Communication method and apparatus

Abstract

The present application provides a communication method and apparatus. The method comprises: a terminal sends a first message to a first network element, wherein the first network element is located in a first satellite; the terminal receives a second message from the first network element, the second message comprising first information, and the first information being used for triggering the terminal to enter a sleep state; and the terminal enters the sleep state on the basis of the first information. By using the method, the terminal can enter the sleep state on the basis of the second message, without needing to repeatedly send the first message, thereby reducing the power consumption of the terminal.

Description

Communication method and device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of the People's Republic of China on January 19, 2024, with application number 202410084594.2 and invention name "A Communication Method and Device", the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of communication technology, and in particular to a communication method and device. Background Art

[0004] Currently, communication links exist simultaneously between satellites and terminals, and between satellites and terrestrial core network equipment. Satellites can forward data or signaling from terminals to terrestrial core network equipment, and vice versa. Furthermore, communication links between satellites and terminals, and between satellites and terrestrial core network equipment, may not exist simultaneously. For example, satellites may not be able to cover both terminals and terrestrial core network equipment simultaneously.

[0005] When satellites cannot cover terminals and ground core network equipment at the same time, how to optimize the communication process between satellites and terminals, and between satellites and ground core network equipment, and improve communication efficiency is an issue worthy of attention. Summary of the Invention

[0006] The embodiments of the present application provide a communication method and apparatus for optimizing the communication process between a satellite and a terminal, and between a satellite and a ground core network device.

[0007] In a first aspect, the present application provides a communication method, which includes: a terminal sends a first message to a first network element, wherein the first network element is located on a first satellite; the terminal receives a second message from the first network element, the second message includes first information, and the first information is used to trigger the terminal to enter a sleep state; the terminal enters a sleep state according to the first information.

[0008] By adopting the above method, the terminal can enter the dormant state according to the second message, and there is no need to repeatedly send the first message, thereby saving the power consumption of the terminal.

[0009] In one possible design, the first information is capability information of the first network element, and the capability information of the first network element indicates that the first network element supports storage and forwarding; or, the first information indicates that there is no power feeding information between the first network element and the core network device.

[0010] In one possible design, the first message is a non-access stratum NAS message or uplink data.

[0011] In one possible design, the first message is a first registration request message; before the terminal enters a sleep state, the terminal sends a second registration request message to the first network element based on the first information.

[0012] In one possible design, the first message is a first registration request message; the second message also includes second information, and the second information is used to trigger the reporting of at least one parameter; before the terminal enters a sleep state, the terminal sends a second registration request message to the first network element according to the second information, and the second registration request message includes the at least one parameter.

[0013] With the above design, the terminal can send messages to the first network element multiple times.

[0014] In one possible design, after the terminal sends the second registration request message to the first network element, the terminal receives a third message from the first network element, where the third message is used to indicate that the first satellite no longer provides service for the terminal.

[0015] With the above design, the terminal may enter a dormant state or start the first timer after receiving the third message.

[0016] In one possible design, the second message or the third message includes information of a first timer; the first timer is used to indicate the length of time the terminal is in a sleep state; after the first timer times out, the terminal resends the first message.

[0017] In one possible design, the second message also includes third information, and the third information is used to determine a second satellite, which is the next satellite to serve the terminal; the terminal receives a broadcast message; the broadcast message indicates the satellite covering the terminal; the terminal determines that the satellite indicated by the broadcast message is the second satellite based on the third information; the terminal resends the first message to a second network element, and the second network element is located at the second satellite.

[0018] With the above design, the terminal can listen to the broadcast message, and determine that the satellite covering the terminal is the second satellite based on the third information, and resend the first message to the second network element.

[0019] In one possible design, the third information includes an identifier of the second network element, an identifier of the second satellite, or at least one of identifiers of other devices located on the second satellite, wherein the second network element supports storage and forwarding.

[0020] In one possible design, the second satellite covers the terminal earlier than the first satellite, and when there is a communication link between the first satellite and the core network device, there is also a communication link between the second satellite and the core network device, and the core network device is located on the ground.

[0021] In a second aspect, the present application provides a communication method, which includes: a first network element receives a first message from a terminal, wherein the first network element is located on a first satellite; when there is no communication link between the first network element and a core network device, the first network element sends a second message to the terminal, the second message includes first information, and the first information is used to trigger the terminal to enter a sleep state, and the core network device is located on the ground.

[0022] With the above design, if the first network element determines that there is no communication link between it and the core network device, it can notify the terminal to enter a dormant state.

[0023] In one possible design, the first information is capability information of the first network element, and the capability information of the first network element indicates that the first network element supports storage and forwarding; or, the first information indicates that there is no power feeding information between the first network element and the core network device.

[0024] In one possible design, the first message is a NAS message or uplink data.

[0025] In one possible design, the first message is a first registration request message; after the first network element sends a second message to the terminal, the first network element receives a second registration request message from the terminal.

[0026] In one possible design, the first network element determines second information based on the first registration request message, and the second information is used to trigger reporting of at least one parameter; the second message also includes second information; and the second registration request message includes the at least one parameter.

[0027] With the above design, the first network element can parse the first registration message and notify the terminal of the parameters that need to be uploaded.

[0028] In one possible design, when there is a communication link between the first network element and the core network device, the first network element sends a third registration request message to the core network device, wherein the third registration request message is determined based on the first registration request message and the second registration request message.

[0029] With the above design, the first network element can merge the received NAS messages.

[0030] In one possible design, after the first network element receives the second registration request message from the terminal, the first network element sends a third message to the terminal, where the third message is used to indicate that the first satellite no longer provides service for the terminal.

[0031] With the above design, the first network element can notify the first network element that the terminal is no longer covered.

[0032] In one possible design, the second message or the third message also includes information of a first timer; the first timer is used to indicate the length of time the terminal is in a sleep state.

[0033] In one possible design, the second message also includes third information, and the third information is used to determine the second satellite, which is the next satellite to serve the terminal; the first network element determines the third information based on ephemeris information, the location information of the terminal, and at least one of the receiving beam information of the first message.

[0034] With the above design, the first network element can determine the next satellite to provide services to the terminal.

[0035] In one possible design, the third information includes an identifier of a second network element, an identifier of the second satellite, or at least one of identifiers of other devices located on the second satellite, wherein the second network element is located on the second satellite and the second network element supports storage and forwarding.

[0036] In one possible design, the receiving beam information includes at least one of receiving time information, beam angle, beam identifier, or physical deployment location information of the satellite where the beam is located.

[0037] In one possible design, the second satellite covers the terminal earlier than the first satellite, and when a communication link exists between the first satellite and the core network device, a communication link also exists between the second satellite and the core network device.

[0038] In one possible design, when a communication link exists between the first network element and the core network device, the first network element sends the third information to the core network device.

[0039] In a third aspect, the present application provides a communication method, which includes: a first network element receives a first identifier and a first message from a first access device; the first message is used for a terminal to request registration with a network, the first identifier is used to trigger the first network element to assign a second identifier to the terminal, and the first network element and the first access device are located on a first satellite; the first network element assigns a second identifier to the terminal based on the first identifier and information of the first satellite, and the second identifier is used to identify the terminal; when there is a communication link between the first network element and a core network device, the first network element sends the first message and the second identifier to the core network device, wherein the core network device is located on the ground.

[0040] The above method ensures that the terminal registration process can be completed even when there is no communication link between the satellite and the core network equipment. In this case, the first network element can assign a second identifier to the terminal even without the ability to parse NAS messages. The core network equipment can also combine various information to determine the next satellite to provide service to the terminal, thereby improving message forwarding efficiency and shortening the registration process.

[0041] In one possible design, before the first network element assigns a second identifier to the terminal based on the first identifier and the identifier of the first satellite, the first network element determines that the number of terminals that have accessed the first satellite is less than a preset threshold.

[0042] In one possible design, the information of the first satellite includes an identifier of the first satellite, an identifier of the first network element, an identifier of the first access device, or one or more items in a prefix address pool corresponding to the first satellite.

[0043] In one possible design, the first network element allocates storage space for the terminal, where the storage space is used to store uplink messages from the terminal and / or downlink messages of the terminal, and the storage space corresponds to the second identifier.

[0044] In one possible design, the first network element receives a second message and the second identifier sent from the core network device; the first network element saves the second message based on the first identifier; when there is a communication link between the first network element and the terminal, the first network element sends the second message to the terminal.

[0045] With the above design, the first network element can forward the message based on the second identifier.

[0046] In one possible design, the first network element sends the second identifier to the terminal; the first network element receives a third message and the second identifier from the terminal; the first network element saves the third message based on the first identifier; when there is a communication link between the first network element and the core network device, the first network element sends the third message to the core network device.

[0047] With the above design, the first network element can forward the message based on the second identifier.

[0048] In one possible design, the first identifier is a cell radio network temporary identifier C-RNTI.

[0049] In one possible design, when a communication link exists between the first network element and the terminal, the first network element sends information of a first timer to the terminal; the first timer indicates the length of time the terminal is in a sleep state.

[0050] In one possible design, when a communication link exists between the first network element and the core network device, the first network element also sends the remaining value of the first timer to the core network device.

[0051] In a fourth aspect, the present application provides a communication method, the method including: a core network device receives a first message and a second identifier from a first network element, the second identifier being used to indicate the terminal, wherein the first network element is located on a first satellite and the core network device is located on the ground; the core network device determines a second satellite, which is the next satellite to provide services to the terminal; wherein the core network device determines the second satellite based on ephemeris information and the location information of the terminal; or, the core network device sends ephemeris information and the location information of the terminal to a computing device, the core network device receives indication information from the computing device, the indication information indicating the second satellite; the core network device sends a second message and the second identifier to the second network element based on the first message, wherein the second network element is located on the second satellite.

[0052] By adopting the above method, the core network device can determine the next satellite to provide services for the terminal and forward the message to be sent to the terminal via the satellite.

[0053] In one possible design, the core network device receives the remaining value of the first timer from the first network element, where the first timer indicates the length of time the terminal is in a sleep state; the core network device determines the second satellite based on the ephemeris information and the location information of the terminal; the core network device determines the second satellite based on the ephemeris information, the location information of the terminal, and the remaining value of the first timer.

[0054] With the above design, the core network device can determine the next satellite to provide services to the terminal based on the remaining value of the first timer.

[0055] In one possible design, the core network device receives the remaining value of the first timer from the first network element, where the first timer indicates the length of time the terminal is in a sleep state; the core network device also sends the remaining value of the first timer to the computing device.

[0056] In one possible design, the second network element supports store-and-forward.

[0057] In one possible design, the core network device receives capability information of the second network element from the second network element, and the capability information of the second network element indicates that the second network element supports storage and forwarding.

[0058] In one possible design, the second satellite covers the terminal earlier than the first satellite, and when a communication link exists between the first satellite and the core network device, a communication link also exists between the second satellite and the core network device.

[0059] In one possible design, the first message is used by the terminal to request registration with the core network device, and the second message is a response message to the first message.

[0060] In one possible design, the core network device receives capability information of the first network element from the first network element, and the capability information of the first network element indicates that the first network element supports storage and forwarding.

[0061] In a fifth aspect, the present application provides a communication device, which may be a first device, or a module or unit (for example, a chip, or a chip system, or a circuit) in the first device that corresponds one-to-one to the method / operation / step / action described in any one of the first to fourth aspects, or a device that can be used in combination with the first device.

[0062] In a sixth aspect, the present application provides a communication device comprising at least one processing element and at least one storage element, wherein the at least one storage element is used to store programs and data, and the at least one processing element is used to read and execute the programs and data stored in the storage element, so that the method described in any one of the first to fourth aspects of the present application is implemented.

[0063] In a seventh aspect, the present application further provides a computer program, which, when executed on a computer, enables the computer to execute any one of the methods described in any one of the first to fourth aspects above.

[0064] In an eighth aspect, the present application provides a communication device comprising: an interface circuit and at least one processor; the interface circuit is used to provide input and / or output of programs or instructions to the at least one processor; the at least one processor is used to execute the programs or instructions so that the communication device can implement any of the methods described in any one of the first to fourth aspects above.

[0065] In one possible manner, the communication device includes the at least one memory, and the at least one memory is used to store the program or instruction.

[0066] In a ninth aspect, the present application provides a computer storage medium storing a software program. When the software program is read and executed by one or more processors, the software program can implement any of the methods described in any one of the first to fourth aspects above.

[0067] In a tenth aspect, the present application provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute any one of the methods described in any one of the first to fourth aspects above.

[0068] In the eleventh aspect, the present application provides a chip system, which includes at least one chip and a memory, and the at least one chip is used to read and execute the program stored in the memory to implement any one of the methods described in any one of the first to fourth aspects above.

[0069] In the twelfth aspect, the present application provides a communication system, which includes a first network element, a terminal, a first access network device and a core network device, wherein the terminal executes the first aspect, the first network element executes the uplink second aspect, the method described in any one of the third aspects, and the core network device executes the method described in any one of the fourth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] FIG1A shows a schematic diagram of a 5G network architecture based on a service-oriented architecture;

[0071] FIG1B shows a 4G network system architecture diagram;

[0072] FIG2 shows a schematic diagram of the structure of a satellite network;

[0073] FIG3A is a schematic diagram showing a satellite and a terminal satellite and a core network device having communication links at the same time;

[0074] FIG3B is a schematic diagram showing a satellite and a terminal satellite and a core network device having communication links at the same time;

[0075] FIG4A shows an overview flow chart of a communication method;

[0076] FIG4B shows an overview flow chart of another communication method;

[0077] FIG5 shows an overview flow chart of yet another communication method;

[0078] FIG6A shows one of the initial registration flow charts in a 4G scenario;

[0079] FIG6B shows one of the initial registration flow charts in a 4G scenario;

[0080] FIG7A shows a second flowchart of the initial registration process in a 4G scenario;

[0081] FIG7B shows a second flowchart of the initial registration process in a 4G scenario;

[0082] FIG8 shows the third initial registration flow chart in the 4G scenario;

[0083] FIG9A shows one of the initial registration flow charts in a 5G scenario;

[0084] FIG9B shows one of the initial registration flow charts in a 5G scenario;

[0085] FIG10 shows the second initial registration flow chart in the 5G scenario;

[0086] FIG11 shows a flow chart of a session establishment process;

[0087] FIG12 shows a schematic structural diagram of a communication device;

[0088] FIG13 shows a schematic structural diagram of a communication device. DETAILED DESCRIPTION

[0089] The specific implementation of the present application is described below with reference to the accompanying drawings in the embodiments of the present application. However, the implementation of the present application may also include combining these embodiments without departing from the spirit or scope of the present application, such as adopting other embodiments and making structural changes. Therefore, the detailed description of the following embodiments should not be understood in a restrictive sense. The terms used in the examples section of the present application are only used to explain the specific embodiments of the present application and are not intended to limit the present application.

