminal, which can ensure that the first terminal successfully accesses the new access network device and avoid service transmission failure.

Optionally, the first access network device sending the context information of the first terminal to the core network device serving the first terminal may include: the first access network device receiving a request message from the core network device, the request message being used to request the context of the first terminal, and sending the context information of the first terminal to the core network device according to the request message. For example, if the CN determines that the eNB does not cover the UE, or the UE needs to perform services in SF mode, and the eNB has not transferred the context to the CN, then the MME network element in the CN requests the UE context from the eNB.

Optionally, when the core network device receives downlink data, it sends a request message to an access network device. Correspondingly, the first access network device receives the request message and sends the context information of the first terminal to the core network device based on the request message. Thus, the core network device can send downlink data to a new access network device that provides services to the first terminal. When the new access network device provides services to the first terminal, it will send the downlink data to the first terminal.

In summary, when the first access network device is about to disconnect from the first terminal, based on the fact that the third access network device serving the first terminal after the first access network device is operating in the second mode, it is determined not to release the first terminal to the idle state. This allows the first access network device and the first terminal to align with the next operating mode, and the third access network device to operate correctly, thus avoiding the failure of the first terminal's service transmission.

The overall flow of the communication method provided in the embodiments of this application has been illustrated above with reference to Figures 10 and 11. The specific flow of the communication method provided in the embodiments of this application under specific scenarios is described below with reference to Figures 12 to 14.

Figure 12 is a flowchart illustrating the communication method provided in this embodiment. This communication method is applicable to the aforementioned communication system and specifically involves the interaction between a connected UE, an idle UE (i.e., the first terminal), an eNB (i.e., the first access network device), and an MME network element (i.e., the mobility management entity in the core network device). When the eNB switches from normal mode to SF mode, the connected UE indicates to the network whether it accepts SF service. This allows the eNB to perform different processing based on whether the UE currently accepts SF service, determining whether it needs to change the serving base station for the UE, thus avoiding UE service transmission failure. Furthermore, by turning off or extending the timer duration, the UE accepting SF service can successfully transmit data in SF mode.

Specifically, as shown in Figure 12, the communication method flow is as follows:

S1201, the eNB broadcasts a switch from normal mode to SF mode, triggering connected UEs and idle UEs to read system information updates.

The eNB can be a satellite eNB under a regenerative architecture. For example, the eNB changes the broadcast S&F indication information to true and sends a short message to trigger the UE to read system information updates, so that the UE can obtain the eNB mode conversion information.

S1202, the connected UE sends an RRC message to the eNB.

The RRC message is used to indicate to the eNB whether the UE in the connected state currently accepts SF mode service (i.e., whether it accepts or does not accept SF mode service). This RRC message can be a dedicated RRC message, or it can reuse the capability information reported by the UE (e.g., the eNB determines whether the UE has the capability to support SF based on the capability information reported by the UE; optionally, the UE capability information is reported in the UECapabilityInformation message) to indicate whether the UE accepts SF mode service. For the case of not accepting SF mode service, please refer to the description of the third information in S1001, which will not be elaborated here.

S1202 is an optional step, and at least one of S1202 and S1203 must exist. S1202 can occur after S1201 or before S1201. If it occurs before S1201, the UE can periodically indicate to the eNB whether its current service supports SF mode, or the UE can report to the eNB whether it has SF capability.

S1203, the MME network element sends an S1 message to the eNB.

The S1 message indicates whether the UE accepts SF service. Since the CN knows the type of service the UE is currently using, the CN can determine whether the UE's current service accepts SF mode based on the subscription information. The MME network element in the CN indicates to the eNB whether the UE accepts SF service, and carries the UE's identifier, such as the UE S1AP ID.

Step S1203 is optional; at least one of S1202 and S1203 must exist. Step S1203 can occur after or before S1201. If it occurs before S1201, it could be that the core network periodically indicates to the eNB whether the UE's current service supports SF mode, or the core network reports to the eNB whether the UE has SF capability.

S1204 If the idle-state UE does not support the SF function, then cell reselection will be performed.

