Communication method, communication apparatus, and storage medium

Abstract

The present application relates to a communication method and apparatus, and a storage medium. The method comprises: a terminal sending a network connection request to a satellite, the network connection request being used for instructing the terminal to establish a network connection with the satellite; and receiving a target response message returned to the terminal by a device on the satellite. By means of said method, an IoT terminal device can establish a network connection with a network on the basis of a satellite having on-board store-and-forward characteristics, such that full communication coverage is enhanced and the reliability of terminal communication is ensured, thereby providing a communication basis for terminals in remote areas, and better meeting the communication requirements of terminal devices.

Description

Communication Method, Communication Device, and Storage Medium Cross - reference This application claims priority to Chinese Patent Application No. 2024100449758, titled "Communication Method, Device, Computer Equipment, and Storage Medium", filed on January 11, 2024, which is hereby incorporated by reference in its entirety into this application. Technical Field This application relates to the field of on - satellite store - and - forward technology, and particularly to a communication method, a communication device, a storage medium, and a computer program product. Background Art In areas where it is not easy to deploy devices such as base stations and gateway stations, information interaction needs to be achieved through satellites. By deploying 4G / 5G base stations on satellites, the cost requirements for ground - based satellite deployment can be reduced. Since the deployment of gateway stations is also limited, when the satellite is in the air, it may not be able to connect to the gateway station in time, and thus data may not be immediately transmitted back to the core network. In practical application scenarios, due to limited device resources on the satellite, only a minimum number of core network devices can be deployed on the satellite. With a large number of Internet of Things (IoT) devices, it is impossible to store the subscription information of each device on the satellite. Related core network devices such as Home Subscriber Server (HSS) / Authentication Server Function (AUSF) / Unified Data Management (UDM) are deployed on the ground. Therefore, when the satellite is in the on - satellite store - and - forward working mode, the registration request of User Equipment (UE) cannot be sent to the ground in time for service authorization. How to timely implement UE authentication and authorization is an urgent problem to be solved. Summary of the Invention Based on this, this application provides a communication method, a communication device, a computer - readable storage medium, and a computer program product. In a first aspect, this application provides a communication method, which is applied to a terminal. The method includes: Sending a network connection request to a satellite, where the network connection request is used to instruct the terminal to establish a network connection with the satellite. Receiving a target response message returned by a device on the satellite to the terminal. In some embodiments, the network connection request includes the ability to support store - and - forward and a terminal identifier. In some embodiments, the receiving the target response message returned by a device on the satellite to the terminal includes: Receiving a first request acceptance response message returned by a device on the satellite to the terminal, where the first request acceptance response message carries the data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward, and the first request acceptance response message is generated by the satellite after determining that the terminal is in an accessible network state based on the terminal identifier and the ability to support store-and-forward. In some embodiments, the network connection request includes the ability to support store-and-forward and a terminal identifier; the receiving the target response message returned by the device on the satellite to the terminal includes: Receiving a second request acceptance response message returned by a device on the satellite to the terminal, where the second request acceptance response message carries the data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward, and the second request acceptance response message is generated by the satellite after determining that the terminal is in a restricted transmission state based on a second configuration policy, the terminal identifier, and the ability to support store-and-forward. In some embodiments, the network connection request includes the ability to support store-and-forward; the receiving the target response message returned by the device on the satellite to the terminal includes: Receiving a request staging response message returned by a device on the satellite to the terminal, where the request staging response message is generated by the device on the satellite based on the satellite being in a store-and-forward mode, the terminal meeting the conditions for initial access to the satellite, and the terminal's ability to support store-and-forward; the request staging response message carries a satellite identifier. In some embodiments, the network connection request includes the ability to support store-and-forward; the receiving the target response message returned by the device on the satellite to the terminal includes: Receiving a rejection response message returned by a device on the satellite to the terminal, where the rejection response message is generated by the device on the satellite based on the satellite being in a store-and-forward mode, the terminal meeting the conditions for initial access to the satellite, and the terminal's ability to support store-and-forward; the rejection response message carries a rejection reason message and a satellite identifier. In some embodiments, the target response message further carries a satellite identifier and a bearer session identifier. In some embodiments, the target response message further carries the satellite flyback time. In some embodiments, before the step of sending a network connection request to the satellite, the method further includes: Receiving a satellite broadcast message. In some embodiments, the satellite broadcast message carries store-and-forward characteristics and / or a satellite identifier. In some embodiments, the method further includes: Send the data to be transmitted that meets the data storage quota to the satellite. In a second aspect, the present application provides a communication method applied to a satellite. The method includes: Receive a network connection request sent by a terminal, where the network connection request is used to instruct the terminal to establish a network connection with the satellite; Generate a target response message based on the network connection request, and return the target response message to the terminal. In some embodiments, the network connection request carries a terminal identifier and the ability to support store-and-forward. In some embodiments, the generating a target response message based on the network connection request and returning the target response message to the terminal includes: Based on the terminal identifier and the ability to support store-and-forward, determine that the terminal is in an accessible network state, and determine the data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward based on the available satellite coverage time; Return a first request acceptance response message to the terminal, where the first request acceptance response message carries the data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward. In some embodiments, the method further includes: If the satellite covers a gateway station and receives the data to be transmitted that meets the data storage quota sent by the terminal, forward the data to be transmitted. In some embodiments, the if the satellite covers a gateway station and receives the data to be transmitted that meets the data storage quota sent by the terminal, then forward the data to be transmitted includes: If the satellite covers a gateway station and receives the data to be transmitted that meets the data storage quota sent by the terminal, perform secondary authentication processing on the terminal; If it is determined that the terminal passes the secondary authentication, forward the data to be transmitted. In some embodiments, the network connection request carries a terminal identifier and the ability to support store-and-forward. The generating a target response message based on the network connection request and returning the target response message to the terminal includes: Based on a second configuration policy, the terminal identifier, and the ability to support store-and-forward, determine that the terminal is in a restricted transmission state, and determine the data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward based on the available satellite coverage time; Return a second request acceptance response message to the terminal, where the second request acceptance response message carries the data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward. In some embodiments, the method further includes: If the satellite covers the gateway station, obtain the subscription information of the terminal; if it is determined based on the subscription information that the authentication of the terminal passes and the data to be transmitted that meets the data storage quota sent by the terminal is received, forward the data to be transmitted, and update the restricted transmission state of the terminal to an unrestricted transmission state. In some embodiments, the method further includes: If it is detected that the terminal obtains the coverage of the satellite, send a status update message to the terminal, where the status update message indicates that the restricted transmission state of the terminal is updated to an unrestricted transmission state. In some embodiments, the target response message further carries a satellite identifier and a bearer session identifier. In some embodiments, generating a target response message based on the network connection request and returning the target response message to the terminal includes: Generate a request for temporary storage response message based on the satellite being in the store-and-forward mode, the terminal meeting the initial access satellite condition, and the store-and-forward support ability of the terminal; Return the request for temporary storage response message to the terminal, where the request for temporary storage response message carries a satellite identifier. In some embodiments, generating a target response message based on the network connection request and returning the target response message to the terminal includes: Generate a rejection response message based on the satellite being in the store-and-forward mode, the terminal meeting the initial access satellite condition, and the store-and-forward support ability of the terminal; Return the rejection response message to the terminal, where the rejection response message carries a rejection reason message and a satellite identifier. In some embodiments, the method further includes: Send a broadcast message, where the broadcast message is used to instruct the terminal to connect to the satellite. In some embodiments, the broadcast message includes store-and-forward characteristics and / or a satellite identifier. In some embodiments, the target response message further carries a satellite flyback time. In a third aspect, the present application provides a communication device, which is applied to a terminal, and the device includes: A first sending unit, configured to send a network connection request to a satellite, where the network connection request is used to instruct the terminal to establish a network connection with the satellite; A first receiving unit, configured to receive a target response message returned by a device on the satellite to the terminal. In a fourth aspect, the present application provides a communication device, which is applied to a satellite, and the device includes: A second receiving unit, configured to receive a network connection request sent by a terminal, where the network connection request is used to indicate that the terminal establishes a network connection with the satellite; A second sending unit, configured to generate a target response message based on the network connection request and return the target response message to the terminal. In a fifth aspect, the present application provides a communication device, including a memory, a transceiver, and a processor: The memory is used to store a computer program; the transceiver is used to transmit and receive data under the control of the processor; the processor is configured to read the computer program in the memory and implement the steps of the communication method provided in the above embodiments when executing the computer program. In a sixth aspect, the present application provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the communication method provided in the above embodiments are implemented. In a seventh aspect, the present application further provides a computer program product, including a computer program, and when the computer program is executed by a processor, the steps of the communication method provided in the above embodiments are implemented. For the above communication method, device, and storage medium, the terminal may send a network connection request to the satellite, where the network connection request is used to indicate that the terminal establishes a network connection with the satellite; and receive a target response message returned by a device on the satellite to the terminal. By adopting this method, the terminal IoT device can establish a network connection with the network based on a satellite with on-board store-and-forward characteristics, improve the comprehensiveness of communication coverage, and ensure the reliability of terminal communication, providing a communication foundation for the communication of terminals in remote areas and better meeting the communication needs of terminal devices. The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features, and advantages of the present application more obvious and understandable, the following specifically illustrates the specific embodiments of the present application. Description of the Drawings By reading the detailed description of the following embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the embodiments and are not considered to be a limitation of the present application. And in all the drawings, the same reference numerals are used to represent the same components. In