CN117411533A

CN117411533A - Communication method, device and system of non-ground network

Info

Publication number: CN117411533A
Application number: CN202210957934.9A
Authority: CN
Inventors: 樊亮亮; 徐海博; 薛丽霞
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2022-07-06
Filing date: 2022-08-10
Publication date: 2024-01-16

Abstract

The embodiment of the application provides a communication method, a device and a system of a non-ground network, which relate to the non-ground network communication technology and are used for triggering a terminal to sense whether the terminal is in the coverage area of a cell served by a new satellite on the ground or not under the condition that the cell identifications of the new satellite and the old satellite are the same when the new satellite and the old satellite alternate, so as to ensure that the subsequent communication of the terminal is normal. The method comprises the following steps: the terminal receives a message from a first network device indicating that a satellite serving a first cell is updated to a second satellite, the first message including information for determining a coverage area on the ground of the second cell served by the second satellite. And the terminal determines that the terminal is positioned in or out of the coverage area according to the position of the terminal and the coverage area of the second cell on the ground. In the scheme, the terminal can sense the alternation of new satellites and old satellites and judge whether the terminal is positioned in the coverage area of the second cell on the ground, so that the terminal can conveniently execute different processes according to different judging results.

Description

Communication method, device and system of non-ground network

Technical Field

The embodiment of the application relates to the technical field of non-ground network communication, in particular to a communication method, device and system.

Background

Non-terrestrial network (Non-Terrestrial Networks, NTN) refers to a network or network segment that uses radio frequencies on board satellites (unmanned aerial vehicle system (unmanned aircraft System, UAS) platforms). Satellite communication has the advantages of wide coverage area, long communication distance, high reliability, high flexibility, high throughput and the like, is not influenced by geographic environment, climate conditions and natural disasters, and has been widely applied to the fields of aviation communication, maritime communication, military communication and the like. The introduction of satellites into the future fifth Generation mobile network (5G) can provide communication services for areas that are difficult to cover by ground networks, such as the ocean, forests, etc., can enhance the reliability of 5G communication, such as providing more stable and better communication services for trains, airplanes, and users on these vehicles, can also provide more data transmission resources, and supports a greater number of connections.

In servicing cells by satellites, each satellite may cover one or more cells on the ground, as the satellites are mobile, the satellite coverage may also be different on the ground at different times as the satellites move. But typically the cell to which the terminal is connected is unchanged for a period of time, and due to the movement of the old satellite, the new satellite is served only after the old satellite is no longer able to serve a certain physical area, such as the cell. Typically serviced by other satellites in the same orbit. The distance between two satellites is relatively large due to the spacing between the satellites. Because the distances between the new satellite and the old satellite reach a certain terminal are different, the coverage area of the cell served by the new satellite on the ground may be different from the coverage area of the cell served by the old satellite on the ground, so when the new satellite and the old satellite alternate, how to make the terminal perceive whether the new satellite is in the coverage area of the cell served by the new satellite on the ground, thereby being more beneficial to the NTN communication system, and being a technical problem to be solved urgently.

Disclosure of Invention

The embodiment of the application provides a communication method, device and system, which are used for triggering a terminal to sense whether a cell served by a new satellite is within the coverage area of the cell served by the new satellite on the ground or not under the condition that the cell identifications of the new satellite and the cell served by the old satellite are the same when new satellite and old satellite alternate, so as to ensure that the subsequent communication of the terminal is normal.

In a first aspect, an embodiment of the present application provides a communication method, including: the terminal receives a first message from a first network device. Wherein the first message is for indicating that a satellite serving the first cell is updated from a first satellite to a second satellite. The first cell is a cell accessed by the terminal, the first network equipment corresponds to a first satellite, and the first message comprises first information which is used for determining the coverage area of a second cell served by a second satellite on the ground. And responding to the first message, and determining that the terminal is positioned in the coverage area or out of the coverage area according to the position of the terminal and the coverage area of the second cell on the ground by the terminal, wherein the first cell and the second cell have the same cell identification.

In the method, when it is determined that a satellite serving a first cell is updated from a first satellite to a second satellite, that is, when new and old satellites alternate, the first network device sends a first message to the terminal, and the first message is used for indicating that the satellite serving the first cell is updated from the first satellite to the second satellite by the terminal, so that the terminal can perceive that the satellite covering the first cell is changed. And the second satellite serves the second cell, the first cell and the second cell have the same cell identity, and although the first cell and the second cell have the same cell identity, the coverage of the first cell and the second cell on the ground may be possible, because the terminal may be located outside the coverage of the second cell on the ground or may be located within the coverage of the second cell on the ground. Therefore, in order to prevent the terminal from being unable to normally access the second cell when the terminal is located outside the coverage area of the second cell, and thus causing communication interruption, in the present application, the first network device sends the information of the coverage area of the second cell served by the second satellite to the terminal, so that the terminal can conveniently judge whether the terminal is located in the coverage area of the second cell on the ground or outside the coverage area by combining with the position of the terminal, and appropriate processing measures are adopted, so that communication interruption of the terminal can be avoided.

In one possible implementation manner of the present application, after the terminal determines that the terminal is located in the coverage area or outside the coverage area according to the location of the terminal and the coverage area of the second cell on the ground, the method provided by the embodiment of the present application may further include: the terminal sends a second message to the first network device. Wherein the second message is used for indicating that the terminal is located in the coverage area of the second satellite on the ground, or the second message is used for indicating that the terminal is located outside the coverage area of the second satellite on the ground. The sending of the second message facilitates the first network device to determine whether the terminal is located within the coverage area of the second satellite on the ground, thereby facilitating subsequent processing by the first network device.

In one possible implementation manner of the present application, the second message includes second indication information, where the second indication information is used to indicate that the terminal is located in a coverage area of a second cell served by the second satellite on the ground. Or, the second indication information is used for indicating that the terminal is located outside the coverage of the second cell of the second satellite service on the ground. For example, the second indication information may be a first indicator, where the first indicator indicates that the terminal is located within a coverage area on the ground of a second cell served by a second satellite. The second indication information may be a second indicator indicating that the terminal is located outside the coverage of the second cell of the second satellite service on the ground. By carrying the second indication information in the second message, this may be indicated to the first network device explicitly.

In one possible implementation manner of the present application, after determining that the terminal is located in the coverage area or outside the coverage area according to the location of the terminal and the coverage area of the second cell on the ground, the method provided by the embodiment of the present application may further include: the terminal sends the position information of the terminal and/or the measurement report information of the terminal to the first network equipment. This facilitates the first network device to confirm whether the terminal is located within the coverage area of the second cell of the second satellite service on the ground based on the location information of the terminal. The measurement report information facilitates the first network device to select a third cell for the terminal or configure a condition for the second terminal to perform cell handover when the terminal is located outside the coverage area of the second cell served by the second satellite on the ground.

In one possible implementation of the present application, the location information of the terminal, and/or the measurement report information of the terminal may be carried in the second message. This saves signaling overhead.

In one possible implementation manner of the present application, in a case where the terminal is located in a coverage area of a second cell served by a second satellite on the ground, the method provided by the embodiment of the present application further includes: and the terminal performs downlink synchronization in the second cell to synchronize to second network equipment to which the second cell belongs. And under the condition that the terminal is positioned in the coverage area of the second cell of the second satellite service on the ground, the terminal performs downlink synchronization on the current service cell (namely the first cell), so that the terminal can conveniently receive downlink broadcast messages from the second network equipment after synchronizing to the second network equipment to which the second cell belongs, and the normal operation of subsequent communication is ensured.

In one possible implementation of the present application, the terminal is synchronized to the second network device corresponding to the second cell before the end time of coverage of the first satellite on the ground and/or after the start time of coverage of the second cell served by the second satellite.

In one possible implementation manner of the present application, in a case that the terminal is synchronized to the second network device, the method provided by the embodiment of the present application may further include: the terminal initiates a random access procedure to the second network device. This facilitates subsequent communication by the terminal over the connection established with the second network device, such as receiving a downlink transmission from the second network device or sending an uplink transmission to the second network device.

In one possible implementation manner of the present application, the terminal initiates the random access procedure to the second network device if the following first condition is satisfied, where the first condition includes any one of the following: the first satellite is before the end time of coverage on the ground; the second satellite is after a start time of coverage on the ground; there is a need for data transmission; the uplink time adjustment timer of the terminal does not time out.

In one possible implementation manner of the present application, the terminal does not need to initiate a random access procedure to the second network device if the second condition is satisfied, where the second condition includes at least that the uplink time adjustment timer of the terminal is timeout or that the uplink time adjustment timer of the terminal is not started.

In one possible implementation manner of the present application, the method provided by the embodiment of the present application further includes: during random access, the terminal receives a first command (e.g., an uplink time adjustment command) from the second network device. And restarting the uplink time adjustment timer of the terminal by the terminal according to the uplink time adjustment command.

In one possible implementation manner of the present application, in a case that the terminal is located in a coverage area of the second cell on the ground, the method provided by the embodiment of the present application further includes: the terminal does not evaluate other CHO conditions; or the terminal does not execute the measurement of the candidate target cell corresponding to the CHO; alternatively, the terminal releases other CHO configurations.

In one possible implementation manner of the present application, in a case that the terminal is located in a coverage area of the second cell on the ground, the method provided by the embodiment of the present application further includes: the terminal sends a fifth message to the first network device, the fifth message being used to instruct the terminal not to evaluate the CHO configuration or not to measure the CHO configuration or the released CHO configuration. For example, the fifth message includes an indication information for indicating that the terminal does not evaluate the CHO configuration or does not measure the CHO configuration or the released CHO configuration.

In one possible implementation manner of the present application, in a case that the terminal is located outside the coverage area of the second cell on the ground, the method provided by the embodiment of the present application further includes: the terminal receives a third message from the first network device. The third message is used for indicating the terminal to switch to the target cell, the target cell and the first cell have different cell identifications, and the terminal is located in the coverage area of the target cell. And the terminal switches the service cell of the terminal from the first cell to the target cell according to the third message.

In one possible implementation of the present application, the third message includes indication information for indicating that the terminal is handed over to the target cell. Alternatively, the third message may be a cell handover message.

In one possible implementation of the present application, the third message includes: the first configuration information is used for determining the information of the target cell by the terminal, and correspondingly, the terminal switches the serving cell of the terminal from the first cell to the target cell according to the third message, and the first configuration information comprises: the terminal determines the information of the target cell according to the first configuration information; and the terminal switches the service cell of the terminal from the first cell to the target cell according to the information of the target cell.

In one possible implementation of the present application, the third message includes: second configuration information, wherein the second configuration information comprises cell switching conditions configured for the terminal; the terminal switches the service cell of the terminal from the first cell to the target cell according to the third message, and the method comprises the following steps: and under the condition that the cell switching condition included in the second configuration information is met, the terminal switches a serving cell of the terminal from the first cell to the target cell.

In one possible implementation of the present application, the first message includes a first time parameter and/or a second time parameter, where the first time parameter is used to determine a coverage start time of the second satellite on the ground corresponding to the second cell, and the second time parameter is used to determine a coverage end time of the second satellite on the ground corresponding to the second cell. The method provided by the embodiment of the application further comprises the following steps: and the terminal synchronizes to the second network equipment corresponding to the second satellite after the coverage start time of the second satellite on the ground or transmits a second message to the first network equipment before the coverage start time of the second satellite on the ground according to the first time parameter and/or the second time parameter.

In one possible implementation of the present application, the first message further includes one or more of the following information: the terminal executes time information of downlink synchronization in the second cell;

the NTN parameter information of the second satellite comprises parameter information required by the terminal to access an NTN network corresponding to the second satellite;

third indication information, the third indication information is used for indicating the position information of the NTN parameter information;

and the information of the measurement timing configuration is used for indicating the terminal to search the downlink synchronous signal of the second cell under the second satellite according to the measurement timing configuration.

In a second aspect, an embodiment of the present application provides a communication method, including: the method comprises the steps that first network equipment corresponding to a first satellite sends a first message, the first message is used for indicating that a satellite serving a first cell is updated from the first satellite to a second satellite, the first message comprises first information, the first information is used for determining the coverage area of a second cell serving the second satellite on the ground, and the first cell and the second cell have the same cell identification.

In one possible implementation of the present application, the first message includes a first time parameter and/or a second time parameter; wherein the first time parameter is used to determine a start time of coverage of the second cell on the ground for the second satellite. And the second time parameter is used for determining the coverage end time of the second satellite on the ground corresponding to the second cell.

In one possible implementation of the present application, the first message further includes one or more of the following information: the terminal executes time information of downlink synchronization in the second cell through the second satellite; the NTN parameter information of the second satellite comprises parameter information required by the terminal to access the second cell; third indication information, the third indication information is used for indicating the position information of the NTN parameter information; and the information of the measurement timing configuration is used for indicating the terminal to search the downlink synchronous signal of the second cell under the second satellite according to the measurement timing configuration.