If an idle UE that does not support SF function reselects to a normal cell, that is, a cell of an eNB operating in normal mode, and there is no normal cell that meets the conditions, that is, there is no suitable cell, the UE considers the cell currently operating in SF mode to be an available cell and keeps camping on the available cell, but will not initiate entry into connected mode; or, it does not camp on the current cell and is always in cell search state.

S1205, if the connected UE accepts SF mode service, then stop transmitting non-SF services, start transmitting SF services, and turn off the NAS timer or increase the timer duration.

The NAS timer can be found in the description of S1004, and will not be repeated here.

S1206 If the connected UE does not accept the service in SF mode, the eNB will switch the connected UE to the eNB operating in normal mode, or perform RRC release.

S1207, after the eNB determines that the connected-state UE will not accept SF mode services and completes the handover or RRC release, it disconnects the S1 interface from the MME network element and disconnects the power supply link.

The specific implementation principles of S1201-S1207 are similar to those of S1001-S1004 above, and can be understood by referring to them.

In summary, when the eNB switches from normal mode to SF mode, the connected UE indicates to the network whether it accepts SF service. This allows the eNB to handle the situation differently based on whether the UE currently accepts SF service, determining whether to change the serving base station for the UE and avoiding UE service transmission failure. Furthermore, by turning off or extending the timer duration, UEs accepting SF service can successfully transmit data in SF mode.

Figure 13 is a flowchart illustrating the communication method provided in this embodiment. This communication method is applicable to the aforementioned communication system and specifically involves the interaction between a connected UE, an idle UE (i.e., the first terminal), an eNB (i.e., the first access network device), an MME network element (i.e., the mobility management entity in the core network device), and a new eNB (the third access network device). When the eNB switches from SF mode to normal mode, the eNB and UE sides align their operating modes. Similarly, when the connection to the UE is lost from normal mode, the eNB and UE sides align their next operating modes, thus preventing UE service transmission failures.

Specifically, as shown in Figure 13, the communication method flow is as follows:

S1300, eNB establishes S1 interface with MME network element.

S1300 can also be executed after S1303 (not shown in the figure). The eNB restores the connection with the gateway station, that is, it enters normal mode from SF mode. Since SF mode is a special state, the transmission performance of the UE is better when the eNB works in normal mode. Therefore, it enters normal mode first and then changes the broadcast information.

S1301, the eNB broadcasts a switch from SF mode to normal mode and triggers connected UEs and idle UEs to read system information updates.

S1302, the NAS timer of the connected UE is turned on or shortened to the normal value, and non-SF services are started.

In addition, for UEs that have not initiated access under this satellite eNB and are waiting for other satellite eNBs operating in SF mode, they can also initiate access under this satellite and establish an RRC connection with this satellite once the satellite eNB switches to normal mode.

S1303, if the idle UE does not accept SF mode service, and the cell of the eNB currently operating in SF mode is an available cell, then the cell of the eNB currently operating in SF mode will be changed to a suitable cell.

Camping in an available cell does not allow entering the connected state, but camping in a suitable cell allows you to initiate entering the connected state later.

S1301-S1303 are optional. That is, S1300, S1304, and the steps after S1304 can constitute a separate embodiment. In this case, the conversion from SF mode to normal mode is not involved, but only the case where the eNB disconnects from the UE from normal mode and the new eNB is in SF mode.

S1304, the eNB sends instruction message #1 to the MME network element.

Indication message #1 is used to indicate whether the eNB is currently covering the UE, or whether the eNB is currently operating in SF mode for the UE. Indication message #1 can carry the UE's identifier. In this case, if the eNB is still covering the UE, the UE coverage indication information in indication message #1 is true, the satellite is operating in normal mode, and the SF indication information is false.

S1304 is an optional step. The CN can determine whether the eNB is currently covering the UE based on the UE's location and the eNB's ephemeris information.

S1305, when the eNB switches to normal mode and still covers the UE, the UE context will not be transferred to the CN and/or other eNBs.

In the SF scenario, when an eNB connects to a CN, it transfers the UE context to other eNBs through the CN. At this time, the eNB is operating in normal mode and does not need to transfer the context to other base stations.