the drawings: FIG. 1 is an application environment diagram of the communication method in an embodiment of the present application; FIG. 2 is a flowchart of the communication method in an embodiment of the present application; FIG. 3 is a flowchart of the communication method in an embodiment of the present application; FIG. 4 is a flowchart of the communication method in an embodiment of the present application; FIG. 5 is a schematic flowchart of the communication method in an embodiment of the present application; FIG. 6 is a schematic flowchart of the communication method in an embodiment of the present application; FIG. 7 is a signaling diagram of the communication method in an embodiment of the present application; FIG. 8 is a signaling diagram of the communication method in an embodiment of the present application; FIG. 9 is a signaling diagram of the communication method in an embodiment of the present application; FIG. 10 is a structural block diagram of the communication device in an embodiment of the present application; FIG. 11 is a structural block diagram of another communication device in an embodiment of the present application; FIG. 12 is an internal structural diagram of the communication device in an embodiment. Detailed implementation manners The embodiments of the technical solution of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of the present application more clearly, so they are only examples and cannot be used to limit the protection scope of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above drawings are intended to cover non-exclusive inclusion. In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present application, "a plurality" means more than two unless otherwise specifically defined. Referring to "embodiment" herein means that a specific feature, structure or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments. In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after. In the description of the embodiments of the present application, the term "plurality" means more than two (including two). Similarly, "multiple groups" means more than two groups (including two groups), and "multiple pieces" means more than two pieces (including two pieces). In the description of the embodiments of the present application, the orientation or positional relationship indicated by technical terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the embodiments of the present application. In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection, an electrical connection or a communication connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific situations. The embodiments of the present application provide a communication method and device for realizing communication between a terminal and a satellite, and between a satellite and a ground network based on an on-satellite store-and-forward mode. Among them, the method and the device are based on the same inventive concept. Since the principles of solving problems by the method and the device are similar, the implementation of the device and the method can be referred to each other, and the repeated parts will not be described again. Figure 1 shows a schematic diagram of the architecture of the communication system provided by the embodiments of the present application. As shown in Figure 1, the communication system architecture may include the following logical network elements: User Equipment (UE), SAT (Satellite), and terrestrial network elements. Among them, the satellite may include an evolved Node B (eNodeB), a Mobility Management Entity (MME), a Store-and-Forward Control Function (SFCF), and a target network element, which may be a Service Capability Exposure Function (SCEF) or a Serving Gateway (S-GW); the terrestrial network elements may include a Store-and-Forward Management Function (SFMF) and a server network element, which may be a Home Subscriber Server (HSS), a Packet Switch (P-SW), or a Store-and-Forward server; optionally, 5GC and a base station may be deployed on the SAT, and the 5GC includes an Access and Mobility Management Function (AMF), a Session Management Function (SMF), a User Plane Function (UPF), and an Authentication Server Function (AUSF); there are various deployment methods for the functions of all network elements on the satellite, which may be new network elements or enhancements to existing network elements. AMF: A core network unit, mainly responsible for functions related to registration management, connection management, access management, mobility management, and security and access management and authorization. SMF: A core network unit, mainly responsible for creating, updating, and deleting Protocol Data Unit (PDU) sessions. UPF: A core network unit, mainly responsible for user plane network traffic transmission. For IoT devices, a lightweight EPC (MME, S-GW, P-GW) or 5GC (AMF + SMF + UPF + AUSF) and a base station are deployed on the same satellite, and other CIoT devices are on the ground (or all CIoT devices may be on the satellite). The functions of the above devices can be set up as multiple separate network elements or as one device; devices such as HSS / UDM are on the ground. That is, the functions of the on-satellite devices include the function of processing NAS information, and only need to compare the authentication function of the UE and the network subscription information; optionally, it includes the function of allocating IP addresses for terminals and the function of user plane network elements; it may be an independent module or a new integrated network element. Optionally, in the requirements study of 3GPP SA1 R19, the scenarios where data needs to be stored and forwarded on satellites can be as follows. For some research institutions, they need to study the living habits, movement trajectories, etc. of animals; for government departments, they need to give early warnings in a timely manner to mitigate or avoid disasters, such as the detection of submarine cables, etc. These IoT devices deployed on animals or equipment are located in special or remote areas where there are no communication base stations, so satellite communication is required for data transmission. When the terminal device has low requirements for latency, the terminal can first upload the data to the satellite and store it on the satellite (there may be a base station or a core network element on the satellite), and then forward the data when the satellite can access the gateway station. It should be understood that the communication system architecture in FIG. 1 is only introduced as an example to illustrate the possible application environments of the solutions of this application. Those skilled in the art can understand that the embodiments of this application can be applied to the communication system architecture in FIG. 1 or a communication system architecture similar to FIG. 1. The communication architectures obtained by making appropriate deformations and changes based on the communication system architecture in FIG. 1 are still applicable to the solutions of the embodiments of this application. The technical solutions provided by the embodiments of this application can be applicable to multiple systems. For example, the applicable systems can be a Long Term Evolution (LTE) system, an LTE Frequency Division Duplex (FDD) system, an LTE Time Division Duplex (TDD) system, a Long Term Evolution Advanced (LTE-A) system, a Universal Mobile Telecommunication System (UMTS), a Worldwide Interoperability for Microwave Access (WiMAX) system, a 5G New Radio (NR) system and its evolved communication systems, etc. These multiple systems can include terminal devices and network devices. The systems can also include a core network part, such as an Evolved Packet System (EPS), a 5G System (5GS), etc. The terminal device involved in the embodiments of the present application may refer to a terminal IoT (Internet of Things) device, or a CIoT (Cellular Internet of Things) device; it may also refer to a device that provides voice and / or data connectivity to users, such as a handheld device with wireless connection capabilities, or other processing devices connected to a wireless modem, etc. In different systems, the name of the terminal device may also be different. For example, in a 5G system, the terminal device may be called a User Equipment (UE). The wireless terminal device may be a USB storage device, other personal computer memory devices, and dongles, and may also communicate with one or more core networks (CNs) via a Radio Access Network (RAN). The wireless terminal device may be a mobile terminal device, such as a mobile phone (or a "cellular" phone) and a computer with a mobile terminal device. For example, it may be a portable, pocket-sized, handheld, computer-integrated, or vehicle-mounted mobile device that exchanges voice and / or data with the wireless access network. For example, devices such as Personal Communication Service (PCS) phones, cordless phones, Session Initiated Protocol (SIP) phones, Wireless Local Loop (WLL) stations, Personal Digital Assistants (PDAs), personal computers, tablets, Machine-type Communication (MTC) terminal devices, etc. The wireless terminal device may also be referred to as a system, subscriber unit, subscriber station, mobile station, mobile, remote station, access point, remote terminal, access terminal, user terminal, user agent, user device, and wireless access points and routers / modems that meet the limitations of this definition, etc., which are not limited in the embodiments of the present application. The network device involved in the embodiments of the present application can be a base station, which may include multiple cells that provide services to terminals. Depending on the specific application scenario, the base station can also be referred to as an access point, or it can be a device in the access network that communicates with wireless terminal devices through one or more sectors over the air interface, or other names. The network device can be used to mutually replace the received airframe with Internet Protocol (IP) packets and act as a router between the wireless terminal device and the rest of the access network, where the rest of the access network may include an Internet Protocol (IP) communication network. The network device can also coordinate the management of the attributes of the air interface. For example, the network device involved in the embodiments of the present application can be an evolved network device (eNB or e-NodeB) in a Long-Term Evolution (LTE) system, a 5G base station (gNB) in a 5G network architecture (next generation system), etc., or it can also be a Home evolved Node B (HeNB), a relay node, a femto, a pico, a network test device, etc. The embodiments of the present application do not limit this. In some network architectures, the network device can include a centralized unit (CU) node and a distributed unit (DU) node, and the centralized unit and the distributed unit can also be arranged separately geographically. In the embodiments of the present application, the terminal device sends relevant information or a similar description to the network-side device, which only indicates that the relevant information is sent in the form of a wireless signal by the terminal device, and the intended recipient is the network device. The network device can obtain the relevant information by receiving the wireless signal. In an exemplary embodiment, as shown in Figure 2, a communication method is provided. Taking the terminal shown in Figure 1 as an example, this communication method may include: Step 202: Send a network connection request to the satellite. Among them, the network connection request is used for the terminal to establish a network connection with the satellite. Optionally, the terminal sends a network connection request to the MME in the satellite. This network connection request can carry corresponding data information based on the actual application scenario and requests to establish a network connection with the satellite. Step 204: Receive a target response message returned by the device on the satellite to the terminal. Optionally, after receiving the network connection request, the satellite can generate a target response message based on the communication mode in which the current satellite is located and return the target response message to the terminal. The device on the satellite can be the MME. In one example, the terminal can generate a network connection request based on its ability to support store-and-forward, and send the network connection request to the satellite. The network connection request carries an indication of the support for the store-and-forward feature. In one example, the terminal can send the network connection request to the MME in the satellite, and the network connection request carries an indication of the support for the store-and-forward feature. After receiving the network connection request, the MME on the satellite can generate a target response message based on the communication mode in which the current satellite is located, and return the target response message to the terminal. In the above communication method, the terminal can send a network connection request to the satellite, and the network connection request is used to indicate that the terminal requests to establish a network connection with the satellite; receive a target response message, which is returned by the device on the satellite to the terminal. By adopting this method, the terminal IoT device can establish a network connection with the network based on the satellite with the on-board store-and-forward feature, improve the comprehensiveness of communication coverage and ensure the reliability of terminal communication, provide a communication foundation for the communication of terminals in remote areas, and better meet the communication needs of terminal devices. In one embodiment, the network connection request includes the ability to support store-and-forward and the terminal identifier; optionally, carrying the ability to support store-and-forward can be carrying identification information indicating "support for the store-and-forward feature", characterizing that the terminal supports the store-and-forward feature. For example, the terminal can be an Internet of Things device that is not sensitive to and has low requirements for latency. The terminal identifier can be the device identification information of the terminal, etc., such as International Mobile Subscriber Identity (IMSI). In one embodiment, the step of receiving the target response message returned by the device on the satellite to the terminal may include: Receiving a first request acceptance response message returned by the device on the satellite to the terminal. Among them, the first request acceptance response message carries the data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward; the first request acceptance response message is generated by the satellite after determining that