In one possible implementation of the present application, the first message includes information of the measurement timing configuration, where the measurement timing configuration is obtained by a downlink timing relationship configuration of the first cell in the first satellite, or the measurement timing configuration is obtained by a downlink timing relationship configuration of the second cell in the second satellite, where the downlink timing relationship is used to determine a first subframe number and a system frame number of a downlink synchronization signal of the second cell.

In one possible implementation of the present application, in a case where the first network device determines that the first terminal accessing the first cell is located outside the coverage area of the second cell on the ground, the method provided by the embodiment of the present application further includes: the first network equipment sends a third message to the first terminal, wherein the third message is used for indicating the first terminal to switch to a target cell, the target cell is different from the cell identifier of the first cell, and the first terminal is located in the coverage range of the target cell.

In one possible implementation of the present application, the method provided by the embodiment of the present application further includes: the first network device sends first configuration information and/or second configuration information to the first terminal, wherein the first configuration information is used for the first terminal to determine the information of the target cell, and the second configuration information is used for the first terminal to determine the condition of cell switching.

In one possible implementation of the present application, one or more of the first configuration information and the second configuration information is determined by location information of the first terminal and/or measurement report information of the first terminal, the measurement report information including information indicating signal quality of a neighbor cell of the first terminal.

In one possible implementation of the present application, the method provided by the embodiment of the present application further includes: the first network device receives a second message from a first terminal, which is a terminal accessing the first cell. And the first network equipment determines that the first terminal is positioned outside the coverage area of the second cell on the ground or positioned in the coverage area of the second cell on the ground according to the second message.

In one possible implementation of the present application, the second message includes location information of the first terminal, and the first network device determines, according to the second message, that the first terminal is located outside a coverage area of the second cell on the ground, or that the first terminal is located within a coverage area of the second cell on the ground, including: and the first network equipment determines that the first terminal is positioned outside the coverage area of the second cell on the ground or the first terminal is positioned in the coverage area of the second cell on the ground according to the position information of the first terminal and the coverage area of the second cell on the ground.

In a third aspect, embodiments of the present application provide a communication device, which may implement the method in the first aspect or any possible implementation manner of the first aspect, and thus may also implement the beneficial effect in the first aspect or any possible implementation manner of the first aspect. The communication device may be a terminal, or may be a device supporting the terminal to implement the method of the first aspect or any possible implementation manner of the first aspect, e.g. a chip applied in the terminal. The communication device may implement the above method by software, hardware, or by hardware executing corresponding software.

An example, an embodiment of the present application provides a communication apparatus, which is a terminal or a chip applied in the terminal, including: the system comprises a communication unit and a processing unit, wherein the processing unit is used for processing information, and the communication unit is used for receiving or sending information. For example, the communication unit is configured to receive a first message from a first network device, where the first message is used to instruct a satellite that serves a first cell to update from a first satellite to a second satellite, where the first cell is a cell that the terminal accesses, and the first network device corresponds to the first satellite, and the first message includes first information, where the first information is used to determine a coverage area on the ground of a second cell served by the second satellite, and the first cell and the second cell have the same cell identifier. And the processing unit is used for determining that the terminal is positioned in the coverage area or outside the coverage area according to the position of the terminal and the coverage area of the second cell on the ground based on the first message.

In a possible implementation of the present application, the communication unit is further configured to send a second message to the first network device, where the second message is used to indicate that the terminal is located in a coverage area of the second cell on the ground, or the second message is used to indicate that the terminal is located outside a coverage area of the second cell on the ground.

In a possible implementation of the present application, the communication unit is further configured to send location information of the terminal and/or measurement report information of the terminal to the first network device. Wherein the measurement report information includes information for indicating signal quality of a neighbor cell of the terminal.

In a possible implementation of the present application, if the terminal is located in a coverage area of a second cell served by a second satellite on the ground, the processing unit is further configured to perform downlink synchronization in the second cell to synchronize to a second network device corresponding to the second cell, where the second network device corresponds to the second satellite.

In a possible implementation of the present application, the communication unit in the embodiment of the present application is further configured to initiate a random access procedure to the second network device if the following first condition is met, where the first condition includes any one or more of the following: before the end time of coverage of the first satellite; after a coverage start time of the second satellite; there is a need for data transmission; the uplink time adjustment timer of the terminal does not time out.

In a possible implementation of the present application, the communication unit is configured to, without initiating a random access procedure to the second network device, if a second condition is met, where the second condition includes at least that an uplink time adjustment timer of the terminal is timed out, or that the uplink time adjustment timer of the terminal is not started.

In a possible implementation of the present application, if the terminal is located outside the coverage area of the second cell served by the second satellite on the ground, the communication unit is further configured to receive a third message from the first network device, where the third message is used to instruct the terminal to switch to a target cell, and the target cell has a different cell identifier from the first cell, and the terminal is located within the coverage area of the target cell; and the processing unit is further used for switching the service cell of the terminal from the first cell to a target cell according to the third message.

In one possible implementation of the present application, the third message includes: and the first configuration information is used for determining the information of the target cell by the terminal. The processing unit is specifically configured to determine information of the target cell according to the first configuration information. And the processing unit is used for switching the service cell of the terminal from the first cell to the target cell according to the information of the target cell.

In one possible implementation of the present application, the third message includes: and second configuration information, wherein the second configuration information comprises cell switching conditions configured for the terminal. And a processing unit, configured to switch a serving cell of the terminal from the first cell to the target cell when the cell switching condition included in the second configuration information is satisfied.

In one possible implementation of the present application, the first message includes a first time parameter and/or a second time parameter, where the first time parameter is used to determine a coverage start time of the second satellite on the ground corresponding to the second cell, and the second time parameter is used to determine a coverage end time of the second satellite on the ground corresponding to the second cell. And the processing unit is further used for synchronizing to the second network equipment corresponding to the second satellite after the coverage start time of the second satellite on the ground or sending a second message to the first network equipment before the coverage start time of the second satellite on the ground according to the first time parameter and/or the second time parameter.

In one possible implementation of the present application, the first message further includes one or more of the following information: the terminal executes time information of downlink synchronization in a second cell; NTN parameter information for the second satellite. The NTN parameter information comprises parameter information required by the terminal to access the NTN network corresponding to the second satellite; third indication information for indicating location information of the NTN parameter information; and the information of the measurement timing configuration is used for indicating the terminal to search the downlink synchronous signal of the second cell under the second satellite according to the measurement timing configuration.

In a fourth aspect, embodiments of the present application provide a communication device, which may implement the method in the second aspect or any possible implementation manner of the second aspect, and thus may also implement the beneficial effect in the second aspect or any possible implementation manner of the second aspect. The communication means may be the first network device, or may be means supporting the first network device to implement the second aspect or any possible implementation of the method in the second aspect, e.g. applied to a chip in the first network device. The communication device may implement the above method by software, hardware, or by hardware executing corresponding software.

An example, an embodiment of the present application provides a communication apparatus, which is a first network device or a chip applied in the first network device, including: the system comprises a communication unit and a processing unit, wherein the processing unit is used for processing information, and the communication unit is used for receiving or sending information. For example, a communication unit is configured to send a first message, where the first message is configured to instruct a satellite serving a first cell to update from the first satellite to a second satellite, the first message includes first information, where the first information is configured to determine a coverage area on the ground of a second cell served by the second satellite, and the first cell and the second cell have a same cell identifier.

In one possible implementation of the present application, the first message includes a first time parameter and/or a second time parameter; wherein the first time parameter is used for determining a coverage start time of the second satellite on the ground corresponding to the second cell; and the second time parameter is used for determining the coverage end time of the second satellite on the ground corresponding to the second cell.

In a possible implementation of the present application, the communication unit is further configured to send a third message to the access first terminal, where the third message is used to instruct the first terminal to switch to a target cell different from the cell identity of the first cell. The first terminal is located within the coverage area of the target cell.

In a possible implementation of the present application, the communication unit is further configured to send the first configuration information and/or the second configuration information to the first terminal. The first configuration information is used for the first terminal to determine the information of the target cell, and the second configuration information is used for the first terminal to determine the condition of cell switching.

In one possible implementation of the present application, one or more of the first configuration information and the second configuration information is determined by location information of the first terminal and/or measurement report information of the first terminal, the measurement report information including information for indicating signal quality of a neighbor cell of the first terminal.

In a possible implementation of the present application, the communication unit is further configured to receive a second message from a first terminal, where the first terminal is a terminal accessing the first cell. And the processing unit is further used for determining that the first terminal is located outside the coverage area of the second cell on the ground or the first terminal is located in the coverage area of the second cell on the ground according to the second message.

In one possible implementation of the present application, the second message includes location information of the first terminal, and the processing unit is specifically configured to determine, according to the location information of the first terminal and a coverage area of the second cell on the ground, that the first terminal is located outside the coverage area of the second cell on the ground or that the first terminal is located within the coverage area of the second cell on the ground.

In a fifth aspect, embodiments of the present application provide a computer-readable storage medium having stored therein a computer program or instructions which, when run on a computer, cause the computer to perform a communication method as described in any one of the possible implementations of the first aspect to the first aspect.

In a sixth aspect, embodiments of the present application provide a computer-readable storage medium having stored therein a computer program or instructions which, when run on a computer, cause the computer to perform a communication method as described in any one of the possible implementations of the second aspect to the second aspect.

In a seventh aspect, embodiments of the present application provide a computer program product comprising instructions which, when run on a computer, cause the computer to perform a communication method as described in the first aspect or in various possible implementations of the first aspect.

In an eighth aspect, embodiments of the present application provide a computer program product comprising instructions which, when run on a computer, cause the computer to perform a communication method as described in the second aspect or in various possible implementations of the second aspect.

In a ninth aspect, embodiments of the present application provide a communications device for implementing various methods in various possible designs of any of the above first to second aspects. The communication device may be the above-described terminal, or a device including the above-described terminal, or a component (e.g., a chip) applied to the terminal. Alternatively, the communication means may be the first network device described above, or an apparatus including the first network device described above, or the communication means may be a component (e.g., a chip) applied in the first network device. The communication device comprises corresponding modules and units for realizing the method, and the modules and units can be realized by hardware, software or realized by executing corresponding software by hardware. The hardware or software includes one or more modules or units corresponding to the functions described above.

In a tenth aspect, embodiments of the present application provide a communication apparatus, including: at least one processor and a communication interface. Wherein the processor, when the communication device is running, executes computer-executable instructions or programs stored in the communication device to cause the communication device to perform the method as in any of the various possible implementations of any of the first or second aspects described above. For example, the communication device may be a terminal or a component applied in a terminal. For example, the communication means may be the first network device or a component applied in the first network device.

It should be understood that the communication apparatus described in the tenth aspect may further include: a bus and a memory for storing code and data. Optionally, at least one processor communication interface and the memory are coupled to each other.

In an eleventh aspect, embodiments of the present application provide a communication apparatus, including: at least one processor. Wherein at least one processor is coupled to the memory, the processor executing computer-executable instructions or programs stored in the memory when the communication device is operated to cause the communication device to perform the method as described above in the first aspect or any of the various possible implementations of any of the first aspect. For example, the communication device may be a terminal, or a chip applied in a terminal.

In a twelfth aspect, embodiments of the present application provide a communication apparatus, including: at least one processor. Wherein at least one processor is coupled to the memory, the processor executing computer-executable instructions or programs stored in the memory when the communication device is operated to cause the communication device to perform the method of any of the various possible designs of the second aspect or any of the second aspect as described above. For example, the communication means may be the first network device or a chip applied in the first network device.

It should be understood that the memory described in any of the tenth to twelfth aspects may also be replaced with a storage medium, which is not limited by the embodiments of the present application. In a possible implementation manner, the memory described in any of the tenth to twelfth aspects may be a memory inside the communication device, and of course, the memory may also be located outside the communication device, but at least one processor may still execute the computer-executable instructions or programs stored in the memory.

In a thirteenth aspect, embodiments of the present application provide a communications device, where the communications device includes one or more modules configured to implement the method of any one of the first aspect and the second aspect, where the one or more modules may correspond to the steps of the method of any one of the first aspect and the second aspect.

In a fourteenth aspect, embodiments of the present application provide a chip comprising a processor and a communication interface, the communication interface and the processor being coupled, the processor being for running a computer program or instructions to implement a communication method as described in the first aspect or in various possible implementations of the first aspect. The communication interface is used for communicating with other modules outside the chip.

In a fifteenth aspect, embodiments of the present application provide a chip comprising a processor and a communications interface, the communications interface and the processor being coupled, the processor being for running a computer program or instructions to implement a communications method as described in the second aspect or in various possible implementations of the second aspect. The communication interface is used for communicating with other modules outside the chip.

Specifically, the chip provided in the embodiments of the present application further includes a memory, configured to store a computer program or instructions.

