Communication method and communication apparatus

Abstract

The present application provides a communication method and a communication apparatus. The method comprises: determining one or more second non-terrestrial network devices, wherein the one or more second non-terrestrial network devices are non-terrestrial network devices that, following a first non-terrestrial network device, provide services for a communication apparatus in a first area, the first area comprises a registration area of a terminal device, the terminal device is in an idle state, and the first non-terrestrial network device is a non-terrestrial network device that currently stores context information of the terminal device; and sending the context information of the terminal device to the one or more second non-terrestrial network devices. On this basis, the latency of the terminal device acquiring the context information from a satellite can be reduced.

Description

Communication methods and communication devices

[0001] This application claims priority to Chinese Patent Application No. 202510061873.1, filed on January 14, 2025, entitled "Communication Method and Communication Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communications, and more specifically, to a communication method and a communication device. Background Technology

[0003] The development of communication services supported by low-Earth orbit (LEO) satellites is rapid. A constellation of LEO satellites can include multiple sets of orbits with the same altitude / inclination. These sets of orbits can be collectively referred to as a shell, and a shell can contain multiple orbits, each containing multiple satellites. In scenarios where satellites are moving at high speeds, when a terminal device enters a connected state, the distance between the satellite storing the terminal device's context information and the satellite currently serving the terminal device may be relatively large, resulting in a long latency for the terminal device to obtain the context information. Therefore, reducing the latency for terminal devices to obtain context information from satellites is a pressing problem to be solved in this field. Summary of the Invention

[0004] This application provides a communication method and a communication device that can reduce the latency of terminal devices obtaining context information from satellites.

[0005] Firstly, a communication method is provided. This method can be applied to a first non-terrestrial network device; that is, the method can be executed by the first non-terrestrial network device or by components of the first non-terrestrial network device (such as a chip, chip system, circuit, communication module, or processor). This application does not limit this. The following description mainly uses a first non-terrestrial network device as an example, which is located on a first satellite.

[0006] The method may include: determining one or more second non-terrestrial network devices, wherein the one or more second non-terrestrial network devices are non-terrestrial network devices that provide services to communication devices in a first area after the first non-terrestrial network device, the first area including a registration area of ​​a terminal device, the terminal device being in an idle state, and the first non-terrestrial network device being a non-terrestrial network device currently storing the context information of the terminal device; and sending the context information of the terminal device to the one or more second non-terrestrial network devices.

[0007] Based on the above technical solution, the first non-terrestrial network device that currently stores the terminal device's context information can determine the second non-terrestrial network device. This second non-terrestrial network device can then provide services to communication devices within the terminal device's registration area, following the first non-terrestrial network device. By transmitting the context information to the second non-terrestrial network device, the first non-terrestrial network device ensures that even after the first satellite where the first non-terrestrial network device is located leaves the terminal device's registration area, the terminal device can still obtain its context information through the second non-terrestrial network device. Therefore, the terminal device's context information can be chained between satellites, ensuring that at least one of the non-terrestrial network devices serving the terminal device stores its context information. This reduces the latency for the terminal device to obtain context information and decreases the amount of inter-satellite signaling.

[0008] Conversely, if the terminal device still obtains context information from the first non-terrestrial network device, then inter-satellite signaling is required to transmit the context information. Furthermore, since the distance between the first non-terrestrial network device and the satellite of the currently serving terminal device may be relatively far, the latency of obtaining context information from the first non-terrestrial network device is also relatively large.

[0009] In conjunction with the first aspect, in some implementations of the first aspect, determining one or more second non-terrestrial network devices includes: the second non-terrestrial network device being located on a second satellite, and determining one or more second satellites based on the first region, the shell to which the first satellite belongs, the direction of travel of the first satellite, and the ephemeris of the satellites included in the shell to which the first satellite belongs.

[0010] In conjunction with the first aspect, in some implementations of the first aspect, the second satellite has the same direction of operation and belongs to the same shell as the first satellite.

[0011] Based on the above technical solution, the first non-terrestrial network device in the first satellite can transmit the context information of the terminal device to the second non-terrestrial network device in the second satellite, which belongs to the same shell layer as the first satellite and has the same direction of operation. Thus, when the terminal device enters the connected state again, it can find the context information of the terminal device in the second satellite, which belongs to the same shell layer as the first satellite and has the same direction of operation. In this way, the path for the terminal device to obtain the context information is shorter, reducing the latency of the terminal device to obtain the context information.

[0012] In conjunction with the first aspect, in some implementations of the first aspect, the registration area includes a tracking area indicated by the tracking area list of the terminal device, wherein the tracking area indicated by the tracking area list belongs to the Internet Protocol (IP) geographic area of ​​the terminal device, the tracking area and the IP geographic area are areas fixed to the ground, the IP geographic area is associated with the IP address of the terminal device, and the IP address of the terminal device remains unchanged when the terminal device moves within the IP geographic area.

[0013] Based on the above technical solution, the tracking area and IP geographic area are fixed on the ground, which allows network devices to find the satellite serving the terminal device based on the terminal device's IP address or tracking area. Thus, there is no need for fixed anchor points. The system can directly send data packets to the terminal device based on the tracking area or IP geographic area. This avoids the need to establish tunnels and perform frequent tunnel updates, simplifies system design, and reduces routing detours caused by fixed anchor points.

[0014] In conjunction with the first aspect, in some implementations of the first aspect, sending the context information of the terminal device to the one or more second non-terrestrial network devices includes: sending the context information of the terminal device to the one or more second non-terrestrial network devices at a first moment, wherein the first moment is the moment when the first non-terrestrial network device no longer or is about to no longer provide services to communication devices in the first area, and the first moment is determined based on the ephemeris of the first satellite.

[0015] Based on the above technical solution, the first non-terrestrial network device can transmit the context information of the terminal device to the second non-terrestrial network device when it no longer or is about to stop providing services to the communication device in the first area, thereby ensuring that after the first satellite where the first non-terrestrial network device is located leaves the registration area of ​​the terminal device, the terminal device can obtain its context information through the second non-terrestrial network device.

[0016] Secondly, a communication method is provided. This method can be applied to a second non-terrestrial network device; that is, the method can be executed by the second non-terrestrial network device itself, or by a component of the second non-terrestrial network device (such as a chip, chip system, circuit, communication module, or processor). This application does not limit the scope of the method. The following description mainly uses a second non-terrestrial network device as an example.

[0017] The method may include: receiving context information of a terminal device, the context information of the terminal device coming from a first non-terrestrial network device, the first non-terrestrial network device providing services to communication devices in a first area, the first area including the registration area of ​​the terminal device, the terminal device being in an idle state, and a second non-terrestrial network device being a satellite providing services to communication devices in the first area after the first non-terrestrial network device, wherein the second non-terrestrial network device is located on a second satellite, and the first non-terrestrial network device is located on a first satellite.

[0018] In conjunction with the second aspect, in some implementations of the second aspect, the second satellite has the same direction of operation and belongs to the same shell as the first satellite.

[0019] In conjunction with the second aspect, in some implementations of the second aspect, the method may further include: receiving a first message from the terminal device, the first message being used to request access to the second non-terrestrial network device; and accessing the terminal device according to the context information.

[0020] Based on the above technical solution, after receiving the context information of the terminal device, the second non-terrestrial network device also receives the access request from the terminal device, and the second non-terrestrial network device can access the terminal device according to the context information.

[0021] In conjunction with the second aspect, in some implementations of the second aspect, the method may further include: receiving a second message, the second message including a data packet sent to the terminal device; and paging the terminal device according to the context information.

[0022] Based on the above technical solution, after receiving the context information of the terminal device, the second non-terrestrial network device also receives the data packets of the terminal device, and then the second non-terrestrial network device can page the terminal device according to the context information.

[0023] In conjunction with the second aspect, in some implementations of the second aspect, paging the terminal device based on the context information includes: sending a third message based on the context information, the third message being used to paging the terminal device; and / or sending a fourth message to a third non-terrestrial network device, the fourth message being used to trigger the third non-terrestrial network device to paging the terminal device, the third non-terrestrial network device being any non-terrestrial network device in a first non-terrestrial network device group other than the second non-terrestrial network device; wherein, the first non-terrestrial network device group includes one or more non-terrestrial network devices that provide services to communication devices within the IP geographical area of ​​the terminal device, the IP geographical area being determined based on the IP address of the terminal device.

[0024] Based on the above technical solution, after receiving the context information of the terminal device, the second non-terrestrial network device can page the terminal device according to the context information, or trigger other non-terrestrial network devices in the non-terrestrial network device group to page the terminal device, so that the terminal device can be paged even when it is not in the service area of ​​the second non-terrestrial network device.

[0025] In conjunction with the second aspect, in some implementations of the second aspect, the fourth message includes the context information and / or the data packet, the context information including the IP address, the context information being used by the third non-terrestrial network device to page the terminal device, and the data packet being used to send to the terminal device after the terminal device accesses the third non-terrestrial network device.

[0026] In conjunction with the second aspect, in some implementations of the second aspect, the method may further include: receiving first indication information from the third non-terrestrial network device, the first indication information indicating that the terminal device accesses the third non-terrestrial network device; and sending data packets of the terminal device to the third non-terrestrial network device.

[0027] Based on the above technical solution, the third non-terrestrial network device can instruct the second non-terrestrial network device to access the third non-terrestrial network device through the first instruction information, so that the second non-terrestrial network device can send the data packets sent to the terminal to the third non-terrestrial network device.

[0028] In conjunction with the second aspect, in some implementations of the second aspect, the IP geographic region includes a tracking area indicated by the tracking area list of the terminal device, and the tracking area and the IP geographic region are areas fixed to the ground.

[0029] For the beneficial effects and possible designs of the second aspect, please refer to the relevant description in the first aspect, which will not be repeated here.

[0030] Thirdly, a communication method is provided. This method can be applied to a fourth non-terrestrial network device; that is, the method can be executed by the fourth non-terrestrial network device itself, or by a component of the fourth non-terrestrial network device (such as a chip, chip system, circuit, communication module, or processor). This application does not limit the scope of the method. The following description mainly uses a fourth non-terrestrial network device as an example.

[0031] The method may include: receiving a fifth message; determining a second region based on the fifth message, wherein the terminal device is located within the second region; determining a second non-terrestrial network device group based on the second region, wherein the second non-terrestrial network device group includes the fourth non-terrestrial network device and at least one second non-terrestrial network device, wherein at least one of the at least two second non-terrestrial network devices stores the context of the terminal device.

[0032] Based on the above technical solution, the fourth non-terrestrial network device can determine the second area where the terminal device is located based on the fifth message, and determine the second non-terrestrial network device group based on the area. At least one non-terrestrial network device in the second non-terrestrial network device group stores the context of the terminal device. That is, the fourth non-terrestrial network device can determine the location of the terminal device's context information based on the area where the terminal device is located, which facilitates further utilization of the terminal device's context information.

[0033] In conjunction with the third aspect, in some implementations of the third aspect, the method may further include: the at least one second non-terrestrial network device is located on at least one second satellite, the at least one second non-terrestrial network device and the at least one second satellite correspond one-to-one, the fourth non-terrestrial network device is located on a fourth satellite, and the second satellite and the fourth satellite have the same direction of operation and belong to the same shell.

[0034] In conjunction with the third aspect, in some implementations of the third aspect, the fifth message originates from the terminal device, the fifth message is used to request access to the fourth non-terrestrial network device, the fifth message includes the registration area information of the terminal device's last registration, and the step of determining the second area based on the fifth message includes: determining the second area based on the registration area information, the second area being the registration area of ​​the terminal device's last registration.

[0035] In conjunction with the third aspect, in some implementations of the third aspect, the method may further include: sending a sixth message to the at least one second non-terrestrial network device, the sixth message being used to request context information of the terminal device; receiving the context information of the terminal device; and connecting the terminal device to the network based on the context information of the terminal device.

[0036] Based on the above technical solution, the fifth message is a message used by the terminal device to request access to the fourth non-terrestrial network device. The second region is the registration region that the terminal device last registered. Therefore, the fourth non-terrestrial network device can determine the second non-terrestrial network device group based on the registration region that the terminal device last registered, and obtain the context information of the terminal device from the second non-terrestrial network device group. Then, the fourth non-terrestrial network device can access the terminal device based on the obtained context information.

[0037] In conjunction with the third aspect, in some implementations of the third aspect, the fifth message is a data packet sent to the terminal device, the data packet including the IP address of the terminal device, and determining the second region based on the fifth message includes: determining the second region based on the IP address, the second region being the IP geographical region of the terminal device, and the IP address remaining unchanged when the terminal device moves within the IP geographical region.

[0038] In conjunction with the third aspect, in some implementations of the third aspect, the method may further include: sending a seventh message to the at least one second non-terrestrial network device, the seventh message including the data packet, the seventh message being used to request that the data packet be sent to the terminal device.