S1306, the MME network element sends DL data to the eNB according to instruction message #1.

S1305 can be executed before or after S1306, without restriction.

S1307, when the eNB and UE are about to disconnect or have already disconnected, send indication message #2 to the MME network element.

Indication message #2 is the opposite of indication message #1. Indication message #2 indicates that the eNB does not cover the UE, or indicates that the eNB is currently operating in SF mode for the UE.

S1307 is optional; the CN can also determine whether the eNB is currently covering the UE based on the UE's location and the eNB's ephemeris information.

S1308, the eNB determines that it will not release the UE to the idle state after disconnecting from the UE, based on the fact that the new eNB serving the UE after the eNB is operating in SF mode.

The eNB can also indicate to the UE whether the new eNB is working in SF mode. For details, please refer to the description in S1103, which will not be repeated here.

S1309, the MME network element sends a request message to the eNB.

The request message is used to request the UE context. At this time, the CN determines that the eNB does not cover the UE, or the UE needs to perform SF mode services, and the eNB has not transferred the context to the CN. In this case, the CN sends a request message to the eNB. Optionally, the request message is sent to the eNB when the DL data arrives.

S1309 is an optional step; you can directly execute S1310.

S1310, the eNB sends the UE context to the MME network element, or sends the UE context to the new eNB through the MME network element.

Even without receiving a request message from an MME network element, the eNB can also proactively transfer the UE context to the CN.

S1311, the MME network element sends the UE's DL data to the new eNB.

The CN determines that the UE will subsequently access the new eNB and sends the UE's DL data to the new eNB. After the new eNB covers the UE, the new eNB will send the DL data back to the UE.

The specific implementation principles of S1301-S1311 are similar to those of S1101-S1103 mentioned above, and can be understood by referring to them.

In summary, when the eNB switches from SF mode to normal mode, the eNB and UE sides align their operating modes, and when the eNB disconnects from the UE from normal mode, the eNB and UE sides align their next operating modes, thus avoiding UE service transmission failures.

Figure 14 is a flowchart illustrating the communication method provided in this embodiment. This communication method is applicable to the O-RAN architecture and mainly involves the interaction between the RIC and the eNB. The RIC uses E2 messages to control the eNB to change the SF indication information. Other steps in this embodiment involve interactions between the eNB and the UE, or interactions with the MME network element, and are unrelated to the O-RAN architecture.

Specifically, as shown in Figure 14, the communication method flow is as follows:

S1401, RIC indicates that the power supply link is about to disconnect.

S1402, RIC sends E2 message #1 to eNB.

E2 message #1 instructs the eNB to change the broadcast SF indication information to true.

S1403, RIC confirms that the power supply link has been restored.

S1404, RIC sends E2 message #2 to eNB.

E2 message #2 instructs the eNB to change the broadcast SF indication information to false.

In this way, through E2 messages, the RIC can indicate whether the eNB is operating in SF mode, enabling the eNB to further correctly send relevant information in different modes to the UE.

The method provided by the embodiments of this application has been described in detail above with reference to Figures 10-14. The communication apparatus used to perform the communication method provided by the embodiments of this application is described in detail below with reference to Figures 15-16.

Figure 15 is a schematic diagram of the structure of a communication device provided in an embodiment of this application. As exemplarily shown in Figure 15, the communication device 1500 includes a transceiver module 1501 and a processing module 1502. For ease of explanation, Figure 15 only shows the main components of the communication device.

The transceiver module 1501 is used to perform the transceiver function of the method shown in Figure 10, and the processing module 1502 is used to perform other functions of the method shown in Figure 10 besides the transceiver function.

Optionally, the transceiver module 1501 may include a transmitting module (not shown in FIG. 15) and a receiving module (not shown in FIG. 15). The transmitting module is used to implement the transmitting function of the communication device 1500, and the receiving module is used to implement the receiving function of the communication device 1500.

Optionally, the communication device 1500 may further include a storage module (not shown in FIG15) that stores programs or instructions. When the processing module 1502 executes the program or instructions, the communication device 1500 can perform the functions of the terminal or network device in the method shown in FIG10 above.