[0090] The embodiments of the present application can be applied to various communication systems, such as: global system for mobile communications (GSM) system, code division multiple access (CDMA) system, wideband code division multiple access (WCDMA) system, general packet radio service (GPRS), long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD), universal mobile telecommunication system (UMTS), world-wide interoperability for microwave access (WIMAX) communication system, fifth generation (5G) system or new radio (NR), or applied to future communication systems or other similar communication systems.

[0091] Figure 1A is a schematic diagram of a 5G network architecture based on a service-oriented architecture. The 5G network architecture shown in Figure 1A may include terminal devices, access devices, and core network devices. The terminal device accesses the data network (DN) through the access device and the core network device. Among them, the core network device includes a variety of network functions (NFs) or network elements, for example, including some or all of the following network elements: unified data management (UDM) network element, unified data repository (UDR) network element, application function (AF) network element, policy control function (PCF) network element, access and mobility management function (AMF) network element, session management function (SMF) network element, user plane function (UPF) network element, etc.

[0092] Terminals, also known as terminal devices, can include various handheld devices with wireless communication capabilities, vehicle-mounted devices, wearable devices, computing devices, or other processing devices connected to a wireless modem. Terminal devices can also be called terminals. Terminal equipment may also refer to user equipment (UE), access terminal, subscriber unit, user agent, cellular phone, smart phone, wireless data card, personal digital assistant (PDA), tablet computer, wireless modem, handheld device, laptop computer, smart point of sale (POS), customer-premises equipment (CPE), machine type communication (MTC) terminal, communication equipment carried by high-altitude aircraft, wearable device, drone, robot, terminal in D2D, terminal in vehicle to everything (V2X), virtual reality (VR) terminal device, augmented reality (AR) terminal device, wireless terminal in industrial control, wireless terminal in self-driving, wireless terminal in remote medical, wireless terminal in smart grid, wireless terminal in transportation security, etc. Wireless terminals in smart cities, smart homes, satellite-specific terminals, or terminal devices in future communication networks, etc.

[0093] Access equipment can also be called access network equipment, base stations, or radio access network (RAN). The RAN manages radio resources, provides access services to user devices, and forwards user device data between the user device and the core network. The RAN can also be understood as a base station in the network.

[0094] Exemplarily, the access device in the embodiment of the present application may be any communication device with wireless transceiver functionality for communicating with user equipment. The access device includes but is not limited to: evolved Node B (eNB), radio network controller (RNC), Node B (NB), base station controller (BSC), base transceiver station (BTS), home evolved NodeB (HeNB, or home Node B, HNB), baseband unit (BBU), access point (AP) in wireless fidelity (WIFI) system, wireless relay node, wireless backhaul node, transmission point (TP) or transmission and reception point (TRP), etc., and can also be a 5G mobile communication system, such as a gNB in ​​an NR system, or a transmission point (TRP or TP), one or a group of (including multiple antenna panels) antenna panels of a base station in a 5G mobile communication system, or it can also be a network node constituting a gNB or a transmission point, such as a baseband unit (BBU) or a distributed unit (DU), etc.

[0095] In some deployments, a gNB may include a centralized unit (CU) and a DU. The gNB may also include an active antenna unit (AAU). The CU implements some gNB functions, while the DU implements some gNB functions. For example, the CU is responsible for processing non-real-time protocols and services, implementing the functions of the radio resource control (RRC) and packet data convergence protocol (PDCP) layers. The DU is responsible for processing physical layer protocols and real-time services, implementing the functions of the radio link control (RLC), media access control (MAC), and physical (PHY) layers. The AAU implements some physical layer processing functions, RF processing, and active antenna-related functions. RRC layer information is generated by the CU and ultimately encapsulated by the DU's PHY layer into PHY layer information, or is converted from PHY layer information. Therefore, in this architecture, higher-layer signaling, such as RRC layer signaling, can also be considered to be sent by the DU, or by a combination of the DU and the AAU. It is understood that the access device may be a device including one or more of a CU node, a DU node, and an AAU node. In addition, the CU may be classified as an access device in an access network, or as an access device in a core network (CN), which is not limited in this application.

[0096] Data networks, used to provide services such as operator services, Internet access, or third-party services, include servers that implement video source encoding and rendering.

[0097] The following is a brief introduction to some core network equipment:

[0098] 1. User plane network element: Serves as the interface with the data network, completing functions such as user plane data forwarding, session / flow-level billing and statistics, and bandwidth limiting. This includes packet routing and forwarding, as well as quality of service (QoS) processing for user plane data.

[0099] 2. Access and mobility management: This function is mainly used for mobility management and access management. In addition, it is also responsible for delivering user policies between terminals and PCF network elements.

[0100] 3. Session management network element: mainly used for session management, which is used for session management after user access, including PDU session establishment, modification, activation, deactivation, and release, etc., including execution of session management, execution of PCF-delivered control policies, UPF selection, and Internet Protocol (IP) address allocation for terminal devices.

[0101] 4. Policy control network element: mainly used to manage network behavior with a unified policy framework, provide policy rules to the control plane function (AMF, SMF) and access contract information related to policy decisions in UDR.

[0102] 5. Unified data management network element: mainly used to generate authentication certificates, unified management of data related to access authorization based on contract information, service NF registration management, contract information management, etc.

[0103] 6. Unified Data Repository: Mainly used for UDM to store and obtain contract data, PCF to store and obtain policy data, store and use structured data for capability exposure, and store application data for application detection.

[0104] Figure 1B is a schematic diagram of a 4G network architecture, which may include terminal equipment (eg, UE), access equipment (eg, eNB), and core network equipment.

[0105] The S-GW is the local access gateway for user terminals, the P-GW is the gateway for user terminals to access external data networks, and the policy and charging rules function (PCRF) serves as the control node for QoS and charging policies. The functions of the home subscriber server (HSS) are similar to those of the UDM network element, the functions of the serving gateway (S-GW) and the packet data network (PDN) gateway (P-GW) are similar to those of the UPF network element, the access control and mobility management functions in the MME are similar to those of the AMF, and the functions of the PCRF are similar to those of the PCF.

[0106] It can be understood that the above network elements are examples of one implementation method, and this application does not exclude the existence of network elements or devices with the above network element functions in future wireless communication systems with other names or other forms.

[0107] It is understood that the above-mentioned network element or function can be a network element in a hardware device, a software function running on dedicated hardware, or a virtualized function instantiated on a platform (e.g., a cloud platform). As a possible implementation method, the above-mentioned network element or function can be implemented by a single device, or can be implemented by multiple devices together, or can be a functional module within a single device, which is not specifically limited in the embodiments of the present application.

[0108] In Figure 1, Nudr, Npcf, Namf, Nudm, and Nsmf are the service interfaces provided by the above-mentioned UDR, PCF, AMF, UDM, and SMF, respectively, which are used to call corresponding service operations.

[0109] The following is a brief introduction to the technical terms involved in this application:

[0110] 1. Ephemeris information

[0111] Ephemeris, also known as ephemeris, almanac, etc., is information used to locate the position of celestial bodies at any time. Ephemeris information refers to some information related to the satellite constellation. In general, it can include the satellite's three-dimensional spatial position information, velocity state vector information, satellite orbit information, etc. Specifically, this information can be divided into the satellite's position and velocity state vector, orbital plane parameters, and satellite level parameters. For example, the basic elements (parameters) of the satellite ephemeris of the 3rd Generation Partnership Project (3GPP) RAN Working Group at the RAN2#108 meeting are shown in Table 1 below.

[0112] Table 1

[0113] The ascending node is the point where the satellite intersects the Earth's equatorial plane when it passes through it from south to north. The argument of perigee is the angle from the ascending node to the perigee within the satellite's orbital plane, measured in the direction of the satellite's movement. Its value ranges from 0 to 360 degrees.

[0114] It should be understood that Table 1 is only an example of some specific parameters that the ephemeris parameters may include. In the embodiment of the present application, the ephemeris information may not include one or more of the above parameters, and may also include other types of parameters. The embodiment of the present application does not limit the specific content of the ephemeris information.

[0115] It should also be understood that in the embodiments of the present application, the ephemeris information may also be referred to as ephemeris parameters, ephemeris parameters of a satellite, ephemeris parameters of a satellite in a satellite access network, ephemeris parameters of a satellite in a satellite return trip, or other possible names, and the present application does not limit this.

[0116] The ephemeris information occupies a large space, and is generally configured in a pre-configured manner. In some embodiments of the present application, the ephemeris information can be pre-configured for network elements on satellites or network elements on the ground.

[0117] 2. Ground cover information

[0118] Ground coverage information, also known as satellite ground coverage information, satellite coverage information, satellite reachable information, satellite available information or satellite coverage available information, etc. Ground coverage information can represent the area on the ground that can be covered by a certain satellite signal. Exemplarily, the ground coverage information may include: for each area in one or more areas (such as grid points, matrix area maps, business area ranges), the time point when one or more satellites cover the area, or the time period when one or more satellites cover the area. For example, for the first business area and the first satellite that can cover the area, the ground coverage information includes the time point information when the first satellite covers the first business area. The time point can be the starting time of entry and the duration of coverage, or the time period information when the first satellite covers the first business area.

[0119] The ground coverage information of a satellite can be determined through the ephemeris information. That is, there is a mapping relationship between the ephemeris information and the ground coverage information. For example, the ground coverage information 1 of satellite A can be determined through the ephemeris information 1 of satellite A.

[0120] 3. Feeder link connection information

[0121] Feeder link connection information, also referred to as feed information, describes the status of the signal path between onboard network elements (e.g., onboard RAN, onboard store and forward (S&F)) and the gateway (ground station). For example, it describes whether the path is unobstructed. If both the transmitted and received signals can reach each other, the path is considered unobstructed. If at least one of the two signals fails to reach the other, the path is considered unobstructed.

[0122] In a possible implementation of the embodiment of the present application, the feed information may be signal strength information. For example, when the satellite-borne RAN receives a signal from a gateway station and the signal strength becomes stronger and stronger and reaches a set threshold, it can be considered that the signal channel between the satellite-borne RAN and the gateway station is unobstructed, or that the satellite enters the area covered by the gateway station; when the satellite-borne RAN perceives that the signal strength with the gateway station is getting weaker and weaker and is lower than the set threshold, it can be considered that the signal channel between the satellite-borne RAN and the gateway station is not unobstructed, or that the satellite leaves (or moves out of) the area covered by the gateway station. Furthermore, the satellite-borne RAN can send information on whether the feed link channel is unobstructed or not to satellite-borne devices such as the satellite S&F through the satellite's internal connection / interface.

[0123] In another possible implementation of the embodiment of the present application, the feeding information can also be perceived by a satellite-borne router or a satellite-borne S&F. When the feeding link between the satellite and the gateway station is through laser communication, the router or the satellite-borne S&F can perceive the laser communication status on the link, and then send the perceived information on whether the channel of the feeding link is unobstructed or not to the satellite-borne RAN and other satellite-borne devices through the internal connection / interface of the satellite.

[0124] In the present application, one or more onboard devices can be deployed on a satellite at the same time. For example, a network element with a store-and-forward function (e.g., onboard S&F) and an access device (e.g., onboard RAN) can be deployed on a satellite, wherein the network element with a store-and-forward function and the access device can be set up together or separately, that is, the store-and-forward function can be understood as having some functions of an access device and having an extended and enhanced storage capacity. Alternatively, the network element with a store-and-forward function can be understood as a core network device, for example, the network element with a store-and-forward function can also have some functions of a mobility management entity (MME) or an AMF network element or some functions of a UPF network element or an S-GW network element.

[0125] The following description uses the independent configuration of a store-and-forward network element as an example. An interface exists between the store-and-forward network element and the access device. This interface supports communication between the store-and-forward network element and the access device. For example, the access device can send signaling (e.g., non-access stratum (NAS) messages) or data to the store-and-forward network element. Simultaneously, the store-and-forward network element can also send stored NAS messages or data to the access device.

[0126] Unless otherwise specified, in this application, network elements and access devices with store-and-forward functions are deployed on satellites. Ground core network equipment is hereinafter referred to as core network equipment and is deployed on the ground.

[0127] A network element with store-and-forward functionality can sense the air interface connection information between the access device and the terminal, as well as the power feed information between the satellite and the ground gateway. In other words, a network element with store-and-forward functionality can determine whether a communication link exists with the terminal or with core network equipment. Alternatively, it can be described as determining whether normal communication with the terminal or with core network equipment is possible.

[0128] As shown in Figure 2, satellite 1 is equipped with onboard RAN1 and S&F1. Satellite 2 is equipped with onboard RAN2 and S&F2. Satellite 3 is equipped with onboard RAN3 and S&F3. Satellites 1, 2, and 3 can determine whether a communication link exists with any UE from UE1 to UE100. Satellites 1, 2, and 3 can also determine whether a communication link exists with any ground station from ground station 1 to ground station 2. Ground stations, also known as ground gateways or satellite gateways (also called transmission or hubs), connect satellites and terrestrial networks.

[0129] Generally, each terminal can communicate with a single satellite covering it. If multiple satellites cover the terminal, the terminal generally communicates with only one satellite. If at least one satellite covers a gateway connected to a core network device, and the core network device can connect to one or more gateways, the core network device can communicate with some or all of the at least one satellite.

[0130] As shown in Figure 3A, when communication links exist between the satellite and the terminal (e.g., UE1) and the satellite and the core network device (e.g., MME) at the same time, the satellite can forward the signaling or data received from the terminal to the core network device, and forward the signaling or data received from the core network device to the terminal.

[0131] As shown in Figure 3B, there are no simultaneous communication links between the satellite and the terminal, or between the satellite and the core network device (or gateway). Alternatively, there are only single-sided links between the satellite and the terminal, or between the satellite and the core network device (or gateway).

[0132] As shown in Figure 3B, there are no simultaneous communication links between the satellite and UE1, and between the satellite and the core network device. However, there are simultaneous communication links between the satellite and UE2, and between the satellite and the core network device. In this application, the simultaneous communication links between the satellite and the terminal, and between the satellite and the core network device, mean that for a certain terminal, when the satellite covers the terminal, the satellite does not simultaneously cover the core network device. Therefore, the message sent by the terminal to the core network device cannot be forwarded to the core network device in a timely manner via the satellite. When the satellite covers the core network device, the satellite cannot simultaneously cover the terminal, but the satellite may cover other terminals. Therefore, the message sent by the core network device to the terminal cannot be forwarded to the terminal in a timely manner via the satellite.

