Communication method and communication apparatus

Abstract

Provided in the embodiments of the present application are a communication method and a communication apparatus. The method comprises: a terminal device receiving first information, wherein the first information comprises an identifier and coverage information of each of at least one satellite; on the basis of the first information, the terminal device determining at least one target satellite from among the at least one satellite, wherein the terminal device is to be covered by the target satellite in the future; and the terminal device sending information of each of the at least one target satellite. By means of the present application, a terminal device can select a target satellite that is to cover the terminal device in the future, thereby helping to ensure the normal communication of the terminal device, and avoiding additional power consumption caused by a first apparatus failing to find the target satellite.

Description

Communication method and communication apparatus

[0001] The present application claims priority to the Chinese patent application No. 202411088754.7, filed on August 8, 2024, and entitled "Communication method and communication apparatus", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] Embodiments of the present application relate to the field of communication, and more particularly, to a communication method and a communication apparatus. BACKGROUND

[0003] Satellite network is a hot topic in the world today, and satellite communication technology has become mature, for example, non-terrestrial network (NTN) uses satellite on-board radio frequency network to realize communication, which can provide wider coverage, and satellite base station is not easy to be damaged by natural disasters or external forces.

[0004] In NTN, due to the movement of the source satellite, the source satellite cannot always cover the user equipment (UE), so the source satellite may need to select a target satellite for the UE according to the location information of the UE.

[0005] However, the source satellite may not be able to obtain accurate location information of the UE, so it cannot select a suitable target satellite for the UE, i.e., the target satellite selected by the source satellite for the UE may not cover the UE. SUMMARY

[0006] The present application provides a communication method and a communication apparatus, so that the terminal device can more accurately select a target satellite that will cover the terminal device in the future, thereby facilitating to ensure the normal communication of the terminal device.

[0007] In a first aspect, a communication method is provided. The method can be applied to the terminal side, i.e., the method can be executed by a terminal device, or can be executed by a component (such as a chip or a chip system or a circuit or a communication module) of the terminal device, which is not limited in the present application. Hereinafter, the terminal device will be mainly taken as an example for description.

[0008] The method comprises: receiving first information from a source satellite, the first information comprising an identifier and coverage range information of each of at least one satellite; determining at least one target satellite in the at least one satellite according to the first information, the terminal device being covered by the target satellite in the future; and sending information of each of the at least one target satellite.

[0009] Exemplarily, the coverage range information of the first satellite comprises one or more of the following: a reference point of the coverage range of the first satellite and / or time information corresponding to the reference point, a radius of the coverage range of the first satellite, left-right elevation angle information of the coverage range of the first satellite, or ephemeris information of the first satellite. The first satellite is any one of the at least one satellite.

[0010] Exemplarily, the first information is carried in broadcast signaling or dedicated signaling.

[0011] Exemplarily, the information of the target satellite comprises an identifier of the target satellite and / or coverage time information of the target satellite covering the terminal device. The coverage time information can comprise a time of coverage start, a time of coverage end, a certain time between the time of coverage start and the time of coverage end, or a coverage duration, etc.

[0012] Based on the above technical solutions, the terminal device can select a target satellite according to the coverage range information of the at least one satellite, and send the information of the target satellite to the source satellite. Compared with the scheme in which the source satellite selects a target satellite for the terminal device, the terminal device can obtain accurate position information of the terminal device, so that the terminal device can select a suitable target satellite more accurately when selecting a target satellite according to the coverage range information of the at least one satellite, that is, a target satellite that can cover the terminal device in the future can be selected, thereby facilitating to ensure normal communication of the terminal device, and avoiding additional power consumption of the terminal device due to failure to search for a target satellite.

[0013] In combination with the first aspect, in some implementations of the first aspect, after the information of each target satellite of the at least one target satellite is sent, the method further comprises: receiving information of a first target satellite, the at least one target satellite comprising the first target satellite.

[0014] Exemplarily, an end time of the time period during which the feeder link of the first target satellite is available is later than a start time of the time period during which the feeder link of the source satellite is available, and the source satellite is a satellite currently providing services for the terminal device.

[0015] Based on the technical solution, after the terminal device sends the information of the at least one target satellite to the source satellite, the source satellite can select a more accurate first target satellite for the terminal device from the at least one target satellite according to other information. For example, the source satellite can determine the first target satellite according to the available time information of the feeder link of the source satellite and the available time information of the feeder link of the at least one target satellite, and if the end time of the time period during which the feeder link of the first target satellite is available is later than the start time of the time period during which the feeder link of the source satellite is available, the first target satellite is a target satellite that is likely to carry downlink data and / or downlink messages, thereby avoiding the terminal device being unable to receive downlink data and / or downlink messages after being connected to a target satellite that does not carry downlink data and / or downlink messages.

[0016] In combination with the first aspect, in some implementations of the first aspect, the method further includes: receiving, by the terminal device, second information, the second information being used to determine the available time information of the feeder link of each satellite of the at least one satellite; determining, by the terminal device, the at least one target satellite of the at least one satellite according to the first information includes: determining, by the terminal device, the at least one target satellite according to the first information and the second information; the terminal device will be covered by the target satellite in the future, and the end time of the time period during which the feeder link of the target satellite is available is later than the start time of the time period during which the feeder link of the source satellite is available, and the source satellite is a satellite currently providing services for the terminal device.

[0017] Based on the technical solution, the end time of the time period during which the feeder link of the target satellite selected by the terminal device is available is later than the start time of the time period during which the feeder link of the source satellite is available, so the target satellite selected by the terminal device is a target satellite that is likely to carry downlink data and / or downlink messages, thereby avoiding the terminal device being unable to receive downlink data and / or downlink messages after being connected to a target satellite that does not carry downlink data and / or downlink messages.

[0018] In combination with the first aspect, in some implementations of the first aspect, the end time of the time period during which the feeder link of each satellite of the at least one satellite is available is later than the start time of the time period during which the feeder link of the source satellite is available, and the source satellite is a satellite currently providing services for the terminal device.

[0019] Based on the technical solution, the target satellite selected by the terminal device from the at least one satellite is a satellite that can cover the terminal device in the future and is a satellite that is likely to carry downlink data, so it can be avoided that the terminal device is unable to receive downlink data and / or downlink messages after being connected to a target satellite that does not carry downlink data and / or downlink messages.

[0020] With reference to the first aspect, in some implementations of the first aspect, each of the at least one satellite supports a store-and-forward mode.

[0021] With reference to the first aspect, in some implementations of the first aspect, before sending the information of each of the at least one target satellite, the method further includes: receiving, by the terminal device, third information, the third information being used to indicate that a source satellite supports the store-and-forward mode, the source satellite being a satellite currently providing service for the terminal device.

[0022] Based on the above technical solution, the terminal device can determine that the source satellite supports the store-and-forward mode according to the third information. In the case that the source satellite supports the store-and-forward mode, the process (such as the registration process or the tracking area update process) currently performed by the terminal device through the source satellite can not be completed, i.e., the terminal device can need to access a target satellite to continue the process currently performed through the source satellite in the future. In this case, the terminal device can select the target satellite more accurately according to the first information and send the information of the target satellite to the source satellite, so that the source satellite can be avoided from selecting an unsuitable target satellite for the terminal device.

[0023] With reference to the first aspect, in some implementations of the first aspect, before sending the information of each of the at least one target satellite, the method further includes: sending, by the terminal device, a first message in the first process, the first message being used to request registration or tracking area update; and receiving, by the terminal device, a second message, the second message being used to indicate that the registration or the tracking area update cannot be completed, and the first process cannot be completed.

[0024] Based on the above technical solution, the terminal device can determine that the process (such as the registration process or the tracking area update process) currently performed by the terminal device through the source satellite can not be completed according to the second message, i.e., the terminal device can need to access a target satellite to continue the process currently performed through the source satellite in the future. In this case, the terminal device can select the target satellite more accurately according to the first information and send the information of the target satellite to the source satellite, so that the source satellite can be avoided from selecting an unsuitable target satellite for the terminal device.

[0025] With reference to the first aspect, in some implementations of the first aspect, the second message includes an identifier of each of at least one second satellite, the at least one satellite includes the at least one second satellite, and one or more of the at least one second satellite will not cover the terminal device in the future; and before sending the information of each of the at least one target satellite, the method further includes: determining, by the terminal device, that the one or more of the at least one second satellite will not cover the terminal device in the future according to the first information.

[0026] Based on the technical solution, the terminal device determines, according to the second message and the first information, that the second satellite selected by the source satellite for the terminal device cannot cover the terminal device in the future, and then the terminal device selects a target satellite according to the first information and sends information of the target satellite to the source satellite, so that the terminal device can avoid extra power consumption caused by the terminal device failing to search for the second satellite.

[0027] With reference to the first aspect, in some implementations of the first aspect, the method further includes: receiving, by the terminal device, an identity of a second target satellite from the at least one target satellite, the second target satellite being a target satellite that the terminal device first searches for among the at least one target satellite; and sending, by the terminal device, a third message to the second target satellite, the third message being used for radio resource control (RRC) connection establishment, or being used for RRC connection recovery, or being used for RRC connection reestablishment.

[0028] With reference to the first aspect, in some implementations of the first aspect, the second target satellite can be a target satellite that the terminal device first searches for after expiration of a timer, and before the terminal device receives the identity of the second target satellite from the at least one target satellite, the method further includes: receiving fourth information, the fourth information being used for configuring the timer.

[0029] With reference to the first aspect, in some implementations of the first aspect, the method further includes: receiving fourth information, the fourth information being used for configuring the timer; and before the second target satellite stops covering the terminal device, and / or before the timer expires, closing or deactivating or suspending an access layer.

[0030] Based on the technical solution, before the second target satellite stops covering the terminal device, and / or before the timer expires, the terminal device closes or deactivates or suspends the access layer, which is beneficial to saving power consumption.

[0031] With reference to the first aspect, in some implementations of the first aspect, the method further includes: receiving an identity of a third target satellite from the at least one target satellite, the third target satellite being a target satellite that the terminal device searches for after the second target satellite among the at least one target satellite; and not sending the first message to the third target satellite.

[0032] Based on the technical solution, after the terminal device establishes a connection with the second target satellite that is first searched for, the terminal device does not establish a connection with the third target satellite that is searched for later, so that unnecessary signaling interaction can be avoided.

[0033] In a second aspect, a communication method is provided. The method can be applied to a network side, i.e., the method can be performed by a network device, or can be performed by a component (e.g., a chip or a chip system or a circuit or a communication module) of the network device, which is not limited in the application. In the following, the network device is mainly taken as an example for description. The network device can be replaced by a source satellite, or a core network element on the source satellite, and the like.

[0034] The method comprises: sending first information, the first information comprising an identifier and coverage range information of each of at least one satellite, the coverage range information of a first satellite being used for enabling a terminal device to predict whether the terminal device will be covered by the first satellite in the future, the first satellite being any one of the at least one satellite; and receiving information of each of at least one target satellite, the terminal device being covered by the target satellite in the future.

[0035] The beneficial effects of the second aspect can refer to the description of the first aspect.

[0036] In combination with the second aspect, in some implementations of the second aspect, the method further comprises: sending information of a first target satellite, the at least one target satellite comprising the first target satellite.

[0037] In combination with the second aspect, in some implementations of the second aspect, an end time of a time period during which a feeder link of the first target satellite is available is later than a start time of a time period during which a feeder link of a source satellite is available, the source satellite being a satellite currently providing services for the terminal device.

[0038] In combination with the second aspect, in some implementations of the second aspect, before receiving the information of each of the at least one target satellite, the method further comprises: sending second information, the second information being used for determining available time information of a feeder link of each of the at least one satellite; the terminal device being covered by the target satellite in the future, and an end time of a time period during which a feeder link of the target satellite is available being later than a start time of a time period during which a feeder link of a source satellite is available, the source satellite being a satellite currently providing services for the terminal device.

[0039] In combination with the second aspect, in some implementations of the second aspect, an end time of a time period during which a feeder link of each of the at least one satellite is available is later than a start time of a time period during which a feeder link of a source satellite is available, the source satellite being a satellite currently providing services for the terminal device.

[0040] In combination with the second aspect, in some implementations of the second aspect, each of the at least one satellite supports a store-and-forward mode.

[0041] With reference to the second aspect, in some implementations of the second aspect, the method further includes: sending third information, the third information being used to indicate that the source satellite supports the store-and-forward mode.

[0042] With reference to the second aspect, in some implementations of the second aspect, the coverage information of the first satellite includes one or more of the following: a reference point of the coverage of the first satellite and / or time information corresponding to the reference point, a radius of the coverage of the first satellite, left-right elevation information of the coverage of the first satellite, or ephemeris information of the first satellite.