In a sixteenth aspect, embodiments of the present application provide a communication system, including: a terminal and a first network device for performing the second aspect or the communication method in any one of the possible implementations of the second aspect. The terminal is configured to perform the first aspect or the communication method in any of the possible implementations of the first aspect.

Any of the apparatuses or computer storage media or computer program products or chips or communication systems provided above are used to perform the corresponding methods provided above, and thus, the advantages achieved by the methods can refer to the advantages of the corresponding schemes in the corresponding methods provided above, and are not described herein.

Drawings

Fig. 1 is two deployment schemes for identifying a cell in a satellite according to an embodiment of the present application;

fig. 2 is a schematic architecture diagram of a communication system according to an embodiment of the present application;

fig. 3 is a schematic architecture diagram of another communication system according to an embodiment of the present application;

fig. 4 is a schematic distribution diagram of a base station according to an embodiment of the present application;

fig. 5 is a schematic architecture diagram of a transparent satellite communication system according to an embodiment of the present application;

fig. 6 is a schematic architecture diagram of another satellite communication system according to an embodiment of the present application;

fig. 7 is a schematic architecture diagram of still another satellite communication system according to an embodiment of the present application;

FIG. 8 is a schematic architecture diagram of yet another satellite communication system according to an embodiment of the present disclosure;

fig. 9 is a schematic flow chart of a communication method according to an embodiment of the present application;

fig. 10 is a flow chart of another communication method according to an embodiment of the present application;

fig. 11 is a schematic structural diagram of a communication device according to an embodiment of the present application;

fig. 12 is a schematic structural diagram of another communication device according to an embodiment of the present application;

fig. 13 is a schematic structural diagram of a chip according to an embodiment of the present application.

Detailed Description

In the present application, "at least one" means one or more, and "a plurality" means two or more. "and/or", describes an association relationship of an association object, and indicates that there may be three relationships, for example, a and/or B, and may indicate: a alone, a and B together, and B alone, wherein a, B may be singular or plural. The character "/" generally indicates that the context-dependent object is an "or" relationship. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (one) of a, b, or c may represent: a, b, c, a-b, a-c, b-c, or a-b-c, wherein a, b, c may be single or plural.

The technical solution of the present application may be applied to various communication systems, for example: long term evolution (long time evolution, LTE) systems, LTE frequency division duplex (frequency division duplex, FDD) systems, LTE time division duplex (time division duplex, TDD) systems, universal mobile telecommunications system (universal mobile telecommunication system, UMTS), worldwide interoperability for microwave access (worldwide interoperability for microwave access, wiMAX) communication systems, public land mobile network (public land mobile network, PLMN) systems, device-to-device (D2D) network systems or machine-to-machine (machine to machine, M2M) network systems, future 5G communication systems, and the like.

The network architecture and the service scenario described in the embodiments of the present application are for more clearly describing the technical solution of the embodiments of the present application, and do not constitute a limitation on the technical solution provided in the embodiments of the present application, and those skilled in the art can know that, with the evolution of the network architecture and the appearance of the new service scenario, the technical solution provided in the embodiments of the present application is also applicable to similar technical problems.

In terrestrial communications, a network device (e.g., a base station) may cover one or more cells whose cell identity (physical cell identifier, PCI), broadcast area identity (e.g., tracking area code (tracking area code, TAC) or tracking area identity (tracking area identity, TAI)) generally does not change over a long period of time. However, in satellite communication, the physical area (such as a cell) covered by the satellite on the ground varies due to the high speed of movement of the satellite. For the identification of cells in the satellite and the identification of broadcast areas, the following deployment schemes are currently adopted:

scheme (1), as shown in fig. 1 (a), establishes an association relationship between a cell identifier and a physical area. I.e. for a certain physical area, the cell identity and the broadcasted area identity corresponding to that physical area are unchanged. After one satellite (satellite 1) is removed, the physical area is serviced by the other satellite (satellite 2). The cell identity and broadcast area identity in satellite 2 are the same as satellite 1. The main benefit of this scheme is that, for a certain physical area, it is assumed that the location of the UE (user equipment, also called terminal) is unchanged, and since the cells perceived by the terminal are unchanged, the network device does not need to trigger the procedure of cell handover for the terminal, so as to reduce the number of handovers in the network and reduce the signaling overhead of the air interface. In this scenario, in general, one satellite is always servicing a certain physical area for a period of time (i.e., the satellite is always covering a certain physical area), and when the satellite is no longer servicing the physical area due to the movement of the satellite, the other satellites are servicing the physical area. As shown in fig. 1 (a), when the satellite 1 is located at the geographic position 2 at the time t+t1, the cell of the cell included in the coverage area on the ground is identified as the cell 2, and when the satellite is located at the geographic position 1 at the time T, the cell of the cell included in the coverage area on the ground is identified as the cell 1.

Scheme (2), shown in figure 1 (b), cell identification is associated with the satellite. When a satellite moves, resulting in a change in the coverage area of the satellite, the cell identity in the satellite does not change. In this scenario, it is understood that the cell identity is scanned over the physical coverage area as the satellites move. In this scheme, even if the position of a certain terminal is unchanged, because the satellite is mobile, when the coverage of the satellite on the ground can not cover the terminal any more, the network side needs to inform the terminal to switch to other cells. As shown in fig. 1 (b), due to the cell identity and satellite association, the cell of the cell comprised by the coverage on the ground is identified as cell 1 when the satellite 1 is located at the geographic position 2 at time t+t1, and the cell of the cell comprised by the coverage on the ground is identified as cell 1 when the satellite is located at the geographic position 1 at time T. Although the cell identities of the cells served by the satellites 1 at different geographic locations are the same in the (b) view of fig. 1, the coverage of the cells at different geographic locations may be different.

In New Radio (NR) systems, NTN is introduced. In NTN, base stations or portions of base station functionality are deployed on an aerial platform or satellite to provide seamless coverage for terminals. As the satellites orbit the earth, the terminals are also moving relative to the earth, which results in the corresponding satellite of the cell to which the terminal is accessing using network services changing from one satellite to another. To ensure continuity and quality of service of communications, the terminal needs to perceive the alternation of new and old satellites and determine whether it is located in the coverage area of the cell served by the new satellite on the ground.

As shown in fig. 2 or fig. 3, an embodiment of the present application provides a communication system, including: one or more terminals (e.g., terminal 1-terminal n), network device 100, and satellite 200. Wherein the terminal accesses a cell 300, which cell 300 is one of one or more cells covered by the network device 100. The cell 300 is served by the satellite 200, or the cell 300 may be a cell covered by the satellite 200 on the ground.

Where the terminal is located at the surface of the earth and the satellite 200 and the satellite 400 described below are located in earth orbit. Satellite 200 or satellite 400 may provide communication services to a physical area of signal coverage (e.g., cell 300 or cell 500) and may communicate with terminals located within the physical area of signal coverage.

As one example, satellites typically produce one or more beams (or "beamfootprints") on the ground, and the one or more beams form a cell on the ground.

In satellite communication, the physical area covered by satellites on the ground varies due to the high speed of movement of the satellites. Thus, the coverage of the same satellite on the ground may be different for different periods of time, assuming that the satellite 200 serves the cell 300 during the first period of time. The start time of the first period is the start time of the coverage of the satellite 200 on the ground, and the end time of the first period is the end time of the coverage of the satellite 200 on the ground. The network device 100 corresponds to the satellite 200 during the first period of time.

As shown in fig. 2 (a), at time T1 (belonging to the first time period), the cell 300 is covered by the satellite 200, i.e., the coverage of the satellite 200 on the ground at time T1 includes the coverage of the cell 300 on the ground. Due to the movement of the satellite 200, at time T2, the satellite 400 moves to a position where it can cover the cell 300, and the satellite 200 gradually moves to a position far from the cell 300, as shown in the diagram (b) of fig. 2, the satellite 400 can cover the coverage of the cell 300 on the ground, and the coverage of the cell 500 covered by the satellite 400 on the ground and the cell 300 can be considered to be the same. Finally, as the satellite 200 moves, the coverage of the satellite 200 on the ground does not include the coverage of the cell 300, and as shown in fig. 2 (c), the coverage of the cell 300 is covered by the satellite 400 at the time T3, and it can be considered that the cell 500 covered by the satellite 400 on the ground at the time T3 is the cell 300.

It will be appreciated that when the cell 300 is served by the satellite 200, the cell 300 may be one of one or more cells covered by the network device 100, in which case any one of the terminals 1 to n may communicate with the satellite 200 via the network device 100. When the cell 500 is served by the satellite 400, the cell 500 may be one of one or more cells covered by the network device 600, in which case any one of the terminals 1 to n may communicate with the satellite 200 via the network device 600. Of course, the network device 100 and the network device 600 may be the same network device, i.e. although the satellite serving a certain cell has changed, the network device to which the terminal accesses is unchanged.

As an example, network device 600 and network device 100 may be the same network device, i.e., although the satellite serving cell 300 changes from satellite 200 to satellite 400, the network device to which cell 300 belongs does not change. As another example, network device 600 and network device 100 are different network devices, i.e., the satellite that serves cell 300 changes from satellite 200 to satellite 400, as does the network device to which cell 300 belongs.

It should be noted that, when the cells served by the satellite 400 and the satellite 200 have the same cell identifier, the coverage of the cell 500 served by the satellite 400 on the ground may be the same as the coverage of the cell 300 served by the satellite 200 on the ground, as shown in fig. 2 (b). However, there may be a scenario as shown in the (b) diagram in fig. 3, where the coverage of the cell 500 served by the satellite 400 on the ground is different from the coverage of the cell 300 served by the satellite 200, for example, there is an intersection between the two, and of course, there may be no intersection between the coverage of the cell 500 served by the satellite 400 on the ground and the coverage of the cell 300 served by the satellite 200 on the ground. In summary, fig. 2 and 3 differ in that: in fig. 2 the satellite of cell 300 changes from satellite 200 to satellite 400, but the coverage of cell 500 covered by satellite 400 on the ground is the same as the coverage of cell 300 served by satellite 200 on the ground, it being understood that cell 500 and cell 300 are one cell with the same cell identity. Whereas in the system shown in fig. 3 the satellite of cell 300 changes from satellite 200 to satellite 400, but the coverage of cell 500 covered by satellite 400 on the ground is not the same as the coverage of cell 300 served by satellite 200 on the ground, e.g. terminal 1 is located outside the coverage of cell 500 on the ground and terminals 2 to n are located within the coverage of cell 500 on the ground.

Fig. 2 (c) and fig. 3 (c) are schematic diagrams of the coverage cell 500 of satellite 2 after the departure of satellite 1.

In one possible embodiment of the present application, the communication system as shown in fig. 2 or fig. 3 may further include: core network equipment (not shown). The core network device refers to a device in a Core Network (CN) that provides service support for a terminal. Currently, examples of some core network devices are: access and mobility management function (access and mobility management function, AMF) entities, session management function (session management function, SMF) entities, user plane function (user plane function, UPF) entities, and the like, to name but a few. The AMF entity can be responsible for access management and mobility management of the terminal; the SMF entity may be responsible for session management, such as session establishment for a user, etc.; the UPF entity may be a functional entity of the user plane, mainly responsible for connecting to external networks. It should be noted that, in this application, an entity may also be referred to as a network element or a functional entity, for example, an AMF entity may also be referred to as an AMF network element or an AMF functional entity, and for example, an SMF entity may also be referred to as an SMF network element or an SMF functional entity.

In particular, the satellites in embodiments of the present application may be considered as spacecraft carrying transparent payload (bent pi pepayload) or regenerative payload (regenerative payload) signal transmitters, which typically operate as Low Earth Orbit (LEO) at a height between 300 kilometers (km) and 1500km, as mid earth orbit (medium earth or bit, MEO) at a height between 7000 and 25000km, as synchronized earth orbit (geostationary earth orbit, GEO) at a height of 35786km, or as high elliptical orbit (highelliptical orbit, HEO) at a height between 400 and 50000 km. That is, the satellites may be LEO satellites, MEO satellites, GEO satellites, HEO satellites, or the like according to the orbit heights.

A terminal in the embodiments of the present application, which is also referred to as a User Equipment (UE), a Mobile Station (MS), a Mobile Terminal (MT), etc., is a device that provides voice and/or data connectivity to a user. Such as a handheld device, an in-vehicle device, etc., having a wireless connection function. Currently, some examples of terminals are: a mobile phone, a tablet, a notebook, a palm, a mobile internet device (mobile internet device, MID), a wearable device, a Virtual Reality (VR) device, an augmented reality (augmented reality, AR) device, a wireless terminal in industrial control (industrial control), a wireless terminal in unmanned (self driving), a wireless terminal in teleoperation (remote medical surgery), a wireless terminal in smart grid (smart grid), a wireless terminal in transportation security (transportation safety), a wireless terminal in smart city (smart city), a wireless terminal in smart home (smart home), and the like.