[0133] For example, when a communication link exists between the satellite and a terminal but not between the satellite and the core network device, the satellite (e.g., a network element deployed on the satellite with store-and-forward functionality) can receive signaling or data from the terminal via the access device and store the received content. As the satellite rotates, when a communication link exists between the satellite and the core network device but not between the satellite and the terminal, the satellite can forward the stored content to the core network device.

[0134] Similarly, when a communication link exists between the satellite and core network equipment but not between the satellite and the terminal, the satellite can also receive signaling or data from the core network equipment and store the received content. As the satellite rotates, when a communication link exists between the satellite and the terminal but not between the satellite and the core network equipment, the satellite can forward the stored content to the terminal via the access device.

[0135] A network element with store-and-forward functionality can parse received signaling, i.e., has the ability to parse signaling. For example, the network element can specifically parse NAS messages. Alternatively, a network element with store-and-forward functionality does not parse received signaling, i.e., does not have the ability to parse signaling. For example, the network element only transparently transmits NAS messages but does not parse them.

[0136] The fact that communication links do not exist between the satellite and the terminal, or between the satellite and the core network equipment at the same time can also be understood as: the coverage provided by the satellite can cover the terminal and the core network equipment at the same time, but there is an abnormality in the link between the satellite and the terminal or the gateway, such as the communication link between the satellite and the terminal is normal, while the communication link between the satellite and the core network equipment is faulty; or, the communication link between the satellite and the terminal is faulty, while the communication link between the satellite and the core network equipment is normal.

[0137] Based on the above network system architecture and the related technical descriptions, the embodiments of the present application provide several possible communication methods. The entities involved in each communication method include a terminal, a first network element, a first access device, a core network device, and the like. For example, the terminal may be any one of UE1 to UE100 in Figure 2 . The first network element may be the satellite-based S&F in Figure 2 , the first access device may be the satellite-based RAN in Figure 2 , and the core network device may be the MME or AMF in Figure 2 . Furthermore, it should be understood that the above entities may also be replaced by a communication device having the corresponding entity functions, or a chip, unit, or module within a communication device having the corresponding entity functions. For example, the terminal may also be replaced by a communication device having terminal functions, or a chip, unit, or module within a communication device having terminal functions. In the following embodiments, the first network element and the first access device are located on the first satellite. The second network element and the second access device are located on the second satellite. Core network devices such as the MME and AMF are located on the ground.

[0138] The present application provides a communication method for completing the terminal registration process when there is no communication link between the satellite and the core network device at the same time. As shown in Figures 4A and 4B, the method includes:

[0139] Step 400: The terminal sends a first message to a first access device.

[0140] The first message is used by the terminal to request registration with the network. Exemplarily, the first message is a NAS message.

[0141] For example, the first message is an attach request, and the attach message includes one or more of an international mobile subscriber identity (IMSI), capability information of the terminal, and location information of the terminal.

[0142] For another example, the first message is a registration request, and the attach message includes a user hidden identifier (SUCI), capability information of the terminal, location information of the terminal, and the like.

[0143] The UE capability information may indicate whether the terminal supports a network element with a store-and-forward function.

[0144] Step 410: The first access device allocates a first identifier to the terminal, wherein the first identifier is used to trigger the first network element to allocate a second identifier to the terminal.

[0145] Exemplarily, the first identifier is used to identify a terminal accessing the first access device. For example, the first identifier is used to identify a terminal in a cell of the first access device, and the terminal is in a random access success state. For example, the first identifier is a cell-radio network temporary identifier (C-RNTI).

[0146] Step 420: The first access device sends a first identifier and a first message to the first network element.

[0147] Step 430: The first network element allocates a second identifier to the terminal according to the first identifier and information of the first satellite, where the second identifier is used to identify the terminal.

[0148] The second identifier is a unique identifier for identifying the terminal in the satellite network where the first network element is located. In addition, the second identifier can also reduce the exposure of the IMSI or SUCI and improve communication security.

[0149] It is understood that the first identifier may be a unique identifier used to identify a terminal within a single access device. For example, the first identifier assigned by the first access device to UE1 is different from the first identifier assigned by the first access device to UE2, but the first identifier assigned by the first access device to UE1 may be the same as the first identifier assigned by the second access device to UE3. Therefore, the first access device needs to notify the first network element to assign a second identifier to the terminal.

[0150] Exemplarily, the information of the first satellite includes one or more of an identifier of the first satellite, an identifier of the first network element, an identifier of the first access device, or a prefix address pool corresponding to the first satellite.

[0151] In one possible implementation, if the information about the first satellite includes at least one of an identifier of the first satellite, an identifier of the first network element, and an identifier of the first access device, the first network element may determine the second identifier based on the first identifier and the information about the first satellite. The first network element may further store a correspondence between the first identifier and the second identifier.

[0152] For example, if the information of the first satellite includes the identifier of the first satellite, the second identifier can be determined according to the first identifier and the identifier of the first satellite, for example, the second identifier=the first identifier+the identifier of the first satellite.

[0153] In a possible implementation, if the information of the first satellite includes a prefix address pool corresponding to the first satellite, the first network element determines to allocate a second identifier for the terminal according to the first identifier, and selects an unallocated prefix address from the prefix address pool as the second identifier.

[0154] Among them, the prefix address pool corresponding to the first satellite can also be called the prefix address segment corresponding to the first satellite, and can also be called the terminal identification range interval corresponding to the first satellite, or the address pool corresponding to the first satellite. The prefix address pool corresponding to the first satellite can be pre-configured. The prefix address pools corresponding to different satellites are different to ensure that the second identifier only identifies one terminal, that is, the identifiers allocated by the first satellite (for example, the first network element) and other satellites (for example, network elements with storage and forwarding functions on other satellites) do not conflict. Exemplarily, each satellite (that is, a network element with storage and forwarding functions on each satellite) can maintain the allocated prefix addresses and / or unallocated prefix addresses so that the prefix addresses subsequently allocated to other terminals do not conflict with the allocated prefix addresses.

[0155] Furthermore, in one possible implementation, before the first network element assigns the second identifier to the terminal, the first network element may further determine whether the number of terminals that have accessed the first satellite is less than a preset threshold. If the number of terminals that have accessed the first satellite is greater than or equal to the preset threshold, the first network element may send a rejection message to the terminal. After receiving the rejection message, the terminal may wait for another satellite to provide service. If the number of terminals that have accessed the first satellite is less than the preset threshold, the first network element may assign the second identifier to the terminal.

[0156] The number of connected terminals can be understood as the number of terminal entries stored by the first network element, the number of second identifiers allocated by the first network element, or the number of terminals that have established RRC connections with the first access device. The number of stored terminal entries can also be understood as the number of terminals to which the stored messages belong. For example, if the first network element stores message 1, message 2, and message 3, where message 1 and message 2 are from UE1 and message 3 is from UE2, then the number of stored terminal entries is 2.

[0157] In one possible implementation, after the first network element assigns the second identifier to the terminal, the first network element further assigns storage space to the terminal, where the storage space is used to store uplink messages from the terminal and / or downlink messages of the terminal, and the storage space corresponds to the second identifier. Exemplarily, the first network element stores the first message in the storage space corresponding to the terminal.

[0158] In addition, after the first network element assigns the second identifier to the terminal, the first network element may also send the second identifier to the terminal. The terminal saves the second identifier. Furthermore, the terminal may also send a third message and the second identifier to the first network element. The first network element saves the third message based on the second identifier. Exemplarily, the first network element saves the third message to the storage space corresponding to the terminal based on the second identifier. When a communication link exists between the first network element and the core network device, the first network element may also send a third message to the core network device. The existence of a communication link between the first network element and the core network device can be understood as the first satellite no longer covering the terminal as the first satellite moves, and the first satellite covers the core network device.

[0159] It is understood that before the first satellite loses coverage of the terminal, the first network element may receive one or more messages from the terminal. For example, the first network element may receive a first message, or the first network element may receive a first message and a third message from the same terminal. When the first network element receives multiple messages, it stores the multiple messages in sequence, that is, in the order in which the messages arrive at the first network element. Exemplarily, the multiple messages are stored in sequence in the storage space corresponding to the terminal. When a communication link exists between the first network element and a core network device, the first network element may send the stored messages to the core network device in sequence.

[0160] For example, the first network element first receives the first message and then receives the third message. When there is a communication link between the first network element and the core network device, the first network element can first send the first message to the core network device and then send the third message.

[0161] Exemplarily, the first message is a first registration request message, and the third message is a second registration request message. The second registration request message may be a supplement to the first registration request message. For example, the second registration request message may include all parameters required for the registration process, or the second registration request message may be a supplement to the first registration request message, that is, include parameters not included in the first registration request message. The first registration request message and the second registration request message together constitute all parameters required for the registration process.

[0162] In addition, in a possible implementation manner, the first network element may further send capability information of the first network element and / or information of the first timer to the terminal.

[0163] Among them, the capability information of the first network element indicates that the first network element supports store-and-forward. The first timer indicates the length of time the terminal is in a dormant state. Among them, based on the received capability information of the first network element or the first timer, the terminal will be in a dormant state, that is, remain silent and no longer send messages, and can choose whether to listen to the broadcast messages issued by the satellite. In addition, the first timer can also be understood as the estimated length of time the terminal needs to wait or hang up, or the length of time the terminal needs to wait to send a message again the next time it is connected to the satellite. Exemplarily, the length of time indicated by the first timer can be determined based on the time it takes for the first satellite to move to the gateway, or the time it takes for the satellite to move to the area where the terminal is located next time. When there is a communication link between the first network element and the core network device, the first network element can also send the remaining value of the first timer to the core network device.

[0164] Step 440: When a communication link exists between the first network element and the core network device, the first network element sends a first message and a second identifier to the core network device.

[0165] Through the above process, the first network element assigns a second identifier to the terminal and forwards the first message from the terminal and the second identifier to the core network device when a communication link exists between the first network element and the core network device. The second identifier is used to identify the terminal and can be used throughout the registration process.

[0166] Step 450: The core network device determines the next satellite to provide services to the terminal.

[0167] In a possible implementation, the core network device may directly determine whether the next satellite to provide services to the terminal is still the first satellite.

[0168] In another possible implementation, the core network device determines the next satellite to provide services to the terminal based on the ephemeris information and the terminal's location information; or, the core network device sends the terminal's location information to the computing device (e.g., a satellite management platform). Optionally, the core network device may also send time information to the computing device, for example, the time when the core network device receives the first message, so that the computing device provides satellite information that can provide services to the terminal calculated based on the time information and location information. The core network device receives indication information from the computing device, and the indication information indicates the next satellite to provide services to the terminal.

[0169] For example, the core network device may calculate, based on the ephemeris information and the location information of the terminal, a satellite that can cover the terminal the fastest among at least one satellite to which the core network device is currently connected as the next satellite to provide services to the terminal.

[0170] The next satellite that provides services to the terminal may still be the first satellite, or the next satellite that provides services to the terminal may be the second satellite, where the second satellite is different from the first satellite.

[0171] For example, the core network device may further receive a remaining value of a first timer from the first network element, and may determine the second satellite based on the ephemeris information, the terminal's location information, and the remaining value of the first timer. Alternatively, the core network device may further send the remaining value of the first timer to the computing device.

[0172] For example, the core network device may calculate the satellite that first covers the terminal after the first timer expires as the next satellite to provide services to the terminal based on the ephemeris information, the terminal's location information, and the remaining value of the first timer.

[0173] In addition, the core network device may also determine multiple candidate satellites. For example, the first network element calculates the first X satellites that can quickly reach the terminal, or calculates the first Y satellites that will reach the terminal after the first timer expires. X and Y are positive integers. Furthermore, the core network device may select a satellite from the multiple candidate satellites based on various factors as the next satellite to provide service to the terminal.

[0174] Factor a: Whether network elements with store-and-forward capabilities are deployed on the satellite.

[0175] In one example, the core network device can use pre-configured information to determine which satellites have deployed network elements with store-and-forward capabilities. Furthermore, if there are multiple candidate satellites, the core network device selects a satellite with a store-and-forward network element deployed as the next satellite to provide service to the terminal based on the pre-configured information.

[0176] In another example, a core network device may receive capability information of a second network element from a second network element, where the capability information of the second network element indicates that the second network element supports store-and-forward. The second network element is located on a second satellite, and the plurality of candidate satellites includes the second satellite. Furthermore, the core network device may select the second satellite as the next satellite to provide service to the terminal based on the received capability information of the second network element.

[0177] Factor b: whether the satellite that covers the terminal is earlier than the first satellite.

[0178] It can be understood that the satellite that covers the terminal earlier than the first satellite can forward the second message determined by the core network device to the terminal more quickly.

[0179] Factor c: whether the storage resources are greater than the storage resources of the first satellite.

[0180] It should be noted that the above factors can be used alone or in combination, and the above factors are only examples and are not intended to limit the present application.

[0181] Exemplarily, the next satellite to provide service to the terminal is a second satellite. The second satellite covers the terminal earlier than the first satellite, and when a communication link exists between the first satellite and the core network device, the second satellite also has a communication link with the core network device. When a communication link exists between the first satellite and the core network device, the second satellite also has a communication link with the core network device, ensuring that the second satellite can receive the second message and second identifier sent by the core network device.

[0182] Exemplarily, the next satellite to provide services to the terminal is a second satellite. The storage resources of the second satellite are greater than the storage resources of the first satellite, and when a communication link exists between the first satellite and the core network device, a communication link also exists between the second satellite and the core network device.

[0183] Exemplarily, the next satellite to provide service to the terminal is a second satellite. The second satellite covers the terminal earlier than the first satellite, the second satellite has greater storage resources than the first satellite, and when a communication link exists between the first satellite and the core network device, the second satellite also has a communication link with the core network device.

[0184] As shown in FIG4A , the following steps 460A to 480A correspond to a scenario in which the core network device determines that the next satellite to provide services to the terminal is the first satellite.

[0185] Step 460A: The core network device sends a second message and a second identifier to the first network element according to the first message.

[0186] Exemplarily, the second message is a response message to the first message. Exemplarily, the second message may include one or more of the following: a second or third identifier, UE network capabilities, an encryption algorithm, an integrity algorithm, an authentication vector, a satellite identifier, an HSS / UDM identifier, an evolved packet system (EPS) bearer identity (EBI), a tunnel endpoint identifier (TEID) of S1-U or S11-U, and information such as IP, APN, UE IP, and quality of service (QoS).

[0187] Step 470A: The first network element saves the second message according to the second identifier.

[0188] Step 480A: When a communication link exists between the first network element and the terminal, the first network element sends a second message to the terminal. In addition, a second identifier may also be sent.

[0189] Exemplarily, before the first network element sends the second message to the terminal, the first satellite may page the terminal, or the terminal may reselect and send the first message to the first network element.