the terminal is in an accessible network state based on the terminal identifier and the ability to support store-and-forward. The data retention period (SandF data retention period) can be a data retention cycle determined based on the available time of satellite coverage, or it can also be the duration of the unavailability period (Unavailability Period Duration); the data storage quota (SandF data storage quota) can be the data capacity allowed by the satellite for the terminal to transmit, such as including the number of data transmissions and the size of each transmission, etc. Optionally, when the terminal wants to transmit information through the network, it can send a network connection request to the MME on the satellite. The terminal can generate a network connection request, which carries the ability to support store-and-forward, the terminal identifier, and send the network connection request to the MME on the satellite; after receiving the network connection request, if the MME on the satellite determines that the terminal is in an accessible state, the MME on the satellite can determine the data retention period and data storage quota for on-board store-and-forward based on the available satellite coverage time, and generate a first request acceptance response message based on the data retention period and data storage quota for on-board store-and-forward. Based on this, the MME on the satellite can return the first request acceptance response message to the terminal; after receiving the first request acceptance response message, the terminal can determine that the current terminal can transmit data to the satellite. In this embodiment, the data forwarding process can be simplified, and the user experience and the network registration efficiency of the terminal can be improved. In one embodiment, the network connection request includes the ability to support store-and-forward, the terminal identifier, and the first configuration information; optionally, carrying the ability to support store-and-forward can be carrying identification information indicating "supporting the store-and-forward feature", indicating that the terminal supports the store-and-forward feature. For example, the terminal can be an Internet of Things device that is not sensitive to and has low requirements for latency. The terminal identifier can be the device identification information of the terminal, etc., such as International Mobile Subscriber Identity (IMSI); the first configuration information can be pre-configured information, such as terminal information, specifically, it can be the security information of the terminal, the subscription information of the terminal, or the user plane information of the terminal, etc. The satellite can perform security authentication on the terminal based on this terminal information, or authenticate the terminal, etc. For example, the satellite can determine that the terminal can access the network based on this terminal information. Correspondingly, the step of receiving the target response message returned by the device on the satellite to the terminal may include: Receiving the first request acceptance response message returned by the device on the satellite to the terminal. Among them, the first request acceptance response message carries the on-board store-and-forward data retention period and the on-board store-and-forward data storage quota; the first configuration information is used to enable the satellite to authenticate the terminal, and the first request acceptance response message is generated by the satellite after determining that the terminal is in an accessible network state based on the first configuration policy, the terminal identifier, the ability to support store-and-forward, and the first configuration information. The data retention period (SandF data retention period) can be a data retention cycle determined based on the available time of satellite coverage, or it can also be the duration of the unavailability period (Unavailability Period Duration); the data storage quota (SandF data storage quota) can be the data capacity allowed by the satellite for the terminal to transmit, for example, it can include the number of data transmissions and the size of each transmission, etc. Optionally, when the terminal wants to transmit information through the network, it can send a network connection request to the MME on the satellite. The terminal can generate a network connection request, which carries the ability to support store-and-forward, the terminal identifier, and the first configuration information, and send the network connection request to the MME on the satellite; after receiving the network connection request, the MME on the satellite can, based on the first configuration policy, first authenticate the terminal. If the MME on the satellite determines that the terminal is in an accessible state, the MME on the satellite can determine the on-board store-and-forward data retention period and the on-board store-and-forward data storage quota based on the available time of satellite coverage, and generate a first request acceptance response message based on the on-board store-and-forward data retention period and the on-board store-and-forward data storage quota. Based on this, the MME on the satellite can return the first request acceptance response message to the terminal; after receiving the first request acceptance response message, the terminal can determine that the current terminal can transmit data to the satellite. In this embodiment, sending the first configuration information of the terminal to the satellite during the registration process avoids secondary data interaction between the terminal and the satellite, simplifies the data forwarding process, and improves the user experience and the network registration efficiency of the terminal. In one embodiment, the network connection request includes the ability to support store-and-forward and the terminal identifier; optionally, carrying the ability to support store-and-forward can be carrying identification information indicating "support for store-and-forward characteristics", characterizing that the terminal supports store-and-forward characteristics. For example, the terminal can be an Internet of Things device that is not sensitive to delay and has low requirements, etc.; the terminal identifier can be the device identification information of the terminal, etc., for example, it can be IMSI. Correspondingly, the step of "receiving the target response message returned by the device on the satellite to the terminal" can include: Receiving the second request acceptance response message returned by the device on the satellite to the terminal. Among them, the second request acceptance response message carries the data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward. After determining that the terminal is in a restricted transmission state based on the second configuration policy, the terminal identifier, and the ability to support store-and-forward, the satellite generates the second request acceptance response message. The second configuration policy can be a pre-configured operator configuration policy. The specific content of the second configuration policy can be that if the terminal supports the store-and-forward feature, it is determined that the terminal is in a restricted transmission state (limited state), and the terminal is supported to send limited data to the satellite. Optionally, when the terminal wants to transmit information through the network, it can send a network connection request to the MME on the satellite. The terminal can generate a network connection request based on the ability to support store-and-forward and the terminal identifier, and send the network connection request to the satellite. After receiving the network connection request sent by the terminal, the MME on the satellite can determine that the terminal is in a restricted transmission state based on the terminal identifier reported by the terminal, the ability to support store-and-forward, and the pre-configured second configuration policy. The MME in the satellite can determine the data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward based on the available time of satellite coverage, and generate a second request acceptance response message. Based on this, the MME on the satellite can return the second request acceptance response message to the terminal. After receiving the second request acceptance response message, the terminal can determine that the current terminal can transmit limited data to the satellite. In one example, the second request acceptance response message may also carry a satellite identifier, a bearer session identifier (Bearer ID), etc. The satellite can return the request acceptance response message to the terminal. In this embodiment, a network connection request carrying the ability to support store-and-forward can be sent to the satellite, so that the satellite returns a second request acceptance response message to quickly establish communication between the terminal and the satellite. In one embodiment, the network connection request includes the ability to support store-and-forward. Carrying the ability to support store-and-forward can be carrying identification information indicating "supporting the store-and-forward feature", indicating that the terminal supports the store-and-forward feature. For example, the terminal can be an Internet of Things device that is not sensitive to delay and has low requirements. Correspondingly, the step of "receiving the target response message returned by the device on the satellite to the terminal" may include: Receiving the request staging response message returned by the device on the satellite to the terminal. Among them, the request staging response message is generated by the device on the satellite based on the satellite being in the store-and-forward mode, the terminal meeting the initial access satellite conditions, and the terminal's ability to support store-and-forward; the request staging response message carries the satellite identifier. Optionally, when the terminal needs to establish a network connection with a satellite, it generates a network connection request carrying the ability to support store-and-forward, and sends the network connection request to the satellite. After receiving the network connection request carrying the ability to support store-and-forward, the satellite can determine that the terminal sending the network connection request supports the store-and-forward feature based on the ability to support store-and-forward carried in the network connection request. If the satellite is currently in the store-and-forward mode and the terminal sending the network connection request is a terminal that has newly accessed the satellite, the satellite can store the terminal identifier and terminal capabilities of this terminal, generate a request staging response message, and return the request staging response message to the terminal, indicating that the satellite has cached the network connection request sent by this terminal. Optionally, after receiving the request staging response message sent by the satellite, the terminal can switch to a low-power mode, such as a power-saving mode. In one example, before switching to the power-saving mode, the terminal can determine the next wake-up time based on ephemeris information, and after determining the next wake-up time, switch to the power-saving mode until the current time reaches the next wake-up time, after which the terminal can exit the power-saving mode and switch to the normal operating state. The ephemeris information can be an accurate position or trajectory table that changes with time as a function of time for celestial body operations. Optionally, after the terminal is covered by the satellite, it can initiate an attach request again, that is, send the network connection request to the satellite, and the network connection request carries the ability to support store-and-forward. If the MME in the satellite determines that the terminal is a non-newly accessed terminal based on the terminal identifier of the terminal, the satellite can authenticate the terminal based on the authentication information stored locally, and send a message to the terminal, and the message carries the information required for the terminal to authenticate the network, completing mutual authentication. Another possible implementation is that after the terminal is covered by the satellite, it can establish an RRC connection with the satellite that is consistent with the satellite identifier carried in the rejection response message, and based on this RRC connection, the terminal can initiate an attach request again, that is, send the network connection request to the satellite through this RRC connection, and the network connection request carries the ability to support store-and-forward. After receiving the network connection request, the satellite can perform mutual authentication based on the terminal identifier carried in the network connection request and the authentication information of this terminal stored locally in the satellite. Based on this, after the satellite determines that the terminal has passed the authentication, the satellite can accept the network connection request sent by the terminal, determine the data retention period based on the available satellite coverage time, and determine the data storage quota corresponding to the terminal, generate a request acceptance response message based on the data retention period and the data storage quota, and return the request acceptance response message to the terminal. In this embodiment, by sending a network connection request carrying the ability to support store-and-forward from the terminal to the satellite, reliable communication between the terminal device and the satellite can be achieved. By requesting to temporarily store the response message to prompt the terminal that the network request has been temporarily stored by the satellite, the terminal can initiate a request to re-connect to the network in a timely manner when it is covered by the satellite in the subsequent process, improving the flexibility of the terminal to access the network. In one embodiment, the network connection request includes the ability to support store-and-forward. Carrying the ability to support store-and-forward may be carrying identification information indicating "supporting the store-and-forward feature", characterizing that the terminal supports the store-and-forward feature. For example, the terminal may be an Internet of Things device that is not sensitive to and has low requirements for latency. Correspondingly, the step of "receiving the target response message returned by the device on the satellite to the terminal" may include: Receiving a rejection response message returned by the device on the satellite to the terminal. Wherein, the device on the satellite generates a rejection response