The network device in the embodiments of the present application refers to a radio access network (radio access network, RAN) node (or device) that accesses a terminal to a wireless network, which may also be referred to as a base station. May be a base station (base transceiver station, BTS) in a global system for mobile communications (global system ofmobile communication, GSM) communication system or a code division multiple access (code division multiple access, CDMA) communication system, a base station (nodeB, NB) in a wideband code division multiple access (widebandcode division multiple access, WCDMA) communication system, an evolved base station (evolutional node B, eNB or eNodeB) in a long term evolution (longterm evolution, LTE) communication system, or a base station (the next Generation Node B, gNB) in a new wireless communication system. The network device may also be an Access Point (AP) in a wireless local area network (Wireless Local Area Network, WLAN), a relay station, a network device in a future evolved public land mobile network (Public Land Mobile Network, PLMN) network, or a network device in an NTN communication system, etc.

Currently, some examples of RAN nodes are: a further evolved Node B (gNB), a transmission and reception point (transmission reception point, TRP), an evolved Node B (eNB), a radio network controller (radio network controller, RNC), a Node B (Node B, NB), a base station controller (base station controller, BSC), a base transceiver station (base transceiver station, BTS), a home base station (e.g., home evolved NodeB, or home Node B, HNB), a baseband unit (BBU), or a wireless fidelity (wireless fidelity, wifi) Access Point (AP), etc.

In addition, in one network structure, as shown in fig. 4, the network device may be a RAN device including a Centralized Unit (CU) node, or a Distributed Unit (DU) node, or a CU node and a DU node. The RAN equipment comprising CU nodes and DU nodes splits protocol layers of gNB in NR system, part of functions of the protocol layers are controlled in CU, and the rest or all functions of the protocol layers are distributed in DU, and the CU controls DU in a centralized manner. Optionally, as shown in FIG. 4, CUs can also be divided into control plane (CU-CP) and user plane (CU-UP). The CU-CP is responsible for the control plane function and mainly includes RRC and packet data convergence layer protocol (packet data convergence protocol, PDCP), i.e., PDCP-C, corresponding to the control plane. The PDCP-C is mainly responsible for encryption and decryption of control plane data, integrity protection, data transmission and the like. The CU-UP is responsible for the user plane functions, mainly comprising the service data adaptation protocol (service data adaptation protocol, SDAP) and the PDCP (i.e. PDCP-U) corresponding to the user plane. Wherein the SDAP is mainly responsible for processing data of the core network and mapping flows to bearers. The PDCP-U is mainly responsible for encryption and decryption of a data surface, integrity protection, header compression, sequence number maintenance, data transmission and the like. Wherein CU-CP and CU-UP are connected through E1 interface. CU-CP stands for gNB connected to the core network via NG interface. And the connection is realized through F1 interface control surfaces, namely F1-C and DU. CU-UP is connected through F1 interface user plane, namely F1-U and DU. Of course, a further possible implementation is that the PDCP-C is also in the CU-UP.

Currently TR38.821 defines 5 NTN-based RAN architectures (NTN-based NG-RAN architectures), and the method provided by the embodiments of the present application may be applied to any of the following architectures:

the architecture 1 shown in fig. 5 is a schematic diagram of an architecture with a transparent satellite (RAN architecture with transparent satellite) communication system according to an embodiment of the present application, where the architecture 1 includes: terminal, access network node (NG-RAN), 5G core network (5 GC), and Data Network (DN).

Wherein the NG-RAN comprises: a remote radio unit (remote radio unit, RRU) and a gNB. The RRU includes a satellite and an NTN gateway (gateway), among others.

Wherein the terminal, non-terrestrial network gateway and gNB are located at the earth's surface and the satellites are located at earth orbit. Meanwhile, the satellite, the non-terrestrial network gateway, and the gNB may function as a 5G radio access network (NG-radio accessnetwork, NG-RAN), and the NG-RAN connects to the 5G core network through a second interface (e.g., NG interface).

Communication is performed between the terminal and the gNB in architecture 1 via a first interface (e.g., NR Uu). The 5G core network is communicated with the data network through an N6 interface.

In a transfant scenario, the role of the satellite is: radio frequency filtering (Radio Frequency filtering), frequency conversion and amplification (Frequency conversion and amplification). I.e. the satellite is mainly acting as an L1 relay, regenerating the physical layer signal and does not have other higher protocol layers.

Architecture 2 as shown in fig. 6: the architecture 2 differs from the architecture 1 in that in architecture 2 the NG-RAN includes a gNB, which is a satellite, and the satellite communicates with the terminal through a first interface, and a second interface is provided between the satellite and the 5G core network.

The regenerated satellite with no inter-satellite link in architecture 2 has the processing functions Regenerative satellite without ISL, gNB processed payload of the base station, where the inter-satellite link (ISL). In this architecture, the satellite acts as a gNB.

Architecture 3 as shown in fig. 7: the common point of this architecture 3 and architecture 2 is that satellites are used as the gnbs, but the architecture 3 differs from architecture 2 in that: there is an ISL in the scenario shown in architecture 3.

Architecture 4 as shown in fig. 8: the architecture 4 differs from the architecture 1 in that: the access network node (NG-RAN) comprises a satellite and network equipment in architecture 4. The satellite is used as a gNB-DU, the network equipment is used as a gNB-CU, the gNB-DU and the gNB-CU are communicated through an F1 interface, and the terminal and the gNB-DU are communicated through a first interface.

Architecture 4: a regenerated satellite (NG-RAN with a regenerative satellite based on gNB-DU) with the DU processing function of the base station, in this scenario the satellite is as a DU.

Architecture 5: an IAB-capable base station (gNB processed payload based on relay-like architectures), in this scenario, the satellite is acting as a relay node (integrated access and backhual, IAB).

In terrestrial communications, in some scenarios (for example, because some parameters configured by the network side for the terminal need to be changed, or the network side needs to change the key allocated to the terminal), the network side triggers the terminal to perform intra-cell handover, that is, although the cell to which the terminal accesses is not changed, the network side needs the terminal to re-access the cell. The general network side sends a handover command (for example, called as carrying a reconfiguration message requiring synchronization) to the terminal, and the terminal re-performs random access in the cell according to the handover command (note: the terminal is required to perform random access in the current protocol, possibly in the subsequent protocol evolution, the terminal may not need to perform random access). The protocol now specifies a formula for calculating the interruption time caused by the handover in the handover scenario. Including the time Tsearch to search for the target cell. Tsearch=0 if the target cell is known; otherwise, the value of Tsearch is specified in the protocol.

In satellite communications, in other scenarios, the network side may also notify the terminal to perform intra-cell handover (e.g., due to movement of the location of the terminal, the terminal enters one country into another country, and different countries use different core networks, at this time the network side needs to select a new core network for the terminal, so the network side may trigger intra-cell handover).

For the deployment scenario shown in fig. 1 (a), due to the movement of the old satellite (the first satellite described below), the old satellite is served by the new satellite (the second satellite described below) after the old satellite is no longer serving a certain physical area on the ground (the coverage of the satellite is a certain physical area of the satellite on the ground surface). Typically serviced by other satellites in the same orbit. The distance between two satellites is relatively large due to the spacing between the satellites. Because the distances between the new satellite and the old satellite reach a certain terminal are different, the terminal can not synchronously receive the downlink signals of the same cell, and meanwhile, the time when the uplink signals of the terminal reach the two satellites is also different. (note: the fact that the downlink signal is not synchronous refers to that the time when the terminal detects the downlink pilot signal changes, or refers to that the starting point or the ending point of the frame number, the subframe number, the time slot number and the symbol detected by the terminal changes). If the terminal is not located within the coverage of the cell served by the new satellite on the ground, the terminal may not be able to perform downlink synchronization with the new satellite while the new satellite is in coverage. Thus, the terminal cannot correctly receive the downlink signal sent by the current cell in the satellite, and the terminal cannot successfully send the uplink signal to the cell served by the new satellite. As shown in fig. 3 or fig. 2, when a new satellite (e.g., satellite 400) has the same cell identity as an old satellite (e.g., satellite 200) has an above-ground cell 500, the coverage of the above-ground cell 500 by satellite 400 may or may not be the same as the coverage of cell 300 (as shown in fig. 2). Therefore, how to make any one of the terminals 1 to n in the access cell 300 determine whether or not to be located within the coverage of the cell 500 covered by the satellite 400 on the ground is a technical problem to be solved in the present application.

In the embodiment of the present application, the specific structure of the execution subject of one communication method is not particularly limited as long as communication can be performed with one communication method according to the embodiment of the present application by running a program in which the code of one communication method of the embodiment of the present application is recorded. For example, the execution body of a communication method provided in the embodiment of the present application may be a functional module in the first network device that can call a program and execute the program, or a communication apparatus, such as a chip, applied to the first network device. The execution body of a communication method provided in the embodiment of the present application may be a functional module in a terminal that can call a program and execute the program, or a communication device, for example, a chip, applied to the terminal. This application is not limited thereto. The following embodiments take an execution body of a communication method as a first network device and a terminal as an example.

As shown in fig. 9, an interactive flow chart of a communication method of a non-ground network according to an embodiment of the present application is provided, where the method includes:

step 901, a first network device corresponding to a first satellite sends a first message. Accordingly, the terminal receives a first message from the first network device. The first network device is a network device to which a first cell belongs, and the first cell is a cell to which the terminal accesses.

Wherein the first message is for indicating that a satellite serving the first cell is updated from a first satellite to a second satellite. Alternatively, the first message is used to indicate to the terminal that the satellite serving the first cell is about to change, i.e. to indicate that the old and new satellites alternate.

Alternatively, the first network device corresponds to the first satellite, which may be the first satellite, i.e. the first network device, such as the base station, as shown in fig. 5 or as shown in fig. 6. For example, as shown in fig. 8, the first network device is a gNB-CU and the first satellite is a gNB-DU.

In one possible implementation of the present application, the first message may carry the first information in order to facilitate the terminal to determine whether the terminal is located in the coverage area of the second cell served by the second satellite on the ground. Wherein the first information is used to indicate the coverage of a second cell of a second satellite service on the ground. Wherein the second cell and the first cell have the same cell identity. Or it may be understood that the first cell and the second cell are the same cell, i.e. the first cell is the same as the second cell.

As an example, the first information may be information of a physical area covered on the ground by a second cell of the second satellite service. The information of the physical area is used to determine the coverage of a second cell of a second satellite service on the ground. Alternatively, the first information may be coverage parameter information of the second cell, for example, information that may indicate a physical area covered by the second cell served by the second satellite on the ground by a reference point and a radius (or a distance threshold), or may be indicated by a series of coordinate points.

It will be appreciated that the coverage of the first cell is almost encompassed by the coverage of the second satellite on the ground. For example, the second satellite may serve one or more cells, i.e., the coverage area of the second satellite on the ground includes one or more cells. The one or more cells include a second cell, or may be understood as: the cell identity in the second satellite is the same as the cell identity of the first cell.

As an example, the terminal in the embodiment of the present application may be a terminal in a radio resource control protocol (radio resource control, RRC) connected state, or may be a terminal in an rrc_idle (IDLE)/rrc_inactive (INACTIVE) state.

The terminal may be any terminal accessing the first cell.

In one possible implementation of the present application, the above step 901 may be implemented in the following manner: the first network device broadcasts a first message to the terminal, i.e. the first message is a broadcast message sent by the first network device. Thus, the plurality of terminals accessing the first cell or the plurality of terminals located in the first cell can receive the first message, so that the terminals can determine that the satellite serving the first cell is to be changed. For example, the terminal accessing the first cell includes terminal a and terminal B, and the first message is sent by broadcasting, so that the first network device may cause the terminal a and terminal B to perceive that the satellite serving the first cell is updated from the first satellite to the second satellite, and that the coverage area of the second cell served by the second satellite is on the ground by sending the broadcast message once.

In another possible implementation manner of the present application, the above step 901 may be implemented in the following manner: the first message sent by the first network device to the terminal is a dedicated message. I.e. the first network device sends the first message to a specific terminal in the first cell by means of a dedicated message. For example, the first message may be an RRC message, a medium access control (medium access control, MAC) message, or the like. In this scenario, the first network device may send a first message to terminal a, provided that the terminal accessing the first cell comprises terminal a and terminal B. The first message may also be sent to terminal B.

In step 902, the terminal determines that the terminal is located in the coverage area of the second cell on the ground or is located outside the coverage area of the second cell on the ground according to the first message, the location of the terminal and the coverage area of the second cell on the ground.

As an example, in connection with fig. 2, the first network device may be the network device 100 described above. The first satellite may be satellite 200 described above. The first cell may be cell 300. The second satellite may be satellite 400 described above. The second cell may be cell 500.

It will be appreciated that after receiving the first message, the terminal may determine, in real time or periodically, whether the location of the terminal is within the coverage area of the second cell on the ground.

Optionally, in the case that the first message does not carry the first information, the terminal may request the first network device to provide the coverage area of the second cell serving the second satellite to the terminal on the ground, where the satellite serving the first cell is determined to change by the first message.