[0043] With reference to the second aspect, in some implementations of the second aspect, the first information is carried in broadcast signaling or dedicated signaling.

[0044] The third aspect provides a communication apparatus, which is configured to execute the method in any possible implementation of the first aspect to the second aspect. Specifically, the apparatus can include units and / or modules for performing the method in any possible implementation of the first aspect to the second aspect, such as a processing unit and / or a communication unit.

[0045] In one implementation, the apparatus is a communication device (e.g., a terminal device, or a network device). When the apparatus is a communication device, the communication unit can be a transceiver, or an input / output interface; and 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.

[0046] In another implementation, the apparatus is a chip, a chip system, or a circuit, or a communication module for a communication device (e.g., a terminal device, or a network device). When the apparatus is a chip, a chip system, or a circuit for a communication device, the communication unit can be an input / output interface, an interface circuit, an output circuit, an input circuit, a pin, or related circuitry, etc. on the chip, the chip system, or the circuit; and the processing unit can be at least one processor, a processing circuit, or a logic circuit, etc.

[0047] The fourth aspect provides a communication apparatus, which includes at least one processor configured to execute computer programs or instructions to perform the method in any possible implementation of the first aspect to the second aspect. Optionally, the apparatus further includes a memory configured to store the computer programs or instructions. Optionally, the apparatus further includes a communication interface coupled to the processor, which can be configured to input the computer programs or instructions to the processor, or output information in the processor.

[0048] In one implementation, the apparatus is a communication device (e.g., a terminal device, or a network device).

[0049] In another implementation, the apparatus is a chip, a chip system or a circuit or a communication module for a communication device, such as a terminal device, or a network device.

[0050] In a fifth aspect, a processor is provided for performing the method provided in any of the first aspect to the second aspect.

[0051] For the sending and obtaining / receiving operations involved by the processor, if no special description is made, or if it does not contradict the actual role or the inherent logic in the related description, it can be understood as the processor output and receive, input, and the like, or it can be understood as the sending and receiving operations performed by the radio frequency circuit and the antenna, and the present application does not limit this.

[0052] Optionally, the apparatus further comprises a memory for storing a program, and correspondingly, the at least one processor is configured to execute the computer program or the instruction in the memory.

[0053] Optionally, the apparatus further comprises a communication interface. The communication interface is coupled with the processor, and can be used to input information to the processor, or output information in the processor.

[0054] In a sixth aspect, a computer readable storage medium is provided. The computer readable medium stores program codes for execution by a device. The program codes comprise codes for performing the method in any of the possible implementation manners of the first aspect to the second aspect.

[0055] In a seventh aspect, a computer program product containing instructions which, when the computer program product is run on a computer, cause the computer to execute the method in any of the possible implementation manners of the first aspect to the second aspect.

[0056] In an eighth aspect, a chip is provided. The chip comprises a processor and a communication interface. The processor reads instructions on a memory through the communication interface, and executes the method provided in any of the implementation manners of the first aspect to the second aspect.

[0057] Optionally, the chip is a Modem chip, also known as a baseband chip, or a system on chip (SoC) chip or a system in package (SIP) chip containing a modem core.

[0058] Optionally, as an implementation manner, the chip further comprises a memory. The memory stores computer programs or instructions. The processor is configured to execute the computer programs or instructions on the memory. When the computer programs or instructions are executed, the processor is configured to execute the method provided in any of the implementation manners of the first aspect to the second aspect.

[0059] In a ninth aspect, a computer program product including instructions, which when executed on a computer, cause the computer to perform the method provided by any one of the implementations of the first aspect to the second aspect.

[0060] In a tenth aspect, a communication system is provided, including the terminal device and the network device described above. BRIEF DESCRIPTION OF DRAWINGS

[0061] FIG. 1 shows a schematic diagram of a network architecture suitable for embodiments of the present application.

[0062] FIG. 2 shows a schematic diagram of an architecture of a communication system suitable for embodiments of the present application.

[0063] FIG. 3 shows a schematic diagram of a quasi-fixed cell.

[0064] FIG. 4 shows a schematic diagram of a moving cell.

[0065] FIG. 5 shows a schematic diagram of interaction between a UE and a satellite when a store-and-forward mode is applied.

[0066] FIG. 6 shows a schematic diagram of selection of a target satellite for a UE by a source satellite.

[0067] FIG. 7 shows a schematic flowchart of a communication method provided by embodiments of the present application.

[0068] FIG. 8 shows a schematic flowchart of a communication method provided by embodiments of the present application.

[0069] FIG. 9 shows a schematic flowchart of a communication method provided by embodiments of the present application.

[0070] FIG. 10 is a schematic diagram of a communication apparatus 1000 provided by embodiments of the present application.

[0071] FIG. 11 is a schematic diagram of another communication apparatus 1100 provided by embodiments of the present application.

[0072] FIG. 12 is a schematic diagram of a chip system 1200 provided by embodiments of the present application. DETAILED DESCRIPTION

[0073] The technical solutions in the present application will be described below with reference to the accompanying drawings.

[0074] The technical solutions provided in the present application can be applied to various communication systems, for example, a 5th generation (5G) or new radio (NR) system, a long term evolution (LTE) system, an LTE frequency division duplex (FDD) system, an LTE time division duplex (TDD) system, a wireless local area network (WLAN) system, a satellite communication system, a future communication system, or a fusion system of multiple systems, and the like. The technical solutions provided in the present 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 system or other communication systems.

[0075] The technical solutions provided in the present application can also be applied to non-terrestrial network (NTN) systems such as inter-satellite communication and satellite communication. As an example, a satellite communication system includes a satellite base station and a terminal device. The satellite base station provides communication services for the terminal device. The satellite base station can also communicate with a base station. The satellite can act as a base station or a terminal device. The satellite can refer to a drone, a hot air balloon, a low earth orbit satellite, a medium earth orbit satellite, a high earth orbit satellite, and the like. The satellite can also refer to a non-ground base station or a non-ground device, and the like.

[0076] A device in a communication system can send a signal to another device or receive a signal from another device. The signal can include information, signaling, or data, and the like. The device can be replaced by an entity, a network entity, a communication device, a mobile device, a network element, a communication module, a node, a communication node, a communication apparatus, and the like. The present disclosure describes the device as an example. For example, the communication system can include at least one terminal device and at least one network device. The network device can send a downlink signal to the terminal device, and / or the terminal device can send an uplink signal to the network device. It can be understood that the terminal device in the present disclosure can be replaced by a first communication apparatus, and the network device can be replaced by a second communication apparatus, both of which perform the corresponding communication method in the present disclosure. Alternatively, the corresponding communication method in the present disclosure can be applied between network devices or between terminal devices, which is not limited herein.

[0077] The terminal device in the embodiments of the present application can be a device or module with corresponding communication functions for accessing the above-mentioned communication system. The terminal device can include various devices with wireless communication functions, which can be used to connect people, things, machines, etc. The terminal device can be widely used in various scenarios, such as cellular communication, D2D, V2X, peer to peer, M2M, MTC, IoT, virtual reality (VR), augmented reality (AR), industrial control, autonomous driving, remote medical treatment, smart power grid, smart furniture, smart office, smart wear, smart transportation, smart city UAV, robot, remote sensing, passive sensing, positioning, 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. The terminal device can be a user equipment, terminal, fixed device, mobile station device or mobile device, subscriber unit, handheld device, vehicle-mounted device, wearable device, cellular phone, smart phone, session initiation protocol (SIP) phone, wireless data card, personal digital assistant (PDA), computer, tablet computer, notebook computer, wireless modem, handset, laptop computer, computer with wireless transceiver function, smart book, vehicle, satellite, global positioning system (GPS) device, aircraft (such as a drone, helicopter, multi-helicopter, quad-helicopter, or airplane, etc.), ship, remote control device smart home device, industrial device, transport vehicle with wireless communication function, communication module, road side unit (RSU) with terminal function, or device built-in in the above-mentioned devices (such as a communication module, modem or chip in the above-mentioned devices, etc.), or other processing devices connected to the wireless modem. For the sake of description, the terminal device will be described as an example of a terminal or UE hereinafter.

[0078] It should be understood that in some scenarios, the UE can also be used to act as a base station. For example, the UE can act as a scheduling entity, which provides sidelink signals between UEs in V2X, D2D or peer to peer scenarios, etc.

[0079] In the embodiments of the present application, the apparatus for implementing the function of the terminal device can be a terminal device, or an apparatus capable of supporting the terminal device to implement the function, for example, a chip system, which can be installed in the terminal device or used in combination with the terminal device. In the embodiments of the present application, the chip system can be composed of a chip, or can include a chip and other discrete devices. In the embodiments of the present application, only the apparatus for implementing the function of the terminal device is taken as an example for description, and the scheme of the embodiments of the present application is not limited in this way.

[0080] The network device in the embodiments of the present application can be a device or module with corresponding communication function. The network device can be a device for communicating with the terminal device, and the network device can also be referred to as an access network device or a radio access network device, for example, the network device can be a base station. The network device in the embodiments of the present application can refer to a radio access network (RAN) node (or device) for accessing the terminal device to the wireless network. The base station can broadly cover various names in the following or be replaced by the following names, such as: node B (NodeB), evolved node B (eNB), next generation node B (gNB), relay station, access point, transmitting and receiving point (TRP), transmitting point, primary station, secondary station, motor slide retainer (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. The base station can be a macro base station, a micro base station, a relay node, a donor node or the like, or a combination thereof. The base station can also refer to a communication module, modem or chip for being arranged in the foregoing device or apparatus. The base station can also be a mobile switching center, and a device assuming the function of a base station in D2D, V2X, M2M communication, a device assuming the function of a base station in future communication systems, etc. The base station can support networks of the same or different access technologies. The embodiments of the present application do not limit the specific technology and specific device form of the network device.

[0081] A base station can be fixed, or mobile. For example, a helicopter or unmanned aerial vehicle can be configured to function as a mobile base station, one or more cells can move according to the location of the mobile base station. In other examples, a helicopter or unmanned aerial vehicle can be configured to function as a device that communicates with another base station.

[0082] In some deployments, the network device mentioned in the embodiments of the present application can be a device including a CU, or a DU, or a device including a CU and a DU, or a control plane CU node (central unit-control plane (CU-CP)) and a user plane CU node (central unit-user plane (CU-UP)) and a DU node. For example, the network device can include a gNB-CU-CP, a gNB-CU-UP and a gNB-DU.

[0083] In some deployments, a plurality of RAN nodes cooperate to assist a terminal to implement wireless access, and different RAN nodes respectively implement part of the functions of a base station. For example, the RAN node can be a CU, a DU, a CU-CP, a CU-UP, or a radio unit (RU), etc. The CU and the DU can be separately arranged, or can also be included in the same network element, for example, in a BBU. The RU can be included in a radio frequency device or a radio frequency unit, for example, included in an RRU, an AAU or an RRH.

[0084] In some deployments, the CU is a logical node that hosts the radio resource control (RRC) layer, service data adaptation protocol (SDAP) layer, packet data convergence protocol (PDCP) layer, and other control functions of the access network device. The CU connects with network nodes such as a core network over some interfaces, which can be an E2 interface or the like. Optionally, the CU has some of the functionality of the core network. The CU (e.g., PDCP layer and higher) connects with the DU (e.g., radio link control (RLC) layer and lower) over some interfaces, which can be an Fl interface or the like. In some examples, the interfaces (e.g., Fl interface) can provide control plane (C-Plane) and user plane (U-Plane) functions (e.g., interface management, system information management, UE context management, RRC message transfer, etc.). The Fl application protocol (FlAP) is an application protocol for the Fl interface, which defines, in some examples, signaling procedures for the Fl. The Fl interface supports a control plane (Fl-C), a user plane (Fl-U).

[0085] In some deployments, a CU can be split into a CU-CP and a CU-UP. The CU-CP is a logical node that carries the control plane part of PDCP (PDCP-C) layer and RRC layer, and is used to implement the control plane function of the CU. The CU-CP can interact with a network element in the core network that is used to implement the control plane function. The network element in the core network that is used to implement the control plane function can be an access and mobility function network element. The CU-UP is a logical node that carries the user plane part of PDCP (PDCP-U) layer and SDAP layer, and is used to implement the user plane function of the CU. The CU-UP can interact with a network element in the core network that is used to implement the user plane function. The network element in the core network that is used to implement the user plane function. The above configurations of the CU and the DU are merely examples, and the CU and the DU can have other functions according to needs. For example, the CU or the DU can be configured to have more protocol layer functions, or the CU or the DU can be configured to have partial processing functions of the protocol layers. For example, partial functions of the RLC layer and functions of the protocol layers above the RLC layer are arranged in the CU, and the remaining functions of the RLC layer and functions of the protocol layers below the RLC layer are arranged in the DU. For another example, the functions of the CU or the DU can be divided according to service types or other system requirements. For example, functions that need to meet a relatively short delay requirement in processing time are arranged in the DU, and functions that do not need to meet the delay requirement are arranged in the CU.