[0190] The existence of a communication link between the first network element and the terminal can be understood as follows: as the first satellite moves, the first satellite no longer covers the core network device, and the first satellite covers the terminal.

[0191] The subsequent message forwarding process can be specifically referred to in Example 1 below, which will not be repeated here.

[0192] As shown in FIG4B , the following steps 460B to 480A correspond to a scenario in which the core network device determines that the next satellite to provide services to the terminal is the second satellite.

[0193] Step 460B: The core network device sends a second message and a second identifier to a second network element according to the first message, where the second network element is located on a second satellite.

[0194] Step 470B: The second network element saves the second message.

[0195] Exemplarily, the second network element further allocates corresponding storage space to the terminal, and the storage space corresponding to the terminal corresponds to the second identifier.

[0196] Step 480B: When a communication link exists between the second network element and the terminal, the second network element sends a second message to the terminal. In addition, a second identifier may also be sent.

[0197] Exemplarily, before the second network element sends the second message to the terminal, the second satellite may page the terminal, or the terminal may reselect to send the first message to the second network element.

[0198] The subsequent message forwarding process can be specifically referred to Example 2 and / or Example 4 below, which will not be repeated here.

[0199] The above method ensures that the terminal registration process can be completed even when there is no communication link between the satellite and the core network equipment. In this case, the first network element can assign a second identifier to the terminal even without the ability to parse NAS messages. The core network equipment can also combine various information to determine the next satellite to provide service to the terminal, thereby improving message forwarding efficiency and shortening the registration process.

[0200] The present application also provides a communication method for enabling the terminal to enter a sleep state in a timely manner when there is no communication link between the satellite and the core network equipment at the same time, thereby saving the power consumption of the terminal.

[0201] As shown in FIG5 , the method includes:

[0202] Step 500: The terminal sends a first message to a first network element, where the first network element is located on a first satellite.

[0203] Exemplarily, the first message may be a NAS message or uplink data.

[0204] Step 510: When there is no communication link between the first network element and the core network device, the first network element sends a second message to the terminal, where the second message includes first information, and the first information is used to trigger the terminal to enter a dormant state.

[0205] Exemplarily, the first information is capability information of the first network element, and the capability information of the first network element indicates that the first network element supports store-and-forward;

[0206] Alternatively, the first information indicates that there is no power feeding information between the first network element and the core network device. It can also be understood that the first information indicates that there is no communication link between the first network element and the core network device.

[0207] Alternatively, the first information indicates that the first message has not been forwarded (or delivered) but has been stored (or saved).

[0208] Alternatively, if the first message is a first registration request message, the first message may further indicate that the registration process needs to be paused and waited, or indicate that the registration process is suspended.

[0209] In addition, before sending the second message to the terminal, the first network element can determine the delay requirement of the service initiated by the first message based on the message type of the first message, or information such as the service type in the first message. If the delay requirement is low, the first satellite sends the second message to the terminal.

[0210] Step 520: The terminal enters a dormant state according to the first information.

[0211] By adopting the above method, the terminal enters the dormant state according to the second message, and there is no need to repeatedly send the first message, which can save the power consumption of the terminal.

[0212] It is understandable that, before the terminal enters the dormant state and when the first satellite covers the terminal, the terminal may further send one or more messages so that the first network element stores them.

[0213] In a possible implementation, if the first message is a first registration request message, before the terminal enters the dormant state, the terminal may further send a second registration request message to the first network element according to the first information.

[0214] For example, if the first information is capability information of the first network element, and the terminal learns that the first network element supports store-and-forward, the terminal may send the required registration parameters to the first network element via a second registration message. For example, the second registration request message may include all parameters required for the registration process, or the second registration request message may be a supplementary message to the first registration request message, i.e., include parameters not included in the first registration request message, and the first registration request message and the second registration request message together constitute all parameters required for the registration process.

[0215] In another possible implementation, the first network element may determine second information based on the first registration request message, where the second information is used to trigger reporting of at least one parameter. The second message may also include second information. If the first message is a first registration request message, before the terminal enters the dormant state, the terminal may send a second registration request message to the first network element based on the second information, where the second registration request message includes at least one parameter.

[0216] Exemplarily, the first network element may determine the second information based on parameters not included in the first registration request message, and the first registration request message and the second registration request message together constitute all parameters required for the registration process. The terminal sends a second registration request message based on the second information. The second registration request message may include all parameters required for the registration process, or only include at least one parameter indicated by the second information. This application is not limited to this.

[0217] It can be understood that the above-mentioned first message may also be a first attach request message.

[0218] In addition, when the first satellite no longer provides service to the terminal or is about to lose coverage of the terminal, the first network element may send a third message to the terminal, indicating that the first satellite no longer provides service to the terminal or that the first satellite has left the area where the terminal is located. The terminal may then enter a dormant state based on the message.

[0219] Exemplarily, after the first network element receives the second registration request message from the terminal, the first network element sends a third message to the terminal. At this time, the third message may also indicate that the second registration request message has been saved. The third message can also be understood as a response message to the second registration request message, or a default reply.

[0220] The second message or the third message may further include information of a first timer. The first timer is used to indicate the duration of the terminal being in the dormant state.

[0221] The terminal may start the first timer after receiving the third message. For the relevant content of the first timer, please refer to the relevant description of the embodiments shown in Figures 4A and 4B, which will not be repeated here.

[0222] It should be noted that when the terminal is in a dormant state, it can choose to listen to broadcast messages or not, but the terminal will not actively resend the first message or other messages. However, after the dormant state ends, or after the terminal enters a state where it can actively send messages again, or after the terminal resumes an active state or an activated state, or after the first timer expires, the terminal resends the first message. For example, after the first timer expires, if there is a satellite air interface link, after listening to the satellite sending a broadcast message carrying public land mobile network (PLMN) information over the air interface, the broadcast PLMN information matches the terminal's PLMN information, and the terminal can resend the first message.

[0223] Furthermore, before the first satellite leaves the area where the terminal is located, if the first network element stores multiple messages, the first network element may also process these messages.

[0224] In one example, if the multiple messages are NAS messages, the first network element may merge the multiple messages into one message.

[0225] Exemplarily, if the first network element saves the first registration request message and the second registration request message, when there is a communication link between the first network element and the core network device, the first network element can send a third registration request message to the core network device, wherein the third registration request message is determined based on the first registration request message and the second registration request message.

[0226] In another example, if the first satellite also stores the first authentication parameter (or first authentication parameter) from the core network device and receives the second authentication parameter (or second authentication parameter) from the terminal, the first network element may also determine whether the two authentication parameters are consistent.

[0227] For example, the first network element saves an expected response (XRES) from a core network device (eg, MME) and receives a response (RES) from the terminal, and the first network element may determine whether the two are the same.

[0228] Furthermore, in one possible implementation, the first network element determines third information based on at least one of ephemeris information, terminal location information, and receive beam information in the first message. The third information is used to identify a second satellite, which is the next satellite to serve the terminal. The second message also includes the third information, and when a communication link exists between the first network element and the core network device, the first network element sends the third information to the core network device.

[0229] Illustratively, the third information includes at least one of an identifier of a second network element, an identifier of a second satellite, or an identifier of another device located on the second satellite, wherein the second network element is located on the second satellite and supports store-and-forward. The receive beam information includes at least one of receive time information, a beam angle, a beam identifier, or information about the physical deployment location of the satellite where the beam is located.

[0230] It is understandable that the first network element may also determine multiple candidate satellites and select one satellite from among them as the next satellite to serve the terminal. The specific selection method can be referred to the relevant content about multiple factors in the embodiments shown in Figures 4A and 4B above, and will not be repeated here.

[0231] Furthermore, the terminal may receive a broadcast message indicating a satellite covering the terminal. For example, the terminal may receive the broadcast message while in a dormant state, after a first timer expires, or after escaping from a dormant state. The terminal may determine, based on the third information, whether the satellite indicated in the broadcast message is the second satellite. If so, the terminal may resend the first message to the second network element, which is located on the second satellite. Otherwise, the terminal may not send the first message and continue to listen for broadcast messages.

[0232] Exemplarily, if the second message also includes third information, and the first network element also notifies the core network device of the third information, the core network device may send the message to the terminal to the second network element based on the third information. When the second satellite moves to the area where the terminal is located, the second satellite may send a broadcast message indicating the second satellite, for example, the broadcast message includes an identifier of the second satellite. The terminal may receive the broadcast message, and if the identifier of the second satellite in the third information is determined to be the same as the identifier of the satellite in the broadcast message, the terminal may resend the first message to the second network element and may also receive messages from the core network device stored by the second network element.

[0233] The following further illustrates the embodiments shown in Figures 4A, 4B and 5 with reference to specific examples, wherein the terminal corresponds to UE1, and the first access device is the first RAN.

[0234] Example 1: One of the initial registration processes in a 4G scenario, wherein a first network element and a first RAN are located on a first satellite, and the first network element is a network element with a store-and-forward function and does not have the ability to parse NAS messages.

[0235] As shown in Figures 6A and 6B, the following attachment process can be divided into several stages:

[0236] Time period 1: The first satellite is above UE1 and has no communication gateway connection. At this time, there is a communication link between the first network element and UE1, but no communication link between the first network element and the MME.

[0237] S601: UE1 sends an attach request 1 to the first RAN.

[0238] Exemplarily, UE1 sends an attach request 1 to the first RAN.

[0239] The attach request 1 is a NAS message including the IMSI, UE1 capability information, and optionally, any one or more of an access point name (APN), an additional update type, and UE1 location information.

[0240] Exemplarily, the UE1 capability information may further indicate whether the UE1 supports a network element with a store-and-forward function.

[0241] S602: The first RAN allocates a C-RNTI to UE1.

[0242] S603: The RAN sends an attach request 1 and a C-RNTI to the first network element.

[0243] S604: The first network element allocates a second identifier to UE1 according to the C-RNTI and information about the first satellite.

[0244] For details, please refer to the above step 420, which will not be repeated here.

[0245] S605: The first network element sends a response message 1 to UE1 through the first RAN.

[0246] Among them, response message 1 can be a reply to attachment request 1, and response message 1 includes a second identifier, which is used to identify UE1. It can also indicate that the attachment request 1 of UE1 has been stored, or that the attachment request 1 of UE1 has been received by the satellite network.

[0247] In addition, optionally, the response message 1 may also include the first information and / or information of the timer 1.

[0248] The first information is the capability information of the first network element, and the capability information of the first network element indicates that the first network element supports store-and-forward. Alternatively, the first information indicates that the attachment request 1 has not been forwarded (or delivered) but has been stored (or saved), or indicates that the attachment process is paused and needs to wait, or indicates that the attachment process is suspended. Alternatively, the first information is used to indicate that there is no power feed information between the first network element and the core network device, or that there is no communication link between the first network element and the core network device. Alternatively, the first information is used to indicate that the first satellite is about to leave the airspace above UE1.

[0249] For example, timer 1 can be understood as the duration for UE1 to enter the sleep state. For example, UE1 can enter the sleep state within this duration, that is, remain silent and no longer send messages, and can choose whether to listen to broadcast messages issued by the satellite.

[0250] Timer 1 can also be understood as the estimated waiting or suspending time for UE1, or the waiting time for UE1 to send a message (such as an attach request) the next time it establishes a connection with the satellite. For example, Timer 1 can be recorded as Timer1. Exemplarily, the duration of Timer 1 can be determined based on the time it takes for the first satellite to move to the gateway, or the time it takes for the satellite to next move to the area where UE1 is located.

[0251] S606: After receiving the response message 1, UE1 saves the second identifier.

[0252] Exemplarily, if the response message 1 further includes first information, the UE 1 may enter a dormant state according to the first information.

[0253] Exemplarily, if the response message 1 further includes information of the timer 1, the UE 1 may start the timer 1 and remain in the dormant state before the timer 1 times out.

[0254] Furthermore, in one possible implementation, before UE1 enters the dormant state according to the first information, UE1 may further send a second identifier and Attach Request 2. Attach Request 2 is a NAS message. Attach Request 2 may include all parameters required for the registration process, or Attach Request 2 may be a supplementary message to Attach Request 1, i.e., include parameters not included in Attach Request 1. Attach Request 1 and Attach Request 2 together constitute all parameters required for the registration process.

[0255] For example, the NAS message in the attach request 1 includes the IMSI and the capability information of UE1, and the NAS message in the attach request 2 includes the APN and the location information of UE1.

[0256] For another example, the NAS message in the attach request 1 includes the IMSI and the capability information of UE1, and the NAS message in the attach request 2 includes the IMSI, the capability information of UE1, the APN, and the location information of UE1.

[0257] Correspondingly, the first network element stores the attach request 2 in sequence in the storage space corresponding to UE1 according to the second identifier.

[0258] After sending the attach request 2, UE1 enters the dormant state and starts timer 1.

[0259] Optionally, after receiving the attachment request 2, the first network element may further send a response message 2, where the response message 2 includes the timer 1, or indicates that the timer 1 is started, or the response message 2 indicates that the first satellite no longer provides services for the UE1.

[0260] Time period 2: The first satellite moves above the gateway and no longer has a connection to UE1. Specifically, as the first satellite orbits the Earth, it leaves the area above UE1 and arrives above the gateway. The gateway is able to communicate with the MME. At this point, the first network element has no communication link with UE1, but a communication link exists between the first network element and the MME.

[0261] S607: The first network element sends an attach request 1 and a second identifier to the MME.

[0262] Exemplarily, the first network element senses that the MME is reachable, and forwards the stored messages from UE1 to the MME in sequence.

[0263] For example, if UE1 only sends the attach request 1, the first network element sends the attach request 1 and the second identifier to the MME.

[0264] For another example, if UE1 sends attach request 1 and attach request 2, the first network element first sends attach request 1 and the second identifier to the MME, and then sends attach request 2 and the second identifier.

[0265] In addition, the first network element may also send capability information of the first network element to the MME.

[0266] S608: The MME sends an authentication request to the HSS, where the authentication request includes the IMEI.

[0267] S609: The HSS sends an authentication response to the MME.

[0268] The authentication response includes an authentication vector, which includes information such as an authentication token (AUTN), a random number (RAND), Kasme, and an expected response (XRES). The authentication vector is determined based on the IMEI in the authentication request.

[0269] S610: The MME saves the authentication vector.

[0270] In addition, the MME also saves the attach request 1 and the attach request 2.

[0271] S611: The MME sends a user authentication request and a second identifier to the first network element.

[0272] The user authentication request is a NAS message, which includes AUTN and RAND.

[0273] S612: The first network element saves the user authentication request.

[0274] Exemplarily, the first network element saves the user authentication request to the storage space corresponding to UE1 according to the second identifier.