In a possible embodiment of the present application, the method provided by the embodiment of the present application may further include, before step 901: the first network device determines that a satellite that serves the first cell is updated from a first satellite to a second satellite.

As one possible implementation, the updating of the satellite serving the first cell by the first network device from the first satellite to the second satellite may be implemented by: the information of the second satellite is sent by the operator to the first network device. Or the satellite control function of the second satellite transmits ephemeris information of the second satellite to the first network device (base station); or the satellite control function of the second satellite sends the ephemeris information of the second satellite to the core network, and then the core network forwards the ephemeris information to the first network device (base station).

In another possible implementation, the second network device (e.g., the second base station) corresponding to the second satellite sends the information of the second satellite to the first network device (e.g., the first base station) corresponding to the first satellite.

In one possible implementation of the present application, the first message may further carry seventh indication information. The seventh indication information is used for indicating the terminal to judge whether the position of the terminal is located in the coverage area of the second cell of the second satellite service on the ground. Thus, after receiving the seventh indication information, the terminal can execute the action of judging whether the terminal is in the coverage area of the second cell on the ground. Of course, the seventh indication information may be carried in a message other than the first message, which is not limited in the embodiment of the present application. In another possible implementation of the present application, the first message does not need to carry seventh indication information, and the terminal can perform the action of determining whether the terminal is in the coverage area of the second cell on the ground according to the first information after receiving the first message.

In one possible implementation manner of the present application, the first network device does not need to instruct the terminal, and after the terminal receives the first information, the first network device actively reports a result of determining whether the second cell is located in a coverage area of the second cell on the ground. In another possible implementation manner, the first network device may further instruct the terminal to report a result of determining the coverage area of the second cell on the ground. For example, the first message may carry the indication information x, or the first network device sends other messages except the first message to the terminal, so as to notify the terminal to report the judging result. For example, the indication information x is used for indicating that the terminal reports the judgment result under the condition that the terminal is located outside the coverage area of the second cell on the ground, so that if the first network device does not receive the judgment result reported by the terminal, it can be determined that the terminal is located in the coverage area of the second cell on the ground. Of course, in the case that the first network device receives the determination result from the terminal, it may be determined that the terminal is located outside the coverage area of the second cell on the ground. Or the indication information x is used for indicating the terminal to report the judging result under the condition that the terminal is positioned in the coverage area of the second cell on the ground. Or the indication information x is used for indicating that the terminal needs to report the judging result no matter whether the position of the terminal is located in the coverage area of the second satellite or outside the coverage area of the second satellite. The first network device sends the indication information x to the terminal or notifies the terminal of the judging result of whether to report the coverage area of the second cell, so that the terminal can perform corresponding actions according to the indication from the first network device. Or the indication information x is used for indicating the terminal to report when the judging result is the first judging result, and not reporting when the judging result is the second judging result. For example, the first determination result and the second determination result are different, for example, the first determination result is: the terminal is located within the coverage area of the second satellite on the ground. And the second judgment result is that the terminal is positioned outside the coverage area of the second satellite on the ground.

In one possible implementation manner, after receiving the first information, the terminal may actively report the location information of the terminal to the first network device. In another possible implementation manner, the terminal reports the location information of the terminal to the first network device based on the trigger of the first network device. For example, the first network device may also instruct the terminal to report the location information of the terminal through the indication information y. The indication information y is carried in the first message or other messages except the first message, which is not limited in the embodiment of the present application.

It will be appreciated that the first network device may send both the indication information a and the indication information y to the terminal.

In one possible implementation of the present application, in case the terminal has an end of coverage time of the first satellite on the ground, the terminal may further send a request message to the first network device before the end of coverage time of the first satellite on the ground to request information of the second cell covered by the second satellite on the ground.

In one possible implementation of the present application, the first network device sends the first message to the terminal earlier than the start time of coverage on the ground of the second satellite serving the second cell. The coverage start time indicates a time when the second satellite corresponding to the second cell starts to cover the physical area of the first satellite corresponding to the first cell (including the first cell) on the ground.

For example, in the case that the first network device determines the coverage start time of the second satellite corresponding to the second cell, it is assumed that, before the coverage start time of the second satellite corresponding to the second cell, the terminal still accesses the first cell, and if there is a downlink data/signaling transmission requirement between the first network device and the terminal, the first network device may send the first message to the terminal in the process of sending the downlink data/signaling to the terminal. Assuming that there is no downlink data/signaling transmission requirement between the first network device and the terminal before the coverage start time of the second satellite corresponding to the second cell, the first network device may choose to send the first message to the terminal at any time or in case the terminal is in RRC connected state.

In one possible embodiment of the present application, the first message may be a predefined message dedicated to informing the terminal of an update of satellites serving the cell, such that reception of the first message is known to the terminal that satellite alternation is imminent. Of course, the first message may also be an existing message existing between the terminal and the first network device, which is not limited in the embodiment of the present application.

In another possible embodiment of the present application, the first message includes first indication information for indicating that a satellite serving the first cell is updated from the first satellite to the second satellite or that a satellite serving the first cell is about to change. In this way, for the terminal, the terminal can determine that the satellite of the first cell accessed by the terminal is updated from the first satellite to the second satellite according to the first indication information, and the manner can be regarded as that the first network device indicates to the terminal in an explicit manner. Of course, the first message may be the first indication information, or the first indication information is a field in the first message, which is not limited in the embodiment of the present application. Alternatively, the first indication information may be information of a physical area covered on the ground by the second cell served by the second satellite.

Of course, the first network device may indicate to the terminal that satellite alternation is imminent, in addition to explicitly indicating to the terminal that satellite alternation is imminent.

As an example of an implicit indication, the first message in embodiments of the present application may further include one or more of the following parameters: the terminal measures timing configuration information according to the first time parameter, the second time parameter, the time information of downlink synchronization executed by the terminal in the second cell through the second satellite, NTN parameter information of the second satellite, and third indication information.

Wherein the first time parameter is used to determine a start time of coverage on the ground for a second satellite serving the second cell. A second time parameter for determining an end-of-coverage time on the ground for a second satellite serving a second cell. Thus, the terminal can determine the coverage start time and the coverage end time of the second satellite on the ground after receiving the first time parameter and/or the second time parameter. The terminal may then synchronize to a second network device corresponding to the second satellite after the start time of its coverage on the ground or send a second message or a fourth message to the first network device before the start time of its coverage on the ground.

It is of course possible for the terminal to acquire the information of the updated satellite of the second cell and/or the coverage of the updated satellite coverage cell from the second network device corresponding to the second satellite before the end time of the coverage of the second satellite on the ground, assuming that the subsequent terminal communicates through the second satellite, while knowing the end time of the coverage of the second satellite on the ground.

As an example, the first time parameter is a coverage start time of the second satellite on the ground. Or the first time parameter is the first time information plus the preset time length. The second time parameter is the coverage end time of the second satellite on the ground corresponding to the second cell, or the second time parameter includes the first time parameter and the duration of the second satellite serving the second cell.

Of course, in the case that the first message includes the first indication information, one or more parameters of the above parameters may also be included in the first message, for example, the first message includes the first indication information and the first time parameter.

And third indication information, configured to indicate location information of the NTN parameter information, for example, system message block information where the NTN parameter information is located.

As one example, the information of the measurement timing configuration is used to determine the measurement timing configuration. The measurement timing configuration is used for indicating the terminal to search the downlink synchronous signal of the second cell under the second satellite according to the measurement timing configuration. The measurement timing configuration includes a measurement window for receiving the downlink synchronization signal, and a period (periodicity) and an offset (offset) of the measurement window.

Optionally, the measurement timing configuration is configured based on a downlink timing relationship of a first cell in the first satellite. Optionally, the measurement timing configuration is configured based on a downlink timing relationship of the second cell in the second satellite. The terminal calculates a first subframe number and a system frame number for searching the downlink synchronization signal of the second cell according to the following formula. (i.e., the first measurement window starts with the time corresponding to the first subframe number and the system frame number, the duration is the length of the measurement window, and then the measurement window is performed with periodic periodicity).

SFN mod T＝(FLOOR(Offset/10))；

If the period Periodicity is greater than 5 subframes;

subframe＝Offset mod 10；

otherwise, subframe=offset or (offset+5). Where t=ceil (periodic/10).

MOD, a mathematical operator. The modulo (or remainder) operator is pointed to.

FLOOR is a mathematical operator that rounds the number down to the nearest integer (rounding down).

CEIL is a mathematical operator that rounds numbers up to the nearest integer (rounding up).

The above-mentioned scheme describes the process that the terminal perceives that the satellite of the first cell changes, after the first network device informs the terminal that the satellite of the first cell is about to alternate, although the second cell and the first cell have the same cell identifier, the second cell and the first cell may have different coverage areas on the ground, so the terminal may be located in the coverage area of the second cell served by the second satellite on the ground, the terminal may also be located outside the coverage area of the second cell served by the second satellite on the ground, and in different scenarios, the subsequent actions performed by the terminal are generally different, and therefore, the embodiments of the present application will be described in connection with different scenarios respectively:

the scene (1), the terminal is located outside the coverage of a second cell of a second satellite service on the ground.

In the scenario (1), as shown in fig. 10, fig. 10 is a specific process of another communication method provided in the embodiment of the present application, and steps 1001 to 1002 in fig. 10 are the same as steps 901 to 902, which are not described in detail herein. Optionally, the method provided in the embodiment of the present application may further include, after step 1002:

step 1003a, the terminal sends a second message to the first network device. Accordingly, the first network device receives the second message from the terminal. Wherein the second message is used to indicate that the terminal is located outside the coverage area of the second cell of the second satellite service on the ground.

It should be noted that, the step 1003a is an optional step, that is, in a case where the terminal determines that the second cell is located outside the coverage area of the ground, the terminal may omit the process of sending the second message to the first network device.

Under the condition that the terminal determines that the terminal is located outside the coverage area of the second cell on the ground, the terminal sends a second message to the first network equipment, so that the first network equipment can know that the terminal is located outside the coverage area of the second cell on the ground in time, and the terminal is triggered to conduct cell switching in time, and the follow-up communication of the terminal is guaranteed to be normal. Particularly, when the first network device sends the first message in a broadcast manner, since there may be a plurality of terminals accessing the first cell, and there may be some terminals located outside the coverage area of the second cell on the ground and some terminals located within the coverage area of the second cell on the ground in the plurality of terminals, if the terminal feeds back the second message to the first network device, the first network device is convenient to trigger the terminal to perform cell handover, and it is not necessary to trigger cell handover for terminals that do not feed back the second message or feed back the terminals that are located within the coverage area of the second cell on the ground. Optionally, the second message may further include an identification of the terminal, so that the first network device determines which terminal is located outside the coverage area of the second cell on the ground.

Optionally, the second message may include second indication information, where the second indication information is used to indicate that the terminal is located outside the coverage area of the second cell on the ground. Or, the second message is the second indication information, which is not limited in the embodiment of the present application.

It may be appreciated that in the case that the second message includes the second indication information, the first network device determines that the terminal is located outside the coverage area of the second satellite on the ground according to the second indication information, for example, the first network device parses the second message to obtain the second indication information.

Alternatively, the second message may be a predefined message dedicated to the interaction between the terminal and the first network device that the terminal is outside the area of coverage of the second satellite on the ground, so that the first network device can know that the terminal is outside the area of coverage of the second satellite on the ground by receiving the second message, e.g. without parsing the second message. Alternatively, the second message may be an existing message communicated between the terminal and the first network device.

It should be noted that, when the first network device does not instruct the terminal to report the judgment result, the behavior of the terminal to send the second message is the spontaneous behavior of the terminal. Of course, if the first network device instructs the terminal to report the judgment result, the terminal may send the second message to the first network device according to the instruction of the first network device.

Of course, whether the terminal reports the second message to the first network device or whether the terminal is located in the coverage area of the second cell on the ground or is located outside the coverage area of the second cell on the ground may be predefined by a protocol, which is not limited in the embodiment of the present application.

In one possible embodiment of the present application, in case the terminal acquires the first time parameter of the second satellite, the terminal may send the second message to the first network device before the coverage start time of the second satellite. As to the sending time of the second message, the sending time may be determined by the terminal or may be indicated to the terminal by the first network device, which is not limited in this embodiment of the present application. For example, in the process of notifying the terminal of satellite alternation, the first network device notifies the terminal to report the judgment result before the coverage start time of the second satellite, or notifies the terminal to report the judgment result before the coverage end time of the first satellite on the ground.

In a possible implementation manner of the present application, in a case where the terminal is located outside the coverage area of the second cell on the ground, optionally, as shown in fig. 10, the method provided in the embodiment of the present application may further include:

Step 1004a, the terminal sends the location information of the terminal and/or the measurement report information of the terminal to the first network device. Accordingly, the first network device receives location information from the terminal and/or measurement report information of the terminal.