[0086] In some deployments, a DU is a logical node that carries an RLC layer, a medium access control (MAC) layer, a higher physical (Higher PHY) layer, and other functions. In some examples, a DU can control at least one RU. The DU is connected to the RU through some interfaces, which can be a front-haul interface. In some examples, the Higher PHY layer includes part of the PHY layer processing, such as forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, and other processing functions.

[0087] In some deployments, a RU is a logical node that hosts lower physical layer (Lower PHY) and radio frequency (RF) processing. In some examples, a RU can be a TRP or a RRH or other similar functional entity. In some examples, Lower PHY includes portions of PHY processing such as fast Fourier transform (FFT), inverse fast Fourier transformation (IFFT), digital beamforming and filtering, etc. processing functions. A RU communicates with one or more UEs over a wireless link.

[0088] A DU and a RU can cooperate to collectively implement the functionality of the PHY layer. One DU can be connected to one or more RUs. The functionality that a DU and a RU have can be configured in multiple ways according to design. For example, a DU is configured to implement baseband functionality and a RU is configured to implement mid- RF functionality. As another example, a DU is configured to implement high layer functionality in the PHY layer and a RU is configured to implement low layer functionality in the PHY layer or implement the low layer functionality and RF functionality. The high layer functionality in the PHY layer can include a portion of the functionality of the PHY layer that is closer to the MAC layer and the low layer functionality in the PHY layer can include another portion of the functionality of the PHY layer that is closer to the mid-RF side.

[0089] In one possible design, the processing unit in a BBU that implements baseband functionality is referred to as a base band high (BBH) unit and the processing unit in a RRU / AAU / RRH that implements baseband functionality is referred to as a base band low (BBL) unit.

[0090] In different systems, the CU (or CU-CP and CU-UP), DU or RU can also have different names, but those skilled in the art can understand their meanings. For example, the radio access network can also be an open radio access network (O-RAN) architecture, in which the CU can also be referred to as an open CU (O-CU), the DU can also be referred to as an open DU (O-DU), the CU-CP can also be referred to as an open CU-CP (O-CU-CP), the CU-UP can also be referred to as an open CU-UP (O-CU-UP), and the RU can also be referred to as an open RU (O-RU). Any of the CUs (or CU-CPs, CU-UPs), DUs and RUs in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0091] In the embodiments of the present application, the apparatus for implementing the function of the network device can be a network device, or an apparatus capable of supporting the network device to implement the function, such as a chip system or a chip or a circuit or a communication module (i.e., a communication module performing a communication function), which can be installed in the network device. In the embodiments of the present application, the chip system can be composed of a chip, or can include a chip and other discrete devices. In addition, program instructions for performing corresponding communication functions can also be configured in the apparatus. In the embodiments of the present application, only the apparatus for implementing the function of the network device is taken as an example for description, and the scheme of the embodiments of the present application is not limited.

[0092] The network device and the terminal device can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; can also be deployed on the water surface; and can also be deployed on aircraft, balloons and satellites in the air. The scenarios in which the network device and the terminal device are located are not limited in the embodiments of the present application. In addition, the terminal device and the network device can be hardware devices, or software functions running on special hardware, software functions running on general hardware, such as virtualized functions instantiated on a platform (for example, a cloud platform), or entities including special or general hardware devices and software functions. The specific forms of the terminal device and the network device are not limited in the present application.

[0093] In actual network deployment, the ground network cannot cover all areas, especially in sparsely populated areas such as deserts, oceans, the North and South Poles, and the like. The NTN has a wide coverage range and is more likely to provide coverage in sparsely populated areas, and is suitable for deployment in sparsely populated areas. The embodiments of the present application are applicable to NTN communication, and NTN refers to a network or network segment using a satellite (or unmanned aircraft system (UAS) platform or high-altitude platform) onboard radio frequency. The network architecture applicable to the embodiments of the present application is described in detail below with reference to FIG. 1 taking a satellite communication system as an example. In the satellite communication system, the network device can include a satellite.

[0094] FIG. 1 is a schematic diagram of a network architecture applicable to the embodiments of the present application. A ground mobile terminal UE accesses a 5G new air interface network, and a 5G access network device is deployed on a satellite and connected to a ground core network through a wireless link. At the same time, there is a wireless link between satellites to complete signaling interaction and user data transmission between access network devices. The various network elements in FIG. 1 and their interfaces are described as follows:

[0095] Terminal device: a mobile device supporting a 5G new air interface, such as a typical mobile device such as a mobile phone, a pad, and the like. The mobile device can access a satellite network through an air interface and initiate a call, access the Internet, and the like.

[0096] 5G access network device: mainly providing wireless access services, scheduling wireless resources to access terminals, providing reliable wireless transmission protocols and data encryption protocols, and the like, such as a base station and the like.

[0097] 5G core network: user access control, mobility management, session management, user security authentication, charging, and the like. It is composed of multiple functional units and can be divided into control plane and data plane functional entities. For example, the control plane functional entities can include an access and mobile management function (AMF) and a session management function (SMF), and the like, the AMF is responsible for user access management, security authentication, and mobility management. The SMF is mainly used for session management in a mobile network, such as session establishment, modification, release, and the like. The data plane functional entities can include a user plane function (UPF), and the like, the UPF is responsible for managing user plane data transmission, traffic statistics, and the like.

[0098] Ground station: responsible for forwarding signaling and service data between the satellite access network device and the 5G core network.

[0099] 5G new air interface: a wireless link between a terminal and an access network device.

[0100] Xn interface: interface between 5G access network devices and access network devices, mainly for signaling interaction such as handover.

[0101] NG interface: interface between 5G access network devices and 5G core network, mainly for interaction of core network non-access layer (NAS) signaling and user service data.

[0102] It should be understood that the network architecture in FIG. 1 is illustrated by taking the UE accessing the 5G new air interface network as an example, and the network accessed by the UE is not limited in the present application. For example, the UE can access the network through the 4G or future communication system.

[0103] FIG. 2 is a schematic diagram of an architecture of a communication system suitable for embodiments of the present application. As shown in FIG. 2, the communication system can include at least one network device, such as the satellite device shown in FIG. 1; the communication system can also include at least one terminal device, such as the terminal device shown in FIG. 1. The network device and the terminal device can communicate through a wireless link.

[0104] It should be understood that the network device in the wireless communication system can be any device with wireless transceiving function. The device includes but is not limited to a base station controller (BSC), a base transceiver station (BTS), etc., and can also be one or a group (including multiple antenna panels) of antenna panels of a base station in a 5G system, or a satellite, etc.

[0105] It should be understood that only one network device and one terminal device are shown in FIG. 2 as an example, and the communication system is not limited to including more terminal devices. For example, in a satellite communication network, a satellite can cover multiple terminal devices for communication. Each terminal device is also not limited to communicating with one network device. For example, after the satellite moves, the terminal device can need to reselect a satellite for access communication.

[0106] It can be understood that FIG. 2 is only an example and does not constitute any limitation on the protection scope of the present application. The communication method provided by the embodiments of the present application can also involve network elements or devices not shown in FIG. 2. Of course, the communication method provided by the embodiments of the present application can also only include part of the network elements shown in FIG. 2.

[0107] It should be understood that the network architecture shown above is only an example, and the network architecture suitable for the embodiments of the present application is not limited thereto, and any network architecture capable of realizing the functions of the above-mentioned network elements is suitable for the embodiments of the present application.

[0108] It should also be understood that the above network elements or functions can be divided into one or more services, and further, services independent of network functions can also exist. In this application, the above-mentioned function instances, or the instances of the services included in the above-mentioned functions, or the instances of the services independent of the network functions can be referred to as service instances.

[0109] It should also be understood that the above-mentioned names are only defined for the purpose of distinguishing different functions and should not constitute any limitation on the present application. The present application does not exclude the possibility of using other names in the future in other networks.

[0110] It should also be understood that the interface names between the various network elements in FIGS. 1 and 2 are only an example, and the names of the interfaces in the specific implementation can be other names, which are not specifically limited in the present application. In addition, the names of the messages (or signaling) transmitted between the above-mentioned various network elements are also only an example, and do not constitute any limitation on the functions of the messages themselves.

[0111] The following unified description or introduction is made on some technical terms or concepts involved in the present application for the convenience of reading.

[0112] 1. NTN:

[0113] NTN refers to a network or network segment using a satellite (or UAS platform or high-altitude platform) on-board radio frequency. Satellite communication has the advantages of wide coverage, long communication distance, high reliability, great flexibility, high throughput, etc. The introduction of satellites into 5G can provide communication services for areas that are difficult to cover by ground networks, such as oceans, forests, etc., can enhance the reliability of 5G communication, such as providing more stable and high-quality communication services for trains, airplanes and users on these transportation tools, and can also provide more data transmission resources to support a larger number of connections.

[0114] 2. Quasi-Earth-fixed cell:

[0115] The quasi-Earth-fixed cell can also be referred to as a quasi-fixed cell. The quasi-fixed cell is a beam that covers a geographical area within a limited time and covers a different geographical area within another time (for example, the case of a Non-Geosynchronous orbit (NGSO) satellite generating a steerable beam). As shown in FIG. 3, the steerable beam generated by satellite 1 covers geographical area 1 at time t1, t2 and t3, i.e., the geographical area 1 can be referred to as a quasi-fixed cell.

[0116] 3. Earth-moving cell:

[0117] The earth-moving cell can also be referred to as a moving cell. The moving cell is a beam coverage area that moves on the earth's surface with the satellite (for example, in the case of a NGSO satellite generating a fixed or non-steerable beam). As shown in FIG. 4, the fixed or non-steerable beam generated by satellite 1 covers geographical areas 1, 2 and 3 at times t1, t2 and t3, respectively, i.e., the geographical areas 1, 2 and 3 can all be referred to as moving cells.

[0118] 4. NTN-based RAN architectures:

[0119] The NTN-based RAN architecture includes a RAN architecture with a transparent satellite, a regenerative satellite without an inter-satellite link (ISL), a gNB processed payload, a regenerative satellite with an ISL, a gNB processed payload, a regenerative satellite with a DU processing function of a base station (NG-RAN with a regenerative satellite based on gNB-DU), a gNB processed payload based on a relay-like architecture, and the like.

[0120] It should be noted that the specific description of the NTN-based RAN architecture described above can refer to the description of the existing protocol or standard. Here, in order to avoid repetition, the present application will not be described in detail.

[0121] It should be noted that the several architectures of the NTN-based RAN architecture described above are only examples, and the NTN-based RAN architecture can also include other architectures with the same or similar architecture, which is not limited by the present application.

[0122] 5. Store and forward (S&F):

[0123] The store-and-forward scenario refers to a scenario in which a service link (or a traffic link) and a feeder network (or a feeder link) cannot exist simultaneously. As shown in FIG. 5, at T1, the service link between satellite 1 and a UE is unavailable, but the feeder link between satellite 1 and a ground station (or a ground core network or a ground gateway station) is available; at T2, the service link between satellite 1 and the UE is available, but the feeder link between satellite 1 and the ground station (or the ground core network or the ground gateway station) is unavailable.

[0124] The store-and-forward scenario requires that the satellite has at least the function of a base station or the function of a partial base station, in other words, the satellite is on-boarded with a base station or a partial base station. In the store-and-forward scenario, there is no path between a core network, a base station and a UE, for example, in a case where a link between the core network and the base station is available, a link between the base station and the UE is unavailable; and vice versa.

[0125] 6. A mobile management entity (MME) split architecture:

[0126] In the MME split architecture, a home subscriber server (HSS) is located on the ground. The HSS stores all service-related data of users in the network, and provides management of user subscription information and user location.

[0127] The MME is responsible for mobility management of a control plane, management of user context and mobile state, and allocation of a user temporary identity, etc. The functions of the MME are divided into two parts: an MME-onboard part on the satellite, and an MME-ground part on the ground network.

[0128] When the service link is available and the feeder link is unavailable, mobile originated (MO) data is stored in the MME-onboard, and when the feeder link is available, the MO data is transferred from the MME-onboard to the ground (the ground network). When the feeder link is unavailable, mobile terminated (MT) data is stored in the MME-ground or a serving gateway (S-GW), and when the feeder link is available, the MT data is transferred from the MME-ground or the S-GW to the MME-onboard, and is stored in the MME-onboard, and is transmitted to the UE by the MME-onboard when the service link is available.

[0129] The MO data can be understood as data to be sent by the UE, which needs to be sent to the network. The MT data can be understood as data to be received by the UE, which needs to be sent from the network to the UE.