[0039] Based on the above technical solution, the fifth message is a data packet sent to the terminal device, and the second region is the IP geographic region of the terminal device. Therefore, the fourth non-terrestrial network device can determine the second non-terrestrial network device group based on the IP geographic region of the terminal device and send the terminal device's data packet to at least one of the second non-terrestrial network devices in the second non-terrestrial network device group. Furthermore, the second non-terrestrial network device that has stored the terminal device's context information can page the terminal device and then send the aforementioned data packet to the terminal device.

[0040] In conjunction with the third aspect, in some implementations of the third aspect, the registration area includes a tracking area indicated by the tracking area list of the terminal device, the tracking area being an area fixed to the ground.

[0041] In conjunction with the third aspect, in some implementations of the third aspect, the IP geographic region includes the registration region of the terminal device, and the IP geographic region is a region fixed to the ground.

[0042] For the beneficial effects and possible designs of the third aspect, please refer to the relevant descriptions in the first or second aspects, which will not be repeated here.

[0043] Fourthly, a communication method is provided. This method can be applied to a terminal device; that is, the method can be executed by the terminal device itself, or by components of the terminal device (such as a chip, chip system, circuit, communication module, or processor). This application does not limit the scope of the method. The following description mainly uses a terminal device as an example.

[0044] The method may include: determining a fifth non-terrestrial network device, wherein the fifth non-terrestrial network device provides services to the communication device at the current location of the terminal device, and the first non-terrestrial network device is the non-terrestrial network device that the terminal device accessed when it last entered an idle state or the non-terrestrial network device that the terminal device is currently residing in, wherein the fifth non-terrestrial network device is located on a fifth satellite, and the first non-terrestrial network device is located on a first satellite, and the fifth satellite and the first satellite have the same direction of operation and belong to the same shell layer; and residing in the fifth non-terrestrial network device.

[0045] Based on the above technical solution, the terminal device can reside on the fifth non-terrestrial network device in the fifth satellite with the same operating direction and shell layer as the first satellite. The first non-terrestrial network device in the first satellite is the non-terrestrial network device that the terminal device accessed when it last entered the idle state or the non-terrestrial network device that the terminal device is currently residing on. Therefore, the terminal device can always reside on the non-terrestrial network device in the satellite with the same operating direction and shell layer as the first satellite, ensuring that the satellite on which the terminal device resides is as consistent as possible with the satellite that stores the terminal device's context, thereby reducing context transfer.

[0046] In conjunction with the fourth aspect, in some implementations of the fourth aspect, the method may further include: sending a first message to the fifth non-terrestrial network device, the first message being used to request access to the fifth non-terrestrial network device, the first message including the identifier of the terminal device and the registration area information of the last registration of the terminal device, the last registered registration area being used to determine a second non-terrestrial network device group that stores the context of the terminal device, the second non-terrestrial network device group including the fifth non-terrestrial network device, the satellite where the non-terrestrial network devices in the second non-terrestrial network device group are located has the same direction of operation as the fifth satellite and belongs to the same shell.

[0047] In conjunction with the fourth aspect, in some implementations of the fourth aspect, the first message further includes at least one of the location information and time information of the terminal device when it last entered the idle state, wherein the at least one of the location information and time information of the last time it entered the idle state is used to determine a second non-terrestrial network device that has stored the context of the terminal device.

[0048] In conjunction with the fourth aspect, in some implementations of the fourth aspect, residing on the fifth non-terrestrial network device includes: residing on the fifth non-terrestrial network device at a second time, the second time being the time when the non-terrestrial network device to which the terminal device is currently residing no longer or is about to cease providing services to the communication device at the current location, and the second time being determined based on the ephemeris of the satellite where the currently residing non-terrestrial network device is located.

[0049] Based on the above technical solution, the terminal device can camp on a fifth non-terrestrial network device when the non-terrestrial network device it is currently camping on no longer or is about to stop providing services to the communication device at the current location of the terminal device. This ensures that when the satellite where the non-terrestrial network device it is currently camping on no longer serves the terminal device, the terminal device can immediately determine the next non-terrestrial network device to camp on.

[0050] For the beneficial effects and possible designs of the fourth aspect, please refer to the relevant descriptions of any of the first to third aspects, which will not be repeated here.

[0051] Fifthly, a communication apparatus is provided for performing the methods described in the first or second aspect and any possible implementation thereof. Specifically, the apparatus may include units and / or modules for performing the methods described in the first or second aspect and any possible implementation thereof, such as processing units and / or communication units.

[0052] In one implementation, the device is a communication device (such as a terminal device or a non-terrestrial network device). When the device is a communication device, the communication unit can be a transceiver or an input / output interface; the processing unit can be at least one processor. Optionally, the transceiver can be a transceiver circuit. Optionally, the input / output interface can be an input / output circuit.

[0053] In another implementation, the device is a chip, chip system, circuit, or communication module for communication equipment (such as terminal equipment or non-terrestrial network equipment). When the device is a chip, chip system, or circuit for communication equipment, the communication unit can be an input / output interface, interface circuit, output circuit, input circuit, pin, or related circuit on the chip, chip system, or circuit; the processing unit can be at least one processor, processing circuit, or logic circuit.

[0054] In a sixth aspect, a communication device is provided, the device comprising: at least one processor configured to cause the device to perform the methods of the first or second aspect and any possible implementation thereof.

[0055] Optionally, the at least one processor is configured to execute computer programs or instructions to perform the methods described in the first or second aspect and any possible implementation thereof.

[0056] Optionally, the device further includes a memory for storing the computer program or instructions.

[0057] Optionally, the at least one processor is coupled to a memory for storing the computer program or instructions. The memory may be located externally to the device.

[0058] Optionally, the device also includes a communication interface through which the processor reads instructions from memory. This can be understood as the communication interface being coupled to the processor and used to input computer programs or instructions to the processor, or to output information from the processor.

[0059] Unless otherwise specified, or if the transmission and acquisition / reception operations involved do not contradict their actual function or internal logic in the relevant description, they can be understood as output, input, or other operations, or as transmission and reception operations performed by radio frequency circuits and antennas. This application does not limit them in this regard.

[0060] In one implementation, the device is a communication device (such as a terminal device or a non-terrestrial network device).

[0061] In another implementation, the device is a chip, chip system, circuit, or communication module for communication equipment (such as terminal equipment or non-terrestrial network equipment). Optionally, the chip is a modem chip, also known as a baseband chip, or a system-on-chip (SoC) chip containing a modem core, or a system-in-package (SIP) chip.

[0062] In a seventh aspect, a computer-readable storage medium is provided, on which a computer program (e.g., program code) or instructions are stored, which, when executed on a communication device, cause the communication device to perform the methods of the first or second aspect and any possible implementation thereof.

[0063] Eighthly, a computer program product containing instructions is provided, which, when run on a computer, causes the computer to perform the methods of the first or second aspect and any possible implementation thereof.

[0064] A ninth aspect provides a communication system, including a first communication device and a second communication device. The first communication device is used to execute the method provided in any implementation of the first aspect, and the second communication device is used to execute the method provided in any implementation of the second aspect. Attached Figure Description

[0065] Figure 1 is a schematic diagram of a wireless communication system applicable to an embodiment of this application.

[0066] Figure 2 is a schematic diagram of satellite coverage of the shell applicable to embodiments of this application.

[0067] Figure 3 is a schematic diagram of the 5G NTN network architecture.

[0068] Figure 4 is a schematic diagram of an NTN network architecture provided in an embodiment of this application.

[0069] Figure 5 is a schematic diagram of satellite deployment in a shell.

[0070] Figure 6 is a schematic diagram of satellite deployment in another shell.

[0071] Figure 7 is a schematic diagram of a communication method 700 provided in an embodiment of this application.

[0072] Figure 8 is a schematic diagram of a TA and IP geographical region provided in an embodiment of this application.

[0073] Figure 9 is a schematic diagram of a fifth satellite and a second satellite provided in an embodiment of this application.

[0074] Figure 10 is a schematic diagram of a communication method 1000 provided in an embodiment of this application.

[0075] Figure 11 is a schematic diagram of a communication method 1100 provided in an embodiment of this application.

[0076] Figure 12 is a schematic diagram of a communication device 1200 provided in an embodiment of this application.

[0077] Figure 13 is a schematic diagram of another communication device 1300 provided in an embodiment of this application.

[0078] Figure 14 is a schematic diagram of a chip system 1400 provided in an embodiment of this application. Detailed Implementation

[0079] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0080] Before introducing the scheme of this application, the following points should be noted.

[0081] (1) In this application, "instruction" can include direct instruction, indirect instruction, explicit instruction, implicit instruction, etc. When describing an instruction information as indicating A, it can be understood that the instruction information carries A, carries the identifier of A, carries B which is associated with A, carries the identifier of B which is associated with A, etc. In other words, if the receiving side of an instruction information can determine A based on the instruction information, it can be described as the instruction information indicating A, and the specific method of determination is not limited. When it is understood that the instruction information carries A, "instruction" can be replaced with "includes". In this case, a statement such as "send / receive instruction information, the instruction information indicates A" can be replaced with "send / receive A".

[0082] In this application, the information indicated by the instruction information is called the information to be instructed. In specific implementations, there are many ways to indicate the information to be instructed, such as, but not limited to, directly indicating the information to be instructed, such as the information to be instructed itself or its index. It can also indirectly indicate the information to be instructed by indicating other information, where there is a relationship between the other information and the information to be instructed. It can also indicate only a part of the information to be instructed, while the other parts are known or pre-agreed upon. For example, the instruction of specific information can be achieved by using a pre-agreed (e.g., protocol-defined) arrangement of various pieces of information, thereby reducing instruction overhead to some extent. Furthermore, the information to be instructed can be sent as a whole or divided into multiple sub-information pieces, and the sending period and / or timing of these sub-information pieces can be the same or different.

[0083] (2) In this application, the expression " / " is used to indicate that the objects before and after are in an "or" relationship; for example, A / B can mean: A or B. The expression "and / or" is used to indicate that the objects before and after are in a relationship of either "and" or "or"; for example, A and / or B can mean the following: A exists alone, B exists alone, A and B exist simultaneously, where A and B can be single or multiple. "At least one of the following" or similar expressions are used to indicate any combination of the listed items; for example, at least one of A, B and / or C can mean the following: A exists alone, B exists alone, C exists alone, A and B exist simultaneously, B and C exist simultaneously, A and C exist simultaneously, A, B and C exist simultaneously, where A, B, and C can be single or multiple.

[0084] (3) In this application, "send" and "receive" indicate the direction of signal transmission. For example, "send information to XX" can be understood as the destination of the information being XX, which may include direct transmission via the air interface or indirect transmission by other units or modules via the air interface. "Receive information from YY" can be understood as the source of the information being YY, which may include direct reception from YY via the air interface or indirect reception from YY by other units or modules via the air interface. "Send" can also be understood as the "output" of the chip interface, and "receive" can also be understood as the "input" of the chip interface. In other words, sending and receiving can occur between devices, such as between network devices and terminal devices, or within a device, such as between components, modules, chips, software modules, or hardware modules within the device via a bus, wiring, or interface.

[0085] (4) In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terms and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0086] (5) In this application, "first," "second," and "#1," "#2," and "#A" are merely for descriptive convenience and are used to distinguish objects, and are not intended to limit the scope of the embodiments of this application. They are not used to describe the order or sequence of features. It should be understood that such described objects can be interchanged where appropriate in order to describe solutions other than those in the embodiments of this application.

[0087] (6) In this application, "predefined" can mean a standard protocol predefined, or it can mean a pre-agreed or pre-negotiated agreement between devices. Here, "protocol" can refer to a standard protocol in the field of communications, for example, it may include fourth-generation (4G) protocols. th Generation 4G network, fifth generation (5G) network th This application does not limit the scope to network protocols such as generation (5G), new radio (NR) protocols, 5.5G network protocols, future communication network protocols, and related protocols applied in future communication systems.

[0088] (7) In this application, the words “exemplary,” “for example,” etc., are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as an “example” in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word “example” is intended to present the concept in a concrete manner. In the embodiments of this application, “of,” “corresponding, relevant,” and “corresponding” may sometimes be used interchangeably, and it should be noted that their intended meanings are consistent unless their distinction is emphasized.

[0089] First, let me introduce the communication system to which this application applies.

[0090] The technical solutions provided in this application can be applied to various communication systems, such as 5th generation (5G) or new radio (NR) systems, long term evolution (LTE) systems, LTE frequency division duplex (FDD) systems, and LTE time division duplex (TDD) systems. The technical solutions provided in this application can also be applied to future communication systems, such as future mobile communication networks. The technical solutions provided in this application can also be applied to device-to-device (D2D) communication, vehicle-to-everything (V2X) communication, machine-to-machine (M2M) communication, machine-type communication (MTC), and Internet of Things (IoT) communication systems. The technical solutions provided in this application can also be applied to non-terrestrial network (NTN) systems such as inter-satellite communication and satellite communication.