It can be understood that the measurement report information is a network measurement result obtained by the terminal performing measurement according to the measurement configuration configured by the first network device. Wherein the network measurement result includes: and the signal intensity, the signal quality and other parameter information of the adjacent area or the frequency point of the terminal. The terminal facilitates the first network device to configure the terminal with second configuration information according to the measurement report information by providing the measurement report information to the first network device, the second configuration information including cell handover conditions. Optionally, the first network device may further configure a target cell for the terminal according to the measurement report message.

In a possible implementation manner of the present application, the method provided by the embodiment of the present application may further include, after step 1004 a: the first network device may determine the first configuration information and/or the second configuration information of the terminal using the measurement report information of the terminal. The first configuration information is used for determining a target cell by the terminal. The second configuration information is used for determining a condition for performing cell switching by the terminal.

In one aspect, the terminal provides the location information of the terminal to the first network device, so that the first network device can determine that the terminal is located in or out of the coverage area of the second cell on the ground according to the location information of the terminal and the coverage area of the second cell of the second satellite service on the ground.

On the other hand, the first network device may determine the first configuration information and/or the second configuration information of the terminal using the location information of the terminal. Therefore, the first configuration information and/or the second configuration information configured for the terminal are beneficial to subsequent communication of the terminal, and the subsequent communication of the terminal is ensured not to be interrupted.

In one possible implementation of the present application, the terminal may send the location information of the terminal and/or the measurement report information of the terminal to the first network device based on the trigger of the first network device. For example, after the terminal sends the second message to the first network device, the first network device may send a request instruction to the terminal to request the terminal to provide location information of the terminal and/or measurement report information of the terminal, in order to further determine that the terminal is located outside the coverage of the second cell on the ground, or to configure a switchable target cell or configure a cell switching condition for the terminal (i.e. to determine, for the terminal, that in a case where what condition is met, switching from the first cell to the target cell). Or the first network device may also obtain the location information of the terminal from other devices (such as an AMF network element), which is not limited in the embodiment of the present application.

In another possible implementation of the present application, the terminal may actively send the location information of the terminal and/or the measurement report information of the terminal to the first network device in case the terminal is located outside the coverage of the second cell of the second satellite service on the ground. Or the protocol agrees that, in case the terminal detects that a cell located at a certain satellite service is out of coverage on the ground, the location information of the terminal and/or the measurement report information of the terminal need to be sent to the first network device.

As an example, the location information and/or the measurement report information of the terminal is carried in the second message, and signaling overhead can be saved by using the second message to carry the location information and/or the measurement report information of the terminal. Of course, the location information and/or the measurement report information of the terminal may be carried in a message different from the second message, which is not limited in the embodiment of the present application.

In one possible implementation of the present application, in a case where it is determined that the terminal is located outside the coverage area of the second cell of the second satellite service on the ground, the terminal may determine to report the determination result to the first network device by itself even if the first network device does not instruct the terminal to report the determination result.

In one possible implementation of the present application, the first network device determining that the terminal is located outside the coverage area on the ground of the second cell served by the second satellite may be implemented by: and the first network equipment determines that the terminal is positioned outside the coverage area of a second cell of the second satellite service on the ground according to the second message.

In another possible implementation of the present application, the first network device determines that the terminal is located outside the coverage area of the second cell of the second satellite service on the ground according to the location information of the terminal and the coverage area of the second cell of the second satellite service on the ground.

Or, in the case that the first network device receives the second message, the first network device may further confirm, in combination with the location information of the terminal, whether the terminal is located outside the coverage area of the second cell corresponding to the second satellite on the ground.

In order to ensure that the subsequent communication of the terminal is normal, the first network device may further instruct the terminal to switch the serving cell of the terminal when determining that the terminal is located outside the coverage area of the second cell served by the second satellite on the ground.

It should be noted that, in the embodiment of the present application, the sequence of the step 1003a and the step 1004a is not limited, and the terminal may execute the step 1004a first and then execute the step 1003a, or execute the step 1003a and the step 1004a simultaneously, that is, the second message includes the location information of the terminal and/or the measurement report information of the terminal.

In one possible embodiment of the present application, as shown in fig. 10, in a case where the first network device determines that the terminal is located outside the coverage area of the second satellite on the ground, the method provided in the embodiment of the present application may include, after step 1002:

step 1005a, the first network device sends a third message to the terminal. Accordingly, the terminal receives a third message from the first network device. The third message is used for indicating the terminal to switch the serving cell of the terminal from the first cell to the target cell. I.e. the third message is used to instruct the terminal to perform a cell handover. Wherein the target cell and the first cell have different cell identities.

As an example, the third message includes fourth indication information, where the fourth indication information is used to instruct the terminal to switch the serving cell of the terminal from the first cell to the target cell. The fourth instruction information may be the same information as the first configuration information, or may be different information, which is not limited in the embodiment of the present application.

As another example, the information of the target cell is included in the third message. The target cell is a cell to be switched selected by the first network equipment for the terminal, and the terminal is positioned in the range of the target cell. Optionally, the first network device may select a cell for the terminal as the target cell according to the location information of the terminal and/or the measurement report information of the terminal. For example, the signal quality or signal strength of the target cell is higher than a preset value.

Wherein the target cell and the first cell may belong to the same network device, such as the first network device. Of course, the target cell and the first cell may also belong to different network devices. For example, the first cell belongs to one of the one or more cells covered by the first network device, and the target cell is one of the one or more cells covered by the third network device.

In one possible implementation of the present application, the target cell may also be served by the second satellite, except that the target cell and the second cell are different. For example, the coverage area of the second satellite on the ground includes the coverage area of the target cell on the ground and the coverage area of the second cell on the ground, and although the terminal may be located outside the coverage area of the second cell on the ground, the terminal may be located outside the coverage area of the target cell on the ground, so that the terminal may be switched to the target cell to enable the terminal to continue to communicate through the second satellite, so as to avoid interruption of communication. Of course, the target cell may also be a cell covered by the third satellite on the ground, which is not limited in the embodiment of the present application.

In one possible embodiment of the present application, in a case where the first network device determines that the terminal is located in the coverage area of the second cell served by the second satellite on the ground, as shown in fig. 10, the method provided in the embodiment of the present application may further include:

In step 1006a, the first network device sends the first configuration information and/or the second configuration information to the terminal. Correspondingly, the terminal receives the first configuration information and/or the second configuration information from the first network device.

Optionally, the third message includes: in the case of the first configuration information, and/or the second configuration information, step 1006a may be omitted.

Of course, the first configuration information and/or the second configuration information may also be sent to the terminal through a fourth message, where the fourth message and the third message are different.

In one possible embodiment of the present application, after the first network device sends the third message to the terminal, the first configuration information and/or the second configuration information may be actively provided to the terminal. Or the first network device may send the first configuration information and/or the second configuration information to the terminal if receiving the request from the terminal.

As an example, the second configuration information includes a CHO candidate cell configuration and CHO execution conditions. The CHO execution conditions may be any one or more of a time-based CHO trigger, a location-based trigger, an Event (Event A3), event A4, event A5. For example, CHO execution conditions include CHO trigger conditions based on time, any one or more of the following events: event (Event A3), event A4, event A5.CHO execution conditions include location-based trigger conditions, any one or more of the following events: event (Event A3), event A4, event A5.

It should be noted that, in the embodiment of the present application, the sequence of the step 1005a and the step 1006a is not limited, and the first network device may execute the step 1005a first and then execute the step 1006a, or may execute the step 1006a first and then execute the step 1005a. Of course, step 1005a and step 1006a may also be performed simultaneously. In addition, in case the first network device determines from the terminal that the terminal is located outside the coverage of the second cell on the ground, step 1005a or step 1006a is located after step 1003a or step 1004 a.

Step 1007a, the terminal switches the serving cell of the terminal from the first cell to the target cell according to the third message.

In one possible implementation of the present application, in the case that the terminal obtains the first configuration information and/or the second configuration information, the step 1007a may be implemented in the following manner: and the terminal determines the information of the target cell according to the first configuration information. And the terminal is switched from the first cell to the target cell according to the information of the target cell.

In one possible implementation of the present application, after receiving the third message, the terminal may evaluate a handover condition, and in case the cell handover condition indicated by the second configuration information is satisfied, the terminal switches the serving cell from the first cell to the target cell. Thus, the switching failure caused by blind switching of the terminal is avoided.

In one possible embodiment of the present application, optionally, as shown in fig. 10, the method provided by the embodiment of the present application may include any one or more of step 1008a and step 1009a after step 1002:

step 1008a, the terminal deletes configuration information associated with the second satellite. Such as NTN parameter information for the second satellite. A coverage start time, a coverage end time, etc. of the second satellite. Such as ephemeris information of the second satellite, timing Advance (TA) parameter information of the second satellite, measurement configuration information related to the second cell, and handover and/or conditional handover configuration information related to the second cell.

It should be noted that, in the case that the terminal is located outside the coverage area of the second cell on the ground, in the case that the terminal has the configuration information related to the second satellite, the terminal may perform step 1008a, and in the case that the terminal does not have the configuration information related to the second satellite, step 1008a may be omitted.

Optionally, after step 1008a, the terminal may send a feedback response to the first network device to indicate that the configuration information associated with the second satellite has been deleted.

In the embodiment of the application, under the condition that the terminal is located outside the coverage area of the second cell on the ground, the terminal can reduce the occupation of the terminal memory by deleting the configuration information related to the second satellite.

Of course, in the event that the first network device determines that the terminal is outside the coverage area of the second satellite on the ground, the first network device may instruct the terminal to delete the configuration information associated with the second satellite. For example, when the first network device triggers the terminal to perform cell handover, the sixth indication information may be sent to the terminal, so as to instruct the terminal to delete the configuration information related to the second satellite. Of course, the terminal may actively delete the configuration information related to the second satellite in case the terminal is located outside the coverage area of the second cell on the ground.

Alternatively, in the case that the target cell is a cell where the second satellite is covered on the ground, the terminal may not perform step 1008a, but perform the step of acquiring ephemeris information of the second satellite.

Step 1009a, the terminal does not perform the step of acquiring ephemeris information of the second satellite.

It should be noted that, in the present application, the order of executing the step 1008a and the step 1009a is not limited, for example, the terminal may execute the step 1009a first and then execute the step 1008a.

The scene (2), the terminal is located within the coverage of a second cell of a second satellite service on the ground.

In scenario (2), as shown in fig. 10, optionally, the method provided in the embodiment of the present application may further include, after step 1002: one or more of a notification phase, a synchronization phase, and a random access phase. The notification phase includes step 1003b and step 1004b. The purpose of the notification phase is to enable the first network device to determine that the terminal is located within the coverage of the second cell on the ground, i.e. that the terminal can subsequently communicate using the second satellite.

Step 1003b, the terminal sends a fourth message to the first network device. Accordingly, the first network device receives a fourth message from the terminal. The fourth message is used for indicating that the terminal is located in the coverage area of the second cell on the ground.

Optionally, the fourth message may include fourth indication information, where the fourth indication information is used to indicate that the terminal is located in a coverage area of the second cell on the ground.

Alternatively, the fourth message may be a predefined message dedicated to interaction between the terminal and the network device, where the terminal is located in the coverage area of the second cell of the second satellite service on the ground, so that, for the first network device, receipt of the fourth message determines that the terminal is located in the coverage area of the second cell of the second satellite service on the ground.

The terminal may also send location information of the terminal and/or measurement report information of the terminal to the first network device in case the terminal is located in the coverage area of the second cell on the ground. For a specific procedure and implementation, reference may be made to a procedure in which the terminal sends location information of the terminal and/or measurement report information of the terminal to the first network device in case the terminal is located outside the coverage of the second cell on the ground.

In step 1004b, the first network device determines that the terminal is located in the coverage area of the second cell on the ground.

In a possible implementation of the present application, the step 1003b may be omitted, i.e. the terminal may not need to feed back the fourth message to the first network device in case it determines that the second cell is located in the coverage area on the ground.

In one possible implementation manner of the present application, in a case that the first network device receives the fourth message, the step 1004b may be implemented by: the first network device determines that the terminal is located in the coverage area of the second cell of the second satellite service on the ground according to the fourth message.

Optionally, in the case that the fourth message includes fourth indication information, step 1004b may be implemented by: and the first network equipment determines that the terminal is positioned in the coverage area of the second cell of the second satellite service on the ground according to the fourth indication information.

In a possible implementation manner of the present application, in a case where the first network device obtains the location information of the terminal, step 1004b may be implemented by: the first network device may determine that the terminal is located within the coverage area of the second cell on the ground according to the location information of the terminal and the coverage area of the second cell on the ground.

Optionally, in the case that the terminal informs the first network device that the terminal is located in the coverage area of the second cell on the ground by using the fourth message, the first network device may further confirm that the terminal is actually located in the coverage area of the second cell on the ground according to the location information of the terminal and the coverage area of the second cell on the ground.