[0130] It should be noted that if it is a 5G network, the MME can be replaced by an AMF, and the HSS can be replaced by an authentication server function (AUSF) and / or a unified data management (UDM). The AUSF is used to implement 3GPP and non-3GPP access authentication. The UDM includes support for the following functions: 3GPP authentication key agreement (AKA) authentication, user identification, access authorization, registration, mobility, subscription, short message management, etc.

[0131] 7. Core network (CN) on satellite architecture:

[0132] The entire CN is located on each satellite, and the CN includes at least one of an eNB, an MME, an S-GW, a packet data network gateway (PGW), an HSS, or a short message service center (SMSC).

[0133] Under the CN on satellite architecture, a proxy is deployed on the satellite and the ground for application services, including support for MT services or data, MO services or data, short message services (SMS), etc.

[0134] The S-GW is mainly responsible for the following functions: session management, routing and data forwarding, quality of service (QoS) control, charging, etc.

[0135] The PGW is mainly responsible for the following functions: implementing packet routing and forwarding; Anchor function between 3GPP and non-3GPP networks; UE internet protocol (IP) address allocation, gateway function for accessing external packet data networks (PDNs).

[0136] It should be noted that if it is a 5G network, the eNB can be replaced by a gNB, the S-GW can be replaced by an SMF, and the PGW can be replaced by an UPF.

[0137] The procedure of UE registration (or called attach) or tracking area update (TAU) in store-and-forward scenario is as follows.

[0138] Step 1: When the feeder link between source satellite and ground station is not available, and the source satellite supports S&F operation, the source satellite should be able to inform the UE whether to apply S&F operation. For example, the source satellite can broadcast its support of S&F operation through system information.

[0139] Step 2: When the UE initiates the attach or TAU procedure, the UE indicates to the MME on the source satellite that the UE supports S&F mode according to the existing NAS capability. If the attach or TAU procedure cannot be completed due to S&F operation, the MME sends an attach reject or TAU reject message to the UE. The attach reject or TAU reject message includes the following information.

[0140] a) Information #1, indicating that the UE cannot complete the attach or TAU procedure due to S&F operation, and the UE can re-attempt the attach or TAU in this public land mobile network (PLMN) at the next satellite pass. Information #1 is stored by the MME, and the network will be available to the UE after the MME interacts with the ground network.

[0141] b) Wait timer, indicating the time that the UE should wait before re-attempting the attach or TAU procedure on the source satellite or another satellite of the same PLMN.

[0142] c) Optionally, a list of satellite identities (IDs) through which the UE can re-attempt to perform the attach or TAU procedure after the wait timer expires.

[0143] Step 3: When the feeder link is available, the MME obtains the UE-related authentication vector and other details from the HSS. The MME can trigger an update location interaction with the HSS, i.e., the MME sends an update location request to the HSS, and the MME receives an update location acknowledgement (ACK) (update location ACK) from the HSS. During the update location interaction, all subscription details are retrieved by the MME-ground. The update location request sent by the MME to the HSS includes an indication information indicating that the current location update is temporary. Correspondingly, the HSS determines that the UE is not in a registered state according to the indication information, in other words, the HSS cannot consider the UE as registered before receiving the final update location request.

[0144] Step 4: When the wait timer of the UE expires in step 2, if the UE has not successfully attached to another PLMN, and the UE finds that cell #1 is valid, the UE re-attempts the attach or TAU procedure in cell #1, i.e., the UE re-sends the attach or TAU request message. The satellite ID broadcasted by cell #1 is included in the list of satellite IDs in step 2.

[0145] In step 2 above, the source satellite can select a target satellite for the UE according to the location of the UE, and send the ID of the target satellite to the UE in the attach reject or TAU reject message.

[0146] The accuracy of the selection of the target satellite for the UE by the source satellite depends on whether the source satellite can obtain the location information of the UE, and the accuracy of the location information of the UE obtained by the source satellite. However, the source satellite can not be able to obtain the accurate location information of the UE. For example, the UE can not report the location information to the source satellite due to privacy or other issues. For another example, the source satellite can need to select a suitable target satellite for the UE before the UE reports the location information of the UE. For instance, a UE supporting narrowband (NB)-IOT can report the location information of the UE to the MME on the source satellite through a NAS message (e.g., a security mode command (SMC) message), but the source satellite can need to select a target satellite for the UE to send an identification request and / or an authentication request message to the UE before the UE sends the SMC message, at which time the source satellite has not obtained the location information of the UE.

[0147] Based on the above reasons, the source satellite can not be able to obtain the accurate location of the UE, and thus can not be able to select a suitable target satellite for the UE. In other words, the target satellite selected by the source satellite for the UE can not be able to cover the UE, and thus can not be able to provide services for the UE. In this case, the UE can not be able to complete the attach or TAU procedure, and the UE can frequently search for the wrong target satellite, resulting in additional power consumption of the UE.

[0148] As shown in (a) of FIG. 6, the source satellite can only determine that the UE is in the coverage of the source satellite, but can not be able to obtain the accurate location information of the UE. In this case, even if the coverage of the target satellite selected by the source satellite has a large overlap with the coverage of the source satellite, the UE can still be outside the coverage of the target satellite, and thus the UE can not be able to re-perform the attach or TAU procedure in the target satellite.

[0149] As shown in (b) of FIG. 6, due to the influence of the earth rotation, the position of the UE will change, resulting in that the source satellite cannot obtain the accurate position information of the UE. In this case, the source satellite cannot select a suitable target satellite for the UE.

[0150] Therefore, the present application provides a communication method, which is beneficial to more accurately select a suitable target satellite for the UE, thereby ensuring the normal communication of the UE and avoiding the additional power consumption of the UE due to the failure to search for the target satellite.

[0151] Before introducing the scheme of the present application, the following points are explained.

[0152] (1) In the present application, "indication" can include direct indication, indirect indication, display indication, and implicit indication. When describing that certain indication information is used to indicate A, it can be understood that the indication information carries A, directly indicates A, or indirectly indicates A.

[0153] In the present application, the information indicated by the indication information is referred to as to-be-indicated information. In the specific implementation process, there are many ways to indicate the to-be-indicated information, for example but not limited to, the to-be-indicated information can be directly indicated, such as the to-be-indicated information itself or the index of the to-be-indicated information. The to-be-indicated information can also be indirectly indicated by indicating other information, wherein the other information and the to-be-indicated information have an association relationship. The to-be-indicated information can also be only indicated in part, and the other part of the to-be-indicated information is known or agreed in advance. For example, the indication of a specific information can also be achieved by means of the arrangement order of each information agreed in advance (for example, the protocol stipulates), thereby reducing the indication overhead to a certain extent. In addition, the to-be-indicated information can be sent as a whole, or can be sent separately in multiple sub-information, and the sending period and / or sending time of these sub-information can be the same or different.

[0154] (2) In the present application, "sending" and "receiving" represent the direction of signal transmission. For example, "sending information to XX" can be understood as that the destination of the information is XX, which can include direct sending through the air interface, and also includes indirect sending through the air interface by other units or modules. "Receiving information from YY" can be understood as that the source of the information is YY, which can include direct receiving from YY through the air interface, and also includes indirect receiving from YY through the air interface from other units or modules. "Sending" can also be understood as the "output" of the chip interface, and "receiving" can also be understood as the "input" of the chip interface. In other words, sending and receiving can be carried out between devices, for example, between network devices and terminal devices, or can be carried out within a device, for example, between components, modules, chips, software modules or hardware modules in a device through a bus, wire or interface.

[0155] (3) In each of the embodiments of the present application, the terms and / or descriptions among different embodiments are consistent and can be referred to each other if there is no special description and logical conflict, and the technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0156] (4) In the present application, “first”, “second” are only convenient for description, used for distinguishing objects, and do not limit the scope of the embodiments of the present application. They are not used to describe the order or sequence of characteristics. It should be understood that the objects thus described can be interchanged under appropriate circumstances, so as to be able to describe solutions other than the embodiments of the present application.

[0157] (5) In the present application, “predefined” can mean standard protocol predefined, or can also mean pre-agreed or pre-negotiated between devices.

[0158] (6) In the present application, the words such as “exemplary”, “for example” are used to represent examples, illustrations or descriptions. Any embodiment or design scheme described as “example” in the present application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. Rather, the word “example” is intended to present the concept in a specific way. In the embodiments of the present application, “of”, “corresponding” and “corresponding” can be used interchangeably at times. It should be pointed out that when their differences are not emphasized, the meanings they express are consistent.

[0159] (7) “At least one” in the present application means one or more. “Multiple” means two or more. “And / or” describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the following cases: A exists alone, A and B exist together, B exists alone, where A and B can be singular or plural. In the textual description of the present application, the character “ / ” generally represents that the associated objects before and after are in an “or” relationship; in the formula of the present application, the character “ / ” represents that the associated objects before and after are in a “division” relationship. “Including at least one of A, B and C” can mean: including A; including B; including C; including A and B; including A and C; including B and C; including A, B and C.

[0160] The method provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings. The embodiments provided by the present application can be applied to the communication system shown in FIG. 1, without limitation.

[0161] In the following embodiments, the interaction between the first device and the second device is exemplarily illustrated. The first device can be a terminal device or a component (e.g., a chip or a chip system or a circuit or a communication module) of the terminal device. The second device can be a source satellite, a network device, a core network element, a component (e.g., a chip or a chip system or a circuit or a communication module) of the network device, or a component (e.g., a chip or a chip system or a circuit or a communication module) of the core network element. The network device is deployed on the source satellite, or the source satellite has the function of the network device. The core network element is deployed on the source satellite. The source satellite is a satellite currently providing services for the terminal device. The source satellite can also be replaced by a source cell, which is a cell currently providing services for the first device and belongs to the source satellite.

[0162] In the following embodiments, the target satellite can also be replaced by a target cell, which belongs to the target satellite. The target satellite in the following embodiments refers to a satellite selected by the first device as a future satellite that can provide services for the first device.

[0163] The satellite in the following embodiments can be replaced by an NTN payload. The NTN payload can be a satellite, a drone, a dirigible, a high-altitude platform, etc.

[0164] FIG. 7 shows a schematic flowchart of a communication method according to an embodiment of the present application. As shown in FIG. 7, the method 700 can include the following steps.

[0165] S710, the second device sends first information.

[0166] Correspondingly, the first device receives the first information.

[0167] The first information includes the identification and coverage range information of each satellite in at least one satellite.

[0168] It can be understood that the second device can obtain the information of other satellites from a control center or an operator or a ground base station or a ground gateway on the ground.

[0169] Exemplarily, the coverage range information of the satellite includes one or more of the following: a satellite coverage start time, a reference point of the coverage range of the satellite, time information corresponding to the reference point of the coverage range of the satellite, a radius of the coverage range of the satellite, left and right elevation angle information of the coverage range of the satellite, or ephemeris information of the satellite.

[0170] For example, if the quasi-fixed cell, the satellite coverage range information can include one or more of the following: satellite coverage start time, reference point of the satellite coverage range, radius of the satellite coverage range, or satellite ephemeris information, for example, if the mobile cell, the satellite coverage range information can include one or more of the following: satellite ephemeris information, left and right elevation angle information of the satellite coverage range and / or radius of the satellite coverage range, or the satellite coverage range information can include one or more of the following: satellite ephemeris information, reference point of the satellite coverage range and time information corresponding to the reference point, radius of the satellite coverage range.

[0171] The satellite coverage start time, which can also be the satellite service start time, refers to the time when the satellite starts to cover or serve a specific area; it can also be a time before the satellite starts to cover or serve a specific area; or it can also be a time after the satellite starts to cover or serve a specific area. Because it is difficult to accurately represent an accurate time in the protocol, an approximate time is generally used to represent the accurate time, which can be a time before or after the accurate time. The satellite coverage start time can also be the start time of the coverage or service of the cell or beam corresponding to the satellite.

[0172] The reference point of the satellite coverage range can be a point within the satellite coverage range or a point outside the satellite coverage range. The reference point of the satellite coverage range can also be the reference point of the cell or beam corresponding to the satellite.

[0173] The time information corresponding to the reference point of the satellite coverage range refers to the time reference corresponding to the reference point. The time information corresponding to the reference point of the satellite coverage range can also be the time information corresponding to the reference point of the coverage range of the cell or beam.

[0174] The radius of the satellite coverage range refers to the distance between the reference point of the satellite coverage range and the edge of the satellite coverage range. The radius of the satellite coverage range can also be the distance between the reference point of the cell or beam coverage range and the edge of the cell or beam coverage range.