[0091] As an example, a satellite communication system includes a satellite base station and terminal equipment. The satellite base station provides communication services to the terminal equipment. Satellite base stations can also communicate with each other. A satellite can act as a base station or as a terminal device. Here, "satellite" can refer to drones, hot air balloons, low-Earth orbit satellites, medium-Earth orbit satellites, high-Earth orbit satellites, etc. "Satellite" can also refer to non-terrestrial base stations or non-terrestrial equipment.

[0092] As an example, V2X communication can include: vehicle-to-vehicle (V2V) communication, vehicle-to-infrastructure (V2I) communication, vehicle-to-pedestrian (V2P) communication, and vehicle-to-network (V2N) communication.

[0093] In a communication system, a device can send signals to or receive signals from another device. These signals can include information, signaling, or data. The device can also be replaced by an entity, network entity, communication equipment, communication module, node, communication node, etc. This application uses a device as an example for description.

[0094] The terminal device in this application embodiment can be a device or module that accesses the aforementioned communication system and has corresponding communication functions. The terminal device can include various devices with wireless communication capabilities, which can be used to connect people, objects, machines, etc. The terminal device can be widely applied in various scenarios, such as: cellular communication, D2D, V2X, peer-to-peer (P2P), M2M, MTC, IoT, virtual reality (VR), augmented reality (AR), industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, smart cities, drones, robots, remote sensing, passive sensing, positioning, navigation and tracking, autonomous delivery, etc. The terminal device can be a terminal in any of the above scenarios, such as an MTC terminal, an IoT terminal, etc. Terminal equipment can be user equipment (UE), terminal, fixed equipment, mobile station equipment or mobile equipment, subscriber unit, handheld device, vehicle-mounted equipment, wearable device, cellular phone, smartphone, session initiation protocol (SIP) phone, wireless data card, personal digital assistant (PDA), computer, tablet computer, laptop computer, wireless modem, handset, laptop computer, computer with wireless transceiver capability, smart book, vehicle, satellite, global positioning system (GPS) device, target tracking device, aircraft (e.g., drone, helicopter, multiple helicopters, four helicopters, or airplanes), ship, remote control device, smart home device, industrial equipment, transportation vehicle with wireless communication capability, communication module, or roadside unit with terminal function, all conforming to the 3rd generation partnership project (3GPP) standard. The device may be a wireless communication unit (RSU), or a device built into the aforementioned device (e.g., a communication module, modem, or chip in the aforementioned device), or other processing devices connected to the wireless modem.

[0095] It should be understood that in certain scenarios, a UE can also be used as a base station. For example, a UE can act as a scheduling entity, providing sidelink signaling between UEs in scenarios such as V2X, D2D, or P2P.

[0096] In this embodiment, the device for implementing the functions of a terminal device, i.e., the terminal device, can be the terminal device itself, or it can be any device capable of supporting the terminal device in implementing the functions, such as a chip system, chip, circuit, or communication module (i.e., a communication module that performs communication functions). This device can be installed in the terminal device. In this embodiment, the chip system can be composed of chips, or it can include chips and other discrete devices. Furthermore, the device can also be configured with program instructions for performing corresponding communication functions.

[0097] The network device in this application embodiment can be a device or module with corresponding communication functions. The network device can be a device used to communicate with terminal devices; it can also be called an access network device or a wireless access network device, such as a base station. In this application embodiment, the network device can refer to a radio access network (RAN) node (or device) that connects the terminal device to the wireless network. A base station can broadly encompass, or be replaced by, various names including: NodeB, evolved NodeB (eNB), next-generation NodeB (gNB), relay station, access point, transmitting and receiving point (TRP), transmitter, master station, auxiliary station, multiple standard radio (MSR) node, home base station, network controller, access node, wireless node, access point (AP), transmission node, transceiver node, baseband unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distributed unit (DU), positioning node, etc. A base station can be a macro base station, micro base station, relay node, donor node, or similar, or a combination thereof. A base station can also refer to a communication module, modem, or chip installed within the aforementioned equipment or apparatus. A base station can also be a mobile switching center, a device that performs base station functions in D2D, V2X, and M2M communications, a network-side device in future communication networks, or a device that performs base station functions in future communication systems. A base station can support networks using the same or different access technologies. The embodiments of this application do not limit the specific technologies or device forms used in the network equipment.

[0098] Base stations can be fixed or mobile. For example, a helicopter or drone can be configured to act as a mobile base station, and one or more cells can move depending on the location of the mobile base station. In other examples, a helicopter or drone can be configured as a device to communicate with another base station.

[0099] In some deployments, the network devices mentioned in the embodiments of this application may be devices including CU, or DU, or devices including CU and DU, or devices with control plane CU nodes (central unit-control plane (CU-CP)) and user plane CU nodes (central unit-user plane (CU-UP)) and DU nodes.

[0100] In some deployments, multiple RAN nodes collaborate to assist terminal devices in achieving wireless access, with different RAN nodes each implementing some of the base station's functions. For example, RAN nodes can be CUs, DUs, CU-CPs, CU-UPs, or radio units (RUs). CUs and DUs can be configured separately or included in the same network element, such as a BBU. RUs can be included in radio equipment or radio units, such as RRUs, AAUs, or RRHs.

[0101] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, a radio access network can also be an open radio access network (O-RAN) architecture. In an O-RAN system, CU can also be called an open CU (open CU, O-CU), DU can also be called an open DU (open DU, O-DU), CU-CP can also be called an open CU-CP (O-CU-CP), CU-UP can also be called an open CU-UP (O-CU-UP), and RU can also be called an open RU (open RU, O-RU). Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software modules and hardware modules.

[0102] In this embodiment, the device for implementing the functions of a network device can be a network device itself, or a device capable of supporting the network device in implementing those functions, such as a chip system, chip, circuit, or communication module (i.e., a communication module that performs communication functions). This device can be installed within the network device. In this embodiment, the chip system can be composed of chips, or it can include chips and other discrete devices. Furthermore, the device can be configured with program instructions for performing corresponding communication functions. This embodiment only uses a network device as an example to illustrate the device for implementing the functions of a network device, and does not limit the solution of this embodiment.

[0103] Network devices and terminal devices can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; and they can also be deployed in the air on airplanes, balloons, and satellites. This application does not limit the scenario in which the network devices and terminal devices are located.

[0104] The communication system applicable to the embodiments of this application is briefly described below with reference to Figure 1.

[0105] Referring to Figure 1, as an example, Figure 1 is a schematic diagram of a wireless communication system applicable to an embodiment of this application. As shown in Figure 1, the wireless communication system includes a wireless access network 100. The wireless access network 100 can be a next-generation (e.g., future communication network or higher) wireless access network, or a traditional (e.g., 5G, 4G, 3G, or 2G) wireless access network. One or more terminal devices (120a-120j, collectively referred to as 120) can be interconnected or connected to one or more network devices (110a, 110b, collectively referred to as 110) in the wireless access network 100. Network elements in the wireless communication system are connected through interfaces (e.g., NG, Xn) or air interfaces.

[0106] When network devices and terminal devices communicate, the network device can manage one or more cells, and a cell can include at least one terminal device. A cell can be understood as an area within the wireless signal coverage range of the network device.

[0107] Figure 1 is just a schematic diagram. The wireless communication system may also include other devices, such as core network devices, wireless relay devices and / or wireless backhaul devices, which are not shown in Figure 1.

[0108] To facilitate understanding of the embodiments of this application, the terms used in this application will be briefly explained.

[0109] 1. Low Earth Orbit Satellites:

[0110] The development of communication services supported by low-Earth orbit (LEO) satellites has been rapid. For example, Starlink has launched more than 7,000 satellites to form a global LEO communication satellite network to provide home broadband services. In addition, Starlink will launch satellites for direct mobile phone connections in 2024 to support existing terminals to connect directly to satellites. Furthermore, China's StarNet Corporation has also planned a LEO satellite constellation with a total of more than 10,000 satellites. In addition, there are the Qianfan and Honghu constellations, each planned to have more than 10,000 satellites.

[0111] As an example, a low Earth orbit (LEO) satellite constellation typically consists of multiple sets of orbits with the same altitude / inclination. These sets of orbits with the same altitude / inclination are called a shell, a satellite plane, or a satellite set. A shell can include multiple orbits with the same altitude and inclination, and each orbit can include multiple satellites.

[0112] For example, Table 1 shows an example of Starlink satellite deployment. Taking Starlink as an example, as of now, Starlink satellites consist of 8 shells. Taking the shell at an altitude of 550km as an example, this shell includes 72 orbits, and each orbit includes 22 satellites.

[0113] As an example, satellites covering a single location on the Earth's surface can include satellites with different orbital layers. For satellites operating in different layers, the relative positions between them are unstable due to differences in their speed and orbital orientation, making stable inter-satellite links difficult to establish. For satellites operating in the same orbit, the relative positions are stable; therefore, these satellites typically establish inter-satellite links with two adjacent satellites in the same orbit.

[0114] Referring to Figure 2, as an example, Figure 2 is a schematic diagram of satellite coverage of the shell applicable to an embodiment of this application.

[0115] As an example, the dashed lines in Figure 2 represent satellite orbits, the arrows indicate the direction of satellite movement, and the largest circle represents the Earth. Figure 2 only shows a portion of the satellite orbits as an example. In Figure 2, there are two orbits: left-angled and right-angled. From the perspective of a stationary object on Earth, as shown by the arrows in Figure 2, the satellites on the left-angled and right-angled orbits move in opposite directions. In Figure 2, the satellite on the left-angled orbit moves downwards (from north to south), while the satellite on the right-angled orbit moves upwards (from south to north).

[0116] Furthermore, a terminal device at a given geographical location on Earth (as shown by the pentagram in Figure 2) may connect to satellites orbiting to the left (southward) and right (northward), meaning that satellites covering that geographical location may be deployed in orbits with different directions of motion. Satellites deployed in orbits with different directions of motion face greater difficulty in establishing inter-satellite links due to their higher relative speeds and shorter encounter times. The distance between adjacent satellites in orbits operating in the same direction (i.e., adjacent orbits) changes with their location (the greatest distance is over the equator, and the closest distance is at the poles), and their relative positions are flipped 180 degrees at the poles. Although the relationship between adjacent satellites in adjacent orbits is not constant, inter-satellite links can still be established in most regions.

[0117] Therefore, inter-satellite links are typically established between adjacent satellites in the same orbit, or between adjacent satellites in adjacent orbits within the same shell. For orbits moving in opposite directions, satellites may be close together at certain times, but they usually do not have inter-satellite links, resulting in longer data paths between them.

[0118] 2. 5G NTN Network Architecture:

[0119] Referring to Figure 3, which serves as an example, Figure 3 is a schematic diagram of the 5G NTN network architecture. In the architecture shown in Figure 3, the core network control plane (including access and mobility management function (AMF), session management function (SMF), policy control function (PCF), unified data management (UDM), etc.) and the user plane function (UPF) of the session anchor point are located on the ground. The UPF and access gateway (AGW) are deployed on satellites. The onboard UPF and AGW are used to support UE-SAT-UE calls, that is, terminal devices can communicate directly with each other via satellite (as shown by the dotted lines in the figure).

[0120] As an example, in the 5G NTN architecture shown in Figure 3, when a terminal device moves across satellites (i.e., the satellite serving the terminal changes), a tunnel handover occurs between the onboard base station or UPF and the ground anchor UPF. Due to the rapid movement of low-Earth orbit satellites, when a terminal device is stationary on the ground, a tunnel handover occurs approximately once every 5 minutes for a single user. Simultaneously, because the satellite service area is relatively large (the radius of coverage for a satellite at an orbital altitude of 500km is approximately 500km), when a satellite moves, a large number of terminal devices within its coverage area may simultaneously undergo tunnel handover, causing signaling disruptions.

[0121] Referring to Figure 4, as an example, Figure 4 is a schematic diagram of an NTN network architecture provided in an embodiment of this application.

[0122] As an example, in the network architecture shown in Figure 4, each low-Earth orbit communication satellite can carry one user plane network element and one set of core network control plane equipment. The core network control plane equipment includes at least: mobility management functions, session management functions, and access and authentication functions. The access and authentication functions can be integrated into the mobility management functions, responsible for authenticating and authorizing terminal access. The mobility management functions are responsible for mobility management, where mobility refers to the movement of the terminal across satellites. In satellite scenarios, the movement of the terminal across satellites may be caused by the movement of the satellites or by the movement of the terminal itself; the mobility management functions are responsible for mobility management in both scenarios. When the terminal device is idle due to power saving, the mobility management functions are also responsible for paging the user. The session management functions are responsible for establishing Internet Protocol (IP) connections (or sessions) for the terminal. The IP connection is the connection between the terminal device and the onboard user plane functions, used to forward data packets between the terminal device and the data network or other terminal devices. The user plane functions are responsible for forwarding data packets between the user and the data network or other terminal devices.