Optionally, the first network device may further send NTN parameter information including the second satellite to the terminal in case it is determined that the terminal is located in the coverage area of the second cell on the ground. The NTN parameter information includes parameter information necessary for the terminal to access an NTN network (or a second cell) corresponding to the second satellite. If the terminal accesses the NTN network through the second satellite, the NTN parameter information refers to the satellite ephemeris, the valid time of the ephemeris, the public timing advance parameter and other parameter information.

Optionally, the first network device may further send, to the terminal, indication information of NTN parameter information of the second satellite, in a case where the first network device determines that the terminal is located in a coverage area of the second cell on the ground. The indication information indicates location information of NTN parameters. And system message block information where the NTN parameter information of the second satellite is located.

It should be noted that, in the case that the terminal is located in the coverage area of the second cell on the ground, the first network device sends the NTN parameter information of the second satellite and/or the indication information of the NTN parameter information of the second satellite to the terminal, so that the sent information can be ensured to be available information for the terminal.

Optionally, the NTN parameter information of the second satellite and/or the indication information of the NTN parameter information of the second satellite may also be provided by the first network device to the terminal in the process of notifying the terminal that the satellite alternates, for example, be carried in the first message.

The purpose of the synchronization stage is to synchronize the terminal to the second network device corresponding to the second satellite, so as to receive the downlink transmission, such as the broadcast message, from the second network device. As an example, the synchronization phase includes step 1005b.

Step 1005b, the terminal performs downlink synchronization in the second cell to synchronize to a second network device corresponding to the second satellite.

As an example, the second network device and the first network device may be the same network device. Alternatively, the second network device and the first network device are different network devices, which is not limited in the embodiments of the present application.

In one possible implementation of the present application, the terminal is synchronized to the second network device before the end time of coverage of the first satellite and/or after the start time of coverage of the second satellite.

As an example, step 1005b may be implemented by: the terminal searches the downlink synchronization signal of the second cell in the first cell, and further performs downlink synchronization (for example, searches the synchronization signal of the second cell, and obtains downlink timing, that is, obtains the boundary of the system frame, the subframe, the time slot, and the symbol of the second cell in the second satellite). Or the terminal updates the downlink synchronization of the terminal in the second cell according to the position of the second satellite, the position of the first satellite and the current position information of the terminal, namely, updates the downlink synchronization of the second cell acquired by the first terminal currently.

In a possible embodiment of the present application, as shown in fig. 10, the method provided in the embodiment of the present application may further include, in a case that the terminal is synchronized to the second network device:

step 1006b, the terminal initiates a random access procedure to the second network device.

For example, in the case that the terminal is synchronized to the second network device, the terminal may immediately initiate the random access procedure to the second network device, and of course, may also restart the random access procedure when the first condition is satisfied. The terminal is convenient for the terminal to send uplink to the second network device by initiating a random access process.

Wherein, as an example, the first condition includes any one of:

before the end time of coverage of the first satellite;

after a coverage start time of the second satellite;

there is a data transmission need (e.g., receiving downstream data from the second network device and/or transmitting upstream data to the second network device);

the uplink time adjustment timer of the terminal does not time out.

It can be understood that if the uplink time adjustment timer of the terminal does not time out, uplink data to be transmitted exists between the surface terminal and the first network device corresponding to the first satellite, and the uplink data is not ended.

In one possible implementation of the present application, after the terminal synchronizes to the second network device when the second condition is satisfied, the random access procedure does not need to be initiated to the second network device, where the second condition includes at least that the uplink time adjustment timer of the terminal is overtime, or that the terminal does not have an uplink data transmission requirement, or that the uplink time adjustment timer of the terminal is not started, as an example.

Optionally, when the uplink time adjustment timer of the terminal expires, if the terminal does not initiate a random access procedure to the second network device. When there is an uplink data transmission demand in the follow-up, the terminal can also initiate a random access process.

For a specific implementation of the random access procedure for the terminal to send to the second network device, reference may be made to the description in the prior art, which is not limited in the embodiments of the present application.

In an optional embodiment of the present application, in a case where the terminal accesses the second network device through a random access procedure, as shown in fig. 10, the method provided in the embodiment of the present application may further include:

step 1007b, the second network device sends a first command (e.g., an uplink time adjustment command) to the terminal. Accordingly, the terminal receives a first command (e.g., an uplink time adjustment command) from the second network device.

Step 1008b, the terminal restarts the uplink time adjustment timer of the terminal according to the first command.

In one possible implementation manner of the present application, in a case where the terminal is located in a coverage area of the second satellite on the ground, the method provided by the embodiment of the present application may further include: and before the NTN parameter information corresponding to the second satellite fails, the terminal acquires the NTN parameter information of the second satellite again.

Alternatively, the terminal should obtain NTN parameter information for the second satellite before the first satellite leaves (i.e., before the end of coverage time for the first satellite). I.e. the terminal should ensure that the NTN parameter information of the second satellite is valid when the first satellite leaves.

Alternatively, the terminal may obtain NTN parameter information for the second satellite through the first satellite.

Alternatively, the terminal may obtain NTN parameter information of the second satellite through the second satellite.

Alternatively, the terminal may not evaluate other CHO conditions in case the terminal is located in the coverage area of the second cell on the ground. Alternatively, the terminal may not perform measurement of the candidate target cell corresponding to CHO. Alternatively, the terminal may release other CHO configurations. Optionally, the terminal may also send indication information to the first network device to indicate that the terminal does not evaluate or does not measure or release CHO configurations. Alternatively, the indication of the CHO configuration without evaluation or measurement or release may be carried in a fourth message. As an example. CHO configurations may be released by CHO identification information. And if the terminal reports the identifier corresponding to the CHO configuration to be released.

The foregoing description of the solution of the embodiment of the present application has been mainly presented from the perspective of interaction between network elements. It will be appreciated that each network element, e.g. the first network device, the terminal, etc., comprises corresponding structures and/or software modules for performing the respective functions in order to achieve the above-described functions. Those of skill in the art will readily appreciate that the elements and algorithm steps of the examples described in connection with the embodiments disclosed herein may be implemented as hardware or combinations of hardware and computer software. Whether a function is implemented as hardware or computer software driven hardware depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

The embodiment of the application may illustrate the first network device and the terminal to divide the functional units according to the above method, for example, each functional unit may be divided corresponding to each function, or two or more functions may be integrated into one processing unit. The integrated units may be implemented in hardware or in software functional units. It should be noted that, in the embodiment of the present application, the division of the units is schematic, which is merely a logic function division, and other division manners may be implemented in actual practice.

The method according to the embodiment of the present application is described above with reference to fig. 9 to 10, and the communication device for performing the method according to the embodiment of the present application is described below. It will be appreciated by those skilled in the art that the methods and apparatuses may be combined and cited, and the communication apparatus provided in the embodiments of the present application may perform the steps performed by the terminal and the first network device in the above analysis method.

In case of using an integrated unit, fig. 11 shows a communication apparatus involved in the above-described embodiment, which may include: a communication module 113 and a processing module 112.

In an alternative implementation, the communication device may further comprise a storage module 111 for storing program code and data of the communication device.

The communication device is, for example, a terminal or a chip for application in a terminal. In this case, the communication module 113 is configured to support communication between the communication apparatus and an external network element (e.g., a first network device). For example, the communication module 113 is configured to perform the signal transceiving operation of the terminal in the above-described method embodiment. The processing module 112 is configured to perform the signal processing operation of the terminal in the above-described method embodiment.

The communication module 113 is for performing the receiving action performed by the terminal in step 901 of fig. 9 or step 1001 of fig. 10 of the above-described embodiment, for example. A processing module 112 for supporting the communication device to perform the actions performed by the terminal in step 902 of fig. 9 or step 1002 of fig. 10.

In case the terminal is located outside the coverage of the second cell on the ground, optionally, the communication module 113 is further configured to perform the transmitting action performed by the terminal in step 1003a of fig. 10 of the above-described embodiment. Optionally, the communication module 113 is further configured to perform the sending action performed by the terminal in step 1004a of fig. 10 in the above embodiment. Optionally, the communication module 113 is further configured to perform the receiving action performed by the terminal in step 1005a and/or step 1006a of fig. 10 in the above embodiment. Optionally, the processing module 112 is further configured to perform step 1007a of fig. 10 in the above embodiment. Optionally, the processing module 112 is further configured to perform step 1008a and/or step 1009a of fig. 10 in the foregoing embodiment.

In case the terminal is located in the coverage area of the second cell on the ground, optionally, the communication module 113 is further configured to perform the transmitting actions performed by the terminal in step 1003b and/or step 1004b of fig. 10 of the above-described embodiments. Optionally, the processing module 112 is further configured to perform step 1005b and step 1006b. Optionally, the communication module 113 is further configured to perform the received actions performed by the terminal in step 1007b of fig. 10 in the above embodiment. The processing module 112 is also configured to perform step 1008b.

As another example, the communication apparatus is a first network device or a chip applied in the first network device. In this case, the communication module 113 is used to support the communication device to communicate with an external network element (e.g., a terminal). For example, the communication module 113 is configured to perform the signal transceiving operation of the first network device in the above-described method embodiment. The processing module 112 is configured to perform the signal processing operation of the first network device in the above-described method embodiment.

The communication module 113 is for performing the transmission action performed by the first network device in step 901 of fig. 9 or step 1001 of fig. 10 of the above-described embodiments.

Optionally, the communication module 113 is configured to perform the received actions performed by the first network device in step 1003a or step 1003b of fig. 10 in the above embodiment.

Optionally, the communication module 113 is configured to perform the received action performed by the first network device in step 1004a or step 1004b of fig. 10 in the above embodiment.

Alternatively, in case the terminal is located outside the coverage of the second cell on the ground, the communication module 113 is configured to perform the sending action performed by the first network device in step 1005a of fig. 10 of the above-described embodiment.

Alternatively, in case the terminal is located outside the coverage of the second cell on the ground, the communication module 113 is configured to perform the sending action performed by the first network device in step 1006a of fig. 10 of the above-described embodiment.

It should be noted that, the communication module 113 shown in fig. 11 may be replaced by a communication unit, and the processing module 112 may be replaced by a reference processing unit. The memory module 111 may also be replaced with a memory cell. The processing unit is used for controlling and managing the actions of the communication device, for example, the processing unit is used for executing the steps of information/data processing in the communication device. The communication unit is used for supporting the communication device to transmit or receive information/data.

In one possible implementation, the communication unit may include a receiving unit for receiving the signal and a transmitting unit for transmitting the signal.

The processing module 112 may be a processor or controller, such as a central processing unit, a general purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. Which may implement or perform the various exemplary logic blocks, modules, and circuits described in connection with this disclosure. A processor may also be a combination that performs a computational function, such as a combination comprising one or more microprocessors, a combination of a digital signal processor and a microprocessor, and so forth. The communication module may be a transceiver, a transceiver circuit, a communication interface, or the like. The memory module may be a memory.

When the processing module 112 is the processor 1201 or the processor 1205, the communication module 113 is the communication interface 1203, and the storage module 111 is the memory 1202, the communication apparatus related to the present application may be the communication device shown in fig. 12.

Fig. 12 is a schematic hardware structure of a communication device according to an embodiment of the present application. The structures of the terminal and the first network device in the embodiments of the present application may refer to a schematic structural diagram of a communication device as shown in fig. 12. The communication device comprises a processor 1201, a communication line 1204 and at least one communication interface (illustrated in fig. 12 by way of example as communication interface 1203).

The processor 1201 may be a general purpose central processing unit (central processing unit, CPU), microprocessor, application Specific Integrated Circuit (ASIC), or one or more integrated circuits for controlling the execution of the programs of the present application.

The communication line 1204 may include a pathway to transfer information between the aforementioned components.

The communication interface 1203 is used for information interaction with other devices, e.g. devices using any transceiver or the like, for communication with other devices or communication networks, such as ethernet, radio access network (radio access network, RAN), wireless local area network (wireless local area networks, WLAN), etc.

Optionally, the communication device may also include a memory 1202.

The memory 1202 may be, but is not limited to, read-only memory (ROM) or other type of static storage device that can store static information and instructions, random access memory (random access memory, RAM) or other type of dynamic storage device that can store information and instructions, but may also be electrically erasable programmable read-only memory (EEPROM), compact disc-read only memory (compact disc read-only memory) or other optical disk storage, optical disk storage (including compact disc, laser disc, optical disc, digital versatile disc, blu-ray disc, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. The memory may be implemented separately and coupled to the processor via communication line 1204. The memory may also be integrated with the processor.

The memory 1202 is used for storing computer-executable instructions for executing aspects of the present application, and is controlled by the processor 1201 for execution. The processor 1201 is configured to execute computer-executable instructions stored in the memory 1202, thereby implementing a network access method provided in the following embodiments of the present application.