[0175] The left and right elevation angle information of the satellite coverage range refers to the leftmost and rightmost (relative to the satellite direction) elevation angles. This is two elevation angle parameters, left elevation angle information and right elevation angle information. If the left elevation angle information is missing, the left elevation angle is equal to the right elevation angle; similarly, if the right elevation angle information is missing, the right elevation angle is equal to the left elevation angle. The left and right elevation angle information of the satellite coverage range can also be the left and right elevation angle information of the coverage range of the cell or beam.

[0176] The ephemeris information of the satellite provides satellite ephemeris parameters. The satellite ephemeris information can determine the position of the satellite at each time. For example, the ephemeris information of the satellite can include relevant coordinate information and / or orbital information of the satellite. The relevant coordinate information of the satellite can include earth-centered, earth-fixed (ECEF) coordinate information, or earth centered inertial (ECI) coordinate information. The ECEF coordinate information can include satellite-related three-point coordinates, velocity, and time. The ECI coordinate information can include satellite-related three-point coordinates, velocity, and time. The orbital information includes one or more of the following: right ascension of the ascending node, orbital inclination, semi-major axis of the orbit, orbital eccentricity, argument of perigee, or true anomaly.

[0177] For example, the coverage information of the satellite can be replaced by the coverage information of the satellite beam (NTN payload) or the coverage information of the NTN cell.

[0178] The following describes at least one satellite.

[0179] In a possible implementation, the coverage range of each satellite in the at least one satellite at a future time overlaps with the coverage range of the source satellite. The coverage range of the source satellite can be the coverage range at the current time or in the current period, or the coverage range at a past time or in a past period, or the coverage range at a future time or in a future period.

[0180] In a possible implementation, the end time of the time period during which the feeder link of each satellite in the at least one satellite is available is later than the start time of the time period during which the feeder link of the source satellite is available.

[0181] As shown in Table 1, the time period during which the feeder link of satellite 1 (an example of the source satellite) is available is 11:10-11:30, the time period during which the feeder link of satellite 2 is available is 10:20-10:50, the time period during which the feeder link of satellite 3 is available is 11:10-11:15, and the time period during which the feeder link of satellite 4 is available is 11:20-11:50. Therefore, the at least one satellite includes satellite 3 and satellite 4.

[0182] Table 1

[0183] For example, when comparing the time period during which the feeder link of the source satellite is available with the time period during which the feeder link of the other satellites is available, the time period during which the feeder link of different satellites is available in the same period is compared. For example, taking two hours as a period, in the period of 10:00-12:00, the time period during which the feeder link of satellite 1 to satellite 4 is available is shown in Table 1. Even if the time period during which the feeder link of satellite 2 is available in the next period, i.e. the period of 12:00-14:00, is 12:20-12:45, the end time of the time period during which the feeder link is available is later than the start time of the time period during which the feeder link of satellite 1 is available, but at least one satellite still does not include satellite 2.

[0184] For example, when comparing the time period during which the feeder link of the source satellite is available with the time period during which the feeder link of the other satellites is available, the time period during which the feeder link of different satellites is available in the same period is compared. For example, taking two hours as a period, in the period of 10:00-12:00, the time period during which the feeder link of satellite 1 to satellite 4 is available is shown in Table 1. Even if the time period during which the feeder link of satellite 2 is available in the next period, i.e. the period of 12:00-14:00, is 12:20-12:45, the end time of the time period during which the feeder link is available is later than the start time of the time period during which the feeder link of satellite 1 is available, but at least one satellite still does not include satellite 2.

[0185] It can be understood that since the end time of the time period during which the feeder link of each of the at least one satellite is available is later than the start time of the time period during which the feeder link of the source satellite is available, each of the at least one satellite has the possibility to carry the downlink data and / or downlink signaling sent by the ground network to the first device. Wherein, the downlink data and / or downlink signaling is related to the uplink data or uplink signaling sent by the first device to the ground network through the source satellite.

[0186] For example, when the service link between the source satellite and the first device is available, the source satellite can receive uplink data and / or uplink signaling (e.g., a registration request message) from the first device, and when the feeder link between the source satellite and the ground network is available, the source satellite can send the uplink data and / or uplink signaling to the ground network (e.g., a ground MME or HSS). After the ground network receives the uplink data and / or uplink signaling from the source satellite, the ground network can send downlink data and / or downlink signaling (e.g., an authentication request message or a registration accept message) to the satellite whose feeder link is available. Since the end time of the time period during which the feeder link of each of the at least one satellite is available is later than the start time of the time period during which the feeder link of the source satellite is available, it is equivalent that the feeder link of each of the at least one satellite is available after the ground network receives the uplink data and / or uplink signaling from the source satellite, so that the ground network can send the downlink data and / or downlink signaling to the satellite of the at least one satellite.

[0187] In a possible implementation, each of the at least one satellite supports a store-and-forward mode.

[0188] The embodiments of the present application do not limit the manner in which the second device sends the first information.

[0189] In a possible implementation, the second device can send the first information in a broadcast manner. For example, when the first device is in an idle state or an inactive state, the second device can send the first information in a broadcast manner. Optionally, the first information can be carried in a system information block (SIB).

[0190] In a possible implementation, the second device can send the first information in a unicast manner. For example, when the first device is in a connected state, the second device can send the first information in a unicast manner. The second device sends the first information in a unicast manner, which is equivalent to that the first information is carried in dedicated signaling.

[0191] Compared with the manner of broadcasting the first information, if the broadcast first information is carried in an existing SIB, since the information of satellites that can be carried in the existing SIB is limited, the first device cannot be provided with more accurate satellite ephemeris information and coverage range information, while the first information sent in a unicast manner can provide more accurate satellite ephemeris information and coverage range information. In addition, the first information is sent in a unicast manner, so that there is no need to introduce new broadcast signaling.

[0192] In a possible implementation, the first device is in an idle state or an inactive state, the second device first sends the first information in a broadcast manner, and then the first device is in a connected state, the second device again sends the first information in a unicast manner. The first information sent by the second device twice can be the same or different, which is not limited in the application. For example, the first information broadcasted by the second device first includes the identifier and coverage range information of satellite 2, and the first information unicast by the second device includes the identifier and coverage range information of satellite 3.

[0193] Optionally, the method 700 further includes S720.

[0194] S720, the second device sends the second information.

[0195] Correspondingly, the first device receives the second information.

[0196] The second information is used to determine the available time information of the feeder link of each satellite in the at least one satellite.

[0197] For example, the second information can include the information of the time period in which the feeder link of the satellite is available. The information of the time period in which the feeder link of the satellite is available can include the end time and the start time of the time period in which the feeder link of the satellite is available, or can include the start time and the duration of the time period in which the feeder link of the satellite is available, or can include the index of the time period in which the feeder link of the satellite is available.

[0198] For another example, the second information can include the information of multiple time periods in which the feeder link of the satellite is available, that is, the second information can include a list of time periods in which the feeder link of the satellite is available. Alternatively, the second information can include the information of one time period in which the feeder link of the satellite is available, for example, the second information can include the information of the time period in which the nearest first time in multiple time periods in which the feeder link of the satellite is available is available, or the information of the time period in which the feeder link of the satellite is available in the period in which the current time is located. For example, the first time is 10:30, and multiple time periods in which the feeder link of satellite 2 is available after the first time include 10:20-10:50 and 12:20-12:45, and the first information includes the information of the time period 10:20-10:50. For another example, the current time is 10:30, the period in which the current time is located is 10:00-12:00, and multiple time periods in which the feeder link of satellite 2 is available include 10:20-10:50 and 12:20-12:45, and the first information includes the information of the time period 10:20-10:50.

[0199] In a possible implementation, if the second device does not determine the at least one satellite by comparing the time period during which the feeder link of the source satellite is available with the time period during which the feeder link of the other satellite is available before sending the first information, in other words, the end time of the time period during which the feeder link of the satellite in the at least one satellite is available is not later than the start time of the time period during which the feeder link of the source satellite is available, the second device can send the second information to the first device.

[0200] It should be noted that S720 is an optional step. For example, if the end time of the time period during which the feeder link of each satellite in the at least one satellite is available is later than the start time of the time period during which the feeder link of the source satellite is available, the method 700 can not perform S720.

[0201] It should be further noted that S720 and S710 can be combined into one step, in other words, the first information and the second information can be carried in the same message. For example, the second device sends message #1 to the first device, the message #1 includes the first information and the second information, or in other words, the message #1 includes the identification of each satellite in the at least one satellite, the coverage information and the second information.

[0202] It should be further noted that the execution order of S710 and S720 is not limited in the embodiments of the present application. For example, the second device can first send the first information and then send the second information, or the second device can first send the second information and then send the first information.

[0203] The manner in which the second device sends the second information can refer to the manner in which the second device sends the first information.

[0204] S730, the second device sends third information.

[0205] Correspondingly, the first device receives the third information.

[0206] The third information is used to indicate that the source satellite supports the store-and-forward mode, or the third information is used to indicate that the source satellite is in the store-and-forward mode, or the third information is used to indicate that the feeder link of the current source satellite is unavailable.

[0207] It can be understood that, after the first device receives the third information, the first device can determine that the source satellite supports the store-and-forward mode according to the third information, or determine that the source satellite is in the store-and-forward mode according to the third information, or determine that the feeder link of the current source satellite is unavailable according to the third information.

[0208] It should be noted that S730 is an optional step. For example, if the first device already knows that the source satellite supports the store-and-forward mode, or the first device periodically performs S770 below, or the method 700 performs S750 and S760, the method 700 can not perform S730.

[0209] It should be further noted that S730 can be combined with S710 and / or S720 as one step, in other words, the third information can be carried in the same message as the first information and / or the second information. For example, the second device sends message #2 to the first device, and the message #2 includes the first information, the second information and the third information.

[0210] It should be further noted that the embodiments of the present application do not limit the execution sequence of S710 to S730. For example, the second device can first send the first information, then send the second information, and then send the third information; or the second device can first send the second information, then send the first information, and then send the third information.

[0211] The manner in which the second device sends the third information can refer to the manner in which the second device sends the first information.

[0212] S740, the first device determines at least one target satellite from the at least one satellite according to the first information.

[0213] Correspondingly, the target satellite determined by the first device according to the first information can cover the first device in the future, or in other words, the first device will be covered by the target satellite determined by the first device according to the first information in the future.

[0214] When the first device determines at least one target satellite according to the first information, the first device can determine at least one target satellite according to the coverage range information of each satellite in the at least one satellite included in the first information. For example, the first device determines the first satellite in the at least one satellite as a target satellite if the first device determines that the first device will be covered by the first satellite in the future according to the coverage range information of the first satellite, and the first device determines the first satellite as not a target satellite if the first device determines that the first device will not be covered by the first satellite in the future according to the coverage range information of the first satellite.

[0215] For another example, the first device determines the first satellite as a target satellite if the first device determines that the first device will be covered by the first satellite before a certain time in the future according to the coverage range information of the first satellite.

[0216] In summary, the first device can determine whether the first device will be covered by the first satellite in the future according to the coverage range information of the first satellite, which is equivalent to that the first information is used by the first device to determine or predict whether the first device will be covered by the first satellite in the future.

[0217] Optionally, the first device can determine when the first device will be covered by the first satellite in the future according to the coverage range information of the first satellite, in other words, the first device can determine whether the first device will be covered by the first satellite in the future and time information or time period information when the first device will be covered by the first satellite according to the coverage range information of the first satellite.

[0218] For example, if the coverage information of the first satellite comprises one or more of the following: a coverage start time of the first satellite, a reference point of the coverage of the first satellite, a radius of the coverage of the first satellite, or ephemeris information of the first satellite, the first device can calculate a first distance between the location information of the first device and the reference point of the coverage of the first satellite. If the first distance is less than the radius of the coverage of the first satellite, the first device considers that the first device will be covered or served by the first satellite. The first device can know when it will be covered by the first satellite according to the coverage start time of the first satellite.

[0219] For another example, if the coverage information of the first satellite comprises one or more of the following: ephemeris information of the first satellite, left-right elevation information of the coverage of the first satellite and / or a radius of the coverage of the first satellite, the first device can predict the location information of the first satellite at different time according to the ephemeris information of the first satellite, such as the first device predicting the location information of the satellite at a first time according to the ephemeris information of the first satellite, and the first device knowing the coverage or service range of the first satellite at the first time according to the left-right elevation information of the coverage of the first satellite and / or the radius of the coverage of the first satellite. Further, the first device determines that it is within the coverage range of the first satellite at the first time according to the location information of the first device, and considers that the first device will be covered or served by the first satellite. The earliest first time can be considered as the coverage start time of the first satellite.

[0220] For another example, the coverage information of the first satellite can comprise one or more of the following: ephemeris information of the first satellite, a reference point of the coverage of the first satellite and time information corresponding to the reference point, a radius of the coverage of the first satellite, the first device predicts the reference point (such as a first reference point) of the coverage of the first satellite at a second time according to the ephemeris information of the first satellite, the reference point of the coverage of the first satellite and the time information corresponding to the reference point. Further, the first device calculates a second distance between the location information of the first device and the first reference point, and if the second distance is less than the radius of the coverage of the first satellite, the first device considers that the first device will be covered or served by the first satellite. The earliest second time can be considered as the coverage start time of the first satellite.