[0123] As an example, in the network architecture shown in Figure 4, user subscription data is stored on geostationary Earth orbit (GEO) satellites. Of course, user subscription data can also be stored on low Earth orbit (LEO) satellites; there is no limitation. In addition to subscription data, an IP multimedia subsystem (IMS) network can also be deployed on the satellite (such as a GEO satellite). This allows users to make calls directly using the IMS system deployed on the satellite when ground access is unavailable. Furthermore, user state information (i.e., user context information) can also be stored on the GEO satellite. This information is used to back up the user state so that the user context can be obtained from the GEO satellite when it is impossible to obtain it from other channels.

[0124] As an example, compared to the architecture shown in Figure 3, the architecture shown in Figure 4 does not have a ground anchor point. Data packets sent by the terminal device are directly transmitted from the user plane function of the satellite it accesses to the terrestrial data network. The data transmission path can pass through one or more inter-satellite links. Furthermore, inter-satellite links can be supported between high-Earth orbit (HEO) and low-Earth orbit (LEO) satellites, and the control plane network elements of LEO satellites can obtain user subscriptions and user contexts from other satellites (such as GEO satellites). User plane network elements deployed on LEO satellites can support direct communication between terminal devices.

[0125] As an example, a satellite constellation may include multiple shells, each shell may include multiple orbits with the same altitude and inclination, and each orbit may include multiple satellites. The base station, onboard control plane, and onboard user plane network elements in the architecture shown in Figure 4 can be deployed on each satellite in each low-Earth orbit shell of each satellite constellation.

[0126] See Figure 5, which, as an example, is a schematic diagram of satellite deployment in a shell.

[0127] For example, one shell of Starlink Phase 2 comprises 28 orbits, and each orbit contains 120 satellites. In the deployment pattern shown in Figure 5, above the equator, the distance between two adjacent satellites in adjacent orbits is 1111 km, and the distance between the ground points of satellites in the same orbit is 333 km. It is evident that in this deployment, there is overlap in coverage between adjacent satellites in the same orbit. Assuming the terminal is stationary (as shown by the triangle in Figure 5), each satellite provides service for 5 minutes, meaning that after 5 minutes, the satellite will no longer serve the area where the terminal is located. At time 1, the terminal connects via satellite 1 in orbit 1. As the satellite moves, at times 2, 3, 4, and 5, the terminal connects via satellites 2, 3, 4, and 5 in orbit 1, respectively. At time 6, due to the Earth's rotation (the 25-minute orbit moves 694 km relative to the Earth at the equator), the terminal connects via satellite 6 in orbit 2, and so on. Therefore, based on the satellite's movement and the Earth's rotation, the satellite serving the stationary terminal can be selected from this shell for the next available time, meaning the satellite serving the terminal is predictable.

[0128] See Figure 6, which, as an example, is a schematic diagram of satellite deployment in another shell.

[0129] For example, the ground coverage of the Starlink Phase 1 satellite shell at an altitude of 550km can be shown in Figure 6. During deployment in this shell, the phases of adjacent orbital satellites are staggered to achieve seamless coverage throughout the day. Assuming the terminal device (triangle in Figure 6) is fixed on the ground, at time 1 the terminal device is located to the right of orbit 1 and connects to orbit 1 satellite 1. Assuming the satellite moves upwards and the terminal device moves downwards relative to the satellite, at time 2 the terminal connects to orbit 2 satellite 1, at time 3 the terminal connects to orbit 1 satellite 2, at time 4 the terminal connects to orbit 2 satellite 2, and at time 5 (approximately 20 minutes later), due to the Earth's rotation (assuming the Earth rotates to the right), the orbit shifts to the left and the terminal device connects to orbit 3 satellite 2.

[0130] It is understandable that, as can be seen from the deployment examples shown in Figures 5 and 6, the shell can achieve seamless full-time coverage of the Earth (except for the polar regions) through reasonable satellite deployment during the shell design. Furthermore, the number of satellites covering a certain ground area within the shell can be predicted based on service time.

[0131] As an example, when a terminal device is in idle state, the network device releases the terminal device's air interface context. The core network needs to retain the terminal device's user context so that it can page the terminal device when receiving downlink data. Retaining the context also facilitates quick activation when the terminal device wants to send data again, while maintaining its IP address. The core network's user context includes at least the terminal device's IP address (session context), as well as its subscription permanent identifier (SUPI) and registration area (RA) for paging the terminal device. Furthermore, to reduce latency when entering connected state, the core network context also stores a security context.

[0132] One possible implementation, as shown in Figure 4, involves the core network control plane functions being distributed across various low-Earth orbit satellites. When a user enters an idle state, the context is retained on the satellite the terminal device last connected to. Due to satellite movement and Earth's rotation, when the user re-enters a connected state, the context moves to a more distant location along with the satellite.

[0133] For example, taking Figure 4 as an example, when the terminal device enters the idle state, it is served by S1, that is, the user context of the terminal device is stored in S1. Taking a periodic update cycle of 1 hour as an example, after 1 hour, assuming the orbital altitude is 500km, S1 has rotated about 2 / 3 of its orbit (that is, the distance between the current location and the serving satellite is about 1 / 3 of its orbit), while the Earth rotates 15 degrees (the number of orbits crossed is related to the orbital interval). The actual distance between the satellite serving the current terminal device and S1 exceeds 1 / 3 of the orbital length because of the orbital switching.

[0134] For another example, in a scenario where the terminal device is moving, if the radius of the registration area is 500km and the terminal device moves at a speed of 500km / h, then the average time for the terminal to move out of the registration area is approximately 1 hour. Correspondingly, when the registration update is triggered, the actual distance between the current serving satellite of the serving terminal device and S1 also exceeds 1 / 3 of the orbital length.

[0135] It is understandable that in scenarios where satellites are moving at high speeds, when a user enters the connected state, the distance between S1 and the currently serving satellite may be far. Obtaining context from the source satellite (S1) may result in excessive latency and generate too much inter-satellite signaling.

[0136] In view of this, this application proposes that by enabling the context information of terminal devices to be transmitted in a chain between satellites, it can be ensured that at least one of the non-terrestrial network devices serving the terminal devices stores the context information of the terminal devices, thereby reducing the latency for terminal devices to obtain context information and reducing the amount of inter-satellite signaling.

[0137] The methods provided by the embodiments of this application will be described in detail below with reference to the accompanying drawings. The embodiments provided by this application can be applied to the scenarios shown in the above figures, and are not limited thereto.

[0138] Referring to Figure 7, as an example, Figure 7 is a schematic diagram of a communication method 700 provided in an embodiment of this application. For ease of description, the following example uses a terminal device and a non-terrestrial network device as examples. The terminal device can be replaced by components of a terminal device (e.g., a chip, chip system, circuit, communication module, or processor), and the non-terrestrial network device can be replaced by components of a non-terrestrial network device (e.g., a chip, chip system, circuit, communication module, or processor). Furthermore, the steps described below as being performed by a single execution entity can also be divided into steps performed by multiple execution entities, which can be logically and / or physically separated. The method 700 shown in Figure 7 may include the following steps.

[0139] S710, the first non-terrestrial network device identifies one or more second non-terrestrial network devices.

[0140] As an example, the first non-terrestrial network device may be located on the first satellite, or in other words, the first non-terrestrial network device is a network device deployed on the first satellite.

[0141] The first non-terrestrial network device is the non-terrestrial network device that currently stores the context information of the terminal device; in other words, the first satellite stores the context information of the terminal device. Therefore, the first non-terrestrial network device can also be called the source network device, or the first satellite can also be called the source satellite, etc., and their names do not limit the scope of protection of the embodiments of this application.

[0142] As an example, the terminal device is in an idle state. For details regarding the context information of the terminal device, please refer to the preceding text; these details will not be repeated here.

[0143] As an example, the first non-terrestrial network device can save the context information of the terminal device in the following way.

[0144] Optionally, the terminal device may access the network via a first non-terrestrial network device before entering the idle state, or in other words, the terminal device may access the network via a first satellite before entering the idle state.

[0145] Optionally, the first non-terrestrial network device receives information #1 from non-terrestrial network device #1, which includes context information of the terminal device. That is, the context information stored by the first non-terrestrial network device can be transmitted / provided / sent by other non-terrestrial network devices.

[0146] As an example, the first non-terrestrial network device can provide services to communication devices in the first area. Alternatively, the first satellite can provide services to communication devices in the first area, or the first non-terrestrial network device is a non-terrestrial network device that provides services to communication devices in the first area.

[0147] As an example, the first area may include the registration area of ​​the terminal device, which can also be understood as the area where the terminal device registers and obtains services. The registration area may include the tracking area (TA) indicated by the terminal device's tracking area list. The tracking area list may indicate one or more TAs, which may constitute the registration area of ​​the terminal device.

[0148] As an example, the Tracking Area List indicates that the TA belongs to the IP geographical region of the terminal device, or in other words, the TA is less than or equal to the IP geographical region. The IP geographical region is associated with the terminal device's IP address, and the terminal device's IP address remains unchanged when it moves within the IP geographical region. For example, the association between the IP geographical region and the terminal device's IP address can be such that the terminal device's IP address remains unchanged when it moves within the IP geographical region, and it needs to reacquire an IP address when it moves out of the IP geographical region. Furthermore, the IP geographical region can be determined based on the terminal device's IP address.

[0149] As an example, the geographic regions of TA and IP can be areas fixed to the ground. Here, an area fixed to the ground can be understood as a geographical area defined on the ground, or in other words, an area that does not move on the ground.

[0150] Referring to Figure 8, as an example, Figure 8 is a schematic diagram of a TA and IP geographical region provided in an embodiment of this application. In Figure 8, the TA and IP geographical regions where the terminal device is located overlap; that is, the square area in the figure represents the TA and IP geographical regions where the terminal device is located. When the terminal device moves within the square area, the IP address of the terminal device remains unchanged, so the geographical region where the terminal device is located can be determined based on the IP address of the terminal device.

[0151] In this embodiment, the tracking area and IP geographic area are fixed on the ground, which allows network devices to find the satellite serving the terminal device based on the terminal device's IP address or tracking area. This eliminates the need for fixed anchor points, and the system can directly send data packets to the terminal device based on the tracking area or IP geographic area. This avoids the need to establish tunnels and perform frequent tunnel updates, simplifies system design, and reduces routing detours caused by fixed anchor points.

[0152] As an example, the terminal device and the first non-terrestrial network device can record the time when the terminal device enters the idle state, the location information of the terminal device when it enters the idle state, and the satellite information accessed by the terminal device when it enters the idle state. The location information can be a location at a granular level smaller than the TA (Tracking Area List), such as the terminal device's geographic location information, the cell identifier or beam identifier last accessed by the terminal, etc. The terminal device may currently be located at TA#1, where TA#1 belongs to one or more TAs indicated by the tracking area list described above.

[0153] Optionally, when the terminal device enters an idle state, the satellite to which the terminal is connected can send the context information of the terminal device to the GEO satellite or the ground context storage network element. Alternatively, when the terminal device enters an idle state, the satellite to which the terminal is connected can back up the context information to the GEO satellite or the ground context storage network element, thereby saving the context information of the terminal device in the GEO satellite or the ground context storage network element.

[0154] As an example, the aforementioned one or more second non-terrestrial network devices are non-terrestrial network devices that provide services to communication devices in the first area after the first non-terrestrial network device.

[0155] For example, in Figure 5 mentioned above, the terminal device accesses the network via satellite 1 in orbit 1 at time 1. As the satellite moves, the terminal device accesses the network via satellite 2 in orbit 1 at time 2. Therefore, it can be said that the non-terrestrial network device in satellite 2 in orbit 1 is the non-terrestrial network device that provides services to the terminal device after the non-terrestrial network device in satellite 1 in orbit 1.

[0156] As an example, the first non-terrestrial network device can determine one or more second satellites based on the first region, the shell to which the first satellite belongs, the orbital direction of the first satellite, and the ephemeris of the satellites included in the shell to which the first satellite belongs. The second non-terrestrial network device is located on the second satellite.

[0157] Specifically, before the first non-terrestrial network device ceases to serve the area where the terminal is located, the first non-terrestrial network device can send the context information of the terminal device to the second non-terrestrial network device. The first non-terrestrial network device can determine the non-terrestrial network device serving the area where the terminal is located at the next moment as the second non-terrestrial network device based on information such as the terminal's location when it entered the idle state or the TA (TA#1) where the terminal is located, the satellite that the terminal accessed when it entered the idle state, the time when the terminal entered the idle state, the shell and direction of motion of the last satellite serving the terminal, the time of the next moment, and the ephemeris of the satellites in that shell. In other words, the satellite serving the area where the terminal is located at the next moment is the second satellite.

[0158] Specifically, the second satellite has the same direction of operation and belongs to the same shell as the first satellite.