message based on the satellite being in the store-and-forward mode, the terminal meeting the conditions for initial access to the satellite, and the terminal's ability to support store-and-forward; the rejection response message carries a rejection reason message and a satellite identifier. Optionally, in a scenario where the terminal needs to establish a network connection with the satellite, it generates a network connection request carrying the ability to support store-and-forward and sends the network connection request to the satellite; the satellite can determine that the terminal sending the network connection request supports the store-and-forward feature based on the ability to support store-and-forward carried in the network connection request; if the satellite is currently in the store-and-forward mode and the terminal sending the network connection request is accessing the satellite for the first time, the satellite can temporarily store the network connection request corresponding to the terminal, store the terminal identifier and terminal capabilities of the terminal, and generate a rejection response message carrying a rejection reason message and a satellite identifier, and return the rejection response message to the terminal. Among them, the rejection reason message may be a request caching message, that is, the satellite is in the on-board store-and-forward mode, and the terminal supports the on-board store-and-forward mode, indicating that the satellite has cached the network connection request sent by the terminal. In one example, if the satellite covers the gateway station, that is, if the feeder link between the satellite and the ground is in an available state (Feeder link is available), the MME in the satellite can send the network connection request to the ground network element through the ground C-SCN-Ground, obtain the subscription information (authentication information) of the terminal through the ground network element, and store the authentication information of the terminal in the satellite. Optionally, after the terminal has the coverage of the satellite, it can initiate an attach request again, that is, send the network connection request to the satellite. The network connection request carries the ability to support store-and-forward. If the MME in the satellite determines that the terminal is a non-first-access terminal based on the terminal identifier of the terminal, the satellite can authenticate the terminal based on the authentication information stored locally and send a message to the terminal. The message carries the information required for the terminal to authenticate the network, completing the mutual authentication. Another possible implementation method can be that after the terminal has the coverage of the satellite, it can establish an RRC connection with the satellite that is consistent with the satellite identifier carried in the rejection response message, and based on this RRC connection, the terminal can initiate an attach request again, that is, send the network connection request to the satellite through this RRC connection, carrying the ability to support store-and-forward. After receiving the network connection request, the satellite can perform mutual authentication based on the terminal identifier carried in the network connection request and the authentication information of the terminal stored locally in the satellite. Based on this, after the satellite determines that the terminal has passed the authentication, the satellite can accept the network connection request sent by the terminal, determine the data retention period based on the available time of satellite coverage, and determine the data storage quota corresponding to the terminal. Generate a request acceptance response message based on the data retention period and the data storage quota, and return the request acceptance response message to the terminal. In this embodiment, through multiple requests between the terminal and the satellite, the terminal IoT device can be registered to the network through the satellite with the on-board store-and-forward feature, realizing the communication between the terminal device and the ground through the satellite and improving the communication reliability. In one embodiment, the step of "receiving the target response message returned by the device on the satellite to the terminal" may include: Receiving the connection response message returned by the device on the satellite to the terminal. Among them, the connection response message is the response message of the network connection request. The network connection request carries the terminal identifier and the ability to support store-and-forward. The connection response message carries the data retention period and the data storage quota; the terminal identifier can be the device identifier information of the terminal, etc., for example, it can be IMSI; the target response message can be the connection response message. Optionally, the terminal can generate a network connection request based on the terminal identifier and the ability to support store-and-forward, and send the network connection request to the satellite. After receiving the network connection request, the satellite can parse the network connection request to obtain the terminal identifier and the ability to support store-and-forward carried in the network connection request, determine the data retention period based on the available time of satellite coverage, and determine the data storage quota corresponding to the terminal. Generate a connection response message based on the data retention period and the data storage quota, and return the connection response message to the terminal. In this embodiment, communication between the terminal and the satellite can be achieved, a connection between the terminal and the satellite can be established, providing a communication basis for subsequent data forwarding. In one embodiment, the target response message further carries a satellite identifier and a bearer session identifier. Optionally, in the process of generating the target response message, the satellite can generate a target response message that also carries a satellite identifier and a bearer session identifier. For example, it can generate a first request acceptance response message carrying a satellite identifier and a bearer session identifier, and can also generate a second request acceptance response message carrying a satellite identifier and a bearer session identifier. The terminal can, based on the satellite identifier carried in the target response message, send data to be transmitted to a satellite whose identification information is consistent with this satellite identifier, and so on. In one embodiment, the target response message further carries the satellite flyback time. Optionally, the satellite flyback time can be the time when the satellite flies back next time. The terminal can, based on the satellite flyback time carried in the target response message, when the satellite flyback time is reached, or after an interval of the satellite flyback time, re-initiate a network connection request to this satellite. In this embodiment, it can facilitate the terminal to accurately initiate a network connection request to the satellite in a timely manner after the satellite flyback time. In one embodiment, before the step of sending a network connection request to the satellite, the method further includes: Receiving a satellite broadcast message. Optionally, the satellite can send a broadcast message within the communication coverage area of this satellite. After the terminal is powered on, it can search for the network and camp. After receiving the broadcast message sent by this satellite, it can, based on this broadcast message, send a network connection request to the satellite that sent this broadcast message. In this embodiment, the terminal can initiate a registration request to satellites in a communicable state based on the received broadcast message. In one example, the satellite broadcast message carries a store-and-forward feature and / or a satellite identifier. Among them, the broadcast message includes a store-and-forward feature and / or a satellite ID. The store-and-forward feature indicates that the satellite is a satellite in an on-board store-and-forward mode, that is, a satellite that can perform store-and-forward satellite operations (SandF Satellite Operation). For example, a base station or some core network elements can be deployed on the satellite. The terminal establishes a service link with the satellite to transmit signaling or data. When the satellite moves to establish a feeder link with the ground, the signaling or data can be interacted with the ground core network through a gateway station. The satellite ID represents the identifier of the satellite, such as the satellite number, and so on. Optionally, the terminal may parse the broadcast message to obtain the store-and-forward feature and / or satellite ID carried by the broadcast message. In one example, the terminal may obtain the store-and-forward feature and satellite ID carried by the broadcast message, the terminal may also obtain the store-and-forward feature carried by the broadcast message, and the terminal may also obtain the satellite ID carried by the broadcast, etc. In one embodiment, the communication method further includes: Sending data to be transmitted that meets the data storage quota to the satellite. Optionally, when there is data that meets the emergency transmission condition at the terminal, the terminal may extract the data to be transmitted from the data that meets the emergency transmission condition based on the data storage quota, and send the data to be transmitted to the satellite. In one example, the terminal may send the data to be transmitted to a target network element in the satellite. After receiving the data to be transmitted, the target network element may associate the data to be transmitted with the terminal identifier of the terminal, where the terminal is the terminal that sends the data to be transmitted, and forward the data to be transmitted to the terrestrial network element. Optionally, the target network element may be the MME in the satellite, or the store-and-forward network element in the satellite. In the case of session establishment, the target network element may also be the P-GW. In this embodiment, data transmission between the terminal and the terrestrial network element can be realized through the satellite, improving the comprehensiveness of communication coverage and ensuring the reliability of terminal communication, providing the possibility for the communication of terminals in remote areas. In an exemplary embodiment, as shown in Figure 3, a communication method is provided, which is applied to a satellite. The communication method includes: Step 302, receiving a network connection request sent by the terminal. Wherein, the network connection request is used to indicate that the terminal requests to establish a network connection with the satellite. Optionally, the satellite may receive the network connection request sent by the terminal and parse the network connection request. Step 304, generating a target response message based on the network connection request, and returning the target response message to the terminal. Optionally, the MME in the satellite may receive the network connection request sent by the terminal, and may generate a target response message based on the communication mode in which the current satellite is located, and return the target response message to the terminal. In this embodiment, the terminal IoT device can establish a network connection with a satellite in the on-board store-and-forward mode, which can improve the comprehensiveness of communication coverage, and can also ensure the reliability of terminal communication, providing a communication foundation for the communication of terminals in remote areas and better meeting the communication needs of terminal devices. In one embodiment, the network connection request carries the terminal identifier and the ability to support store-and-forward. Carrying the ability to support store-and-forward may be carrying identification information indicating "supporting the store-and-forward feature", characterizing that the terminal supports the store-and-forward feature. For example, it may indicate that the terminal is an Internet of Things device that is not sensitive to and has low requirements for latency, etc. In one embodiment, the step of "generating a target response message based on the network connection request and returning the target response message to the terminal" may include: Based on the terminal identifier and the ability to support store-and-forward, determine that the terminal is in an accessible network state, and based on the available satellite coverage time, determine the data retention period for on-satellite store-and-forward and the data storage quota for on-satellite store-and-forward; return a first request acceptance response message to the terminal. Among them, the first request acceptance response message carries the data retention period for on-satellite store-and-forward and the data storage quota for on-satellite store-and-forward, and the target response message may be the first request acceptance response message. Optionally, after receiving the network connection request sent by the terminal, the satellite may, based on the terminal identifier and the ability to support store-and-forward reported by the terminal, determine that the terminal may be in an accessible network state. The MME in the satellite may determine the data retention period for on-satellite store-and-forward based on the available satellite coverage time, and the MME in the satellite may determine the data storage quota for on-satellite store-and-forward. Optionally, the satellite may generate a first request acceptance response message based on the determined data retention period for on-satellite store-and-forward and the data storage quota for on-satellite store-and-forward. In one example, the first request acceptance response message may also carry the satellite identifier and the bearer session identifier (Bearer ID), etc. The satellite may return the first request acceptance response message to the terminal. In one example, if the satellite establishes a session based on the information reported by the terminal, the satellite may encapsulate the data storage quota for on-satellite store-and-forward into the NAS information and return the NAS information to the terminal. In this embodiment, the satellite can quickly establish communication between the terminal and the satellite after determining that the terminal is in an accessible network state and returning a first request acceptance response message to the terminal. In one embodiment, the network connection request carries the terminal identifier, the ability to support store-and-forward, and