[0221] It can be understood that the first device determines that the target satellite can cover the first device in the future according to the first information, which is equivalent to the first device determining that the target satellite can cover the location where the first device is located in the future according to the first information, in other words, the first device can determine at least one target satellite in the at least one satellite according to the location where the first device is located and the first information.

[0222] In a possible implementation, if the method 700 performs S720, the first device can determine at least one target satellite from the at least one satellite according to the first information and the second information, the first device in the future will be covered by the target satellite determined by the first device according to the first information and the second information, and the end moment of the time period during which the feeder link of the target satellite is available is later than the start moment of the time period during which the feeder link of the source satellite is available.

[0223] With reference to the description in S710 above, if the end moment of the time period during which the feeder link of the satellite is available is later than the start moment of the time period during which the feeder link of the source satellite is available, the satellite is likely to carry downlink data and / or downlink signaling sent by the ground network to the first device, and therefore the first device determines the satellite with the end moment of the time period during which the feeder link is available later than the start moment of the time period during which the feeder link of the source satellite is available as the target satellite, thereby facilitating the first device to receive the downlink data and / or downlink signaling forwarded by the target satellite.

[0224] Optionally, the method 700 further includes S750 and S760.

[0225] S750, the first device sends a first message.

[0226] Correspondingly, the second device receives the first message.

[0227] The first message is a message sent by the first device in the process of executing the first procedure, or in other words, the first message is used to execute the first procedure.

[0228] The present application does not limit the first procedure. For example, the first procedure is a registration procedure, and the first message can include a registration request, that is, the first message is used to request registration. For another example, the first procedure is a tracking area update procedure, and the first message can include a tracking area update request, that is, the first message is used to request tracking area update. For another example, the first procedure is to execute a first service (for example, a video service, a short message service, etc.), and the first message can include a service request, that is, the first message is used to request execution of the first service. The first message can also be other messages in the above registration procedure, tracking area update procedure, or first service, which are not limited by the present application. For example, the first message can also include an authentication request in the registration procedure.

[0229] S760, the second device sends a second message.

[0230] Correspondingly, the first device receives the second message.

[0231] The second message is used to indicate that the first procedure cannot be completed.

[0232] For example, the first message comprises a registration request, the second message can be a registration reject message for indicating that the registration procedure cannot be completed. For another example, the first message comprises a tracking area update request message, the second message can be a tracking area update reject message for indicating that the tracking area update procedure cannot be completed. For another example, the first message comprises a service request, the second message can be a service request reject message for indicating that the first service cannot be completed.

[0233] In a possible implementation, the second message comprises an identity of each of the at least one second satellite. The second satellite can be understood as a target satellite selected by the second device for the first device, and the target satellite mentioned in the rest of the method 700 refers to a target satellite determined by the first device itself.

[0234] S770, the first device sends information of the at least one target satellite.

[0235] Correspondingly, the second device receives the information of the at least one target satellite.

[0236] The information of the target satellite can comprise an identity of the target satellite and / or coverage time information of the target satellite covering the first device in the future. The coverage time information can comprise a time of coverage start, a time of coverage end, a certain time between the time of coverage start and the time of coverage end, or a coverage duration, etc.

[0237] In a possible implementation, the first device can periodically send the information of the at least one target satellite.

[0238] In a possible implementation, the first device can periodically determine the at least one target satellite according to the first information and send the information of the at least one target satellite.

[0239] In a possible implementation, the first device can trigger sending the information of the at least one target satellite based on a condition, or trigger determining the at least one target satellite according to the first information and sending the information of the at least one target satellite based on a condition.

[0240] The condition can comprise one or more of the following: the first device receives third information from the second device, the first device receives the second message from the second device, or one or more of the at least one second satellite cannot cover the first device in the future.

[0241] For example, if the first device receives the third information from the second device, the first device sends the information of the at least one target satellite to the second device according to the third information in the case that the source satellite supports the store-and-forward mode; or the first device determines the at least one target satellite according to the first information and sends the information of the at least one target satellite to the second device in the case that the source satellite supports the store-and-forward mode according to the third information.

[0242] For another example, if the first device receives the second message from the second device, the first device sends the information of the at least one target satellite to the second device in the case that the first procedure cannot be completed according to the second message; or the first device determines the at least one target satellite according to the first information and sends the information of the at least one target satellite to the second device in the case that the first procedure cannot be completed according to the second message.

[0243] For another example, if the first device receives the second message from the second device, the first device sends the information of the at least one target satellite to the second device in the case that the first procedure cannot be completed according to the second message and one or more of the at least one second satellite cannot cover the first device in the future according to the first information; or the first device determines the at least one target satellite according to the first information and sends the information of the at least one target satellite to the second device in the case that the first procedure cannot be completed according to the second message and one or more of the at least one second satellite cannot cover the first device in the future according to the first information.

[0244] It can be understood that the prerequisite for the first device to determine that one or more of the at least one second satellite cannot cover the first device in the future according to the first information is that the second device obtains the coverage information of the one or more of the at least one second satellite. For example, the first information includes the identification and coverage information of the one or more of the at least one second satellite, or the second message includes the identification and coverage information of the one or more of the at least one second satellite. In the case that the first information includes the identification and coverage information of the one or more of the at least one second satellite, it is equivalent to that the at least one satellite includes the one or more of the at least one second satellite, or the at least one satellite includes the at least one second satellite.

[0245] It should be noted that if the method 700 performs S750, S770 and S750 can be combined into one step, or be two independent steps. If S770 and S750 are combined into one step, the first message can include the information of the at least one target satellite.

[0246] It should be further noted that if S770 and S750 are two independent steps, the present application does not limit the execution order of S770 and S750.

[0247] Optionally, the method 700 further includes S780.

[0248] S780, the second device sends information of the first target satellite.

[0249] Correspondingly, the first device receives the information of the first target satellite.

[0250] The information of the first target satellite can include an identifier of the first target satellite and / or coverage time information of the first target satellite in the future.

[0251] After receiving the information of the at least one target satellite, the second device can determine the first target satellite from the at least one target satellite, and then send the information of the first target satellite to the first device. The second device can determine one first target satellite from the at least one target satellite, or determine multiple first target satellites, which are not limited in the present application.

[0252] In a possible implementation, an ending moment of a time period during which the feeder link of the first target satellite is available is later than a starting moment of a time period during which the feeder link of the source satellite is available.

[0253] For example, if the second device does not determine the at least one satellite by comparing the time period during which the feeder link of the source satellite is available with the time period during which the feeder link of the other satellite is available before sending the first information, in other words, the ending moment of the time period during which the feeder link of the satellite in the at least one satellite is available is not later than the starting moment of the time period during which the feeder link of the source satellite is available, the second device can determine the first target satellite from the at least one target satellite, and send the information of the first target satellite to the first device.

[0254] For another example, if the second device does not send the second information to the first device, the second device can determine the first target satellite from the at least one target satellite, and send the information of the first target satellite to the first device.

[0255] It should be noted that if the method 700 performs S760, S780 and S760 can be combined into one step, or be two independent steps. For example, if the second device receives the information of the at least one target satellite before sending the second message, S780 and S760 can be combined into one step, that is, the second message can include the information of the first target satellite.

[0256] Optionally, the second device can further send fourth information to the first device, the fourth information being used for configuring at least one timer. The length of the timer is related to the length of time that the first device waits before being covered by a target satellite in the at least one target satellite.

[0257] For example, the fourth information is used to configure a timer, a time length of the timer is related to a time length that the first device waits before the first device is covered by a target satellite #A, for example, the time length of the timer is equal to, greater than or less than the time length that the first device waits before the first device is covered by the target satellite #A, the target satellite #A is a satellite that covers the first device earliest in the future among the at least one target satellite.

[0258] For another example, the fourth information is used to configure at least one timer, the at least one timer corresponds to the at least one target satellite in one-to-one correspondence. The at least one target satellite includes a target satellite #B, a time length of the timer corresponding to the target satellite #B is related to a time length that the first device waits before the first device is covered by the target satellite #B, for example, the time length of the timer is equal to, greater than or less than the time length that the first device waits before the first device is covered by the target satellite #B.

[0259] Optionally, if the method 700 performs S780, the at least one timer is related to a time length that the first device waits before the first device is covered by the first target satellite, for example, a time length of the timer is equal to, greater than or less than the time length that the first device waits before the first device is covered by the first target satellite.

[0260] Optionally, the method 700 further includes S790.

[0261] S790, the first device establishes a connection with the second target satellite.

[0262] For example, the first device establishes a connection with the second target satellite, including: the first device receives an identifier of the second target satellite from the second target satellite; the first device sends a third message to the second target satellite. Wherein, the third message is used for RRC connection establishment, that is, the third message can be an RRC connection establishment request message. Or, the third message is used for RRC connection reestablishment, that is, the third message can be an RRC connection reestablishment request message. Or, the third message is used for RRC connection resume, that is, the third message can be an RRC connection resume request message. For example, the first device has not established a connection with the second target satellite before, then the third message is used for RRC connection establishment (RRC connection establishment). For another example, the first device has established a connection with the second target satellite before, then the third message is used for RRC connection resume (RRC connection resume). For another example, the second target satellite can obtain a UE context from a source satellite, then the third message is used for RRC connection reestablishment (RRC connection reestablishment).

[0263] In a possible implementation, the second target satellite is a first target satellite that the first device searches first among the at least one target satellite, in other words, the first device receives the identity of the second target satellite broadcast by the second target satellite first among the at least one target satellite.

[0264] It can be understood that if the method 700 performs S780, the second target satellite is a first target satellite that the first device searches first among the one or more first target satellites.

[0265] In a possible implementation, if the first device further receives fourth information from the second device, the second target satellite is a target satellite that the first device searches first after expiration of the timer among the at least one target satellite.

[0266] For example, if the fourth information is used to configure a plurality of timers, the expiration of the timer refers to expiration of at least one timer among the plurality of timers.

[0267] It can be understood that if the method 700 performs S780, the second target satellite is a first target satellite that the first device searches first after expiration of the timer among the one or more first target satellites.

[0268] Optionally, if the first device does not complete the first procedure performed first, the first device can continue to perform the first procedure after establishing the connection with the second target satellite. For example, the first procedure is a registration procedure, and the first device can send a registration request message to the second target satellite to request registration after establishing the connection with the second target satellite. For example, the first device can receive a fourth message from the second target satellite after sending the third message to the second target satellite, and the fourth message can be an RRC connection setup accept message, or an RRC connection reestablishment accept message, or an RRC connection resume accept message. Further, the first device can send a fifth message to the second target satellite, and the fifth message includes a registration request, and the fifth message can be an RRC connection setup complete message, or an RRC connection reestablishment complete message, or an RRC connection resume complete message.

[0269] Optionally, after establishing the connection with the second target satellite, if the first device further searches for a third target satellite among the at least one target satellite, that is, the first device further receives the identity of the third target satellite broadcast by the third target satellite, the first device does not establish a connection with the third target satellite. The third target satellite is different from the second target satellite.

[0270] Optionally, before the first device is covered by the second target satellite, and / or before expiration of the timer, the first device closes or deactivates or suspends an access stratum (AS).

[0271] It should be noted that, in the case that the first device is closed or deactivated or suspended in the access layer, the first device can save the configuration information related to the AS layer, and the first device can also keep all running timers continue to run, but the first device does not perform any idle state tasks, such as measurement, etc.

[0272] Further, the first device determines that the first device has been or will be covered by the second target satellite according to the time information or time period information in the future covered by the second target satellite, or the first device starts or resumes the access layer after the timer expires, thereby performing the idle state task.

[0273] In the embodiment of the application, the second device can send the identification and coverage range information of at least one satellite to the first device, so that the first device can select a target satellite according to the coverage range information of the at least one satellite, and send the information of the target satellite to the second device. Compared with the scheme that the second device selects a target satellite for the first device, the first device can obtain the accurate position information of the first device, so that when the first device selects a target satellite according to the coverage range information of the at least one satellite, the first device can more accurately select a suitable target satellite, i.e., can select a target satellite that can cover the first device in the future, thereby facilitating to ensure the normal communication of the first device, and avoiding the additional power consumption of the first device due to the failure to search for a target satellite.

[0274] The application of the above method 700 in the registration process or the registration area update process will be described below in combination with FIG. 8 and FIG. 9. The terminal device in FIG. 8 and FIG. 9 below is an example of the first device, and the source satellite is an example of the second device.