[0275] Time period 3: The first satellite is above UE1 and has no communication gateway connection. That is, as the first satellite orbits the Earth, it leaves the area above the MME and reappears above UE1. At this point, the first network element has a communication link with UE1 but no communication link with the MME.

[0276] S613: UE1 sends an attach request 3 and a second identifier.

[0277] Exemplarily, if the response message 1 includes information of the timer 1, then after the timer 1 times out, the UE 1 may resend an attachment request, such as the attachment request 3, to the detected satellite.

[0278] S614: The first network element determines the user authentication request according to the second identifier.

[0279] S615: The first network element sends a user authentication request and a second identifier to UE1.

[0280] Exemplarily, if the first network element receives the attach request 3 and the second identifier, it determines the storage space corresponding to UE1 according to the second identifier, and sends the user authentication request stored in the storage space to UE1.

[0281] S616: UE1 sends a user authentication response and a second identifier to the first network element.

[0282] The user authentication response is a NAS message including a response (RES). UE1 can verify the validity of AUTN in the user authentication request and then calculate RES based on RAND and Key (a long-term key previously preset in UE1).

[0283] S617: The first network element saves the user authentication response.

[0284] Exemplarily, the first network element saves the user authentication response to the storage space corresponding to UE1 according to the second identifier.

[0285] In addition, optionally, when the first satellite moves out of the airspace above UE1 (or the area where UE1 is located), the first network element may further send a response message 3 to UE1, where the response message 3 includes information about the second identifier and timer 1. UE1 may be in a dormant state before timer 1 times out. Timer 1 here may be the same as or different from timer 1 in S605, and is described herein using the example where the two are the same.

[0286] Time period 4: The first satellite is above the gateway and has no connection to UE1. Specifically, as the first satellite orbits the Earth, it leaves the area above UE1 and reappears above the gateway. The gateway is able to communicate with the MME. At this point, there is no communication link between the first network element and UE1, but there is a communication link between the first network element and the MME.

[0287] S618: The first network element sends a user authentication response and a second identifier to the MME.

[0288] Exemplarily, the first network element senses that the MME is reachable, and forwards the stored messages from UE1 to the MME in sequence.

[0289] S619: The MME determines that the RES and the XRES consistently generate the security context information of UE1.

[0290] The security context of UE1 includes NAS keys derived from Kasme, user plane (UP) keys and radio resource control (RRC) keys.

[0291] In addition, the MME may establish a user plane session with the first satellite when determining that the Additional update type is not received, or determine that it is not necessary to establish a user plane session with the first satellite when determining that the Additional update type is received.

[0292] For example, attach request 1 or 2 may carry a parameter value, where a parameter value of 1 indicates that only short message service (SMS) is supported, and voice is not supported, and thus a user plane session does not need to be created. A parameter value of 0 indicates that a user plane session is created.

[0293] S620: The MME sends an attach acceptance and a second identifier to the first network element.

[0294] Optionally, the Attach Accept message includes a third identifier, i.e., the identifier assigned by the MME to UE1, and the MME may delete the second identifier. Furthermore, the Attach Accept message may optionally include a timer W, which is used to indicate the duration for UE1 to enter the dormant state. That is, after timer W expires, UE1 may send uplink data or uplink signaling.

[0295] At the same time, the MME may also send a UE1 attach update message to the HSS.

[0296] S621: The first network element saves the attachment acceptance.

[0297] Exemplarily, the first network element saves the attachment acceptance to the storage space corresponding to UE1 according to the second identifier.

[0298] S622: The MME sends an initial context establishment request to the first RAN.

[0299] In addition, the MME also sends at least one of the control plane (CP) and UP session information, UP key, and RRC key to the first RAN. If there is subsequent UP or CP data, the data can be encrypted and integrity protected using different keys based on the above information.

[0300] Time period 5: The first satellite is above UE1 and has no communication gateway connection. That is, as the first satellite orbits the Earth, it leaves the area above the MME and reappears above UE1. At this point, the first network element maintains a communication link with UE1 and with the MME.

[0301] S623: UE1 sends an attach request 4.

[0302] Exemplarily, if the response message 2 includes information of the timer 1, then after the timer 1 times out, the UE 1 may resend an attachment request, such as the attachment request 4, to the detected satellite.

[0303] The attachment request 4 includes a second identifier.

[0304] S624: The first network element determines that the attachment is accepted according to the second identifier.

[0305] S625: The first network element sends an attach acceptance and a second identifier to UE1.

[0306] Exemplarily, UE1 may save the second identifier in the attach acceptance, and UE1 may also delete the second identifier.

[0307] In addition, if the attach accept may include a timer W, UE1 may start the timer W, which indicates the duration for UE1 to enter the sleep state. After the timer W times out, UE1 may send uplink data or uplink signaling.

[0308] At this point, the attachment process ends;

[0309] When UE1 subsequently sends service data, if UE1 sends service data through the CP plane, the first network element can save it in the signaling plane storage space of UE1 in the form of a NAS message. If UE1 sends service data through the CP plane, the first network element can save it in the user plane storage space of UE1 in IP format. The third identifier of UE1 sent together with the service data can be indexed to these two storage spaces. When the first satellite returns to the signal gateway station again, the stored data can be forwarded to the MME / AMF on the CP plane or the S-GW or UPF on the UP plane. It can be understood that UE1 can also send uplink data or signaling to other satellites, which is not limited here.

[0310] Example 2: Initial registration process (part 2) in a 4G scenario. The first NE and the first RAN are located on the first satellite. The first NE is a store-and-forward NE and does not have the ability to parse NAS messages. The second NE and the second RAN are located on the second satellite. The second NE is a store-and-forward NE and does not have the ability to parse NAS messages. This is shown in Figures 7A and 7B.

[0311] S701 to S710 may refer to the above-mentioned S601 to S610 .

[0312] S711: The MME determines a second network element.

[0313] For details, please refer to the above step 450.

[0314] S712: The MME sends a user authentication request and a second identifier to the second network element.

[0315] The user authentication request is a NAS message, which includes AUTN and RAND.

[0316] S713: The second network element saves the user authentication request.

[0317] Exemplarily, the second network element allocates a corresponding storage space for UE1 and saves the user authentication request in the storage space corresponding to UE1. The storage space also corresponds to the second identifier.

[0318] Time period 3: The second satellite is above UE1 and has no communication gateway connection. That is, as the second satellite orbits the Earth, it leaves the area above the MME and arrives above UE1. At this point, the second network element has a communication link with UE1 but no communication link with the MME.

[0319] S714: UE1 sends an attach request 3 and a second identifier.

[0320] Exemplarily, if the response message 1 includes timer 1, then after timer 1 times out, UE 1 may resend an attachment request, such as attachment request 3, to the detected satellite.

[0321] S715: The second network element determines the user authentication request according to the second identifier.

[0322] Exemplarily, the second network element determines, based on the second identifier received in S714 , that the second identifier is the same as the second identifier stored in S713 , and determines that the user authentication request in the second identifier storage space needs to be sent.

[0323] S716: The second network element sends a user authentication request and a second identifier to UE1.

[0324] Exemplarily, the second network element determines the storage space corresponding to UE1 according to the second identifier, and sends the user authentication request stored in the storage space to UE1.

[0325] S717: UE1 sends a user authentication response and a second identifier to the second network element.

[0326] The user authentication response is a NAS message, which includes a RES.

[0327] S718: The second network element saves the user authentication response.

[0328] Exemplarily, the second network element saves the user authentication response to the storage space corresponding to UE1.

[0329] In addition, optionally, when the second satellite moves out of the airspace above UE1, the second network element may also respond to UE1 with message 3, where the response message 3 includes the second identifier and information of timer 2. UE1 may be in a dormant state before timer 2 times out.

[0330] Time period 4: The second satellite is above the gateway and has no connection to UE1. That is, as the second satellite orbits the Earth, it leaves the area above UE1 and reappears above the gateway. The gateway is able to communicate with the MME. At this point, there is no communication link between the second network element and UE1, but there is a communication link between the second network element and the MME.

[0331] S719: The second network element sends a user authentication response and a second identifier to the MME.

[0332] Exemplarily, the second network element senses that the MME is reachable, and forwards the stored messages from UE1 to the MME in sequence.

[0333] S720: The MME determines that the RES and the XRES are consistent in generating the security context information of the UE1.

[0334] It is understandable that the MME may reselect a satellite at this time, for example, referring to the above step 211. The following description will only be made by taking the case where the MME still selects the second satellite as an example.

[0335] S721: The MME sends an attach acceptance and a second identifier to the second network element.

[0336] Optionally, the Attach Accept message includes a third identifier, i.e., the identifier assigned by the MME to UE1. The MME may delete the second identifier. Furthermore, the MME may send the third identifier to the second network element. Furthermore, optionally, the Attach Accept message may include a timer W, which indicates the duration for UE1 to enter a dormant state. This means that after timer W expires, UE1 may send uplink data or uplink signaling.

[0337] At the same time, the MME may also send a UE1 attach update message to the HSS.

[0338] S722: The second network element saves the attachment acceptance.

[0339] Exemplarily, the second network element saves the attach acceptance to the storage space corresponding to UE1 according to the second identifier.

[0340] S723: The MME sends an initial context establishment request to the first RAN.

[0341] Time period 5: The second satellite is above UE1 and has no communication gateway connection. That is, as the first satellite orbits the Earth, the second satellite leaves the area above the MME and reappears above UE1. At this point, the second network element has a communication link with UE1 and with the MME.

[0342] S724: UE1 sends an attach request 4 and a second identifier.

[0343] Exemplarily, if the response message 2 includes timer 2, then after timer 2 times out, UE1 may resend an attachment request, such as attachment request 4, to the detected satellite.

[0344] S725: The second network element determines that the attachment is accepted according to the second identifier.

[0345] S726: The second network element sends an attach acceptance and a second identifier to UE1.

[0346] Optionally, UE1 may save the third identifier in the attach acceptance, and UE1 may also delete the second identifier.

[0347] In addition, if the attach accept may include a timer W, UE1 may start the timer W, which indicates the duration for UE1 to enter the sleep state. After the timer W times out, UE1 may send uplink data or uplink signaling.

[0348] At this point, the attachment process ends.

[0349] Based on the above example, when UE1 subsequently has service data to send, if UE1 sends service data through the CP plane, the second network element can save it in the signaling plane storage space of UE1 in the form of a NAS message. If UE1 sends service data through the UP plane, the second network element can save it in the user plane storage space of UE1 in IP format. The third identifier of UE1 sent together with the service data can be indexed to these two storage spaces. When the second satellite turns to the signal gateway again, the stored data can be forwarded to the MME / AMF on the CP plane or the S-GW or UPF on the UP plane. It can be understood that UE1 can also send uplink data or signaling to other satellites, which is not limited here.

[0350] Example 3: Initial registration process 3 in a 4G scenario. The first network element and the first RAN are located on the first satellite. The first network element is a store-and-forward network element capable of parsing NAS messages. The second network element and the second RAN are located on the second satellite. The second network element is a store-and-forward network element capable of parsing NAS messages.

[0351] As shown in Figure 8, the following attachment process can be divided into several stages:

[0352] Time period 1: The first satellite is above UE1 and has no gateway connection. At this point, the first network element has a communication link with UE1 but no communication link with the MME. A second network element and a second RAN are located on the second satellite. The second network element is a store-and-forward network element and does not have the ability to parse NAS messages.

[0353] S801: UE1 sends an attach request 1 to the first RAN through the first RAN.

[0354] The attach request 1 is a NAS message, which includes the IMSI, UE1 capability information, etc. Optionally, the NAS message also includes any one or more of the APN, additional update type, and UE1 location information.

[0355] S802: The first network element allocates a second identifier to UE1 according to the attach request 1 and the information of the first satellite.

[0356] S803: The first network element sends a response message 1 to UE1 through the first RAN.

[0357] The response message 1 may be a reply to the attach request 1 , and the response message 1 includes a second identifier, and the second identifier is used to identify UE1 .

[0358] In addition, optionally, the response message 1 may further include one or more of the first information, the information of the timer 1, the second information, or the third information. For details of the first information and the information of the timer 1, refer to the above related description.

[0359] Exemplarily, the first network element may determine second information according to the attach request 1, where the second information is used to trigger reporting of at least one parameter. The attach request 1 does not include the at least one parameter.

[0360] The first network element may also receive an attach request 2 and a second identifier from UE1, where the attach request 2 is a NAS message including at least one parameter.

[0361] Exemplarily, attachment request 2 may include all parameters required for the registration process, or attachment request 2 may be a supplementary message of attachment request 1, that is, it includes parameters not included in attachment request 1, that is, at least one parameter, and attachment request 1 and attachment request 2 together constitute all parameters required for the registration process.

[0362] In addition, in a possible implementation, the first network element generates message 1 according to attach request 1 and attach request 2, and stores message 1 in a storage space corresponding to UE 1. For example, the first network element combines attach request 1 and attach request 2 and stores them as one NAS message.

[0363] S804: After receiving the response message 1, UE1 saves the second identifier.

[0364] Exemplarily, if the response message 1 further includes first information, the UE 1 may enter a dormant state according to the first information.

[0365] Exemplarily, if the response message 1 further includes the timer 1, the UE 1 may start the timer 1 and remain in the dormant state before the timer 1 times out.

[0366] After sending the attach request 2, UE1 enters the dormant state and starts timer 1.

[0367] Optionally, after receiving the attachment request 2, the first network element may further send a response message 2, where the response message 2 includes the timer 1, or indicates that the timer 1 is started, or the response message 2 indicates that the first satellite no longer provides services for the UE1.

[0368] Time period 2: The first satellite moves above the gateway and no longer has a connection to UE1. Specifically, as the first satellite orbits the Earth, it leaves the area above UE1 and arrives above the gateway. The gateway is able to communicate with the MME. At this point, the first network element has no communication link with UE1, but a communication link exists between the first network element and the MME.

[0369] S805: The first network element sends message 1 and the second identifier to the MME.

[0370] Exemplarily, the first network element senses that the MME is reachable, and forwards the stored messages from UE1 to the MME in sequence.

[0371] In addition, the first network element may also send third information to the MME.

[0372] S806: The MME sends an authentication request to the HSS, where the authentication request includes the IMEI.

[0373] S807: The HSS sends an authentication response to the MME.

[0374] The authentication response includes an authentication vector, which includes information such as AUTN, RAND, Kasme, and XRES. The authentication vector is determined based on the IMEI in the authentication request.

[0375] S808: The MME saves the authentication vector.

[0376] In addition, the MME also saves the attach request 1 and the attach request 2.

[0377] S809: The MME sends a user authentication request and a second identifier to the second network element according to the third information.

[0378] The user authentication request is a NAS message, which includes AUTN and RAND.