[0159] It is understandable that if the second satellite and the first satellite share the same orbital direction and belong to the same orbital shell, an inter-satellite link can exist between them, resulting in a shorter transmission path and lower information transmission latency. Conversely, satellites orbiting in different orbital shells or in different directions within the same orbital shell typically do not have inter-satellite links, and even if the satellites are adjacent, the transmission path between them is usually quite long.

[0160] Optionally, if inter-satellite links between satellites can be dynamically established according to transmission needs, the second satellite and the first satellite can have different operating directions and belong to different shell layers.

[0161] For example, in Figure 5 mentioned above, the terminal device accesses the network via satellite 1 in orbit 1 at time 1. Assuming the satellite accessed when the terminal device enters the idle state is satellite 1 in orbit 1, and the time the terminal device enters the idle state is time #1, the shell layer and direction of motion of satellite 1 in orbit 1 are shown in Figure 5. Assuming the current time is time 5, and the satellite currently storing the terminal device's context is satellite 5 in orbit 1, then by combining the ephemeris of this shell layer satellite, it can be determined that the satellite serving the area where the terminal device is located at the next time (time 6) is satellite 6 in orbit 2. In other words, the non-terrestrial network devices serving the area where the terminal device is located at the next time are located on satellite 6 in orbit 2.

[0162] In this embodiment, the first non-terrestrial network device in the first satellite can transmit the context information of the terminal device to the second non-terrestrial network device in the second satellite, which belongs to the same shell as the first satellite and has the same direction of operation. Thus, when the terminal device enters the connected state again, it can find the context information of the terminal device in the second satellite, which belongs to the same shell as the first satellite and has the same direction of operation. In this way, the path for the terminal device to obtain the context information is shorter, reducing the latency of the terminal device to obtain the context information.

[0163] As an example, the first non-terrestrial network device can determine the second non-terrestrial network device when the first non-terrestrial network device no longer serves TA#1 or is about to no longer serve TA#1. Alternatively, the first non-terrestrial network device can also determine the second non-terrestrial network device based on the location information of the terminal device when it enters the idle state.

[0164] Optionally, when determining the second non-terrestrial network device, the first non-terrestrial network device can determine the satellite serving TA#1 at the next moment; that is, the first non-terrestrial network device may not consider the location information of the terminal.

[0165] Optionally, when determining the second non-terrestrial network device, the first non-terrestrial network device may also consider the terminal's location information, that is, the location of the second non-terrestrial network device that the first non-terrestrial network device determines will be the location of the terminal device in the next moment. The location of the terminal device can be the location of the terminal device when it enters the idle state.

[0166] As one possible implementation, correspondingly, in step #A1: the terminal device can determine a fifth non-terrestrial network device that provides services to the communication device at the current location of the terminal device. The first non-terrestrial network device may be the non-terrestrial network device that the terminal device accessed when it last entered the idle state or the non-terrestrial network device that the terminal device is currently residing in. The fifth non-terrestrial network device is located on the fifth satellite, and the first non-terrestrial network device is located on the first satellite. The fifth satellite and the first satellite have the same direction of operation and belong to the same shell.

[0167] Further, step #A2: The terminal device can reside on the fifth non-terrestrial network device.

[0168] Specifically, the terminal device can determine the next satellite to be stationed at based on the shell corresponding to the currently stationed satellite, its orbital direction, the ephemeris of the satellites in that shell, and the terminal device's current position. The next satellite to be stationed at by the terminal device is a satellite in the same shell with the same orbital direction as the currently stationed satellite, either in an adjacent orbit or in the same orbit.

[0169] Specifically, the terminal device can reside on the fifth non-terrestrial network device at the second moment.

[0170] The second moment can be the moment when the non-terrestrial network device currently hosted by the terminal device no longer or is about to cease providing services to the communication device at the current location. For example, the non-terrestrial network device currently hosted by the terminal device no longer or is about to cease providing services to the communication device at the current location can also be understood as the satellite currently hosted by the terminal device no longer or is about to cease covering the current location, or the coverage area of ​​the satellite currently hosted by the terminal device leaves the current location within a first time length greater than or equal to 0.

[0171] As an example, the second time can be determined based on the ephemeris and / or satellite configuration information (e.g., the elevation angle of the satellite service) of the satellite where the currently residing non-terrestrial network device is located. For instance, if the terminal device determines, based on the ephemeris of the satellite where the currently residing non-terrestrial network device is located, that the distance between the nadir of the satellite and the terminal device is greater than or equal to a first threshold at time #2, then the second time can be time #2. Alternatively, time #2 can be determined based on the satellite ephemeris and the minimum elevation angle of the satellite service, at the time when the elevation angle of the current location is less than the minimum service elevation angle of the satellite.

[0172] In this embodiment, the terminal device can reside on a fifth non-terrestrial network device in a fifth satellite with the same operating direction and shell layer as the first satellite. The first non-terrestrial network device in the first satellite is either the non-terrestrial network device that the terminal device accessed when it last entered an idle state or the non-terrestrial network device that the terminal device currently resides on. Based on this, the terminal device can always reside on a non-terrestrial network device in a satellite with the same operating direction and shell layer as the first satellite, ensuring that the satellite on which the terminal device resides is as consistent as possible with the satellite that stores the terminal device's context, thereby reducing context transfer.

[0173] As one possible scenario, since the terminal device may move within TA#1, the fifth satellite where the fifth non-terrestrial network device where the terminal device is stationed may be the same or a different satellite from the second satellite holding the context.

[0174] Referring to Figure 9, as an example, Figure 9 is a schematic diagram of a fifth satellite and a second satellite provided in an embodiment of this application. In Figure 9, when the terminal device enters the idle state, it is located in the overlapping coverage area of ​​SAT1 and SAT2, and the current position of the terminal device is located in the overlapping area of ​​SAT4 and SAT3. The terminal device can then choose to stay on either SAT3 or SAT4 at the next moment; assuming the terminal device selects SAT4. Since the terminal device is in the idle state, SAT1 is unaware of the movement of the terminal device's position. SAT1 can remain at the position when the terminal device entered the idle state, or select the second satellite to serve at the next moment using TA#1. Therefore, SAT1 selects SAT2 as the second satellite. Thus, SAT1 can send the context information of the terminal device to SAT2, while the terminal device can stay on SAT4.

[0175] S720, the first non-terrestrial network device sends the context information of the terminal device to one or more second non-terrestrial network devices. Correspondingly, the one or more second non-terrestrial network devices receive the context information of the terminal device from the first non-terrestrial network device.

[0176] In this embodiment, the first non-terrestrial network device currently storing the terminal device's context information can determine a second non-terrestrial network device. This second non-terrestrial network device can provide services to communication devices within the terminal device's registration area after the first non-terrestrial network device. By passing the context information to the second non-terrestrial network device, the first non-terrestrial network device ensures that after the first satellite where the first non-terrestrial network device is located leaves the terminal device's registration area, the terminal device can obtain its context information through the second non-terrestrial network device. Based on this, the terminal device's context information can be chained between satellites, ensuring that at least one of the non-terrestrial network devices serving the terminal device stores its context information. This reduces the latency for the terminal device to obtain context information and decreases the amount of inter-satellite signaling.

[0177] Conversely, if the terminal device still obtains context information from the first non-terrestrial network device, then inter-satellite signaling is required to transmit the context information. Furthermore, since the distance between the first non-terrestrial network device and the satellite of the currently serving terminal device may be relatively far, the latency of obtaining context information from the first non-terrestrial network device is also relatively large.

[0178] As an example, the first non-terrestrial network device can send the context information of the terminal device to one or more second non-terrestrial network devices at a first moment.

[0179] Here, the first moment is the moment when the first non-terrestrial network device no longer or is about to cease providing services to communication devices within the first area. As an example, the first non-terrestrial network device no longer or is about to cease providing services to communication devices within the first area can also be understood as the first satellite no longer or is about to cease covering the first area, or the coverage area of ​​the first satellite leaving the first area within a second time length, where the second time length is greater than or equal to 0.

[0180] As an example, the first time point can be determined based on the ephemeris and / or satellite configuration information (e.g., the elevation angle served by the satellite). For instance, if the first non-terrestrial network device determines, based on the ephemeris of the first satellite, that the distance between the nadir point of the first satellite and the terminal device is greater than or equal to a second threshold at time #3, then the first time point can be time #3. Alternatively, time #3 can be determined based on the ephemeris of the first satellite and the minimum elevation angle served by the satellite, specifying the time when the elevation angle of the current location is less than the minimum service elevation angle of the satellite.

[0181] In this embodiment, the first non-terrestrial network device can transmit the context information of the terminal device to the second non-terrestrial network device when it no longer or is about to stop providing services to the communication device in the first area. This ensures that after the first satellite where the first non-terrestrial network device is located leaves the registration area of ​​the terminal device, the terminal device can obtain its context information through the second non-terrestrial network device.

[0182] It is understandable that the context information of the terminal device can be chained between multiple non-terrestrial network devices, or in other words, multiple satellites. For example, the second non-terrestrial network device can refer to the content of method 700, and when the second non-terrestrial network device no longer or is about to stop providing services to the communication devices in the first area, send the context information of the terminal device to the non-terrestrial network devices serving the first area after the second non-terrestrial network device, and so on.

[0183] For example, please refer to Figure 5. The satellites serving the terminal device are numbered 1, 2, 3, 4, etc., in chronological order. Accordingly, when satellite 1 moves out of the TA (Target Area) where the terminal device is located at time 1, satellite 1 transmits the terminal device's context information to the next satellite serving that area, namely satellite 2. When the next time point, namely time 2, satellite 2 moves out of the TA area, satellite 2 sends the user context to the next satellite serving that area, namely satellite 3, and so on.

[0184] Understandably, the terminal device can repeat steps #A1 and #A2, continuously selecting new non-terrestrial network devices to camp on. For example, when the fifth non-terrestrial network device no longer or is about to stop providing services to the communication device at its current location, the terminal device can camp on the next non-terrestrial network device that provides services to the communication device at its current location.

[0185] Referring to Figure 10, as an example, Figure 10 is a schematic diagram of a communication method 1000 provided in an embodiment of this application. For ease of description, the following example uses a terminal device and a non-terrestrial network device. The terminal device can be replaced by components of a terminal device (e.g., a chip, chip system, circuit, communication module, or processor), and the non-terrestrial network device can be replaced by components of a non-terrestrial network device (e.g., a chip, chip system, circuit, communication module, or processor). Furthermore, the steps described below as being performed by a single execution entity can also be divided into steps performed by multiple execution entities, which can be logically and / or physically separated.

[0186] The following sections, using scenarios A1 and A2, illustrate the scenarios where a terminal device requests access to a second non-terrestrial network device and a terminal device requests access to a fourth non-terrestrial network device, respectively. The second non-terrestrial network device stores the terminal device's context information, while the fourth non-terrestrial network device does not.

[0187] Case A1: The terminal device requests access to the second non-terrestrial network device. The method 1000 shown in Figure 10 may include the following steps.

[0188] As an example, the second non-terrestrial network device stores the context information of the terminal device, and the fifth non-terrestrial network device mentioned above is the non-terrestrial network device on which the terminal device resides. It can be understood that in case A1, the fifth non-terrestrial network device and the second non-terrestrial network device can be the same non-terrestrial network device.

[0189] It should be understood that, for the sake of readability of the manual, in case A1, the second non-terrestrial network device and the fifth non-terrestrial network device are uniformly referred to as the second non-terrestrial network device.

[0190] S1010, the second non-terrestrial network device receives a first message from the terminal device, the first message being used to request access to the second non-terrestrial network device. Correspondingly, the terminal device sends a first message to the second non-terrestrial network device, the first message being used to request access to the second non-terrestrial network device.

[0191] As an example, the second non-terrestrial network device stores the context information of the terminal device. For instance, as described above, the second non-terrestrial network device can receive the context information of the terminal device transmitted by the first non-terrestrial network device, thereby storing the context information of the terminal device.

[0192] As an example, the terminal device sending the first message can also be replaced by the terminal device initiating a signaling process to enter the connected state. The first message can also be replaced by a request message, etc., and its name does not limit the scope of protection of this application's embodiments.

[0193] As an example, the signaling process initiated by the terminal device can be a service request process or a periodic update process.

[0194] As an example, the first message may include the identifier of the terminal device and the registration area information of the terminal device's last registration. The identifier of the terminal device can uniquely identify the terminal device within TA#1; that is, the identifier is unique within TA#1.

[0195] S1020, the second non-terrestrial network device connects the terminal device based on context information.

[0196] As an example, if the first message is a service request message, the second non-terrestrial network device can activate the air interface of the terminal device according to the service request message, that is, establish the corresponding air interface bearer so that the terminal device can send signaling and data. If the first message is a periodic update request, the second non-terrestrial network device can restart the periodic update timer.