the first configuration information. Optionally, the first configuration information can be the security information of the terminal, the subscription information of the terminal, the user plane information of the terminal, etc. The satellite performs security authentication on the terminal based on the first configuration information, or performs authentication on the terminal, etc. For example, the satellite can determine that the terminal can access the network based on the first configuration information; carrying the ability to support store-and-forward can be carrying identification information indicating "supporting the store-and-forward feature", characterizing that the terminal supports the store-and-forward feature. For example, it can indicate that the terminal is an Internet of Things device that is not sensitive to and has low requirements for latency. Correspondingly, as shown in FIG. 4, the step of "generating a target response message based on the network connection request and returning the target response message to the terminal" may include: Step 402, based on the first configuration policy, the terminal identifier, the ability to support store-and-forward, and the first configuration information, determine that the terminal is in a state where it can access the network, and determine the data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward based on the available time of satellite coverage. Among them, the first configuration policy can be a pre-configured operator configuration policy. The specific content of the first configuration policy can be that if the terminal supports the store-and-forward feature and the terminal reports the first configuration information, then the terminal is supported to send data to the satellite, and the satellite is supported to forward data for the terminal. Optionally, after receiving the network connection request sent by the terminal, the satellite can determine that the terminal can be in a state where it can access the network based on the first configuration information, the terminal identifier, the ability to support store-and-forward reported by the terminal, and the pre-configured first configuration policy. The MME in the satellite can determine the data retention period of on-board store-and-forward based on the available time of satellite coverage, and the MME in the satellite can determine the data storage quota of on-board store-and-forward. Step 404, return a first request acceptance response message to the terminal. Among them, the first request acceptance response message carries the data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward, and the target response message can be the first request acceptance response message. Optionally, the satellite can generate a first request acceptance response message based on the determined data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward. In one example, the first request acceptance response message can also carry the satellite identifier, the bearer session identifier (Bearer ID), etc. The satellite can return the first request acceptance response message to the terminal. In one example, if the satellite establishes a session based on the information reported by the terminal, the satellite can encapsulate the data storage quota for on-board store-and-forward into the NAS information and return the NAS information to the terminal. In this embodiment, when the satellite supports store-and-forward and the terminal reports the first configuration information, the satellite can determine that the terminal is in an accessible network state and return a first request acceptance response message to the terminal to quickly establish communication between the terminal and the satellite. In one embodiment, the communication method further includes: If the satellite covers the gateway station and receives the data to be transmitted that meets the data storage quota sent by the terminal, forward the data to be transmitted. Optionally, if the satellite covers the gateway station, that is, if the satellite moves into the communication coverage range of the gateway station and the satellite receives the data to be transmitted that meets the data storage quota sent by the terminal, the satellite can forward the received data to be transmitted sent by the terminal to the terrestrial network element. In this embodiment, when the terminal supports store-and-forward, a first request acceptance response message can be returned to the terminal to quickly establish communication between the terminal and the satellite, and when there is data to be forwarded corresponding to the terminal, the data can be directly forwarded to the terrestrial network element to ensure the timeliness of data forwarding. In one embodiment, as shown in FIG. 5, the step "If the satellite covers the gateway station and receives the data to be transmitted that meets the data storage quota sent by the terminal, forward the data to be transmitted" may include: Step 502, if the satellite covers the gateway station and receives the data to be transmitted that meets the data storage quota sent by the terminal, perform secondary authentication processing on the terminal. Optionally, if the satellite covers the gateway station, that is, if the satellite moves into the communication coverage range of the gateway station and the satellite receives the data to be transmitted that meets the data storage quota sent by the terminal, the satellite can perform secondary authentication processing on the terminal that has already completed verification. For example, it can be secondary authentication based on the first configuration information reported by the terminal, or the satellite can obtain the subscription information corresponding to the terminal that has already completed verification through the terrestrial network element and perform authentication based on the subscription information. In one example, when the satellite moves into the communication coverage range of the gateway station, the satellite receives the data to be transmitted that meets the data storage quota sent by the terminal, and the terminal that has already completed verification meets the secondary authentication conditions, the satellite can perform secondary authentication processing on the terminal that has already completed verification. Step 504, if it is determined that the terminal passes the secondary authentication, forward the data to be transmitted. Optionally, if the satellite determines that the secondary authentication of the terminal that has already completed verification passes, the satellite can forward the data to be transmitted to the terrestrial network element. In this embodiment, the authentication verification of the terminal can be performed again to further improve the security of data transmission. In one embodiment, the network connection request carries the terminal identifier and the ability to support store-and-forward; optionally, the terminal identifier can be the terminal ID or the IMSI of the terminal. Correspondingly, as shown in Figure 6, the step of "generating a target response message based on the network connection request and returning the target response message to the terminal" may include: Step 602, based on the second configuration policy, the terminal identifier, and the ability to support store-and-forward, determine that the terminal is in a restricted transmission state, and determine the data retention period of on-satellite store-and-forward and the data storage quota of on-satellite store-and-forward based on the available satellite coverage time. Among them, the second configuration policy can be a pre-configured operator configuration policy. The specific content of this second configuration policy can be that if the terminal supports the store-and-forward feature, it is determined that the terminal is in a restricted transmission state (limited state), and the terminal is supported to send limited data to the satellite. Optionally, after receiving the network connection request sent by the terminal, the satellite can determine that the terminal is in a restricted transmission state based on the terminal identifier reported by the terminal, the ability to support store-and-forward, and the pre-configured second configuration policy. The MME in the satellite can determine the data retention period of on-satellite store-and-forward and the data storage quota of on-satellite store-and-forward based on the available satellite coverage time. Step 604, return a second request acceptance response message to the terminal. Among them, the connection response message carries the data retention period of on-satellite store-and-forward and the data storage quota of on-satellite store-and-forward, and this target response message can be a second request acceptance response message. Optionally, the satellite can generate a second request acceptance response message based on the determined data retention period of on-satellite store-and-forward and the data storage quota of on-satellite store-and-forward. In one example, this second request acceptance response message can also carry the satellite identifier and the bearer session identifier (Bearer ID), etc. The satellite can return this second request acceptance response message to the terminal. In this embodiment, when the terminal supports store-and-forward, a second request acceptance response message can be returned to the terminal to quickly establish communication between the terminal and the satellite. In one embodiment, this communication method further includes: If the satellite covers the gateway station, obtain the subscription information of the terminal. If it is determined that the terminal authentication is passed based on the subscription information and the data to be transmitted that meets the data storage quota sent by the terminal is received, forward the data to be transmitted and update the restricted transmission state of the terminal to an unrestricted transmission state. Optionally, if the satellite covers the gateway station, that is, if the satellite moves into the communication coverage range of the gateway station, the satellite can obtain the subscription information corresponding to the terminal in the restricted transmission state, and perform authentication based on the subscription information of the terminal in the restricted transmission state; if the satellite determines that the authentication of the terminal in the restricted transmission state passes, and the satellite receives the data to be transmitted that meets the data storage quota sent by the terminal, the satellite can forward the data to be transmitted sent by the terminal to the ground network element; when the satellite determines that the authentication of the terminal passes, it updates the restricted transmission state of the terminal to an unrestricted transmission state. In this embodiment, when the terminal supports store-and-forward, a second request acceptance response message can be returned to the terminal to quickly establish communication between the terminal and the satellite. After the satellite determines that the terminal authentication passes, the data of the terminal is promptly forwarded to the ground network element to ensure the reliability of data transmission. In one embodiment, after the step of updating the restricted transmission state of the terminal to an unrestricted transmission state, the communication method further includes: If it is detected that the terminal obtains the coverage of the satellite, a status update message is sent to the terminal. Optionally, the status update message indicates that the restricted transmission state of the terminal is updated to an unrestricted transmission state; when the satellite determines that the authentication of the terminal passes, the restricted transmission state of the terminal can be updated to an unrestricted transmission state; if the terminal moves into the communication coverage range of the satellite again, that is, the terminal obtains the coverage of the satellite, the satellite can send the status update message to the terminal, and after receiving the status update message, the terminal can determine that the status of the terminal has been updated from the restricted transmission state to the unrestricted transmission state. In this embodiment, when the terminal obtains the coverage of the satellite again, a status update message can be promptly returned to the terminal. In one embodiment, the step of "generating a target response message based on the network connection request and returning the target response message to the terminal" can include: Generating a request suspend response message based on the satellite being in the store-and-forward mode, the terminal meeting the conditions for initially accessing the satellite, and the store-and-forward capability of the terminal; returning the request suspend response message to the terminal. Among them, the request suspend response message (attach suspend) carries the satellite identifier, and this request suspend response message is used to prompt the terminal that the network connection request of the terminal is cached by the satellite. Optionally, the satellite may determine that the terminal sending the network connection request supports the store-and-forward feature based on the store-and-forward capability carried in the network connection request. If the satellite is currently in the store-and-forward mode and the terminal sending the network connection request is a terminal newly accessing the satellite, the satellite may store the terminal identifier and terminal capabilities of the terminal, generate a request staging response message, and return the request staging response message to the terminal, indicating that the satellite has cached the network connection request sent by the terminal. Optionally, after receiving the request staging response message sent by the satellite, the terminal may switch to a low-power mode, such as a power-saving mode. In one example, before switching to the power-saving mode, the terminal may determine the next wake-up time based on the ephemeris information, and after determining the next wake-up time, switch to the power-saving mode until the current time reaches the next wake-up time, after which the terminal may exit the power-saving mode and switch to the normal operating state. The ephemeris information may be an accurate position or trajectory table that changes with time as celestial bodies move, which is a function of time. In one example, if the satellite covers the gateway station, that is, if the feeder link between the satellite and the ground is in an available state (Feeder link is available), the MME in the satellite may send the network connection request to the terrestrial network element through the terrestrial C-SCN-Ground, obtain the subscription information (authentication information) of the terminal through the terrestrial network