[0275] FIG. 8 shows a schematic flowchart of a communication method provided by the embodiment of the application. As shown in FIG. 8, the method 800 can include the following steps.

[0276] S801, the source satellite sends a message #1.

[0277] Correspondingly, the terminal device receives the message #1.

[0278] The message #1 includes the first information and the third information. Optionally, the message #1 also includes the second information. More description about the first information, the second information and the third information can be referred to the above method 700.

[0279] S802, the terminal device sends a first message.

[0280] Correspondingly, the source satellite receives the first message.

[0281] The first message is used for requesting registration, i.e., the first message can include a registration request. Alternatively, the first message is used for requesting tracking area update, i.e., the first message can include a tracking area update request.

[0282] S803, the terminal device determines at least one target satellite from the at least one satellite according to the first information.

[0283] More description of S803 can refer to S740 in method 700 above, which will not be repeated here for brevity.

[0284] S804, the terminal device sends information of the at least one target satellite.

[0285] Correspondingly, the source satellite receives the information of the at least one target satellite.

[0286] More description of S804 can refer to S750 in method 700 above, which will not be repeated here for brevity.

[0287] It should be noted that when the message #1 includes the third information, the terminal device performs S803 and S804 according to the third information to determine that the source satellite supports the store-and-forward mode. Wherein, the terminal device determines that the source satellite supports the store-and-forward mode according to the third information, which is equivalent to the terminal device can determine that the currently ongoing registration procedure or tracking area update procedure cannot be completed according to the third information, and the terminal device needs to re-access a satellite to continue the currently ongoing registration procedure or tracking area update procedure, so as to trigger the terminal device to select at least one target satellite according to the first information and send information of the at least one target satellite to the source satellite.

[0288] S805, the source satellite sends a second message.

[0289] Correspondingly, the terminal device receives the second message.

[0290] For example, the first message includes a registration request, and the second message can be a registration rejection message for indicating that the registration procedure cannot be completed. For another example, the first message includes a tracking area update request message, and the second message can be a tracking area update rejection message for indicating that the tracking area update procedure cannot be completed.

[0291] Optionally, the second message includes a reason for rejecting the registration request or the tracking area update. For example, the reason for rejecting the registration request or the tracking area update request can be that the source satellite is in the store-and-forward mode, or can be that the feeder link of the current source satellite is unavailable.

[0292] Optionally, the second message includes information of the at least one target satellite, or includes information of a first target satellite. The description of the first target satellite can refer to S780 in method 700 above.

[0293] For example, if the end time of the time period during which the feeder link of the target satellite is available is not later than the start time of the time period during which the feeder link of the source satellite is available, the second message includes information of the first target satellite. If the end time of the time period during which the feeder link of each of the at least one target satellite is available is later than the start time of the time period during which the feeder link of the source satellite is available, the second message includes information of the at least one target satellite.

[0294] Optionally, the second message includes fourth information, the fourth information being used for configuring at least one timer. More description of the fourth information can be referred to S780 in the method 700. The fourth information is equivalent to information used for determining a time that the terminal device should wait before reattempting performing the registration or the tracking area update on one satellite.

[0295] S806, the source satellite sends the message #2.

[0296] Correspondingly, the ground network receives the message #2.

[0297] It should be understood that the source satellite can send the message #2 to the ground network when the feeder link of the source satellite is available.

[0298] The message #2 includes information of the at least one target satellite, or includes information of the first target satellite. For example, if the second message includes information of the at least one target satellite, the message #2 includes information of the at least one target satellite. If the second message includes information of the first target satellite, the message #2 includes information of the first target satellite.

[0299] The message #2 further includes uplink data or uplink signaling sent by the terminal device in the first message. For example, the message #2 further includes a registration request or a tracking area request.

[0300] S807, the ground network sends the message #3.

[0301] Correspondingly, the second target satellite receives the message #3.

[0302] It should be noted that if the message #2 includes information of the at least one target satellite, the ground network can send the message #2 to the at least one target satellite, the at least one target satellite including the second target satellite. If the message #2 includes information of the first target satellite, the ground network can send the message #2 to one or more first target satellites, the one or more first target satellites including the second target satellite.

[0303] The message #3 includes downlink data or downlink signaling sent by the ground network to the terminal device according to the uplink data or uplink signaling in the message #2. For example, the message #3 includes an authentication vector in a registration procedure or a tracking area update procedure.

[0304] S808, the terminal device establishes a connection with the second target satellite.

[0305] More description of S808 can refer to S790 in method 700 above, and is not repeated here for brevity.

[0306] In embodiments of the present application, in a process of initiating registration or tracking area update by the terminal device through the source satellite, if the source satellite fails to complete the registration or tracking area update procedure, the terminal device can more accurately select a suitable target satellite according to the first information sent by the source satellite, and then continue the registration or tracking area update through the target satellite.

[0307] FIG. 9 shows a schematic flowchart of a communication method according to embodiments of the present application. As shown in FIG. 9, method 900 can include the following steps.

[0308] S901, the source satellite sends message #1.

[0309] Correspondingly, the terminal device receives message #1.

[0310] Message #1 includes first information. Optionally, message #1 also includes second information and / or third information. More description of the first information, the second information and the third information can refer to method 700 above.

[0311] S902, the terminal device sends a first message.

[0312] Correspondingly, the source satellite receives the first message.

[0313] The first message is used to request registration, i.e., the first message can include a registration request. Alternatively, the first message is used to request tracking area update, i.e., the first message can include a tracking area update request.

[0314] S903, the source satellite sends a second message.

[0315] Correspondingly, the terminal device receives the second message.

[0316] For example, the first message includes a registration request, and the second message can be a registration rejection message, used to indicate that the registration procedure cannot be completed. For another example, the first message includes a tracking area update request message, and the second message can be a tracking area update rejection message, used to indicate that the tracking area update procedure cannot be completed.

[0317] Optionally, the second message includes a reason for rejecting the registration request or the tracking area update. For example, the reason for rejecting the registration request or the tracking area update request can be that the source satellite is in a store-and-forward mode, or can be that the current source satellite's feeder link is unavailable.

[0318] Optionally, the second message includes an identity of at least one second satellite.

[0319] S904, the terminal device determines at least one target satellite from the at least one satellite according to the first information.

[0320] More description of S904 can refer to S740 in method 700 above, which will not be repeated here for brevity.

[0321] S905, the terminal device sends information of the at least one target satellite.

[0322] Correspondingly, the source satellite receives the information of the at least one target satellite.

[0323] More description of S905 can refer to S750 in method 700 above, which will not be repeated here for brevity.

[0324] In a possible implementation, the terminal device performs S904 and S905 when the terminal device determines, according to the second message, that the ongoing registration procedure or tracking area update procedure cannot be completed.

[0325] In a possible implementation, the second message includes an identifier of at least one second satellite, and the terminal device performs S904 and S905 when the terminal device determines, according to the first information, that one or more second satellites of the at least one second satellite cannot cover the terminal device in the future.

[0326] Optionally, the method 900 further includes S906.

[0327] S906, the source satellite sends message #4.

[0328] Correspondingly, the terminal device receives message #4.

[0329] Message #4 can be a registration reject message or a tracking area update reject message re-sent by the source satellite after receiving the information of the at least one target satellite.

[0330] If the end time of the time period during which the feeder link of the target satellite of the at least one target satellite is available is not all later than the start time of the time period during which the feeder link of the source satellite is available, the method 900 can perform S906, and message #4 includes information of the first target satellite.

[0331] Optionally, message #4 includes fourth information, and the fourth information is used to configure at least one timer. The at least one timer is related to a time length during which the first device waits before being covered by the first target satellite, for example, the time length of the timer is equal to, greater than, or less than the time length during which the first device waits before being covered by the first target satellite.

[0332] S907, the source satellite sends message #2.

[0333] Correspondingly, the ground network receives the message #2.

[0334] More description of S907 can refer to S806 in method 800 above, which will not be repeated here for brevity.

[0335] S908, the ground network sends the message #3.

[0336] Correspondingly, the second target satellite receives the message #3.

[0337] More description of S908 can refer to S807 in method 800 above, which will not be repeated here for brevity.

[0338] S909, the terminal device establishes a connection with the second target satellite.

[0339] More description of S909 can refer to S790 in method 700 above, which will not be repeated here for brevity.

[0340] In the embodiments of the present application, in the process of initiating registration or tracking area update by the terminal device through the source satellite, if the source satellite cannot complete the registration or tracking area update process, the terminal device can more accurately select a suitable target satellite according to the first information sent by the source satellite, and then continue registration or tracking area update through the target satellite.

[0341] It can be understood that some optional features in the embodiments of the present application can not depend on other features in some scenarios, or can be combined with other features in some scenarios, without limitation.

[0342] It can also be understood that in some embodiments described above, the sending of information is mentioned several times. For example, A sends information to B, which can include A directly sending information to B, or A sending information to B through other devices or network elements, without limitation.

[0343] It can also be understood that the schemes in the embodiments of the present application can be reasonably combined, and the explanations or descriptions of various terms appearing in the embodiments can be mutually referenced or explained in various embodiments, without limitation.

[0344] It can also be understood that the methods and operations implemented by the network element in each of the above method embodiments can also be implemented by components (such as chips or circuits) of the device, without limitation.

[0345] The method provided by the embodiments of the present application is described in detail above in combination with FIG. 7 to FIG. 9. The apparatus provided by the embodiments of the present application is described in detail below in combination with FIG. 10 to FIG. 12. It should be understood that the description of the apparatus embodiments corresponds to the description of the method embodiments, and therefore, the content not described in detail can be referred to the method embodiments described above, which will not be described here for brevity.

[0346] FIG. 10 is a schematic diagram of a communication apparatus 1000 provided by an embodiment of the present application. The apparatus 1000 includes a transceiver unit 1010 and a processing unit 1020. The transceiver unit 1010 can be configured to implement corresponding communication functions. The transceiver unit 1010 can also be referred to as a communication interface or a communication unit. The processing unit 1020 can be configured to perform processing. Optionally, the transceiver unit 1010 can include a receiving unit and a sending unit, the receiving unit being configured to implement the function of receiving, and the sending unit being configured to implement the function of sending.

[0347] Optionally, the apparatus 1000 can further include a storage unit, which can be configured to store instructions and / or data. The processing unit 1020 can read the instructions and / or data in the storage unit, so that the apparatus implements the foregoing method embodiments.

[0348] As a design, the apparatus 1000 is configured to perform the steps or processes performed by the apparatus in the foregoing method embodiments, the transceiver unit 1010 is configured to perform the transceiver-related operations on the apparatus side in the foregoing method embodiments, and the processing unit 1020 is configured to perform the processing-related operations on the apparatus side in the foregoing method embodiments.

[0349] In one possible implementation, the apparatus 1000 is configured to perform the steps or processes performed by the first apparatus in the embodiments shown in FIG. 7 to FIG. 9. Optionally, the transceiver unit 1010 is configured to receive first information, the first information including the identity and coverage range information of each of the at least one satellite; the processing unit 1020 is configured to determine at least one target satellite from the at least one satellite according to the first information, the terminal device being covered by the target satellite in the future; and the transceiver unit 1010 is further configured to send the information of the at least one target satellite.

[0350] In another possible implementation, the apparatus 1000 is configured to perform the steps or processes performed by the second apparatus in the embodiments shown in FIG. 7 to FIG. 9. Optionally, the transceiver unit 1010 is configured to send first information, the first information including the identity and coverage range information of each of the at least one satellite; and the transceiver unit 1010 is further configured to receive the information of at least one target satellite, the terminal device being covered by the target satellite in the future.

[0351] It should be understood that the specific process of each unit performing the corresponding steps has been described in detail in the foregoing method embodiments, and therefore, will not be described here for brevity.

[0352] It should also be understood that the apparatus 1000 is embodied in the form of a functional block diagram. The terminology used herein, such as "unit", can refer to an application specific integrated circuit (ASIC), an electronic circuit, a processor (for example, a shared processor, a dedicated processor, or a group processor, etc.) and a memory for executing one or more software or firmware programs, a combination of logic circuitry and / or other suitable components that support the described functions. In an optional example, those skilled in the art can understand that the apparatus 1000 can be embodied as the apparatus in the above embodiments (for example, the first apparatus, or the second apparatus), and can be used to execute the processes and / or steps corresponding to the apparatus in the above method embodiments. To avoid repetition, details are not described here.

[0353] The apparatus 1000 of each of the above schemes has a function of implementing the corresponding steps performed by the apparatus (for example, the first apparatus, or the second apparatus) in the above methods. The function can be implemented by 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 (for example, the transmitting 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 the processing unit, can be replaced by a processor, which respectively performs the transceiving operations and related processing operations in each of the method embodiments.