It is understood that the communication device 1500 may be a terminal or network device, or a chip (system) or other component or assembly that can be set in the terminal or network device, or a device that includes the terminal or network device. This application does not limit it in this respect.

Furthermore, the technical effects of the communication device 1500 can be referred to the technical effects of the communication method shown in Figure 10, and will not be repeated here.

Figure 16 is a second schematic diagram of the structure of the communication device provided in an embodiment of this application. Exemplarily, the communication device can be a terminal, or a chip (system) or other component or assembly that can be disposed in the terminal. As shown in Figure 16, the communication device 1600 may include a processor 1601. Optionally, the communication device 1600 may also include a memory 1602 and/or a transceiver 1603. The processor 1601 is coupled to the memory 1602 and/or the transceiver 1603, for example, by means of a communication bus, an internal chip interface, or other communication lines. Optionally, the memory 1602 may be integrated with the processor 1601.

The following section, with reference to Figure 16, provides a detailed description of each component of the communication device 1600:

The processor 1601 is the control center of the communication device 1600. It can be a single processor or a collective term for multiple processing elements. For example, the processor 1601 can be one or more central processing units (CPUs), application-specific integrated circuits (ASICs), or one or more integrated circuits configured to implement the embodiments of this application, such as one or more digital signal processors (DSPs), or one or more field-programmable gate arrays (FPGAs).

Optionally, the processor 1601 can perform various functions of the communication device 1600 by running or executing software programs stored in the memory 1602 and calling data stored in the memory 1602, such as performing the communication method shown in FIG10 above.

In a specific implementation, as one example, processor 1601 may include one or more CPUs, such as CPU0 and CPU1 shown in FIG16.

In a specific implementation, as one embodiment, the communication device 1600 may also include multiple processors, such as processors 1601 and 1604 shown in FIG. 16. Each of these processors may be a single-core processor (single-CPU) or a multi-core processor (multi-CPU). Here, a processor may refer to one or more devices, circuits, and/or processing cores used for processing data (e.g., computer program instructions).

The memory 1602 is used to store the software program that executes the solution of this application, and is controlled by the processor 1601 to execute it. The specific implementation method can be referred to the above method embodiment, and will not be repeated here.

Optionally, the memory 1602 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, 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 not limited thereto. The memory 1602 may be integrated with the processor 1601 or may exist independently and be coupled to the processor 1601 through the interface circuit of the communication device 1600 (not shown in FIG. 16). This embodiment of the application does not specifically limit this.

Transceiver 1603 is used for communication with other communication devices. For example, if communication device 1600 is a terminal, transceiver 1603 can be used to communicate with a network device or with another terminal device. As another example, if communication device 1600 is a network device, transceiver 1603 can be used to communicate with a terminal or with another network device.

Optionally, transceiver 1603 may include a receiver and a transmitter (not shown separately in Figure 16). The receiver is used to implement the receiving function, and the transmitter is used to implement the transmitting function.

Optionally, the transceiver 1603 can be integrated with the processor 1601 or exist independently and be coupled to the processor 1601 through the interface circuit of the communication device 1600 (not shown in FIG16). This application embodiment does not specifically limit this.

It is understood that the structure of the communication device 1600 shown in Figure 16 does not constitute a limitation on the communication device. Actual communication devices may include more or fewer components than shown, or combine certain components, or have different component arrangements.

Furthermore, the technical effects of the communication device 1600 can be referred to the technical effects of the method described in the above method embodiments, and will not be repeated here.

It should be understood that the processor in the embodiments of this application can be a central processing unit (CPU), or it can be other general-purpose processors, DSPs, ASICs, FPGAs, or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor, etc.

It should also be understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. Non-volatile memory can be ROM, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), EEPROM, or flash memory. Volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (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 thereof. 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 programs are loaded or executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. 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. 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 wired (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more sets of available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. A semiconductor medium can be a solid-state drive.