Alternatively, the computer-executable instructions in the embodiments of the present application may be referred to as application program codes, which are not specifically limited in the embodiments of the present application.

In a particular implementation, the processor 1201 may include one or more CPUs, such as CPU0 and CPU1 in fig. 12, as one embodiment.

In a particular implementation, as one embodiment, the communication device may include multiple processors, such as processor 1201 and processor 1205 in fig. 12. Each of these processors may be a single-core (single-CPU) processor or may be a multi-core (multi-CPU) processor. A processor herein may refer to one or more devices, circuits, and/or processing cores for processing data (e.g., computer program instructions).

Fig. 13 is a schematic structural diagram of a chip 130 according to an embodiment of the present application. Chip 130 includes one or more (including two) processors 1310 and communication interfaces 1330.

Optionally, the chip 130 further includes a memory 1340, which may include read-only memory and random access memory, and provides operating instructions and data to the processor 1310. A portion of memory 1340 may also include non-volatile random access memory (NVRAM).

In some implementations, the memory 1340 stores elements, execution modules or data structures, or a subset thereof, or an extended set thereof.

In the present embodiment, the corresponding operation is performed by calling the operation instruction stored in the memory 1340 (which may be stored in the operating system).

One possible implementation is: the terminal and the chip used by the first network device are similar in structure, and different devices can use different chips to realize respective functions.

The processor 1310 controls processing operations of any one of the terminal, the first network device, and the processor 1310 may also be referred to as a central processing unit (central processing unit, CPU).

Memory 1340 may include read only memory and random access memory, and provides instructions and data to processor 1310. A portion of the memory 1340 may also include NVRAM. Such as an application memory 1340, a communication interface 1330, and memory 1340, are coupled together by bus system 1320, where bus system 1320 may include a power bus, control bus, status signal bus, and the like, in addition to a data bus. The various buses are labeled as bus system 1320 in fig. 13 for clarity of illustration.

The methods disclosed in the embodiments of the present application may be applied to the processor 1310 or implemented by the processor 1310. Processor 1310 may be an integrated circuit chip with signal processing capabilities. In implementation, the steps of the methods described above may be performed by integrated logic circuitry in hardware or instructions in software in processor 1310. The processor 1310 may be a general purpose processor, a digital signal processor (digital signal processing, DSP), an ASIC, an off-the-shelf programmable gate array (field-programmable gate array, FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware components. The disclosed methods, steps, and logic blocks in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of a method disclosed in connection with the embodiments of the present application may be embodied directly in hardware, in a decoded processor, or in a combination of hardware and software modules in a decoded processor. The software modules may be located in a random access memory, flash memory, read only memory, programmable read only memory, or electrically erasable programmable memory, registers, etc. as well known in the art. The storage medium is located in the memory 1340, and the processor 1310 reads information from the memory 1340 and performs the steps of the method in combination with hardware.

In a possible implementation, the communication interface 1330 is configured to perform the steps of receiving and transmitting by the terminal, the first network device in the embodiments shown in fig. 9-10. The processor 1310 is configured to perform the steps of the processing of the terminal, the first network device in the embodiments shown in fig. 6-10.

The above communication module may be a communication interface of the apparatus for receiving signals from other apparatuses. For example, when the device is implemented in a chip, the communication module is a communication interface of the chip for receiving signals from other chips or devices or transmitting signals.

In one aspect, a computer-readable storage medium is provided in which instructions are stored that, when executed, implement the functions performed by a terminal as in fig. 9 or 10.

In one aspect, a computer-readable storage medium is provided having instructions stored therein that, when executed, perform the functions performed by a first network device, such as in fig. 9 or 10.

In one aspect, a computer program product is provided comprising instructions that when executed implement the functions as performed by a terminal in fig. 6.

In yet another aspect, a computer program product is provided comprising instructions that when executed perform the functions as performed by the first network device in fig. 9 or 10.

In one aspect, a chip for use in a terminal is provided, the chip including at least one processor and a communication interface coupled to the at least one processor, the processor for executing instructions to perform functions as performed by the terminal in fig. 9 or 10.

In yet another aspect, an embodiment of the present application provides a chip for use in an access management network element, the chip including at least one processor and a communication interface, the communication interface being coupled to the at least one processor, the processor configured to execute instructions to implement the functions performed by a first network device as in fig. 9 or 10.

The embodiment of the application provides a communication system, which comprises: a first network device and a terminal. Wherein the first network device is configured to perform the functions as performed by the first network device in fig. 9 or fig. 10, and the terminal is configured to perform the functions as performed by the terminal in fig. 9 or fig. 10.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, a network device, a user device, or other programmable apparatus. The computer program or instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer program or instructions may be transmitted from one website site, computer, server, or data center to another website site, computer, server, or data center by wired or wireless means. The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that integrates one or more available media. The usable medium may be a magnetic medium, e.g., floppy disk, hard disk, tape; optical media, such as digital video discs (digital video disc, DVD); but also semiconductor media such as solid state disks (solid state drive, SSD).

Although the present application has been described herein in connection with various embodiments, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed application, from a review of the figures, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Although the present application has been described in connection with specific features and embodiments thereof, it will be apparent that various modifications and combinations can be made without departing from the spirit and scope of the application. Accordingly, the specification and drawings are merely exemplary illustrations of the present application as defined in the appended claims and are considered to cover any and all modifications, variations, combinations, or equivalents that fall within the scope of the present application. It will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the spirit or scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims and the equivalents thereof, the present application is intended to include such modifications and variations as well.

Claims

1. A method of communication, comprising:

a terminal receives a first message from a first network device, wherein the first message is used for indicating a satellite serving a first cell to update from the first satellite to a second satellite, the first cell is a cell accessed by the terminal, the first network device corresponds to the first satellite, the first message comprises first information, the first information is used for determining the coverage area of a second cell served by the second satellite on the ground, and the first cell and the second cell have the same cell identifier;

based on the first message, the terminal determines that the terminal is located in the coverage area or outside the coverage area according to the position of the terminal and the coverage area of the second cell on the ground.

2. The method of claim 1, wherein the terminal determines that the terminal is located within or outside the coverage area based on the location of the terminal and the coverage area of the second cell on the ground, the method further comprising:

the terminal sends a second message to the first network device, where the second message is used to indicate that the terminal is located in a coverage area of the second cell on the ground, or the second message is used to indicate that the terminal is located outside the coverage area of the second cell on the ground.

3. The method according to claim 1 or 2, wherein the terminal determines that the terminal is located within the coverage area or after the terminal is located outside the coverage area according to the location of the terminal and the coverage area of the second cell on the ground, the method further comprising:

the terminal sends location information of the terminal to the first network device and/or measurement report information of the terminal, the measurement report information including information indicating signal quality of a neighbor cell of the terminal.

4. A method according to any one of claims 1 to 3, wherein if the terminal is located within the terrestrial coverage of the second cell of the second satellite service, the method further comprises:

and the terminal performs downlink synchronization in the second cell so as to synchronize to second network equipment corresponding to the second cell, wherein the second network equipment corresponds to the second satellite.

5. The method according to claim 4, wherein in case the first condition is fulfilled, the method further comprises:

the terminal initiates a random access procedure to the second network device, wherein the first condition comprises any one or more of:

Before the end time of coverage of the first satellite;

after a start time of coverage of the second satellite;

there is a need for data transmission;

and the uplink time adjustment timer of the terminal does not timeout.

6. The method of claim 4, wherein the terminal does not need to initiate a random access procedure to the second network device if a second condition is met, the second condition comprising at least that an uplink time adjustment timer of the terminal expires or that the uplink time adjustment timer of the terminal does not start.

7. A method according to any one of claims 1 to 3, wherein if the terminal is located outside the coverage area of a second cell of the second satellite service on the ground, the method further comprises:

the terminal receives a third message from the first network device, wherein the third message is used for indicating the terminal to switch to a target cell, the target cell and the first cell have different cell identifications, and the terminal is located in the coverage range of the target cell;

and the terminal switches the service cell of the terminal from the first cell to the target cell according to the third message.

8. The method of claim 7, wherein the third message comprises: first configuration information for the terminal to determine information of the target cell,

the terminal switches the service cell of the terminal from the first cell to the target cell according to the third message, and the method comprises the following steps:

the terminal determines the information of the target cell according to the first configuration information;

and the terminal switches the service cell of the terminal from the first cell to the target cell according to the information of the target cell.

9. The method according to claim 7 or 8, wherein the third message comprises: second configuration information, wherein the second configuration information comprises cell switching conditions configured for the terminal;

and under the condition that the cell switching condition included in the second configuration information is met, the terminal switches a serving cell of the terminal from the first cell to the target cell.

10. The method according to any one of claims 1 to 9, wherein the first message comprises a first time parameter and/or a second time parameter, wherein the first time parameter is used for determining a coverage start time of the second satellite on the ground corresponding to the second cell, and the second time parameter is used for determining a coverage end time of the second satellite on the ground corresponding to the second cell;

The method further comprises the steps of:

and the terminal synchronizes to a second network device corresponding to the second satellite after the coverage start time of the second satellite on the ground or sends a second message to the first network device before the coverage start time of the second satellite on the ground according to the first time parameter and/or the second time parameter.

11. The method according to any one of claims 1-10, wherein the first message further comprises one or more of the following information:

the terminal executes time information of downlink synchronization in the second cell;

12. A method of communication, comprising:

the method comprises the steps that first network equipment corresponding to a first satellite sends a first message, the first message is used for indicating that a satellite serving a first cell is updated from the first satellite to a second satellite, the first message comprises first information, the first information is used for determining the coverage area of a second cell serving the second satellite on the ground, and the first cell and the second cell have the same cell identification.

13. The method according to claim 12, wherein the first message comprises a first time parameter and/or a second time parameter;

wherein the first time parameter is used for determining a coverage start time of the second cell on the ground corresponding to the second satellite;

and the second time parameter is used for determining the coverage end time of the second satellite on the ground corresponding to the second cell.

14. The method of claim 12 or 13, wherein the first message further comprises one or more of the following information:

the terminal executes time information of downlink synchronization in the second cell through the second satellite;

the NTN parameter information of the second satellite comprises parameter information required by a terminal to access the second cell;

15. The method of claim 14, wherein the first message includes information of the measurement timing configuration, the measurement timing configuration being derived from a downlink timing relationship configuration of the first cell in the first satellite or the measurement timing configuration being derived from a downlink timing relationship configuration of the second cell in the second satellite, the downlink timing relationship being used to determine a first subframe number and a system frame number of a downlink synchronization signal of the second cell.

16. The method according to any of claims 12-15, wherein the first network device determines that a first terminal accessing the first cell is located outside the coverage area of the second cell on the ground, the method further comprising:

the first network device sends a third message to the first terminal, wherein the third message is used for indicating the first terminal to switch to a target cell, the target cell is different from the cell identifier of the first cell, and the first terminal is located in the coverage area of the target cell.

17. The method of claim 16, wherein the method further comprises:

the first network device sends first configuration information and/or second configuration information to the first terminal, wherein the first configuration information is used for the first terminal to determine information of the target cell, and the second configuration information is used for the first terminal to determine a cell switching condition.

18. The method according to claim 17, wherein one or more of the first configuration information and the second configuration information is determined by location information of the first terminal and/or measurement report information of the first terminal, the measurement report information comprising information indicating signal quality of a neighbor cell of the first terminal.

19. The method according to any one of claims 12 to 18, further comprising:

the first network equipment receives a second message from a first terminal, wherein the first terminal is a terminal accessed to the first cell;

and the first network equipment determines that the first terminal is positioned outside the coverage area of the second cell on the ground or the first terminal is positioned in the coverage area of the second cell on the ground according to the second message.

20. The method of claim 19, wherein the second message includes location information of the first terminal, and wherein the first network device determining that the first terminal is located outside the coverage area of the second cell on the ground or that the first terminal is located within the coverage area of the second cell on the ground according to the second message comprises:

and the first network equipment determines that the first terminal is positioned outside the coverage area of the second cell on the ground or the first terminal is positioned in the coverage area of the second cell on the ground according to the position information of the first terminal and the coverage area of the second cell on the ground.

21. A computer readable storage medium having instructions stored therein which, when executed, implement the method of any one of claims 1-11 or 12-20.

22. A chip comprising a processor coupled to a communication interface for communicating with other modules outside the chip, the processor being configured to execute a computer program or instructions to implement the method of any one of claims 1-11 or 12-20.

23. A terminal, comprising: at least one processor connected to a communication interface for receiving or transmitting information, the at least one processor being configured to execute instructions stored in a memory for performing the method of any one of claims 1-11.

24. A network device, comprising: at least one processor coupled to a communication interface for receiving or transmitting information, the at least one processor for executing instructions stored in memory to perform the method of any one of claims 12-20.

25. A communication system, comprising: a terminal for performing the method of any of claims 12 to 20, and a first network device corresponding to a first satellite for implementing the method of any of claims 1 to 11.