[0354] In addition, the transceiver unit 1010 can also be a transceiver circuit (for example, which can include a receiving circuit and a transmitting circuit), and the processing unit can be a processing circuit.

[0355] It should be noted that the apparatus in FIG. 10 can be the apparatus in the above embodiments, or a chip or a chip system, for example, a system on chip (SoC). The transceiver unit can be an input / output circuit, a communication interface; and the processing unit can be a processor or a microprocessor integrated on the chip or an integrated circuit. Here, no limitation is made.

[0356] FIG. 11 is a schematic diagram of another communication apparatus 1100 provided by the embodiments of the present application. The apparatus 1100 includes a processor 1110, and the processor 1110 is coupled with a memory 1120, the memory 1120 is used to store computer programs or instructions and / or data, and the processor 1110 is used to execute the computer programs or instructions stored in the memory 1120, or read the data stored in the memory 1120, to perform the methods in the above method embodiments.

[0357] Optionally, the processor 1110 is one or more.

[0358] Optionally, the memory 1120 is one or more.

[0359] Optionally, the memory 1120 is integrated with the processor 1110, or is separately arranged.

[0360] Optionally, as shown in FIG. 11, the apparatus 1100 further includes a transceiver 1130 for receiving and / or sending signals. For example, the processor 1110 is configured to control the transceiver 1130 to receive and / or send signals. Optionally, the transceiver 1130 can include a receiver and a transmitter, the receiver being configured to receive signals, and the transmitter being configured to send signals.

[0361] For example, the processor 1110 can have the functions of the processing unit 1020 shown in FIG. 10, the memory 1120 can have the functions of a storage unit, and the transceiver 1130 can have the functions of the transceiving unit 1010 shown in FIG. 10.

[0362] As an example, the apparatus 1100 is configured to implement operations performed by an apparatus (e.g., a first apparatus, or a second apparatus) in the various method embodiments.

[0363] For example, the processor 1110 is configured to execute computer programs or instructions stored in the memory 1120, to implement the related operations of an apparatus (e.g., a first apparatus, or a second apparatus) in the various method embodiments.

[0364] It should be understood that the processor mentioned in the embodiments of the present application can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor, or the processor can also be any conventional processor.

[0365] It should also be understood that the memory referred to in the embodiments of the application can be a volatile memory and / or a non-volatile memory. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically EPROM (EEPROM) or a flash memory. The volatile memory can be a random access memory (RAM). For example, the RAM can be used as an external cache. As an example but not limitation, the RAM includes the following various forms: static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM) and direct rambus RAM (DR RAM).

[0366] It should be noted that when the processor is a general processor, a DSP, an ASIC, a FPGA or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, the memory (storage module) can be integrated in the processor.

[0367] The apparatus in FIG. 11 can be the apparatus in the foregoing embodiments, or a chip or a chip system, for example, a system on chip (SoC). Among them, the transceiver can be an input / output circuit, a communication interface; the processor is a processor or microprocessor integrated on the chip or an integrated circuit. Herein, no limitation is made.

[0368] It should also be noted that the memory described herein is intended to include, but not limited to, these and any other suitable types of memory.

[0369] FIG. 12 is a schematic diagram of a chip system 1200 provided by an embodiment of the application. The chip system 1200 (or also can be referred to as a processing system) includes a logic circuit 1210 and an input / output interface 1220.

[0370] The logic circuit 1210 can be a processing circuit in the chip system 1200. The logic circuit 1210 can be coupled with a storage unit, and invoke instructions in the storage unit, so that the chip system 1200 can implement the methods and functions of the embodiments of the present application. The input / output interface 1220 can be an input / output circuit in the chip system 1200, and output information processed by the chip system 1200, or input data or signaling information to be processed by the chip system 1200.

[0371] Specifically, for example, if the terminal device is installed with the chip system 1200, the logic circuit 1210 is coupled with the input / output interface 1220, and the input / output interface 1220 can input the uplink resource configuration information to the logic circuit 1210 for processing. For another example, if the network device is installed with the chip system 1200, the logic circuit 1210 is coupled with the input / output interface 1220, and the input / output interface 1220 can output the uplink resource configuration information to the terminal device.

[0372] As a solution, the chip system 1200 is configured to implement operations performed by the apparatus (e.g., the first apparatus, or the second apparatus) in the above method embodiments.

[0373] For example, the logic circuit 1210 is configured to implement processing-related operations performed by the apparatus (e.g., the first apparatus, or the second apparatus) in the above method embodiments; and the input / output interface 1220 is configured to implement sending and / or receiving-related operations performed by the apparatus (e.g., the first apparatus, or the second apparatus) in the above method embodiments.

[0374] The embodiments of the present application also provide a computer readable storage medium, which stores computer instructions for implementing the method performed by the apparatus (e.g., the first apparatus, or the second apparatus) in the above method embodiments.

[0375] For example, the computer program is executed by a computer, so that the computer can implement the method performed by the apparatus (e.g., the first apparatus, or the second apparatus) in the above method embodiments.

[0376] The embodiments of the present application also provide a computer program product, which contains instructions, and the instructions are executed by a computer to implement the method performed by the apparatus (e.g., the first apparatus, or the second apparatus) in the above method embodiments.

[0377] The embodiments of the present application also provide a communication system, which includes the first apparatus and / or the second apparatus in the above embodiments.

[0378] The explanations and beneficial effects of the related contents in any of the above apparatuses can refer to the corresponding method embodiments provided above, and will not be repeated here.

[0379] In several embodiments provided in the present application, it should be understood that the disclosed apparatus and method can be implemented in other manners. For example, the described apparatus embodiments are merely schematic. For example, the division of the units is only a logical function division. There can be another division manner for the actual implementation, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections between different units, or the among different units, can be indirect couplings or communication connections through some interfaces, devices or units, and can be in electrical, mechanical or other forms.

[0380] In the embodiments described above, all or part of the embodiments can be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments can be implemented 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 the present application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. For example, the computer can be a personal computer, a server, 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 computer-readable storage medium, for example, the computer instructions can be transmitted from one website site, computer, server or data center to another website site, computer, server or data center through wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) manner. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. integrated with one or more available media. The available media can be magnetic media (such as floppy disk, hard disk, magnetic tape), optical media (such as DVD), or semiconductor media (such as solid state disk (SSD), etc. For example, the foregoing available media includes but is not limited to: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), magnetic or optical disk, etc. Various media that can store program codes.

[0381] The above describes only the specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A communication method characterized by comprising: The method is applied to a terminal device, and the method comprises: receiving first information, the first information comprising an identity and coverage information of each of at least one satellite; determining at least one target satellite of the at least one satellite according to the first information, the terminal device being covered by the target satellite in the future; sending information of each of the at least one target satellite.

2. The method of claim 1, wherein, After sending the information of each of the at least one target satellite, the method further comprises: receiving information of a first target satellite, the at least one target satellite comprising the first target satellite.

3. The method of claim 2, wherein, An end time of a time period during which a feeder link of the first target satellite is available is later than a start time of a time period during which a feeder link of a source satellite is available, the source satellite being a satellite currently serving the terminal device.

4. The method of claim 1, wherein, The method further comprises: The terminal device receives second information, the second information being used to determine available time information of a feeder link of each of the at least one satellite; The terminal device determines at least one target satellite of the at least one satellite according to the first information, comprising: The terminal device determines the at least one target satellite according to the first information and the second information, the terminal device being covered by the target satellite in the future, and an end time of a time period during which a feeder link of the target satellite is available being later than a start time of a time period during which a feeder link of a source satellite is available, the source satellite being a satellite currently serving the terminal device.

5. The method of claim 1, wherein, An end time of a time period during which a feeder link of each of the at least one satellite is available is later than a start time of a time period during which a feeder link of a source satellite is available, the source satellite being a satellite currently serving the terminal device.

6. The method according to any one of claims 1 to 5, characterized in that, Each of the at least one satellite supports a store-and-forward mode.

7. The method of claim 6, wherein, Before sending the information of each of the at least one target satellite, the method further comprises: receiving third information, the third information being used to indicate that a source satellite supports a store-and-forward mode, the source satellite being a satellite currently serving the terminal device.

8. The method of claim 6, wherein, Before sending the information of each of the at least one target satellite, the method further comprises: sending a first message, the first message being used to request a registration or tracking area update; receiving a second message, the second message being used to indicate that the registration or tracking area update cannot be completed.

9. The method of claim 8, wherein, The second message comprises an identity of each of at least one second satellite, the at least one satellite comprising the at least one second satellite, one or more of the at least one second satellite being unable to cover the terminal device in the future.

10. The method according to any one of claims 1 to 9, characterized in that, The method further comprises: receiving fourth information, the fourth information being used to configure a timer; before the at least one target satellite does not cover the terminal device, and / or before the timer expires, closing or deactivating or suspending an access layer.

11. The method according to any one of claims 1 to 10, characterized in that, The coverage range information of the first satellite comprises one or more of the following: a reference point of the coverage range of the first satellite and / or time information corresponding to the reference point, a radius of the coverage range of the first satellite, left and right elevation angle information of the coverage range of the first satellite, or ephemeris information of the first satellite; the first satellite is any one of the at least one satellite.

12. The method according to any one of claims 1 to 11, characterized in that, The information of the target satellite comprises an identifier of the target satellite and / or coverage time information of the target satellite covering the terminal device.

13. The method according to any one of claims 1 to 12, characterized in that, The first information is carried in broadcast signaling or dedicated signaling.

14. A communication method, comprising: Comprise: sending first information, the first information comprising an identifier and coverage range information of each satellite in at least one satellite, the coverage range information of a first satellite being used for the terminal device to predict whether the terminal device will be covered by the first satellite in the future, the first satellite being any one of the at least one satellite; receiving information of each target satellite in at least one target satellite, the terminal device being covered by the target satellite in the future.

15. The method of claim 14, wherein, The method further comprises: sending information of a first target satellite, the at least one target satellite comprising the first target satellite.

16. The method of claim 15, wherein, An end moment of a time period during which a feeder link of the first target satellite is available is later than a start moment of a time period during which a feeder link of a source satellite is available, the source satellite being a satellite currently providing service for the terminal device.

17. The method of claim 14, wherein, Before receiving the information of each target satellite in the at least one target satellite, the method further comprises: sending second information, the second information being used to determine available time information of a feeder link of each satellite in the at least one satellite; The terminal device is covered by the target satellite in the future, and an end moment of a time period during which a feeder link of the target satellite is available is later than a start moment of a time period during which a feeder link of a source satellite is available, the source satellite being a satellite currently providing service for the terminal device.

18. The method of claim 14, wherein, An end moment of a time period during which a feeder link of each satellite in the at least one satellite is available is later than a start moment of a time period during which a feeder link of a source satellite is available, the source satellite being a satellite currently providing service for the terminal device.

19. The method according to any one of claims 14 to 18, characterized in that, Each satellite in the at least one satellite supports a store-and-forward mode.

20. The method of claim 19, wherein, The method further comprises: sending third information, the third information being used to indicate that a source satellite supports a store-and-forward mode, the source satellite being a satellite currently providing service for the terminal device.

21. The method according to any one of claims 14 to 20, characterized in that, The coverage range information of the first satellite comprises one or more of the following: a reference point of the coverage range of the first satellite and / or time information corresponding to the reference point, a radius of the coverage range of the first satellite, left and right elevation angle information of the coverage range of the first satellite, or ephemeris information of the first satellite.

22. The method of any one of claims 14 to 21, wherein, The information of the target satellite comprises an identifier of the target satellite and / or coverage time information of the target satellite covering the terminal device.

23. The method of any one of claims 14 to 22, wherein, The first information is carried in broadcast signaling or dedicated signaling.

24. A communications device, characterized by Comprise a module or unit for performing the method of any one of claims 1 to 13.

25. A communications device, characterized by Comprise a module or unit for performing the method of any one of claims 14 to 23.

26. A communications device, characterized by The apparatus comprises at least one processor configured to execute computer programs or instructions to cause the apparatus to perform the method of any one of claims 1 to 13, or to cause the apparatus to perform the method of any one of claims 14 to 23.

27. The apparatus of claim 26, wherein, The apparatus further comprises a memory configured to store the computer programs or instructions; and / or, The apparatus further comprises a communication interface coupled to the at least one processor, the communication interface configured to input and / or output information.

28. A computer-readable storage medium, characterized in that, The computer readable storage medium stores computer programs or instructions which, when executed on a communication apparatus or a computer, cause the communication apparatus to perform the method of any one of claims 1 to 13, or cause the communication apparatus to perform the method of any one of claims 14 to 23.

29. A computer program product, characterised in that, The computer program product comprises computer programs or instructions for performing the method of any one of claims 1 to 13, or the computer program product comprises computer programs or instructions for performing the method of any one of claims 14 to 23.

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