[0379] S810: The second network element saves the user authentication request.

[0380] Exemplarily, the second network element allocates storage space for UE1 and stores the information in a storage space corresponding to UE1, wherein the storage space also corresponds to the second identifier.

[0381] Time period 3: The second satellite is above UE1 and has no communication gateway connection. That is, as the second satellite orbits the Earth, it leaves the area above the MME and arrives above UE1. At this point, the second network element has a communication link with UE1 but no communication link with the MME.

[0382] S811: The second satellite sends a broadcast message, where the broadcast message indicates the second satellite.

[0383] If the response message 1 includes the timer 1, then after the timer 1 times out, the UE 1 can receive the broadcast message sent by the satellite covering the UE 1.

[0384] S812: UE1 determines, based on the third information, that the satellite indicated by the broadcast message is the second satellite and sends an attachment request 3 and a second identifier.

[0385] S813: The second network element determines the user authentication request according to the second identifier.

[0386] S814: The second network element sends a user authentication request and a second identifier to UE1.

[0387] Exemplarily, the second network element determines the storage space corresponding to UE1 according to the second identifier, and sends the user authentication request stored in the storage space to UE1.

[0388] S815: UE1 sends a user authentication response and a second identifier to the second network element.

[0389] The user authentication response is a NAS message, which includes a RES.

[0390] S816: The second network element determines that RES and XRES are consistent in generating security context information of UE1.

[0391] S817: The second network element sends an attach accept to UE1.

[0392] Optionally, the attach acceptance includes a third identifier, that is, an identifier allocated by the second network element to UE1,

[0393] S818: The second network element sends the UP key and the RRC key to the second RAN.

[0394] At this point, the attachment process ends.

[0395] Based on the above example, when UE1 subsequently has service data to send, if UE1 sends service data through the CP plane, the second network element can save it in the signaling plane storage space of UE1 in the form of a NAS message. If UE1 sends service data through the UP plane, the second network element can save it in the user plane storage space of UE1 in IP format. The third identifier of UE1 sent together with the service data can be indexed to these two storage spaces. When the second satellite turns to the signal gateway again, the stored data can be forwarded to the MME / AMF on the CP plane or the S-GW or UPF on the UP plane. It can be understood that UE1 can also send uplink data or signaling to other satellites, which is not limited here.

[0396] Example 4: One of the initial registration processes in a 5G scenario, wherein the first network element and the first RAN are located on the first satellite, and the first network element is a network element with a store-and-forward function and does not have the ability to parse NAS messages.

[0397] As shown in Figures 9A and 9B, the following attachment process can be divided into several stages:

[0398] Time period 1: The first satellite is above UE1 and has no communication gateway connection. At this time, there is a communication link between the first network element and UE1, but no communication link between the first network element and the AMF.

[0399] S901: UE1 sends a registration request 1 to the first RAN.

[0400] Exemplarily, UE1 sends a registration request 1 to the first RAN.

[0401] The registration request 1 is a NAS message, which includes SUCI, etc. Optionally, the NAS message also includes any one or more of the capability information of UE1 and the location information of UE1.

[0402] Exemplarily, the UE1 capability information may further indicate whether the UE1 supports a network element with a store-and-forward function.

[0403] S902: The first RAN allocates a C-RNTI to UE1.

[0404] S903: The RAN sends a registration request 1 and a C-RNTI to the first network element.

[0405] S904: The first network element allocates a second identifier to UE1 according to the C-RNTI and the identifier of the first satellite.

[0406] For details, please refer to the above step 410.

[0407] S905: The first network element sends a response message 1 to UE1 through the first RAN.

[0408] The response message 1 may be a reply to the registration request 1, and the response message 1 includes a second identifier, which is used to identify UE1.

[0409] In addition, optionally, the response message 1 may further include the first information and / or information of the timer 1. For details, please refer to the above S605.

[0410] S906: After receiving the response message 1, UE1 saves the second identifier.

[0411] Exemplarily, if the response message 1 further includes first information, the UE 1 may enter a dormant state according to the first information.

[0412] Exemplarily, if the response message 1 further includes information of the timer 1, the UE 1 may start the timer 1 and remain in the dormant state before the timer 1 times out.

[0413] Furthermore, in one possible implementation, before UE1 enters the dormant state according to the first information, UE1 may further send a second identifier and Registration Request 2. Registration Request 2 is a NAS message. Registration Request 2 may include all parameters required for the registration process, or Registration Request 2 may be a supplementary message to Registration Request 1, i.e., include parameters not included in Registration Request 1. Registration Request 1 and Registration Request 2 together constitute all parameters required for the registration process.

[0414] Correspondingly, the first network element stores the registration request 2 in sequence in the storage space corresponding to UE1 according to the second identifier.

[0415] After sending the registration request 2, UE1 enters the dormant state and starts timer 1.

[0416] Optionally, after receiving the registration request 2, the first network element may further send a response message 2, where the response message 2 includes the timer 1, or indicates that the timer 1 is started, or the response message 2 indicates that the first satellite no longer provides services for the UE 1.

[0417] In addition, before UE1 enters the dormant state according to the first information, UE1 may also send a second identifier and a session creation request 1. The session creation request 1 is a NAS message, and the NAS message includes a PDU session type and an APN, etc.

[0418] Time period 2: The first satellite moves above the gateway and there is no connection with UE1. That is, as the first satellite orbits the Earth, it leaves the area above UE1 and arrives above the gateway, where the gateway is able to communicate with the AMF. At this point, there is no communication link between the first network element and UE1, but there is a communication link between the first network element and the AMF.

[0419] S907: The first network element sends a registration request 1 and a second identifier to the AMF.

[0420] Exemplarily, the first network element senses that the AMF is reachable and forwards the stored messages of UE1 to the AMF in sequence.

[0421] For example, if UE1 sends registration request 1, registration request 2 and session creation request 1, the first network element first sends registration request 1 and the second identifier to the AMF, then sends registration request 2 and the second identifier, and finally sends session creation request 1 and the second identifier.

[0422] In addition, the first network element can also send capability information of the first network element to the AMF.

[0423] S908: AMF sends an authentication request to UDM through the authentication server function (AUSF), where the authentication request includes SUCI.

[0424] S909: The UDM decrypts the SUCI to obtain the subscription permanent identifier (SUPI), and selects an authentication algorithm to generate an authentication vector (AV) 1.

[0425] S910: UDM sends authentication vector 1 to AUSF.

[0426] Among them, the authentication vector 1 includes the 5G Home Environment Authentication Vector (5G HE AV), SUPI.

[0427] Among them, 5G HE AV = {RAND, XRES, AUTN, Kausf}.

[0428] S911: AUSF stores XRES and calculates HRES.

[0429] S912: AUSF sends authentication vector 2 to AMF.

[0430] Authentication vector 2 includes 5G serving environment authentication vector (5G SE AV), SUPI, 5G SE AV = {RAND, AUTN, HXRES}.

[0431] In addition, AMF also obtains more subscription information of UE1 from UDM.

[0432] S913: AMF saves authentication vector 2.

[0433] The AMF also saves the registration request 1, the registration request 2 and the session creation request 1.

[0434] S914: AMF determines the second network element.

[0435] For details, please refer to the above step 450.

[0436] S915: The AMF sends a user authentication request and a second identifier to the second network element.

[0437] The user authentication request is a NAS message, which includes a 5G SE AV.

[0438] S916: The second network element saves the user authentication request.

[0439] Exemplarily, the second network element allocates a corresponding storage space for UE1 and saves the user authentication request in the storage space corresponding to UE1. The storage space also corresponds to the second identifier.

[0440] Time period 3: The second satellite is above UE1 and has no communication gateway connection. That is, as the second satellite orbits the Earth, it leaves the area above the AMF and arrives above UE1. At this point, the second NE has a communication link with UE1 but no communication link with the AMF.

[0441] S917: UE1 sends a registration request 3 and a second identifier.

[0442] Exemplarily, if the response message 1 includes timer 1, then after timer 1 times out, UE 1 may resend a registration request, such as registration request 3, to the detected satellite.

[0443] S918: The second network element determines the user authentication request according to the second identifier.

[0444] S919: The second network element sends a user authentication request and a second identifier to UE1.

[0445] Exemplarily, the second network element determines the storage space corresponding to UE1 according to the second identifier, and sends the user authentication request stored in the storage space to UE1.

[0446] S920: UE1 sends a user authentication response and a second identifier to the second network element.

[0447] The user authentication response is a NAS message, which includes a RES.

[0448] In addition, UE1 may also send a session creation request 2 to the second network element, where the content of the session creation request 2 may be the same as the content of the session creation request 1.

[0449] S921: The second network element saves the user authentication response.

[0450] Exemplarily, the second network element saves the user authentication response to the storage space corresponding to UE1.

[0451] In addition, optionally, when the second satellite moves out of the airspace above UE1, the second network element may also respond to UE1 with message 3, where the response message 3 includes the second identifier and information of timer 2. UE1 may be in a dormant state before timer 2 times out.

[0452] Time period 4: The second satellite is above the gateway and has no connection to UE1. That is, as the second satellite orbits the Earth, it leaves the area above UE1 and reappears above the gateway. The gateway is able to communicate with the AMF. At this point, there is no communication link between the second network element and UE1, but there is a communication link between the second network element and the AMF.

[0453] S922: The second network element sends a user authentication response and a second identifier to the AMF.

[0454] Exemplarily, the second network element senses that the AMF is reachable and forwards the stored messages from UE1 to the AMF in sequence.

[0455] S923: AMF sends a user authentication response to AUSF.

[0456] S924: AUSF determines that RES and XRES are consistent and sends the UE authentication result to AMF.

[0457] The UE authentication combination includes KAMFS and SUPI, as well as indication information, where the indication information indicates that the UE authentication is successful.

[0458] S925: AMF generates security context information of UE1 based on Kamf.

[0459] In addition, the AMF may also create session establishment procedures with different anchor points based on the PDU session type and NEF Identity for NIDD in the information from the UE (e.g., session creation request message 1).

[0460] It is understandable that the AMF may reselect a satellite at this time, for example, referring to the above step 211. The following description will only be made by taking the case where the AMF still selects the second satellite as an example.

[0461] S926: The AMF sends a registration acceptance and a second identifier to the second network element.

[0462] Optionally, the Registration Accept includes a third identifier, i.e., the identifier assigned by the AMF to UE1, and the AMF may delete the second identifier. Optionally, the Attach Accept may also include a timer W, which is used to indicate the duration for UE1 to enter the dormant state. That is, after timer W expires, UE1 may send uplink data or uplink signaling.

[0463] S927: The second network element saves the registration acceptance.

[0464] Exemplarily, the second network element saves the registration acceptance to the storage space corresponding to UE1 according to the second identifier.

[0465] S928: The AMF sends an initial context establishment request to the second RAN. At the same time, the AMF may also send key-related information to the second RAN.

[0466] Time period 5: The second satellite is above UE1 and has no gateway connection. That is, as the first satellite orbits the Earth, the second satellite leaves the area above the AMF and reappears above UE1. At this point, the second network element has a communication link with UE1 and with the AMF.

[0467] S929: UE1 sends a registration request 4 and a second identifier.

[0468] Exemplarily, if the response message 2 includes timer 2, then after timer 2 times out, UE1 may resend a registration request, such as registration request 4, to the detected satellite.

[0469] S930: The second network element determines that the registration is accepted according to the second identifier.

[0470] S931: The second network element sends a registration acceptance and a second identifier to UE1.

[0471] Optionally, UE1 may save the third identifier in the registration acceptance, and UE1 may also delete the second identifier.

[0472] In addition, if the attach accept may include a timer W, UE1 may start the timer W, which indicates the duration for UE1 to enter the sleep state. After the timer W times out, UE1 may send uplink data or uplink signaling.

[0473] This completes the registration process.

[0474] Based on the above example, when UE1 subsequently has service data to send, if UE1 sends service data through the CP plane, the second network element can save it in the signaling plane storage space of UE1 in the form of a NAS message. If UE1 sends service data through the UP plane, the second network element can save it in the user plane storage space of UE1 in IP format. The third identifier of UE1 sent together with the service data can be indexed to these two storage spaces. When the second satellite turns to the signal gateway again, the stored data can be forwarded to the MME / AMF on the CP plane or the S-GW or UPF on the UP plane. It can be understood that UE1 can also send uplink data or signaling to other satellites, which is not limited here.

[0475] Example 5: Initial registration process (2) in a 5G scenario. The first network element and the first RAN are located on the first satellite. The first network element is a store-and-forward network element capable of parsing NAS messages. The second network element and the second RAN are located on the second satellite. The second network element is a store-and-forward network element capable of parsing NAS messages.

[0476] As shown in Figure 10, the following attachment process can be divided into several stages:

[0477] Time period 1: The first satellite is above UE1 and has no communication gateway connection. At this time, there is a communication link between the first network element and UE1, but no communication link between the first network element and the AMF.

[0478] S1001: UE1 sends a registration request 1 to a first network element through a first RAN.

[0479] S1002: The first network element allocates a second identifier to UE1 according to the registration request 1 and the information of the first satellite.

[0480] For details, please refer to the above step 430.

[0481] S1003: The first network element sends a response message 1 to UE1 through the first RAN.

[0482] The response message 1 may be a reply to the registration request 1, and the response message 1 includes a second identifier, which is used to identify UE1.

[0483] In addition, optionally, the response message 1 may also include some or more of the first information, the timer 1 information, the second information or the third information.

[0484] S1004: After receiving the response message 1, UE1 saves the second identifier.

[0485] Exemplarily, if the response message 1 further includes first information, the UE 1 may enter a dormant state according to the first information.

[0486] Exemplarily, if the response message 1 further includes information of the timer 1, the UE 1 may start the timer 1 and remain in the dormant state before the timer 1 times out.

[0487] Furthermore, in one possible implementation, before UE1 enters the dormant state according to the first information, UE1 may further send a second identifier and Registration Request 2. Registration Request 2 is a NAS message. Registration Request 2 may include all parameters required for the registration process, or Registration Request 2 may be a supplementary message to Registration Request 1, i.e., include parameters not included in Registration Request 1. Registration Request 1 and Registration Request 2 together constitute all parameters required for the registration process.

[0488] Correspondingly, the first network element stores the registration request 2 in sequence in the storage space corresponding to UE1 according to the second identifier.

[0489] In a possible implementation, before UE1 enters the dormant state according to the first information, UE1 may further send a second identifier and a session creation request 1. The session creation request 1 is a NAS message including a PDU session type and an APN.

[0490] Exemplarily, the first network element generates message 2 according to registration request 1, registration request 2 and session creation request 1, and stores message 2 in a storage space corresponding to UE1.