It should be understood that the term "and/or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and/or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. Additionally, the character "/" in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and/or" relationship. Please refer to the context for a more accurate understanding.

In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple 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 multiple.

It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply 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 this application.

Those skilled in the art will recognize that the units and algorithm steps of the various examples 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 implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art 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 understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

The units described as separate components may or may not be physically separate. 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 the units can be selected to achieve the purpose of this embodiment according to actual needs.

In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

If the aforementioned functions are implemented as 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 this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes all the various possible memories described above.

Claims (27)

A communication method, characterized in that the method includes: Before the first access network device switches from the first mode to the second mode, the first access network device sends first information to the first terminal served by the first access network device. The first information triggers the first terminal to switch to access the second access network device, or releases the first terminal to an idle state. Herein, the first mode refers to the access network device connecting the terminal and the core network device at the same time, the second mode refers to the access network device not connecting the terminal and the core network device at the same time, the first terminal is a terminal that does not accept the service of the second mode, and the second access network device operates in the first mode. The first access network device switches from the first mode to the second mode. The method according to claim 1, characterized in that, before the first access network device sends the first information to the first terminal served by the first access network device, the method further includes: The first access network device sends a second message, which indicates that the operating mode of the first access network device is changed from the first mode to the second mode. The method according to claim 1 or 2, characterized in that, before sending the first information to the first terminal, the method further includes: The first access network device receives third information from the first terminal or a core network device serving the first terminal, the third information indicating that the first terminal is a terminal that does not accept the service of the second mode. According to the method of claim 3, wherein when the third information comes from the first terminal, the third information is included in service information and/or capability information, the service information indicating that the service currently being performed by the first terminal does not accept the service of the second mode, and the capability information indicating that the first terminal does not have the capability to accept the service of the second mode. The method according to claim 4, wherein the third information further indicates the identifier of the first terminal. A communication method, characterized in that the method includes: Send a third message to the first access network device, the third message indicating that the first terminal is a terminal that does not accept the service of the second mode, the first access network device serves the first terminal, and the second mode refers to the access network device not connecting the terminal and the core network device at the same time; The system receives first information from a first access network device, which triggers the first terminal to switch to accessing a second access network device, or releases the first terminal to an idle state. The second access network device operates in the first mode, which means simultaneously connecting the terminal and the core network device. Based on the first information, the device connects to the second access network device or enters an idle state. The method according to claim 6, wherein entering the idle state based on the first information includes: If the first information indicates that the Radio Resource Control (RRC) connection of the first terminal is released, cell reselection is performed. The method according to claim 6 or 7, characterized in that the method further comprises: The system receives second information from the first access network device, the second information indicating that the operating mode of the first access network device is changed from the first mode to the second mode. According to the method of claim 6, the third information is included in service information and/or capability information, wherein the service information indicates that the service currently being performed by the first terminal does not accept the service of the second mode, and the capability information indicates that the first terminal does not have the capability to accept the service of the second mode. A communication method, characterized in that the method includes: When a first terminal that does not accept the service of the second mode is camped in the cell of the first access network device, second information is obtained. The second information indicates that the working mode of the first access network device is changed from the first mode to the second mode. The first mode refers to the access network device connecting the terminal and the core network device at the same time, and the second mode refers to the access network device not connecting the terminal and the core network device at the same time. The device can either reselect to the second access network device or remain in the cell of the first access network device without entering the connected state, while the second access network device operates in the first mode. A communication method, characterized in that the method includes: Receive second information from the first access network device, the second information indicating that the working mode of the first access network device is changed from the first mode to the second mode, wherein the first access network device serves the first terminal, the first mode means that the access network device connects the terminal and the core network device at the same time, and the second mode means that the access network device does not connect the terminal and the core network device at the same time. If the first terminal accepts the service of the second mode, then the timer is turned off or the timer