[0197] In this embodiment of the application, after receiving the context information of the terminal device, the second non-terrestrial network device also receives an access request from the terminal device, and the second non-terrestrial network device can access the terminal device according to the context information.

[0198] Case A2: The terminal device requests access to the fourth non-terrestrial network device. The method 1000 shown in Figure 10 may include the following steps.

[0199] As an example, the fourth non-terrestrial network device does not store the context information of the terminal device, and the fifth non-terrestrial network device mentioned above is the non-terrestrial network device on which the terminal device resides. It can be understood that in case A2, the fifth non-terrestrial network device and the fourth non-terrestrial network device can be the same non-terrestrial network device, and the fifth message and the first message can be the same message.

[0200] It should be understood that, for the sake of readability of the specification, in case A2, the fourth non-terrestrial network device and the fifth non-terrestrial network device are uniformly referred to as the fourth non-terrestrial network device, and the fifth message and the first message are uniformly referred to as the fifth message.

[0201] S1030, the fourth non-terrestrial network device receives a fifth message from the terminal device, which is used to request access to the fourth non-terrestrial network device. Correspondingly, the terminal device sends a fifth message to the fourth non-terrestrial network device, which is also used to request access to the fourth non-terrestrial network device.

[0202] It should be understood that the description of the terminal device sending the fifth message can be found in the relevant content of sending the first message in S1010, and will not be repeated in this application embodiment.

[0203] As an example, the fifth message may also include at least one of the location information and time information when the terminal device last entered the idle state. The location information and time information when the terminal device last entered the idle state are used to identify a second non-terrestrial network device that has stored the terminal device context.

[0204] The following describes several methods for fourth-party non-terrestrial network devices to obtain context information of terminal devices.

[0205] Optionally, the fourth non-terrestrial network device determines the non-terrestrial network device holding the terminal context, or in other words, the fourth non-terrestrial network device determines the satellite holding the terminal context.

[0206] Specifically, since the fourth non-terrestrial network device does not have a terminal context, the fourth non-terrestrial network device can determine the non-terrestrial network device holding the terminal context, namely the second non-terrestrial network device, based on information such as the satellite that last served the terminal device, the time when the terminal device last entered the idle state, the location when the terminal device last entered the idle state, the shell where the satellite that last served the terminal device is located, and the ephemeris of the satellite in that shell.

[0207] Furthermore, the fourth non-terrestrial network device can obtain the context information of the terminal device from the second non-terrestrial network device.

[0208] Optionally, if the fourth non-terrestrial network device cannot determine the non-terrestrial network device holding the context information of the terminal device, the fourth non-terrestrial network device may obtain the context information from a GEO satellite or a terrestrial context storage network element that stores the context information of the terminal device.

[0209] Optionally, the fourth non-terrestrial network device can determine the second non-terrestrial network device group based on the second area. The following section focuses on this method of obtaining context information about terminal devices.

[0210] S1040, the fourth non-terrestrial network device determines the second area based on the fifth message, and the terminal device is located in the second area.

[0211] As an example, the fifth message includes the registration area information of the terminal device's last registration, and the fourth non-terrestrial network device can determine the second area based on this registration area information. The second area is the registration area of ​​the terminal device's last registration.

[0212] The previously registered registration area is used to identify the second non-terrestrial network device group that stores the terminal device context. The second non-terrestrial network device group includes the fourth non-terrestrial network device. The satellite where the non-terrestrial network device in the second non-terrestrial network device group is located has the same direction of operation as the fifth satellite where the fourth non-terrestrial network device is located and belongs to the same shell.

[0213] As an example, the registration area includes the tracking area indicated by the tracking area list of the terminal device, which is an area fixed to the ground.

[0214] It should be understood that the description of fixing to the ground can be found in the relevant content in S710, and will not be repeated in the embodiments of this application.

[0215] As an example, the second non-terrestrial network device group includes a fourth non-terrestrial network device and at least one second non-terrestrial network device, wherein at least one of the at least second non-terrestrial network devices stores the context of the terminal device. For example, as described above, at least one of the at least second non-terrestrial network devices can receive the context information of the terminal device transmitted by the first non-terrestrial network device, thereby storing the context information of the terminal device.

[0216] As an example, at least one second non-terrestrial network device is located on at least one second satellite.

[0217] Among them, at least one second non-terrestrial network device corresponds one-to-one with at least one second satellite, and the fourth non-terrestrial network device is located on the fourth satellite. The second satellite and the fourth satellite have the same direction of operation and belong to the same shell layer.

[0218] Optionally, the second non-terrestrial network equipment group includes all non-terrestrial network equipment groups of the TA where the serving terminal equipment is located at the current moment, or in other words, the satellites on which the second non-terrestrial network equipment group is located include all satellites of the TA where the serving terminal equipment is located at the current moment, and these satellites belong to the same shell and have the same direction of operation.

[0219] It should be understood that in some scenarios, the satellite on which the terminal is currently hosted and the satellite holding the context may belong to different shells. For example, the terminal device may not be able to select a satellite in the same shell as the satellite that served it before it entered the idle state, or the satellite on which the terminal device is currently hosted and the satellite holding the context may have different operating directions. That is, the terminal device may not be able to select a satellite in the same shell and with the same operating direction as the satellite it served before it entered the idle state. In this scenario, the satellite on which the terminal device is currently hosted can determine, based on the shell and operating direction of the satellite that served it last time, that it needs to directly obtain the terminal device's context from the GEO or the ground context storage network element. Alternatively, the satellite on which the terminal device is currently hosted may determine that it cannot obtain the terminal device's context, for example, if the GEO or the ground context storage network element has not saved the terminal device's context. In this case, the satellite on which the terminal device is currently hosted will re-register the terminal.

[0220] It is understandable that, in conjunction with the content of method 700 described above, at least one non-terrestrial network device in the second non-terrestrial network device group where the terminal device resides (i.e., the fifth non-terrestrial network device) stores the context of the terminal device.

[0221] In this embodiment, the fourth non-terrestrial network device can determine the second region where the terminal device is located based on the fifth message, and determine the second non-terrestrial network device group based on the region. At least one non-terrestrial network device in the second non-terrestrial network device group stores the context of the terminal device. That is, the fourth non-terrestrial network device can determine the location of the terminal device's context information based on the region where the terminal device is located, which facilitates further utilization of the terminal device's context information.

[0222] S1050, the fourth non-terrestrial network device sends a sixth message to at least one second non-terrestrial network device. Correspondingly, at least one second non-terrestrial network device receives the sixth message from the fourth non-terrestrial network device. The sixth message is used to request context information from the terminal device.

[0223] It is understandable that if the non-terrestrial network device where the terminal device resides does not have the context information of the terminal device, for example, the terminal device resides on the fourth non-terrestrial network device, but the context is stored on the second non-terrestrial network device, then the terminal device can send the sixth message to the second non-terrestrial network device to request the context information of the terminal device.

[0224] S1060, the fourth non-terrestrial network device receives the context information of the terminal device. Correspondingly, the second non-terrestrial network device sends the context information of the terminal device.

[0225] S1070, the fourth non-terrestrial network device connects the terminal device based on the context information of the terminal device.

[0226] It should be understood that the description of S1070 can be found in the relevant content of S1020, and will not be repeated in the embodiments of this application.

[0227] Optionally, the fourth non-terrestrial network device sends a response message to the terminal device. Accordingly, the terminal device receives the response message. This response message indicates that the terminal device's service request has been fulfilled.

[0228] In this embodiment, the fifth message is a message from the terminal device requesting access to the fourth non-terrestrial network device. The second region is the registration region where the terminal device was last registered. The fourth non-terrestrial network device can determine the second non-terrestrial network device group based on the registration region where the terminal device was last registered, and obtain the context information of the terminal device from the second non-terrestrial network device group. Then, the fourth non-terrestrial network device can access the terminal device based on the obtained context information.

[0229] Referring to Figure 11, as an example, Figure 11 is a schematic diagram of a communication method 1100 provided in an embodiment of this application. For ease of description, the following example uses a terminal device and a non-terrestrial network device. The terminal device can be replaced by components of a terminal device (e.g., a chip, chip system, circuit, communication module, or processor), and the non-terrestrial network device can be replaced by components of a non-terrestrial network device (e.g., a chip, chip system, circuit, communication module, or processor). Furthermore, the steps described below as being performed by a single execution entity can also be divided into steps performed by multiple execution entities, which can be logically and / or physically separated.

[0230] The following describes, through scenarios B1 and B2, the situations in which the second and fourth non-terrestrial network devices receive data packets sent to the terminal device. Specifically, the second non-terrestrial network device stores the context information of the terminal device, while the fourth non-terrestrial network device does not.

[0231] Case B1: The second non-terrestrial network device receives data packets from the terminal device. The method 1100 shown in Figure 11 may include the following steps:

[0232] S1110, the second non-terrestrial network device receives the second message. Correspondingly, the data source satellite transmits the second message. The second message includes data packets destined for the terminal device.

[0233] As an example, a data source satellite can be understood as the source satellite or originating satellite that sends data packets to the terminal device. The data source satellite can determine the IP geographic region based on the terminal device's IP address, which is the geographic region to which the IP address belongs. Furthermore, the data source satellite can determine the satellite group serving the IP geographic region based on the IP geographic region, the current time, and the satellite's ephemeris, and further select an ingress satellite from this satellite group.

[0234] As an example, the data source satellite can choose any one satellite from the satellite group as the entry satellite.

[0235] It is understandable that the ingress satellite in scenario B1 is the second satellite where the second non-terrestrial network device is located; that is, the ingress satellite stores the context information of the terminal device.

[0236] Optionally, the second non-terrestrial network device caches the context information of the terminal device.

[0237] Furthermore, the second non-terrestrial network device can page the terminal device based on context information. Below are two examples of the second non-terrestrial network device paged the terminal device.

[0238] Example 1, S1120: The second non-terrestrial network device sends a third message based on context information. Correspondingly, the terminal device receives the third message. The third message is used to page the terminal device.

[0239] It is understandable that in Example 1, the second non-terrestrial network device stores the context information of the terminal device, and the second non-terrestrial network device can page the terminal device according to the context information of the terminal device.

[0240] Specifically, the second non-terrestrial network device can determine whether to initiate paging based on the terminal device's previous location information in the context information, i.e., the location information when the terminal device entered the idle state. For example, if the second non-terrestrial network serves that location, it will prioritize paging; otherwise, it will prioritize sending the terminal device's context information and data packets to other non-terrestrial network devices in the first non-terrestrial network device group, allowing those other devices to initiate paging. The first non-terrestrial network device group can also be referred to as the first satellite group, which is the satellite group to which the second satellite belongs.

[0241] Optionally, the second non-terrestrial network device can always initiate paging.

[0242] As an example, when the second non-terrestrial network device pages a terminal device, it can prioritize paging based on the terminal device's location when it entered the idle state. That is, the second non-terrestrial network device can page the area where the terminal device was last located, such as the cell or beam where the terminal device was last located. If the second non-terrestrial network device cannot page the terminal device in that area, it can then page within TA#1. In other words, the second non-terrestrial network device can page the area served by TA#1, or the intersection of its service area and TA#1.

[0243] As an example, the second non-terrestrial network device can determine the IP geographic region based on the IP address of the terminal device, and determine the satellites serving the IP geographic region based on the ephemeris, thereby determining the first non-terrestrial network device group, or in other words, determining the first satellite group.

[0244] As an example, when the second non-terrestrial network device cannot fully cover TA#1, it can also send the terminal device's context information and data packets to other satellites in the first satellite group to trigger these satellites to page the terminal device within TA#1. Thus, the terminal device can be paged even when it is not within the service area of ​​the second non-terrestrial network device. This paging method is illustrated below with Example 2.

[0245] Example 2, S1130: The second non-terrestrial network device sends a fourth message to the third non-terrestrial network device. Correspondingly, the third non-terrestrial network device receives the fourth message. The fourth message is used to trigger the third non-terrestrial network device to page the terminal device.

[0246] As an example, the third non-terrestrial network device is any non-terrestrial network device in the first group of non-terrestrial network devices, excluding the second non-terrestrial network device.

[0247] It should be understood that there may be multiple third non-terrestrial network devices in the first non-terrestrial network device group, or that a second non-terrestrial network device may send a fourth message to multiple non-terrestrial network devices in the first non-terrestrial network device group. This application embodiment does not limit this.

[0248] As an example, the first non-terrestrial network device group includes one or more non-terrestrial network devices that provide services to communication devices within the IP geographical region of the terminal device, wherein the IP geographical region is determined by the second non-terrestrial network device based on the IP address of the terminal device. It should be understood that a description of the IP geographical region can be found in the relevant content of S710, and will not be repeated in this embodiment.

[0249] As an example, an IP geographic region can include tracking areas indicated by a tracking area list for terminal devices. Both the tracking area and the IP geographic region are areas fixed to the ground.