element, and store the authentication information of the terminal in the satellite. Optionally, after the terminal is covered by the satellite, it may initiate an attach request again, that is, send the network connection request to the satellite, and the network connection request carries the store-and-forward capability. If the MME in the satellite determines that the terminal is not a newly accessing terminal based on the terminal identifier of the terminal, the satellite may authenticate the terminal based on the authentication information stored locally, and send a message to the terminal, and the message carries the information required for the terminal to authenticate the network, to complete mutual authentication. In addition, after the terminal is covered by the satellite, it may establish an RRC connection with the satellite that is consistent with the satellite identifier carried in the rejection response message, and based on the RRC connection, the terminal may initiate an attach request again, that is, send the network connection request to the satellite through the RRC connection. After receiving the network connection request, the satellite may perform mutual authentication based on the terminal identifier carried in the network connection request and the authentication information of the terminal stored locally in the satellite. Based on this, after the satellite determines that the terminal has passed the authentication, the satellite may accept the network connection request sent by the terminal, determine the data retention period based on the available time of satellite coverage, and determine the data storage quota corresponding to the terminal, generate a request acceptance response message based on the data retention period and the data storage quota, and return the request acceptance response message to the terminal. In this embodiment, by returning a request staging response message from the satellite to the terminal, reliable communication between the terminal device, the satellite, and the terrestrial network element can be achieved. By using the request staging response message to prompt that the network request of the terminal has been staged by the satellite, the terminal can initiate a request to re-connect to the network in a timely manner when it is covered by the satellite in the subsequent process, improving the flexibility of the terminal to access the network. In one embodiment, the step of "generating a target response message based on the network connection request and returning the target response message to the terminal" may include: Generating a rejection response message based on the satellite being in the store-and-forward mode, the terminal meeting the conditions for initial access to the satellite, and the terminal's ability to support store-and-forward; returning the rejection response message to the terminal. Among them, the rejection response message carries a rejection reason message and a satellite identifier, and this request cache message indicates that the network connection request sent by this terminal has been staged. Optionally, the satellite can determine that the terminal sending the network connection request supports the store-and-forward feature based on the store-and-forward ability carried in the network connection request; if the satellite is currently in the store-and-forward mode and the terminal sending the network connection request is accessing the satellite for the first time, the satellite can stage the network connection request corresponding to this terminal, store the terminal identifier and terminal ability of this terminal, and generate a rejection response message carrying a rejection reason message and a satellite identifier, and return this rejection response message to the terminal. Among them, the rejection reason message can be to indicate that the satellite has cached the network connection request sent by this terminal. In one example, if the satellite covers the gateway station, that is, if the feeder link between the satellite and the ground is in an available state (Feeder link is available), the MME in the satellite can send the network connection request to the terrestrial network element through the ground C-SCN-Ground, obtain the subscription information (authentication information) of this terminal through the terrestrial network element, and store the authentication information of this terminal in the satellite. Optionally, after the terminal has the coverage of the satellite, it can initiate an attach request again, that is, send the network connection request to the satellite, and the network connection request carries the ability to support store-and-forward. If the MME in the satellite determines that the terminal is a non-first access terminal based on the terminal identifier of the terminal, the satellite can authenticate the terminal based on the authentication information stored locally, and send a message to the terminal, and the message carries the information required for the terminal to authenticate the network, and two-way authentication is completed. In addition, after the terminal has the coverage of the satellite, it can establish an RRC connection with the satellite that is consistent with the satellite identifier carried in the rejection response message, and based on this RRC connection, the terminal can initiate an attach request again, that is, send the network connection request to the satellite through this RRC connection. After receiving the network connection request, the satellite can perform two-way authentication based on the terminal identifier carried in the network connection request and the authentication information of the terminal stored locally by the satellite. Based on this, after the satellite determines that the terminal passes the authentication, the satellite can accept the network connection request sent by the terminal, determine the data retention period based on the available time of the satellite coverage, and determine the data storage quota corresponding to the terminal, generate a request acceptance response message based on the data retention period and the data storage quota, and return the request acceptance response message to the terminal. In this embodiment, through multiple requests between the terminal and the satellite, the terminal IoT device can be registered to the network through the satellite with the on-board store-and-forward feature, realizing the communication between the terminal device and the ground through the satellite, and improving the communication reliability. In one embodiment, the communication method further includes: Sending a broadcast message. Among them, the broadcast message is used to indicate the connection between the terminal and the satellite. Optionally, the satellite can send a broadcast message within the communication coverage of the satellite. After the terminal is powered on, it can search for the network and camp. After receiving the broadcast message sent by the satellite, it can parse the broadcast message and send a network connection request to the satellite. In one example, the broadcast message includes the store-and-forward feature and / or the satellite ID. The store-and-forward feature indicates that the satellite is a satellite in the on-board store-and-forward mode, that is, a satellite that can perform store-and-forward satellite operations (SandF Satellite Operation). For example, a base station or some core network elements can be deployed on the satellite. The terminal establishes a service link with the satellite to transmit signaling or data. When the satellite moves to establish a feeder link with the ground, the signaling or data can be interacted with the ground core network through the gateway station. The satellite ID represents the identifier of the satellite, such as the satellite number, etc. In an example, the terminal may obtain the store-and-forward feature and the satellite ID carried by the broadcast message, the terminal may obtain the store-and-forward feature carried by the broadcast message, the terminal may also obtain the satellite ID carried by the broadcast, and so on. In one embodiment, the target response message also carries the satellite return time. Optionally, the satellite return time may be the time when the satellite returns next time. The terminal may re-initiate a network connection request to the satellite based on the satellite return time carried in the target response message, when the satellite return time is reached, or after the satellite return time has elapsed. For example, the rejection response message may also carry the satellite return time, and, for example, the request temporary storage response message may also carry the satellite return time. In this embodiment, the terminal can accurately initiate a network connection request to the satellite in a timely manner after the satellite flies back. The specific implementation process of the above communication method in a specific application scenario is described in detail below in conjunction with specific embodiments. In one example, as shown in FIG. 7 , for example, the terminal may request store-and-forward during the registration process, and the MME / AMF may first suspend the request, and after the feeder link is available, obtain and store the subscription / authentication information of the terminal on the satellite; the terminal may then initiate a registration request, and the MME / AMF may directly complete the authentication, etc.; The following example is taken as an example for application in EPS architecture, including user terminal (UE), satellite SAT and ground network elements. The ground network elements include SFMF and HSS / P-SW; the satellite includes evolved Node B (eNodeB), mobility management entity MME, SFCF and service gateway S-GW / SCEF. Optionally, there are multiple ways to deploy the functions of all network elements on the satellite, which may be new network elements or enhancements to existing network elements. Optionally, if it is 5GC, some AUSF authentication functions can also be configured on the satellite. As shown in FIG7 , the communication method may include the following steps: S0, UE receives the broadcast message of the satellite (UE receives the SIB of the SAT#1). Optionally, the UE turns on to search for the network and resides on it, and receives the broadcast message of the satellite eNB. The broadcast message carries a store-and-forward feature and / or a satellite ID. S1, UE sends a network connection request (attach request); optionally, when the UE needs to register with the network, it can send a network connection request to the on-board MME, and optionally, the network connection request can carry an indication of "supporting the store-and-forward feature". Optionally, if the UE indicates support for EPS connection without a PDN session or SMS only, then S6 and S7 can be skipped to enable communication between the terminal and the satellite without establishing a bearer session; for EPS Attach without PDN Connectivity or SMS only, steps 6 and 7 are skipped. In S2, a rejection response message (attach reject) is returned. Optionally, the on-board MME can determine to temporarily store the UE's network connection request attach request, and store the UE's terminal identifier (device identifier, IMSI) and its corresponding UE capabilities, based on the current satellite being in the store-and-forward mode, the UE's initial access, and the UE supporting the store-and-forward feature, and send a rejection response message (attach reject) to the UE. If the satellite has broadcast the SandF mode (on-board store-and-forward mode), the rejection response message carries the rejection reason and the ID of the satellite. The rejection reason can be that the network connection request is cached; carrying the satellite ID facilitates the UE finding the satellite for registration again next time. Optionally, the rejection response message can also carry the time when the satellite will fly back next time, facilitating the UE to apply for the same satellite after the timer expires; if the terminal finds other suitable target satellites before the timer stops, the UE can send a network connection request to the target satellite. In S3, when the satellite covers the gateway station, i.e., the feeder link is available (Feeder link is available), authentication or authorization processing (authentication / secutity) is performed. Optionally, the MME can send the UE's network connection request to the HSS via the terrestrial C-SCN-Ground to obtain the subscription information (authentication information) of the terminal, and send the authentication information of the UE back to the satellite and store it in the MME or other storage devices. In S4, when the terminal is within the communication coverage of the satellite, the terminal sends a network connection request (attach request) to the satellite again; optionally, when the UE has coverage, an RRC connection is established with the target satellite based on the satellite ID and attach request is initiated again, indicating "support for the store-and-forward feature". Optionally, if the UE indicates support for EPS connection without a PDN session or SMS only, then S6 and S7 can be skipped to enable communication between the terminal and the satellite without establishing a bearer session; for EPS Attach without PDN Connectivity or SMS only, S6 and S7 are skipped. In S5, the MME completes two-way authentication / security based on the UE's IMSI and the stored authentication information. S6. Optionally, the MME sends a Create session request to the SFCF, and the SFCF sends a Create session request to the S-GW / SCEF; that is, the MME establishes a bearer session with the SFCF, and the SFCF establishes a bearer session with the S-GW / SCEF. Optionally, the MME sends a Create bearer request to establish a bearer. If Control Plane CIoT EPS Optimisation applies, then the MME shall also indicate S11-U tunnelling of NAS user data and send its own S11-U IP address and MME DL TEID for DL data forwarding by the SGW. S7. Optionally, the S-GW / SCEF sends a Create session response message to the SFCF, and the SFCF sends a Create session response message to the MME; optionally, the S-GW determines the SandF data storage quota based on the requested data counter and the on-board memory. S8. Determines the SandF the parameters. Optionally, the MME accepts the network connection request; optionally, the MME may determine the SandF data retention period based on the available satellite coverage time, and encapsulate the SandF data retention period and the SandF data storage quota into the NAS information. S9, MME sends an Attach accept response (request acceptance response message) to the UE. Optionally, the request acceptance response message carries satellite ID, SandF data retention period, SandF data storage quota and Bearer ID (bearer ID) and the like. In another example, for example, the terminal may request