duration is increased. The timer is used to determine whether the service transmission of the first terminal is successful within the timer duration. A communication method, characterized in that the method includes: When a first access network device determines that it is about to disconnect from the first terminal, and determines that a third access network device serving the first terminal after the first access network device is operating in a second mode, it sends a first indication message to the first terminal. The first indication message indicates that the first terminal does not enter an idle state, and the first access network device is operating in a first mode. The first mode refers to the access network device simultaneously connecting to the terminal and the core network device, while the second mode refers to the access network device not simultaneously connecting to the terminal and the core network device. The method according to claim 12, characterized in that the method further comprises: The first access network device indicates to the first terminal that the third access network device is operating in the second mode. The method according to claim 12 or 13, characterized in that the method further comprises: When the first access network device provides services to the first terminal, the first access network device sends a second indication message to the core network device serving the first terminal. The second indication message indicates that the first access network device serves the first terminal, and/or the first access network device operates in the first mode for the first terminal. The method according to claim 14, characterized in that the method further comprises: The first access network device receives downlink data sent by the core network device according to the second instruction information. The method according to any one of claims 12 to 15, characterized in that the method further comprises: If the first access network device determines that it is about to disconnect from the first terminal or has already disconnected, the first access network device sends a third indication message to the core network device serving the first terminal. The third indication message indicates that the first access network device does not serve the first terminal, and/or the first access network device operates in the second mode for the first terminal. The method according to any one of claims 12 to 16, characterized in that the method further comprises: When the first access network device determines that it is about to disconnect from the first terminal or has already disconnected, the first access network device sends the context information of the first terminal to the core network device serving the first terminal. According to the method of claim 17, the first access network device sends the context information of the first terminal to the core network device, including: The first access network device receives a request message from the core network device, the request message being used to request the context of the first terminal; The first access network device sends the context information of the first terminal to the core network device according to the request message. A communication method, characterized in that the method includes: Receive second information from the first access network device, the second information indicating that the first access network device changes its working mode from the second mode to the first mode, wherein the first access network device serves the first terminal, the second mode means that the access network device does not connect the terminal and the core network device at the same time, and the first mode means that the access network device connects the terminal and the core network device at the same time. The timer is started or its duration is shortened. The timer is used to determine whether the service transmission of the first terminal is successful within the specified duration. A communication method, characterized in that the method includes: While the first terminal is waiting for the service of the third access network device, it obtains second information. The second information indicates that the working mode of the first access network device is changed from the second mode to the first mode. The first mode means that the access network device connects to the terminal and the core network device at the same time. The second mode means that the access network device does not connect to the terminal and the core network device at the same time. The third access network device works in the second mode. Based on the second information, access the first network device. A communication method, characterized in that it includes: When a first terminal that does not accept the service of the second mode is stationed in the cell of the first access network device and is not allowed to enter the connected state, the second information is obtained. The second information indicates that the working mode of the first access network device is changed from the second mode to the first mode. The first mode means that the access network device connects the terminal and the core network device at the same time, and the second mode means that the access network device does not connect the terminal and the core network device at the same time. Based on the second information, it is determined that the first terminal is allowed to enter the connected state in the cell of the first access network device. A communication device, characterized in that the device comprises: a module for performing the method as described in any one of claims 1-5, 6-9, 10, and 11. A communication device, characterized in that the communication device comprises: a processor and a memory; the memory is used to store computer instructions, which, when executed by the processor, cause the method as described in any one of claims 1-5, 6-9, 10, and 11 to be performed. A communication device, characterized in that the device comprises: a module for performing the method as described in any one of claims 12-18, 19, 20, and 21. A communication device, characterized in that the communication device comprises: a processor and a memory; the memory is used to store computer instructions, which, when executed by the processor, cause the method as described in any one of claims 12-18, 19, 20, and 21 to be performed. A computer-readable storage medium, characterized in that the computer-readable storage medium includes a computer program or instructions that, when executed, cause the method as described in any one of claims 1-5, 6-9, 10, and 11 to be implemented, or cause the method as described in any one of claims 12-18, 19, 20, and 21 to be implemented. A computer program product, characterized in that the computer program product includes a computer program or instructions that, when the computer program or instructions are run on a computer, cause the method as described in any one of claims 1-5, 6-9, 10, and 11 to be executed, or cause the method as described in any one of claims 12-18, 19, 20, and 21 to be executed.