[0250] It should be understood that the description of fixing to the ground can be found in the relevant content in S710, and will not be repeated in the embodiments of this application.

[0251] As an example, the fourth message may include context information and / or data packets. The context information includes an IP address, which is used by the third non-terrestrial network device to page the terminal device. The data packets are sent to the terminal device after it has connected to the third non-terrestrial network device. It should be understood that for further explanation regarding the context information of the terminal device, please refer to the preceding description of Figure 6; this embodiment will not be repeated here.

[0252] Optionally, the fourth message may include only the first packet, that is, the first packet whose destination address is the IP address of the terminal device, and subsequent packets may be cached on the second non-terrestrial network device.

[0253] Optionally, the third non-terrestrial network device stores context information and / or data packets.

[0254] Optionally, the fourth message may only include context information, that is, the second non-terrestrial network device may not send data packets first.

[0255] In this embodiment, after receiving the context information of the terminal device, the second non-terrestrial network device can page the terminal device according to the context information, or trigger other non-terrestrial network devices in the non-terrestrial network device group to page the terminal device, so that the terminal device can be paged even when the terminal device is not in the service area of ​​the second non-terrestrial network device.

[0256] Further, in step S1131, the third non-terrestrial network device can send a paging message to the terminal device. Correspondingly, the terminal device receives the paging message. In other words, the third non-terrestrial network device can page the terminal device.

[0257] Specifically, the third non-terrestrial network device can page the terminal device based on the context of the terminal device. For example, the third non-terrestrial network device can prioritize paging based on the location of the terminal device when it enters the idle state. If paging is unsuccessful, it can then paging within TA#1. That is, paging the area of ​​TA#1 served by the third non-terrestrial network device, or in other words, paging the intersection of the third non-terrestrial network device's service area and TA#1.

[0258] S1140, the second non-terrestrial network device receives first indication information from the third non-terrestrial network device. Accordingly, the third non-terrestrial network device sends the first indication information. The first indication information indicates that the terminal device is connected to the third non-terrestrial network device.

[0259] As an example, prior to S1140, if the terminal device is camped on a third non-terrestrial network device, the terminal device sends a service request message to the third non-terrestrial network device after receiving a paging message from the third non-terrestrial network device. Correspondingly, the third non-terrestrial network device receives the service request message from the terminal device. After receiving the service request message, the third non-terrestrial network device determines that the terminal is currently accessing through the third non-terrestrial network device, and accordingly, the third non-terrestrial network device sends first indication information.

[0260] S1150, the second non-terrestrial network device sends a data packet from the terminal device to the third non-terrestrial network device. Correspondingly, the third non-terrestrial network device receives the data packet.

[0261] In this embodiment of the application, the third non-terrestrial network device can instruct the second non-terrestrial network device through the first instruction information to allow the terminal device to access the third non-terrestrial network device, thereby allowing the second non-terrestrial network device to send the data packets intended for the terminal to the third non-terrestrial network device.

[0262] It is understood that the methods described in Examples 1 and 2 can be implemented individually or in combination, and the embodiments of this application do not limit this.

[0263] Case B2: The fourth non-terrestrial network device receives data packets from the terminal device. The method 1100 shown in Figure 11 may include the following steps:

[0264] It is understandable that the ingress satellite in scenario B2 is the fourth satellite where the fourth non-terrestrial network device is located, meaning that the ingress satellite does not save the context information of the terminal device.

[0265] S1160, the fourth non-terrestrial network device receives the fifth message. Correspondingly, the data source satellite transmits the fifth message.

[0266] Furthermore, the fourth non-terrestrial network device can determine the second area based on the fifth message, and the terminal device is located within the second area.

[0267] As an example, the fifth message is a data packet sent to the terminal device, which includes the terminal device's IP address.

[0268] As an example, the fourth non-terrestrial network device can determine the second region based on its IP address. The second region is the IP geographic region of the terminal device, and the IP address remains unchanged when the terminal device moves within the IP geographic region.

[0269] As an example, an IP geographic region includes the registration area of ​​a terminal device; an IP geographic region is a region fixed on the ground.

[0270] It is understood that other explanations regarding IP geographical regions can be found in the preceding text, and will not be repeated in the embodiments of this application.

[0271] S1170, the fourth non-terrestrial network device determines a second non-terrestrial network device group based on the second area. The second non-terrestrial network device group includes the fourth non-terrestrial network device and at least one second non-terrestrial network device, wherein at least one of the at least two second non-terrestrial network devices stores the context of the terminal device.

[0272] It should be understood that the method for determining the non-terrestrial network device group can refer to the relevant content in Example 2 above, and will not be repeated in the embodiments of this application.

[0273] It is understandable that, in conjunction with the content of method 700 described above, at least one non-terrestrial network device in the group of non-terrestrial network devices serving the second area can store the context of the terminal device.

[0274] S1180, the fourth non-terrestrial network device may send a seventh message to at least one second non-terrestrial network device. Accordingly, at least one second non-terrestrial network device receives the seventh message. The seventh message includes the data packet and is used to request that the data packet be sent to the terminal device.

[0275] It is understandable that the fourth non-terrestrial network device does not store the context information of the terminal device, and the fourth non-terrestrial network device forwards the data packets to other non-terrestrial network devices in the second non-terrestrial network device group.

[0276] Further, in step S1181, the second non-terrestrial network device can send a paging message to the terminal device. Correspondingly, the terminal device receives the paging message. In other words, the second non-terrestrial network device can page the terminal device.

[0277] Specifically, after receiving the data packet from the terminal device, the second non-terrestrial network device can look up the context information of the terminal device based on the destination IP address, that is, the IP address of the terminal device, and page the terminal device based on the context information.

[0278] Optionally, if the second non-terrestrial network device cannot cover the entire TA#1, the second non-terrestrial network device can also send the context and data packets of the terminal device to other non-terrestrial network devices in the second non-terrestrial network device group to trigger paging by the other non-terrestrial network devices. Accordingly, the other non-terrestrial network devices page the terminal device. The specific steps can be referred to the relevant content in case B1 above, and will not be repeated in this embodiment.

[0279] The following describes several optional steps that a terminal device can take after receiving a paging message.

[0280] Optionally, after S1120, S1131, or S1181 described above, the following steps may also be included:

[0281] S1191, after receiving a paging message (or a third message), the terminal initiates a non-access stratum (NAS) request message.

[0282] As an example, the NAS request message can be a service request message. For instance, the NAS request message can be sent to the non-terrestrial network device where the terminal is currently residing. The following example illustrates this by assuming that the terminal is currently residing in the fifth non-terrestrial network device. In Example 1, the fifth non-terrestrial network device can be a non-terrestrial network device in the first non-terrestrial network device group. In Example 2, the fifth non-terrestrial network device can be a non-terrestrial network device in the second non-terrestrial network device group.

[0283] S1192, the fifth non-terrestrial network device processes the NAS request message based on the context information of the terminal device.

[0284] For example, if the NAS request message is a service request message, then S1192 may include notifying the onboard base station to activate the radio bearer for the terminal device so that the terminal device can send and receive data and signaling messages.

[0285] As an example, after activating the radio bearer, if the fifth non-terrestrial network device has cached the terminal device's data packets, the fifth non-terrestrial network device will send the data packets to the terminal device via the radio bearer.

[0286] As an example, a fifth non-terrestrial network device can instruct an ingress satellite to forward subsequent data packets destined for a terminal device to the fifth non-terrestrial network device. The ingress satellite can then forward data packets from the terminal device to the fifth non-terrestrial network device. The ingress satellite can maintain a mapping between the terminal device's IP address and the fifth non-terrestrial network device's IP address to facilitate the forwarding of subsequent data packets.

[0287] S1193, the fifth non-terrestrial network device can send NAS response messages.

[0288] S1194, Non-terrestrial network devices that fail to paging can release the context information of the terminal device after paging failure.

[0289] As an example, when a non-terrestrial network device triggers paging, it can start a paging timeout timer. If the paging timeout timer expires and no NAS request message (such as a service request message) is received from the terminal, the non-terrestrial network device can determine that the paging has failed. At this time, the non-terrestrial network device can release the context information and cached data packets of the terminal device.

[0290] In this embodiment, the fifth message is a data packet from the terminal device, and the second region is the IP geographic region of the terminal device. The fourth non-terrestrial network device can then determine the second non-terrestrial network device group based on the IP geographic region of the terminal device and send the terminal device's data packet to at least one of the second non-terrestrial network devices in the second non-terrestrial network device group. Furthermore, the second non-terrestrial network device that has stored the terminal device's context information can page the terminal device and then send the aforementioned data packet to the terminal device.

[0291] The methods provided by the embodiments of this application have been described in detail above with reference to Figures 7 to 11. The apparatus provided by the embodiments of this application will be described in detail below with reference to Figures 12 to 14. It should be understood that the descriptions of the apparatus embodiments correspond to the descriptions of the method embodiments; therefore, any content not described in detail can be referred to the method embodiments above, and for the sake of brevity, will not be repeated here.

[0292] Referring to Figure 12, as an example, Figure 12 is a schematic diagram of a communication device 1200 provided in an embodiment of this application. The communication device 1200 includes a transceiver unit 1210 and a processing unit 1220. The transceiver unit 1210 can be used to implement corresponding communication functions. The transceiver unit 1210 can also be referred to as a communication interface or a communication unit. The processing unit 1220 can be used to perform processing, such as determining information bits.

[0293] Optionally, the device 1200 may further include a storage unit, which can be used to store instructions and / or data, and the processing unit 1220 can read the instructions and / or data in the storage unit to enable the device to implement the aforementioned method embodiments.

[0294] In a first possible design, the device 1200 can be the terminal device in the foregoing embodiments, which can implement the steps or processes corresponding to those executed by the terminal device in the above method embodiments. Specifically, the transceiver unit 1210 can be used to perform transceiver-related operations (such as sending and / or receiving data or messages) of the terminal device in the above method embodiments, and the processing unit 1220 can be used to perform processing-related operations of the terminal device in the above method embodiments, or operations other than transceiver (such as operations other than sending and / or receiving data or messages).

[0295] One possible implementation includes a processing unit 1220, configured to determine a fifth non-terrestrial network device that provides services to the communication device at the current location of the terminal device; a first non-terrestrial network device that the terminal device accessed when it last entered an idle state or that the terminal device is currently residing in; the fifth non-terrestrial network device being located on a fifth satellite; and the first non-terrestrial network device being located on a first satellite; the fifth satellite and the first satellite having the same direction of operation and belonging to the same shell layer; and a transceiver unit 1210 configured to reside on the fifth non-terrestrial network device.

[0296] In a second possible design, the device 1200 can be a network device as described in the foregoing embodiments. This device 1200 can implement the steps or processes performed by the network device corresponding to those described in the method embodiments above. Specifically, the transceiver unit 1210 can be used to perform transceiver-related operations (such as sending and / or receiving data or messages) of the network device described in the method embodiments above, and the processing unit 1220 can be used to perform processing-related operations of the network device described in the method embodiments above, or operations other than transceiver operations (such as operations other than sending and / or receiving data or messages).

[0297] One possible implementation is a processing unit 1220, configured to determine one or more second non-terrestrial network devices, wherein the one or more second non-terrestrial network devices are non-terrestrial network devices that provide services to communication devices in a first area after the first non-terrestrial network device, the first area including a registration area of ​​a terminal device, the terminal device being in an idle state, and the first non-terrestrial network device being a non-terrestrial network device currently storing the context information of the terminal device; and a transceiver unit 1210, configured to send the context information of the terminal device to the one or more second non-terrestrial network devices.

[0298] It should be understood that the specific process of each unit performing the above-mentioned corresponding steps has been described in detail in the above method embodiments, and will not be repeated here for the sake of brevity.

[0299] It should also be understood that the device 1200 here is embodied in the form of a functional unit. The term "unit" here can refer to an application-specific integrated circuit (ASIC), electronic circuitry, a processor (e.g., a shared processor, a proprietary processor, or a group processor, etc.) and memory for executing one or more software or firmware programs, integrated logic circuitry, and / or other suitable components supporting the described functions. In an alternative example, those skilled in the art will understand that the device 1200 can be specifically the communication device in the above embodiments, and can be used to execute the various processes and / or steps corresponding to the communication device in the above method embodiments; to avoid repetition, these will not be described again here.

[0300] The apparatus 1200 of each of the above-described schemes has the function of implementing the corresponding steps performed by the communication device (such as a terminal device or a network device) in the above-described methods. The function can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions; for example, the transceiver unit can be replaced by a transceiver (e.g., the sending unit in the transceiver unit can be replaced by a transmitter, and the receiving unit in the transceiver unit can be replaced by a receiver), and other units, such as processing units, can be replaced by processors, each performing the transceiver operations and related processing operations in the respective method embodiments.