store-and-forward during the registration process, and the MME / AMF may first suspend the request, and after the feeder link is available, obtain and store the subscription / authentication information of the terminal on the satellite; the terminal may initiate a registration request again, and the MME / AMF may directly complete the authentication, etc. The following is an example of application to the EPS architecture, and the communication method may include the following steps: Step 0, UE receives the broadcast message of the satellite (UE receives the SIB of the SAT#1). Optionally, the UE turns on, searches for the network and resides on it, and receives the broadcast message of the satellite eNB. The broadcast message does not carry the satellite ID and SandF mode. Step 10, UE sends a network connection request (attach request); optionally, when the UE needs to register with the network, it can send a network connection request to the onboard MME, and optionally, the network connection request can carry an indication of "support for store-and-forward feature". Optionally, if the UE indicates support for EPS connection without PDN session, or SMS only, steps 60 and 70 can be skipped to achieve communication between the terminal and the satellite without establishing a bearer session; EPS Attach without PDN Connectivity, or SMS only, then steps 60 and 70 are skipped. Step 20, returning a rejection response message (attach reject). Optionally, the onboard MME can determine to temporarily store the network connection request attach request of the UE based on the current satellite being in store-and-forward mode, the initial access of the terminal, and the terminal supporting the store-and-forward feature, and store the terminal identifier (device identifier, IMSI) of the UE and its corresponding UE capabilities, and send a rejection response message (attach reject) to the UE. If the UE supports on-board store-and-forward, a rejection response message is sent to the UE, which carries the rejection reason and the ID of the satellite. The rejection reason may be the S&F feature mode and the attach request is cached (the network connection request is cached); carrying the satellite ID can facilitate the UE to find the satellite for registration next time; if the UE does not support on-board store-and-forward, the satellite directly sends a rejection response message to the terminal; that is, if the UE does not support S&F, it is directly rejected. Step 30: The satellite covers the gateway, that is, the feeder link is available, and identity authentication or authentication / secutity is performed. Optionally, the MME can send the UE's network connection request to the ground network element (for example, to the HSS via the SFMF), obtain the terminal's subscription information (authentication information), and send the UE's authentication information back to the satellite, and store it in the MME or other storage device. Step 40, when the terminal is within the communication coverage of the satellite, the terminal sends a network connection request (attach request) to the satellite again; optionally, when the UE has coverage, an RRC connection is established with the target satellite based on the satellite ID and an attach request is initiated again, indicating that "store-and-forward feature is supported". Optionally, if the UE indicates support for EPS Attach without PDN Connectivity, or SMS only, steps 60 and 70 can be skipped to achieve communication between the terminal and the satellite without establishing a bearer session; EPS Attach without PDN Connectivity, or SMS only, then steps 60 and 70 are skipped. Step 50: If the MME determines based on the device identifier IMSI that the terminal is the IMSI of the terminal previously requested, the MME can authenticate and authorize the terminal based on the subscription information obtained in step 30; and send the information required by the UE to authenticate the network to complete two-way authentication. Step 60. Optionally, the MME sends a Create session request to the SFCF, and the SFCF sends a Create session request to the S-GW / SCEF; that is, the MME establishes a bearer session with the SFCF, and the SFCF establishes a bearer session with the S-GW / SCEF. Optionally, the MME sends a Create task request to establish a bearer. If Control Plane CIoT EPS allows, the MME shall also indicate S11-U tunnelling of NAS user data and send its own S11-U IP address and MME DL TEID for DL data forwarding by the SGW. If Control Plane CIoT EPS Optimisation applies, then the MME shall also indicate S11-U tunnelling of NAS user data and send its own S11-U IP address and MME DL TEID for DL data forwarding by the SGW. Step 70. Optionally, the S-GW / SCEF sends a Create session response message to the SFCF, and the SFCF sends a Create session response message to the MME; optionally, the S-GW determines the SandF data storage quota based on the requested data counter and the on-board memory. Step 80. Determine the SandF parameters; optionally, the MME accepts a network connection request; optionally, the MME may determine the SandF data retention period based on the satellite coverage available time, and encapsulate the SandF data retention period and the SandF data storage quota into the NAS information. Step 90. The MME sends an Attach accept response (request acceptance response message) to the UE. Optionally, the request acceptance response message carries the satellite ID, SandF data retention period, SandF data storage quota, and Bearer ID, etc. In another example, it could be the terminal network access process for introducing attach suspend. Taking the EPS architecture as an example, the communication method may include the following steps: Step 0: The UE receives the broadcast message of the satellite (UE receives the SIB of the SAT#1). Optionally, the UE powers on, searches for the network, and camps on it, receiving the broadcast message of the satellite eNB. The broadcast message carries the store-and-forward feature and / or the satellite ID. Step 1: The UE sends an attach request. Optionally, when the UE needs to register to the network, it can send an attach request to the on-satellite MME. Optionally, the attach request can carry an indication of "supporting the store-and-forward feature". Optionally, if the UE indicates support for EPS connection without a PDN session or only for SMS, then S6 and S7 can be skipped, and communication between the terminal and the satellite can be achieved without establishing a bearer session; for EPS Attach without PDN Connectivity, or SMS only, then S6 and S7 are skipped. Step 2: Return an attach suspend response message. Optionally, the on-satellite MME can determine to cache the UE's attach request based on the current satellite being in the store-and-forward mode, the terminal's initial access, and the terminal's support for the store-and-forward feature, and store the UE's terminal identifier (device identifier, IMSI) and its corresponding UE capabilities, and send an attach suspend response message to the UE, indicating to the UE that the attach request has been cached. The attach suspend response message can also carry the ID of the satellite, so that the UE can still find the satellite for registration next time; Optionally, the reject response message can also carry the time when the satellite will fly back next time, facilitating the UE to apply for the same satellite after the timer expires. If the terminal finds another suitable target satellite before the timer stops, the UE can send an attach request to the target satellite. Optionally, after receiving the attach suspend response message sent by the satellite, the terminal can switch to the low-power mode, such as the power-saving mode. In one example, before switching to the power-saving mode, the terminal can determine the next wake-up time based on the ephemeris information, and after determining the next wake-up time, switch to the power-saving mode until the current time reaches the next wake-up time, and then the terminal can exit the power-saving mode and switch to the normal working state. The ephemeris information can be an accurate position or trajectory table that changes with time as a function of time. Step 3: When the satellite covers the gateway station, i.e., the feeder link is available, perform authentication or authorization processing (authentication / secutity). Optionally, the MME may obtain the subscription information (authentication information) of the terminal through the terrestrial network element for the UE's network connection request, and send the authentication information of the UE back to the satellite and store it in the MME or other storage devices. Obtaining the authentication information may be, for example, sending it to the HSS through the SFMF to obtain the authentication information of the terminal, etc. Step 4: When the terminal is within the communication coverage of the satellite, the terminal may establish an RRC connection with the target satellite based on the satellite ID and initiate a network connection request (attach request) again. The network connection request carries identification information indicating "support for the store-and-forward feature". The implementation processes of Steps 5 to 9 are the same as those of S5 - S9 provided in the above embodiment and will not be elaborated here. In another example, for instance, a terminal access network process introducing attach suspend may be adopted. Taking the application to the EPS architecture as an example for illustration, this communication method may include the following steps: Step 0: The UE receives the broadcast message of the satellite (UE receives the SIB of the SAT#1). Optionally, the UE powers on to search for the network and camp on it, and receives the broadcast message of the satellite eNB. The broadcast message does not carry the satellite ID and the SandF mode. Step 1: The UE sends a network connection request (attach request); optionally, when the UE needs to register to the network, it may send a network connection request to the on-satellite MME. Optionally, the network connection request may carry an indication of "support for the store-and-forward feature". Optionally, if the UE indicates support for EPS to connect without a PDN session or only for SMS, Steps 6 and 7 may be skipped, and communication between the terminal and the satellite may be achieved without establishing a bearer session; EPS Attach without PDN Connectivity, or SMS only, then Steps 6 and 7 are skipped. Step 2: Return an attach suspend response message. Optionally, the on-satellite MME may determine to cache the UE's network connection request (attach request) based on the fact that the current satellite is in the store-and-forward mode, the terminal is in the initial access state, and the terminal supports the store-and-forward feature, and store the terminal identifier (device identifier, IMSI) of the UE and its corresponding UE capabilities, and send an attach suspend response message to the UE, indicating to the UE that the attach request has been cached. The attach suspend response message may also carry the ID of the satellite, so that the UE can still find the satellite for registration next time; Optionally, the rejection response message may also carry the time when the satellite will fly back next time, facilitating the UE to apply for the same satellite after the timer expires. If the terminal finds other suitable target satellites before the timer stops, the UE may send a network connection request to the target satellite. Optionally, after receiving the attach suspend response message sent by the satellite, the terminal may switch to a low-power mode, such as a power-saving mode. In one example, before switching to the power-saving mode, the terminal may determine the next wake-up time based on the ephemeris information, and after determining the next wake-up time, switch to the power-saving mode until the current time reaches the next wake-up time, and then the terminal may exit the power-saving mode and switch to the normal working state. The ephemeris information may be an accurate position or trajectory table that changes with time as a function of time. The implementation processes of Steps 3 to 9 are the same as those of Steps 30 to 90 provided in the above embodiment, and will not be elaborated here. In another example, as shown in FIG. 8, it may be a restricted transmission: the terminal requests store-and-forward during the registration process. The MME / AMF directly accepts the UE request based on the reported store-and-forward feature and indicates that the UE is in the limited state and can send restricted data. After the feeder link is available, if necessary, the on-satellite device sends the UE request to the ground, such as UDM / SMSF. If the authentication is passed, the data is sent. The following takes EPS as an example for illustration, including a user terminal (UE), a satellite SAT, and ground network elements. The ground network elements include SFMF, HSS / P-SW, and SandF server (S&F server); the satellite includes an evolved Node B (eNodeB), a Mobility Management Entity MME, an SFCF, and a Serving Gateway S-GW / SCEF. Optionally, if it is 5GC, some authentication functions of the AUSF may also be configured on the satellite. The communication method may include the following steps: Step 0: The UE receives the broadcast message of the satellite (UE receives the SIB of the SAT#1). Optionally, the UE powers on to search for the network and camp, and receives the broadcast message of the satellite eNB. The broadcast message carries the store-and-forward feature and / or the satellite ID. Step 1: The UE sends an attach request. Optionally, when the UE wants to transmit information through the network, it can send an attach request to the on-satellite MME. Optionally, this attach request can carry the terminal identifier (IMSI) and indicate "support for the store-and-forward feature". Optionally, if the UE indicates support for EPS to connect without a PDN session or only for SMS, then S3 and S4 can be skipped, and communication between the terminal and the satellite can be achieved without establishing a bearer session; for EPS Attach without PDN Connectivity, or SMS only, then steps 3 and 4 are skipped. Step 2: Determine the UE's state. Optionally, since the UE's subscription and / or security information does not exist locally on the satellite, the on-satellite MME can, based on the IMSI reported by the UE, "support for the store-and-forward feature", and the operator configuration policy (the second configuration policy), determine that the UE can be in a limited transmission state, that is, the satellite supports the UE to send limited data. Optionally, after the on-satellite MME locally stores information such as the terminal identifier and terminal capabilities of the terminal, if the feeder link connection is available, i.e., after the feeder link connection, the UE can obtain the subscription