[0491] Time period 2: The first satellite moves above the gateway and there is no connection with UE1. That is, as the first satellite orbits the Earth, it leaves the area above UE1 and arrives above the gateway, where the gateway is able to communicate with the AMF. At this point, there is no communication link between the first network element and UE1, but there is a communication link between the first network element and the AMF.

[0492] S1005: The first network element sends message 2 to the AMF.

[0493] Exemplarily, the first network element senses that the AMF is reachable and sends message 2.

[0494] In addition, the first network element can also send third information to the AMF.

[0495] S1006: AMF sends an authentication request to UDM through AUSF, where the authentication request includes SUCI.

[0496] S1007: UDM decrypts SUCI to obtain SUPI, and selects an authentication algorithm to generate AV.

[0497] S1008: UDM sends authentication vector 1 to AUSF.

[0498] Among them, authentication vector 1 includes 5G HEAV and SUPI.

[0499] Among them, 5G HE AV = {RAND, XRES, AUTN, Kausf}.

[0500] S1009: AUSF stores XRES and calculates HRES.

[0501] S1010: AUSF sends authentication vector 2 to AMF.

[0502] Authentication vector 2 includes 5G SE AV and SUPI. 5G SE AV = {RAND, AUTN, HXRES}.

[0503] S1011: AMF saves authentication vector 2.

[0504] In addition, AMF also saves Registration Request 1, Registration Request 2 and Session Creation Request 1.

[0505] S1012: The AMF sends a user authentication request and a second identifier to the second network element according to the third information.

[0506] The user authentication request is a NAS message, which includes a 5G SE AV.

[0507] The following is only explained by taking the example of AMF determining the second network element based on the third information. In addition, if the first network element does not send the third message to UE1, AMF can also determine the second network element by itself, which is not limited in this application.

[0508] S1013: The second network element saves the user authentication request.

[0509] Exemplarily, the second network element allocates a corresponding storage space for UE1 and saves the user authentication request in the storage space corresponding to UE1. The storage space also corresponds to the second identifier.

[0510] Time period 3: The second satellite is above UE1 and has no communication gateway connection. That is, as the second satellite orbits the Earth, it leaves the area above the AMF and arrives above UE1. At this point, the second NE has a communication link with UE1 but no communication link with the AMF.

[0511] S1014: UE1 sends a registration request 3 and a second identifier.

[0512] Exemplarily, if the response message 1 includes timer 1, then after timer 1 times out, UE 1 may resend a registration request, such as registration request 3, to the detected satellite.

[0513] S1015: The second network element determines the user authentication request according to the second identifier.

[0514] S1016: The second network element sends a user authentication request and a second identifier to UE1.

[0515] Exemplarily, the second network element determines the storage space corresponding to UE1 according to the second identifier, and sends the user authentication request stored in the storage space to UE1.

[0516] S1017: UE1 sends a user authentication response and a second identifier to the second network element.

[0517] The user authentication response is a NAS message, which includes a RES.

[0518] In addition, UE1 may also send a session creation request 2 to the second network element, where the content of the session creation request 2 may be the same as the content of the session creation request 1.

[0519] S1018: The second network element determines that RES and XRES consistently generate security context information of UE1.

[0520] S1019: The second network element sends a registration acceptance to UE1.

[0521] Optionally, the registration acceptance includes a third identifier, that is, an identifier allocated by the second network element to UE1, and the second network element may delete the second identifier.

[0522] At this point, the registration process ends;

[0523] Based on the above example, when UE1 subsequently has service data to send, if UE1 sends service data through the CP plane, the second network element can save it in the signaling plane storage space of UE1 in the form of a NAS message. If UE1 sends service data through the UP plane, the second network element can save it in the user plane storage space of UE1 in IP format. The third identifier of UE1 sent together with the service data can be indexed to these two storage spaces. When the second satellite turns to the signal gateway again, the stored data can be forwarded to the MME / AMF on the CP plane or the S-GW or UPF on the UP plane. It can be understood that UE1 can also send uplink data or signaling to other satellites, which is not limited here.

[0524] The session establishment process can optionally create different session processes based on the UE's network capabilities or indication information. The selection of anchor points can be different, such as the NIDD creation process, the CP-only creation process, and the common UP plane session creation process. The following is an example description of the session establishment process, as shown in Figure 11.

[0525] S1101: The MME sends a first message to the S-GW.

[0526] The MME can optionally create different session establishment processes based on the UE's network capability information or the presence or absence of an ESM message container in the attach request. This means that if the attach request does not carry an ESM message container, it indicates that a normal session does not need to be created, which means that data may be forwarded in NIDD mode. Therefore, the session is not established between the MME, SGW, or PGW, but between the MME and the SCEF. The first message should be sent to the SCEF. If the ESM message container is present, the first message can be sent to the S-GW.

[0527] The first message includes the second identifier and relevant information carried by the user plane information, such as EBI, APN, S11-U tunneling, S11-U ID, MME DL TEID, etc. The first message also includes indication information. The indication information may include CP CIoT, UP CIoT, and no ESM message container information.

[0528] If the Attach request contains the CP ONLY indication, or the Additional update type contains the SMS or CP CIOT EPS optimization indication, the PGW-related tunnel is not used in the session creation process. Only the information related to the control plane network element to establish the tunnel based on the S11 interface can be transmitted between the satellite and terrestrial MME network elements. That is, the subsequent steps S1102 and S1103 can be skipped;

[0529] When in normal mode, all forwarding-related tunnel information can be transmitted;

[0530] S1102: The S-GW sends a session creation request to the P-GW.

[0531] The session creation request includes the EBI, the control plane TEID of the S-GW, the user plane TEID of the S-GW, and indication information.

[0532] S1103: The P-GW sends a session creation response to the S-GW.

[0533] The session creation response includes the control plane TEID of the P-GW, the user plane TEID of the P-GW, and the EBI.

[0534] S1104: The S-GW sends a second message to the MME.

[0535] The second message includes: EBI, control plane TEID of S-GW, user plane TEID of S-GW, control plane TEID of P-GW, and user plane TEID of P-GW.

[0536] Optionally, when it is CP only mode: the second message includes: EBI, control plane TEID of S-GW, and user plane TEID of S-GW.

[0537] S1105: The MME sends a third message to the second network element.

[0538] The third message includes the EBI and the TEID of the S11-U of the S-GW.

[0539] S1106: The MME sends a fourth message to the second network element.

[0540] The fourth message includes the second identifier, subscription information, authentication vector, EBI, control plane TEID of S-GW, and user plane TEID of S-GW.

[0541] S1107: The MME sends a session creation information notification to the HSS.

[0542] The session creation information notification includes one or more of the EBI, the control plane TEID of the S-GW, the user plane TEID of the S-GW, the control plane TEID of the P-GW, the user plane TEID of the P-GW, the second identifier or the third identifier, and the indication information.

[0543] When transmitting data for NIDD:

[0544] S1108: UE1 sends NAS (NIDD data + EBI) to the second network element

[0545] S1109: The second network element saves the NAS (NIDD data + EBI).

[0546] S1110: When the second satellite moves over the gateway, the second network element sends NAS (NIDD data + EBI) to the MME.

[0547] When transmitting CP-only NAS data, the following methods are available:

[0548] S1108: UE1 sends NAS (data + EBI) to the second network element

[0549] S1109: The second network element saves the NAS (data+EBI).

[0550] S1110: When the second satellite moves over the gateway, it sends NAS data to the MME, with the TEID of S11-U superimposed on the outer layer. (Not shown)

[0551] When transmitting IP data:

[0552] S1108: UE1 sends IP data (data + EBI) to the second network element

[0553] S1109: The second network element saves the IP data (data+EBI).

[0554] S1110: When the second satellite moves over the gateway, it sends IP data to the S-GW, with the TEID of S1-U superimposed on the outer layer. (Not shown)

[0555] It is understood that, to implement the functions in the above embodiments, the first network element and the second network element include hardware structures and / or software modules corresponding to the respective functions. Those skilled in the art should readily appreciate that, in conjunction with the various exemplary units and method steps described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is implemented in hardware or in a hardware-driven manner by computer software depends on the specific application scenario and design constraints of the technical solution.

[0556] Figures 12 and 13 are schematic diagrams of possible communication devices provided in embodiments of the present application. These communication devices can be used to implement the functions of the terminal, first network element, and core network device in the above method embodiments, thereby also achieving the beneficial effects of the above method embodiments.

[0557] As shown in Figure 12, the communication device 1200 includes a processing unit 1210 and a transceiver unit 1220. The communication device 1200 is used to implement the functions of the terminal, the first network element or the core network device in the above method embodiment.

[0558] When the communication device 1200 is used to implement the functions of the terminal in the above method embodiment:

[0559] The transceiver unit 1220 is used to send a first message to a first network element, wherein the first network element is located on a first satellite; receive a second message from the first network element, wherein the second message includes first information, and the first information is used to trigger the terminal to enter a sleep state; the processing unit 1210 is used to enter a sleep state according to the first information.

[0560] In one possible design, the first information is capability information of the first network element, and the capability information of the first network element indicates that the first network element supports storage and forwarding; or, the first information indicates that there is no power feeding information between the first network element and the core network device.

[0561] In one possible design, the first message is a NAS message or uplink data.

[0562] In one possible design, the first message is a first registration request message; before entering the sleep state, the transceiver unit 1220 is used to send a second registration request message to the first network element based on the first information.

[0563] In one possible design, the first message is a first registration request message; the second message also includes second information, and the second information is used to trigger the reporting of at least one parameter; before entering the sleep state, the transceiver unit 1220 is used to send a second registration request message to the first network element according to the second information, and the second registration request message includes the at least one parameter.

[0564] In one possible design, after sending the second registration request message to the first network element, the transceiver unit 1220 is used to receive a third message from the first network element, where the third message is used to indicate that the first satellite no longer provides service to the terminal.

[0565] In one possible design, the second message or the third message includes information of a first timer; the first timer is used to indicate the length of time the terminal is in a sleep state; after the first timer times out, the transceiver unit 1220 is used to resend the first message.

[0566] In one possible design, the second message also includes third information, and the third information is used to determine a second satellite, which is the next satellite to serve the terminal; the transceiver unit 1220 is used to receive a broadcast message; the broadcast message indicates the satellite covering the terminal; the processing unit 1210 is used to determine, based on the third information, that the satellite indicated by the broadcast message is the second satellite; the transceiver unit 1220 is used to resend the first message to a second network element, and the second network element is located on the second satellite.

[0567] In one possible design, the third information includes an identifier of the second network element, an identifier of the second satellite, or at least one of identifiers of other devices located on the second satellite, wherein the second network element supports storage and forwarding.

[0568] In one possible design, the second satellite covers the terminal earlier than the first satellite, and when there is a communication link between the first satellite and the core network device, there is also a communication link between the second satellite and the core network device, and the core network device is located on the ground.

[0569] When the communication device 1200 is used to implement the function of the first network element in the above method embodiment:

[0570] The transceiver unit 1220 is used to send and receive messages, and the processing unit 1210 is used to receive a first message from the terminal through the transceiver unit 1220, wherein the first network element is located on the first satellite; when there is no communication link between the terminal and the core network device, a second message is sent to the terminal, the second message includes first information, and the first information is used to trigger the terminal to enter a sleep state, and the core network device is located on the ground.

[0571] In one possible design, the first information is capability information of the first network element, and the capability information of the first network element indicates that the first network element supports storage and forwarding; or, the first information indicates that there is no power feeding information between the first network element and the core network device.

[0572] In one possible design, the first message is a NAS message or uplink data.

[0573] In one possible design, the first message is a first registration request message; after sending the second message to the terminal, the transceiver unit 1220 is used to receive a second registration request message from the terminal.

[0574] In one possible design, the processing unit 1210 is used to determine second information based on the first registration request message, and the second information is used to trigger reporting of at least one parameter; the second message also includes second information; the second registration request message includes the at least one parameter.

[0575] In one possible design, when there is a communication link between the core network device and the core network device, the transceiver unit 1220 is used to send a third registration request message to the core network device, wherein the third registration request message is determined based on the first registration request message and the second registration request message.

[0576] In one possible design, after receiving the second registration request message from the terminal, the transceiver unit 1220 is used to send a third message to the terminal, where the third message is used to indicate that the first satellite no longer provides service to the terminal.

[0577] In one possible design, the second message or the third message also includes information of a first timer; the first timer is used to indicate the length of time the terminal is in a sleep state.

[0578] In one possible design, the second message also includes third information, and the third information is used to determine a second satellite, which is the next satellite to serve the terminal; the processing unit 1210 is used to determine the third information based on ephemeris information, the location information of the terminal, and at least one of the receiving beam information of the first message.

[0579] In one possible design, the third information includes an identifier of a second network element, an identifier of the second satellite, or at least one of identifiers of other devices located on the second satellite, wherein the second network element is located on the second satellite and the second network element supports storage and forwarding.

[0580] In one possible design, the receiving beam information includes at least one of receiving time information, beam angle, beam identifier, or physical deployment location information of the satellite where the beam is located.

[0581] In one possible design, the second satellite covers the terminal earlier than the first satellite, and when a communication link exists between the first satellite and the core network device, a communication link also exists between the second satellite and the core network device.

[0582] In one possible design, when a communication link exists with the core network device, the transceiver unit 1220 is used to send the third information to the core network device.

[0583] When the communication device 1200 is used to implement the function of the first network element in the above method embodiment:

[0584] The transceiver unit 1220 is used to receive a first identifier and a first message from a first access device; the first message is used by the terminal to request registration with the network, the first identifier is used to trigger the first network element to assign a second identifier to the terminal, and the first network element and the first access device are located on the first satellite; the processing unit 1210 is used to assign a second identifier to the terminal based on the first identifier and information of the first satellite, and the second identifier is used to identify the terminal; when there is a communication link with the core network device, the transceiver unit 1220 is used to send the first message and the second identifier to the core network device, wherein the core network device is located on the ground.

[0585] In one possible design, before allocating a second identifier to the terminal based on the first identifier and the identifier of the first satellite, the processing unit 1210 is used to determine whether the number of terminals that have accessed the first satellite is less than a preset threshold.

[0586] In one possible design, the information of the first satellite includes an identifier of the first satellite, an identifier of the first network element, an identifier of the first access device, or one or more items in a prefix address pool corresponding to the first satellite.

[0587] In one possible design, the first network element allocates storage space for the terminal, where the storage space is used to store uplink messages from the terminal and / or downlink messages of the terminal, and the storage space corresponds to the second identifier.

[0588] In one possible design, the transceiver unit 1220 is used to receive a second message and the second identifier sent from the core network device; the processing unit 1210 is used to save the second message according to the first identifier; when there is a communication link with the terminal, the transceiver unit 1220 is used to send the second message to the terminal.