[0301] In addition, the transceiver unit 1210 may also be a transceiver circuit (for example, it may include a receiving circuit and a transmitting circuit), and the processing unit may be a processing circuit.

[0302] It should be noted that the device in Figure 12 can be the communication device (such as a terminal device or a network device) in the foregoing embodiments, or it can be a chip or a chip system, such as a system on a chip (SoC). The transceiver unit can be an input / output circuit or a communication interface; the processing unit is a processor, microprocessor, or integrated circuit integrated on the chip. No limitations are imposed here.

[0303] Referring to Figure 13, as an example, Figure 13 is a schematic diagram of another communication device 1300 provided in an embodiment of this application. The device 1300 includes a processor 1310, which is coupled to a memory 1320. The memory 1320 is used to store computer programs or instructions and / or data. The processor 1310 is used to execute the computer programs or instructions stored in the memory 1320, or to read the data stored in the memory 1320, in order to execute the methods in the above method embodiments.

[0304] Optionally, there may be one or more processors 1310.

[0305] Optionally, the memory 1320 may be one or more.

[0306] Alternatively, the memory 1320 can be integrated with the processor 1310, or it can be set separately.

[0307] Optionally, as shown in FIG13, the device 1300 further includes a transceiver 1330 for receiving and / or transmitting signals. For example, a processor 1310 is used to control the transceiver 1330 to receive and / or transmit signals.

[0308] As an example, processor 1310 may have the functions of processing unit 1220 shown in FIG12, memory 1320 may have the functions of storage unit, and transceiver 1330 may have the functions of transceiver unit 1210 shown in FIG12.

[0309] As one option, the device 1300 is used to implement the operations performed by a communication device (such as a terminal device or a network device) in the various method embodiments described above.

[0310] For example, processor 1310 is used to execute computer programs or instructions stored in memory 1320 to implement the relevant operations of the communication device in the various method embodiments described above.

[0311] It should be understood that the processor mentioned in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0312] It should also be understood that the memory mentioned in the embodiments of this application can be volatile memory and / or non-volatile memory. Non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory can be random access memory (RAM). For example, RAM can be used as an external cache. By way of example and not limitation, RAM includes the following forms: static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0313] It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA, or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component, the memory (storage module) can be integrated into the processor.

[0314] It should also be noted that the memory described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0315] Referring to Figure 14, as an example, Figure 14 is a schematic diagram of a chip system 1400 provided in an embodiment of this application. The chip system 1400 (or may also be referred to as a processing system) includes logic circuitry 1410 and an input / output interface 1420.

[0316] The logic circuit 1410 can be a processing circuit in the chip system 1400. The logic circuit 1410 can be coupled to a memory unit, calling instructions from the memory unit, enabling the chip system 1400 to implement the methods and functions of the embodiments of this application. The input / output interface 1420 can be an input / output circuit in the chip system 1400, outputting processed information from the chip system 1400, or inputting data or signaling information to be processed into the chip system 1400 for processing.

[0317] As one approach, the chip system 1400 is used to implement operations performed by communication devices (such as terminal devices or network devices) in the various method embodiments described above.

[0318] For example, logic circuit 1410 is used to implement processing-related operations performed by a communication device (such as a terminal device or a network device) in the above method embodiments; input / output interface 1420 is used to implement sending and / or receiving-related operations performed by a communication device (such as a terminal device or a network device) in the above method embodiments.

[0319] This application also provides a computer-readable storage medium storing a computer program or instructions for implementing the methods executed by a communication device (such as a terminal device or a network device) in the above-described method embodiments. For example, when the computer program or instructions are run on the communication device, they cause the communication device (such as a terminal device or a network device) to execute the above-described methods (such as method 700, method 1000, or method 1100).

[0320] This application also provides a computer program product comprising instructions that, when executed by a computer, implement the methods described above as performed by a communication device (such as a terminal device or a network device). For example, when the computer program or instructions are run on the communication device, the communication device (such as a terminal device or a network device) performs the methods described above (such as method 700, method 1000, or method 1100).

[0321] This application also provides a communication system that includes the terminal device and / or network device described in the embodiments above. For example, the system includes the terminal device and network device described in the embodiments of FIG7, FIG10, or FIG11.

[0322] The explanations and beneficial effects of the relevant contents in any of the devices provided above can be found in the corresponding method embodiments provided above, and will not be repeated here.

[0323] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection of apparatus or units may be electrical, mechanical, or other forms.

[0324] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. For example, the computer can be a personal computer, a server, or a network device, etc. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state disks, SSDs). For example, the aforementioned available media include, but are not limited to, USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks, and other media capable of storing program code.

[0325] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A communication method, characterized in that, Applied to a first non-terrestrial network device located on a first satellite, the method includes: One or more second non-terrestrial network devices are identified, wherein the one or more second non-terrestrial network devices are non-terrestrial network devices that provide services to communication devices in a first area after the first non-terrestrial network device, the first area includes a registration area of ​​a terminal device, the terminal device is in an idle state, and the first non-terrestrial network device is the non-terrestrial network device that currently stores the context information of the terminal device; Send the context information of the terminal device to the one or more second non-terrestrial network devices.

2. The method according to claim 1, characterized in that, The determination of one or more second non-terrestrial network devices includes: The second non-terrestrial network device is located on the second satellite. One or more second satellites are determined based on the first region, the shell to which the first satellite belongs, the direction of the first satellite's operation, and the ephemeris of the satellites included in the shell to which the first satellite belongs.

3. The method according to claim 2, characterized in that, The second satellite has the same direction of operation and belongs to the same shell as the first satellite.

4. The method according to any one of claims 1 to 3, characterized in that, The registration area includes the tracking area indicated by the tracking area list of the terminal device, wherein the tracking area indicated by the tracking area list belongs to the Internet Protocol (IP) geographic area of ​​the terminal device, the tracking area and the IP geographic area are fixed on the ground, the IP geographic area is associated with the IP address of the terminal device, and the IP address of the terminal device remains unchanged when the terminal device moves within the IP geographic area.

5. The method according to any one of claims 1 to 4, characterized in that, Sending the context information of the terminal device to the one or more second non-terrestrial network devices includes: The context information of the terminal device is sent to one or more second non-terrestrial network devices at a first moment, which is the moment when the first non-terrestrial network device no longer or is about to stop providing services to communication devices in the first area, and the first moment is determined based on the ephemeris of the first satellite.

6. A communication method, characterized in that, Applied to a second non-terrestrial network device, the method includes: The context information of the terminal device is received from a first non-terrestrial network device. The first non-terrestrial network device provides services to communication devices in a first area. The first area includes the registration area of ​​the terminal device. The terminal device is in an idle state. The second non-terrestrial network device is a satellite that provides services to communication devices in the first area after the first non-terrestrial network device. The second non-terrestrial network device is located on a second satellite, and the first non-terrestrial network device is located on a first satellite.

7. The method according to claim 6, characterized in that, The second satellite has the same direction of operation and belongs to the same shell as the first satellite.

8. The method according to claim 6 or 7, characterized in that, Also includes: Receive a first message from the terminal device, the first message being used to request access to the second non-terrestrial network device; The terminal device is connected based on the context information.

9. The method according to claim 6 or 7, characterized in that, Also includes: Receive a second message, the second message including a data packet sent to the terminal device; The terminal device is paged based on the context information.

10. The method according to claim 9, characterized in that, The step of paging the terminal device based on the context information includes: A third message is sent based on the context information, the third message being used to page the terminal device; and / or, A fourth message is sent to a third non-terrestrial network device, the fourth message being used to trigger the third non-terrestrial network device to page the terminal device. The third non-terrestrial network device is any non-terrestrial network device in the first non-terrestrial network device group other than the second non-terrestrial network device. The first non-terrestrial network device group includes one or more non-terrestrial network devices that provide services to communication devices within the IP geographical area of ​​the terminal device, and the IP geographical area is determined based on the IP address of the terminal device.

11. The method according to claim 10, characterized in that, The fourth message includes the context information and / or the data packet. The context information includes the IP address. The context information is used by the third non-terrestrial network device to page the terminal device. The data packet is used to send to the terminal device after the terminal device accesses the third non-terrestrial network device.

12. The method according to claim 10 or 11, characterized in that, Also includes: The terminal device receives a first indication information from the third non-terrestrial network device, the first indication information indicating that the terminal device accesses the third non-terrestrial network device; The data packets of the terminal device are sent to the third non-terrestrial network device.

13. The method according to any one of claims 10 to 12, characterized in that, The IP geographic region includes the tracking area indicated by the tracking area list of the terminal device, and the tracking area and the IP geographic region are areas fixed to the ground.

14. A communication method, characterized in that, Applied to a fourth non-terrestrial network device, the method includes: Receive the fifth message, determine the second region based on the fifth message, and the terminal device is located in the second region; A second non-terrestrial network device group is determined based on the second region. The second non-terrestrial network device group includes the fourth non-terrestrial network device and at least one second non-terrestrial network device. At least one of the at least two second non-terrestrial network devices stores the context of the terminal device.

15. The method according to claim 14, characterized in that, Also includes: The at least one second non-terrestrial network device is located on at least one second satellite, and there is a one-to-one correspondence between the at least one second non-terrestrial network device and the at least one second satellite. The fourth non-terrestrial network device is located on a fourth satellite, and the second satellite and the fourth satellite have the same direction of operation and belong to the same shell.

16. The method according to claim 14 or 15, characterized in that, The fifth message originates from the terminal device and is used to request access to the fourth non-terrestrial network device. The fifth message includes registration area information from the terminal device's last registration. Determining the second area based on the fifth message includes: The second region is determined based on the registration region information, and the second region is the registration region last registered on the terminal device.

17. The method according to claim 16, characterized in that, Also includes: A sixth message is sent to the at least one second non-terrestrial network device, the sixth message being used to request context information from the terminal device; Receive the context information of the terminal device; The terminal device is accessed based on its context information.

18. The method according to claim 14 or 15, characterized in that, The fifth message is a data packet sent to the terminal device, the data packet including the IP address of the terminal device, and determining the second region based on the fifth message includes: The second region is determined based on the IP address. The second region is the IP geographical region of the terminal device. The IP address remains unchanged when the terminal device moves within the IP geographical region.

19. The method according to claim 18, characterized in that, Also includes: A seventh message is sent to the at least one second non-terrestrial network device, the seventh message including the data packet, the seventh message being used to request that the data packet be sent to the terminal device.

20. The method according to claim 16 or 17, characterized in that, The registration area includes the tracking area indicated by the tracking area list of the terminal device, and the tracking area is an area fixed to the ground.

21. The method according to any one of claims 18 to 20, characterized in that, The IP geographic region includes the registration area of ​​the terminal device, and the IP geographic region is a region fixed on the ground.

22. A communication method, characterized in that, Applied to a terminal device, the method includes: A fifth non-terrestrial network device is identified, which provides services to the communication device at the current location of the terminal device. The first non-terrestrial network device is the non-terrestrial network device that the terminal device accessed when it last entered the idle state or the non-terrestrial network device that the terminal device is currently stationed on. The fifth non-terrestrial network device is located on the fifth satellite, and the first non-terrestrial network device is located on the first satellite. The fifth satellite and the first satellite have the same direction of operation and belong to the same shell. It resides on the fifth non-terrestrial network device.

23. The method according to claim 22, characterized in that, Also includes: A first message is sent to the fifth non-terrestrial network device. The first message is used to request access to the fifth non-terrestrial network device. The first message includes the identifier of the terminal device and the registration area information of the last registration of the terminal device. The last registration area is used to determine the second non-terrestrial network device group that stores the context of the terminal device. The second non-terrestrial network device group includes the fifth non-terrestrial network device. The satellites where the non-terrestrial network devices in the second non-terrestrial network device group are located have the same orbital direction as the fifth satellite and belong to the same shell.

24. The method according to claim 23, characterized in that, The first message also includes at least one of the location information and time information when the terminal device last entered the idle state, and the at least one of the location information and time information when the terminal device last entered the idle state is used to determine a second non-terrestrial network device that has stored the context of the terminal device.

25. The method according to any one of claims 22 to 24, characterized in that, The term "residing on the fifth non-terrestrial network device" includes: The terminal device will reside on the fifth non-terrestrial network device at a second time. The second time is when the non-terrestrial network device on which the terminal device is currently residing no longer or is about to cease providing services to the communication device at the current location. The second time is determined based on the ephemeris of the satellite on which the currently residing non-terrestrial network device is located.

26. A communication device, characterized in that, Includes modules or units for performing the method according to any one of claims 1 to 25.

27. A communication device, characterized in that, Includes a processor, the processor being configured to cause the communication device to perform the method of any one of claims 1 to 25.

28. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program or instructions that, when executed on a communication device, cause the communication device to perform the method as described in any one of claims 1 to 25.

29. A computer program product, characterized in that, The computer program product includes a computer program or instructions that, when executed on a communication device, cause the communication device to perform the method as described in any one of claims 1 to 25.

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