[0589] In one possible design, the transceiver unit 1220 is used to send the second identifier to the terminal; receive a third message and the second identifier from the terminal; the processing unit 1210 is used to save the third message based on the first identifier; and send the third message to the core network device when there is a communication link with the core network device.

[0590] In one possible design, the first identifier is a cell radio network temporary identifier C-RNTI.

[0591] In one possible design, when a communication link exists with the terminal, the transceiver unit 1220 is used to send information of a first timer to the terminal; the first timer indicates the length of time the terminal is in a sleep state.

[0592] In one possible design, when a communication link exists with the core network device, the transceiver unit 1220 is used to also send the remaining value of the first timer to the core network device.

[0593] When the communication device 1200 is used to implement the functions of the core network device in the above method embodiment:

[0594] The transceiver unit 1220 is used to receive a first message and a second identifier from a first network element, where the second identifier is used to indicate the terminal, wherein the first network element is located on a first satellite and the core network device is located on the ground; the processing unit 1210 is used to determine a second satellite, where the second satellite is the next satellite to provide services to the terminal; wherein the second satellite is determined based on ephemeris information and the location information of the terminal; or, the ephemeris information and the location information of the terminal are sent to a computing device through the transceiver unit 1220, and indication information from the computing device is received, where the indication information indicates the second satellite; the transceiver unit 1220 is used to send a second message and the second identifier to the second network element according to the first message, wherein the second network element is located on the second satellite.

[0595] In one possible design, the transceiver unit 1220 is used to receive the remaining value of the first timer from the first network element, where the first timer indicates the length of time the terminal is in a sleep state; when determining the second satellite based on the ephemeris information and the position information of the terminal, the processing unit 1210 is used to determine the second satellite based on the ephemeris information, the position information of the terminal, and the remaining value of the first timer.

[0596] In one possible design, the transceiver unit 1220 is used to receive the remaining value of the first timer from the first network element, where the first timer indicates the length of time the terminal is in a sleep state; the core network device also sends the remaining value of the first timer to the computing device.

[0597] In one possible design, the second network element supports store-and-forward.

[0598] In one possible design, the transceiver unit 1220 is used to receive capability information of the second network element from the second network element, where the capability information of the second network element indicates that the second network element supports storage and forwarding.

[0599] In one possible design, the second satellite covers the terminal earlier than the first satellite, and when a communication link exists between the first satellite and the core network device, a communication link also exists between the second satellite and the core network device.

[0600] In one possible design, the first message is used by the terminal to request registration with the core network device, and the second message is a response message to the first message.

[0601] In one possible design, the transceiver unit 1220 is used to receive capability information of the first network element from the first network element, where the capability information of the first network element indicates that the first network element supports storage and forwarding.

[0602] A more detailed description of the processing unit 1210 and the transceiver unit 1220 can be directly obtained by referring to the relevant description in the above method embodiment, and will not be repeated here.

[0603] As shown in Figure 13, communication device 1300 includes a processor 1310 and an interface circuit 1320. Processor 1310 and interface circuit 1320 are coupled to each other. It is understood that interface circuit 1320 can be a transceiver or an input / output interface. Optionally, communication device 1300 may also include a memory 1330 for storing instructions executed by processor 1310, input data required by processor 1310 to execute instructions, or data generated by processor 1310 after executing instructions.

[0604] When the communication device 1300 is used to implement the method shown in FIG. 5 , the processor 1310 is used to implement the functions of the processing unit 1210 , and the interface circuit 1320 is used to implement the functions of the transceiver unit 1220 .

[0605] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0606] The present application provides another example of a device, which includes at least one processor and at least one memory, the at least one processor and the at least one memory being coupled together, the at least one memory being used to store instructions. When the instructions are executed by the at least one processor, the communication device executes the method in the above-described embodiment. Taking a communication device including a processor and a memory as an example, as shown in FIG13 , a communication device 1300 includes a processor 1310 and a memory 1330. The processor 1310 and the memory 1330 are coupled together, and the memory 1330 stores instructions. When the instructions stored in the memory 1330 are executed by the processor 1310, the communication device 1300 executes the method executed by each network element in the above-described embodiment.

[0607] The method steps in the embodiments of the present application can be implemented in hardware or in software instructions that can be executed by a processor. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disk, mobile hard disk, CD-ROM or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. The storage medium can also be an integral part of the processor. The processor and the storage medium can be located in an ASIC. In addition, the ASIC can be located in the above-mentioned network element. The processor and the storage medium can also exist in the above-mentioned network element as discrete components.

[0608] In the above embodiments, all or part of the embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions may be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a digital video disk; or a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or nonvolatile storage medium, or may include both volatile and nonvolatile types of storage media.

[0609] In this application, "at least one" means one or more, and "more" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. In the text description of this application, the character " / " generally indicates that the previous and next associated objects are in an "or" relationship; in the formula of this application, the character " / " indicates that the previous and next associated objects 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.

[0610] It is understood that the various numbers used in the embodiments of this application are merely for ease of description and are not intended to limit the scope of the embodiments of this application. The order of the sequence numbers of the above-mentioned processes does not necessarily imply a specific order of execution; the order of execution of the processes should be determined by their functions and inherent logic.

Claims

1. A communication method, characterized in that, The method includes: The terminal sends a first message to a first network element, where the first network element is located on a first satellite; The terminal receives a second message from the first network element, and the second message includes first information for triggering the terminal to enter a sleep state; The terminal enters the sleep state according to the first information.

2. The method according to claim 1, wherein The first information is the capability information of the first network element, and the capability information of the first network element indicates that the first network element supports store-and-forward; Alternatively, the first information indicates that there is no power feeding information between the first network element and the core network device.

3. The method according to claim 1 or 2, characterized in that, The first message is a non-access stratum (NAS) message or uplink data.

4. The method according to any one of claims 1-3, characterized in that, The first message is a first registration request message; Before the terminal enters the sleep state, it further includes: The terminal sends a second registration request message to the first network element according to the first information.

5. The method according to any one of claims 1 to 3, characterized in that, The first message is a first registration request message; the second message further includes second information for triggering the reporting of at least one parameter; Before the terminal enters the sleep state, it further includes: The terminal sends a second registration request message to the first network element according to the second information, and the second registration request message includes the at least one parameter.

6. The method according to claim 4 or 5, characterized in that, After the terminal sends the second registration request message to the first network element, the method further includes: The terminal receives a third message from the first network element, and the third message is used to indicate that the first satellite no longer provides services to the terminal.

7. The method according to claim 6, characterized in that The second message or the third message includes information of a first timer; the first timer is used to indicate the duration for which the terminal is in the sleep state; After the first timer times out, the terminal re-sends the first message.

8. The method according to any one of claims 1-7, characterized in that, The second message further includes third information for determining a second satellite, and the second satellite is the next satellite to serve the terminal; The method further includes: The terminal receives a broadcast message; the broadcast message indicates the satellite covering the terminal; The terminal determines that the satellite indicated by the broadcast message is the second satellite according to the third information; The terminal re-sends the first message to a second network element, and the second network element is located on the second satellite.

9. The method according to any one of claims 8, characterized in that, The third information includes at least one of the identifier of the second network element, the identifier of the second satellite, or the identifier of other devices located on the second satellite, where the second network element supports store-and-forward.

10. The method according to claim 8 or 9, characterized in that, The second satellite covers the terminal earlier than the first satellite, and when there is a communication link between the first satellite and the core network device, there is also a communication link between the second satellite and the core network device, and the core network device is located on the ground.

11. A communication method, characterized in that, The method includes: A first network element receives a first message from a terminal, where the first network element is located on a first satellite; When there is no communication link between the first network element and the core network device, the first network element sends a second message to the terminal, and the second message includes first information for triggering the terminal to enter a sleep state, and the core network device is located on the ground.

12. The method according to claim 11, wherein The first information is the capability information of the first network element, and the capability information of the first network element indicates that the first network element supports store-and-forward; Alternatively, the first information indicates that there is no power feeding information between the first network element and the core network device.

13. The method according to claim 11 or 12, characterized in that, The first message is a NAS message or uplink data.

14. The method according to any one of claims 11-13, characterized in that, The first message is a first registration request message; After the first network element sends a second message to the terminal, the method further includes: The first network element receives a second registration request message from the terminal.

15. The method according to claim 14, wherein The method further includes: The first network element determines second information according to the first registration request message, and the second information is used to trigger the reporting of at least one parameter; The second message further includes second information; The second registration request message includes the at least one parameter.

16. The method according to claim 14 or 15, characterized in that, The method further includes: When there is a communication link between the first network element and the core network device, the first network element sends a third registration request message to the core network device, where the third registration request message is determined according to the first registration request message and the second registration request message.

17. The method according to any one of claims 14 to 16, characterized in that, After the first network element receives a second registration request message from the terminal, the method further includes: The first network element sends a third message to the terminal, and the third message is used to indicate that the first satellite no longer provides services to the terminal.

18. The method according to claim 17, wherein The second message or the third message further includes information about a first timer; the first timer is used to indicate the duration of the terminal in the sleep state.

19. The method according to any one of claims 11-18, characterized in that, The second message further includes third information, and the third information is used to determine a second satellite, and the second satellite is the next satellite to serve the terminal; The method further includes: The first network element determines the third information according to at least one of ephemeris information, the location information of the terminal, and the receiving beam information of the first message.

20. The method according to claim 19, wherein The third information includes at least one of the identifier of a second network element, the identifier of the second satellite, or the identifier of other devices located on the second satellite, where the second network element is located on the second satellite and the second network element supports store-and-forward.

21. The method according to claim 19 or 20, characterized in that The receiving beam information includes at least one of receiving time information, beam angle, beam identifier, or beam physical deployment location information of the satellite where the beam is located.

22. The method according to any one of claims 19 - 21, characterized in that, The second satellite covers the terminal earlier than the first satellite, and when there is a communication link between the first satellite and the core network device, there is also a communication link between the second satellite and the core network device.

23. The method according to any one of claims 19-22, characterized in that, The method further includes: When there is a communication link between the first network element and the core network device, the first network element sends the third information to the core network device.

24. A communication method, characterized in that, The method includes: A first network element receives a first identifier and a first message from a first access device; the first message is for a terminal to request registration to the network, the first identifier is used to trigger the first network element to allocate a second identifier to the terminal, and the first network element and the first access device are located on a first satellite; The first network element allocates a second identifier to the terminal according to the first identifier and the information of the first satellite, and the second identifier is used to identify the terminal; When there is a communication link between the first network element and the core network device, the first network element sends the first message and the second identifier to the core network device, where the core network device is located on the ground.

25. The method according to claim 24, wherein Before the first network element allocates a second identifier for the terminal according to the first identifier and the identifier of the first satellite, the method further includes: The first network element determines that the number of terminals accessing the first satellite is less than a preset threshold.

26. The method according to claim 25, characterized in that, The information of the first satellite includes one or more of the identifier of the first satellite, the identifier of the first network element, the identifier of the first access device, or the prefix address pool corresponding to the first satellite.

27. The method according to any one of claims 24-26, characterized in that, The method further includes: The first network element allocates storage space for the terminal, and the storage space is used to store the uplink message from the terminal and / or the downlink message of the terminal, and the storage space corresponds to the second identifier.

28. The method according to any one of claims 24-27, characterized in that, The method further includes: The first network element receives a second message and the second identifier sent by the core network device; The first network element stores the second message according to the first identifier; When there is a communication link between the first network element and the terminal, the first network element sends the second message to the terminal.

29. The method according to any one of claims 24-28, characterized in that, The method further includes: The first network element sends the second identifier to the terminal; The first network element receives a third message and the second identifier from the terminal; The first network element stores the third message according to the first identifier; When there is a communication link between the first network element and the core network device, the first network element sends the third message to the core network device.

30. The method according to any one of claims 24-29, characterized in that, The first identifier is a cell radio network temporary identifier C-RNTI.

31. The method according to any one of claims 24-30, characterized in that, The method further includes: When there is a communication link between the first network element and the terminal, the first network element sends the information of the first timer to the terminal; the first timer indicates the duration for which the terminal is in the sleep state.

32. The method according to claim 31, wherein The method further includes: When there is a communication link between the first network element and the core network device, the first network element also sends the remaining value of the first timer to the core network device.

33. A communication method, characterized in that, The method includes: The core network device receives a first message and a second identifier from the first network element, and the second identifier is used to indicate the terminal, where the first network element is located on the first satellite and the core network device is located on the ground; The core network device determines a second satellite, and the second satellite is the next satellite to provide services for the terminal; wherein, the core network device determines the second satellite according to the ephemeris information and the position information of the terminal; or, the core network device sends the ephemeris information and the position information of the terminal to the computing device, and the core network device receives the indication information from the computing device, and the indication information indicates the second satellite; The core network device sends a second message and the second identifier to the second network element according to the first message, where the second network element is located on the second satellite.

34. The method according to claim 33, wherein The method further includes: The core network device receives the remaining value of the first timer from the first network element, and the first timer indicates the duration for which the terminal is in the sleep state; The core network device determines the second satellite according to ephemeris information and the location information of the terminal, including: The core network device determines the second satellite according to ephemeris information, the location information of the terminal, and the remaining value of the first timer.

35. The method according to claim 33, wherein The method further includes: The core network device receives the remaining value of the first timer from the first network element, and the first timer indicates the duration for which the terminal is in the dormant state; The method further includes: The core network device also sends the remaining value of the first timer to the computing device.

36. The method according to any one of claims 33 to 35, characterized in that The second network element supports store-and-forward.

37. The method according to claim 36, characterized in that, The method further includes: The core network device receives the capability information of the second network element from the second network element, and the capability information of the second network element indicates that the second network element supports store-and-forward.

38. The method according to any one of claims 33 to 37, characterized in that, The second satellite covers the terminal earlier than the first satellite, and when there is a communication link between the first satellite and the core network device, there is also a communication link between the second satellite and the core network device.

39. The method according to any one of claims 33-38, characterized in that, The first message is used for the terminal to request registration to the core network device, and the second message is a response message to the first message.

40. The method according to any one of claims 33-39, characterized in that, The method further includes: The core network device receives the capability information of the first network element from the first network element, and the capability information of the first network element indicates that the first network element supports store-and-forward.

41. A communication device, characterized in that, It includes a unit or module for executing the method according to any one of claims 1 to 40.

42. A communication device, characterized in that, The communication device includes at least one processor; the at least one processor is configured to execute the method according to any one of claims 1 to 40.

43. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a program, and when the program runs on the device, the device is caused to execute the method according to any one of claims 1 to 40.

44. A computer program product, characterized in that, The computer program product includes a program or instruction, and when the program or instruction is executed by the device, the device is caused to execute the method according to any one of claims 1 to 40.

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