and / or security information from a terrestrial network element such as the HSS, and then the satellite can update the UE's limited transmission state to an unrestricted transmission state. If the UE indicates support for EPS to connect without a PDN session or only for SMS, then S3 and S4 can be skipped, and communication between the terminal and the satellite can be achieved without establishing a bearer session; for EPS Attach without PDN Connectivity, or SMS only, then steps 3 and 4 are skipped. Step 3. Optionally, the MME sends a Create session request to the SFCF, and the SFCF sends a Create session request to the S-GW / SCEF; that is, the MME establishes a bearer session with the SFCF, and the SFCF establishes a bearer session with the S-GW / SCEF. Optionally, the MME sends a Create task request to establish a bearer. If Control Plane CIoT EPS Optimisation applies, then the MME shall also indicate S11-U tunnelling of NAS user data and send its own S11-U IP address and MME DL TEID for DL data forwarding by the SGW. Step 4. Optionally, the S-GW / SCEF sends a Create session response message to the SFCF, and the SFCF sends a Create session response message to the MME; optionally, the S-GW determines the SandF data storage quota based on the requested data counter and the on-board memory. Step 5. Determines the SandF the parameters; optionally, the MME may determine the SandF data retention period (this parameter may also be the Unavailability Period Duration) based on the available time of satellite coverage; optionally, if the UE is determined to be in a limited state, the MME determines the SandF data storage quota that the UE can transmit, and this data storage quota may be the number of data items that the satellite allows the terminal to send and the size of each data item. Step 6, the MME sends an Attach accept response to the UE. Optionally, the Attach accept response message carries the satellite ID, SandF data retention period, SandF data storage quota, and Bearer ID, etc. Step 7, send the first uplink data. Optionally, if the UE needs to transmit emergency data, the terminal can send data that meets the quota to the on-satellite device (MME or, if the session is established, the existing S-GW, or a new network element device), and the on-satellite device will store the data associated with the UE's IMSI. Step 8, authentication; optionally, when the satellite covers the gateway station, i.e., the feeder link is available, for a terminal in a restricted transmission state, the MME can send the UE's request to the HSS through the terrestrial network element to obtain the subscription information and / or security information of the terminal and return it to the MME; if the authentication is completed, the MME can remove the limitation of the UE's limited state. If the UE is covered by the satellite again, the satellite can return the status update to the UE. Step 9, optionally, the on-satellite device forwards the received UE data to the ground. In another example, as shown in Figure 9, it can be a direct transmission: the terminal sends security information, etc. in the registration process request to the network. The MME / AMF directly accepts the UE request based on the reported information and UE capabilities. If necessary, the on-satellite device sends the UE request to the ground, such as the UDM / SMSF. If the authentication is passed, the data is sent. Taking EPS as an example for illustration below, it includes a user terminal (UE), a satellite SAT, and terrestrial network elements. The terrestrial network elements include SFMF, HSS / P-SW, and SandF server; the satellite includes an evolved Node B (eNodeB), a Mobility Management Entity (MME), an SFCF, and a Serving Gateway S-GW / SCEF. Optionally, if it is 5GC, some authentication functions of the AUSF can also be configured on the satellite. The communication method may include the following steps: Step 0, the UE receives the broadcast message of the satellite (UE receives the SIB of the SAT#1). Optionally, the UE powers on to search for the network and camp, and receives the broadcast message of the satellite eNB. The broadcast message carries the store-and-forward feature and / or the satellite ID. Step 1, the UE sends a network connection request (attach request); optionally, when the UE wants to transmit information through the network, it can send a network connection request to the on-board MME. Optionally, this network connection request may carry the terminal identifier (IMSI), an indication of "supporting the store-and-forward feature", and terminal information. Optionally, if the UE indicates support for EPS connection without a PDN session or SMS only, then S3 and S4 can be skipped, and communication between the terminal and the satellite can be achieved without establishing a bearer session; for EPS Attach without PDN Connectivity, or SMS only, steps 3 and 4 are skipped. Step 2, authentication; optionally, based on the IMSI reported by the UE, the "support for the store-and-forward feature", and the first configuration policy, as well as the first configuration information reported by the terminal, the MME can authenticate the terminal. For example, it can determine that the terminal can access the network. Optionally, if the UE indicates support for EPS connection without a PDN session or SMS only, then steps 9 and 10 can be skipped, and communication between the terminal and the satellite can be achieved without establishing a bearer session; for EPS Attach without PDN Connectivity, or SMS only, steps 3 and 4 are skipped. Optionally, if the UE indicates support for EPS connection without a PDN session or SMS only, then S3 and S4 can be skipped, and communication between the terminal and the satellite can be achieved without establishing a bearer session; for EPS Attach without PDN Connectivity, or SMS only, steps 3 and 4 are skipped. Step 3. Optionally, the MME sends a Create session request to the SFCF, and the SFCF sends a Create session request to the S-GW / SCEF; that is, the MME establishes a bearer session with the SFCF, and the SFCF establishes a bearer session with the S-GW / SCEF. Optionally, the MME sends a Create task request to establish a bearer. If Control Plane CIoT EPS allows, the MME shall also indicate S11-U tunnelling of NAS user data and send its own S11-U IP address and MME DL TEID for DL data forwarding by the SGW. If Control Plane CIoT EPS Optimisation applies, then the MME shall also indicate S11-U tunnelling of NAS user data and send its own S11-U IP address and MME DL TEID for DL data forwarding by the SGW. Step 4. Optionally, the S-GW / SCEF sends a Create session response message to the SFCF, and the SFCF sends a Create session response message to the MME; optionally, the S-GW determines the SandF data storage quota based on the requested data counter and the on-board memory. Step 5. Determines the SandF parameters; optionally, the MME may determine the SandF data retention period (this parameter may also be the Unavailability Period Duration) based on the available time of satellite coverage; optionally, if the session is established based on the information reported by the UE, the SandF data retention period and the SandF data storage quota are encapsulated into the NAS information. Step 6, the MME sends an Attach accept response to the UE. Optionally, the Attach accept response carries a satellite ID, SandF data retention period, SandF data storage quota, and Bearer ID, etc. Step 7, send the first uplink data. Optionally, if the UE needs to transmit emergency data, the terminal can send data that meets the quota to the on-board device (MME or, if the session is established, the S-GW exists, or a new network element device), and the on-board device stores the data associated with the UE's IMSI. Step 8, authentication; optionally, when the satellite covers the gateway station, i.e., the feeder link is available, if secondary authentication is required, the UE that has completed authentication is re-authenticated, otherwise Step 8 can be skipped. Step 9, optionally, the on-board device forwards the received UE data to the ground. In the communication method provided by the embodiments of the present application, the terminal IoT device can be registered to the network through a satellite with the on-board storage and forwarding feature, enabling devices in remote areas to connect to the network and send data, providing effective communication guarantees for institutions such as scientific research and government, and providing strong support for the vision of ubiquitous communication. It should be understood that although the steps in the flowcharts involved in the above embodiments are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless specifically stated herein, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, at least some of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least a part of other steps or steps or stages in other steps. Based on the same inventive concept, the embodiments of the present application also provide a communication device for implementing the above-mentioned communication method. The solution provided by this device to solve the problem is similar to the solution described in the above method. Therefore, the specific limitations in one or more embodiments of the communication device provided below can refer to the limitations on the communication method in the above text and will not be repeated here. In one embodiment, as shown in FIG. 10, a communication device 1000 is provided, which is applied to a terminal and includes: The first sending unit 1002 is configured to send a network connection request to a satellite, where the network connection request is used to instruct the terminal to establish a network connection with the satellite. The first receiving unit 1004 is configured to receive a target response message returned by a device on the satellite to the terminal. In some embodiments, the network connection request includes the ability to support store-and-forward and a terminal identifier. In some embodiments, the first receiving unit is specifically configured to: Receive a first request acceptance response message returned by a device on the satellite to the terminal. The first request acceptance response message carries the data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward. The first request acceptance response message is generated by the satellite after determining that the terminal is in an accessible network state based on the terminal identifier and the ability to support store-and-forward. In some embodiments, the network connection request includes the ability to support store-and-forward and a terminal identifier; the first receiving unit is specifically configured to: Receive a second request acceptance response message returned by a device on the satellite to the terminal. The second request acceptance response message carries the data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward. The second request acceptance response message is generated by the satellite after determining that the terminal is in a restricted transmission state based on a second configuration policy, the terminal identifier, and the ability to support store-and-forward. In some embodiments, the network connection request includes the ability to support store-and-forward; the first receiving unit is specifically configured to: Receive a request staging response message returned by a device on the satellite to the terminal. The request staging response message is generated by the device on the satellite based on the satellite being in a store-and-forward mode, the terminal meeting the conditions for initially accessing the satellite, and the terminal's ability to support store-and-forward; the request staging response message carries a satellite identifier. In some embodiments, the network connection request includes the ability to support store-and-forward; the first receiving unit is specifically configured to: Receive a rejection response message returned by a device on the satellite to the terminal. The rejection response message is generated by the device on the satellite based on the satellite being in a store-and-forward mode, the terminal meeting the conditions for initially accessing the satellite, and the terminal's ability to support store-and-forward; the rejection response message carries a rejection reason message and a satellite identifier. In some embodiments, the first receiving unit is further configured to: Receive a satellite broadcast message. In some embodiments, the first sending unit is further configured to: Send data to be transmitted that meets the data storage quota to the satellite. In one embodiment, as shown in FIG. 11, a communication device 1100 is provided, which is applied to a satellite and includes: A second receiving unit 1102, configured to receive a network connection request sent by a terminal, where the network connection request is used to indicate that the terminal establishes a network connection with a satellite; A second sending unit 1104, configured to generate a target response message based on the network connection request and return the target response message to the terminal. In some embodiments, the network connection request carries a terminal identifier and the ability to support store-and-forward. In some embodiments, the second sending unit is specifically configured to Determine that the terminal is in an accessible network state based on the terminal identifier and the ability to support store-and-forward, and determine the data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward based on the available time of satellite coverage; Return a first request acceptance response message to the terminal, where the first request acceptance response message carries the data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward. In some embodiments, the apparatus further includes: A forwarding unit, configured to forward the data to be transmitted if the satellite covers the gateway station and the data to be transmitted that meets the data storage quota sent by the terminal is received. In some embodiments, the forwarding unit is specifically configured to: If the satellite covers the gateway station and the data to be transmitted that meets the data storage quota sent by the terminal is received, perform secondary authentication processing on the terminal; If it is determined that the terminal passes the secondary authentication, forward the data to be transmitted. In some embodiments, the network connection request carries a terminal identifier and the ability to support store-and-forward, and the second sending unit is specifically configured to Determine that the terminal is in a restricted transmission state based on a second configuration policy, the terminal identifier, and the ability to support store-and-forward, and determine the data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward based on the available time of satellite coverage; Return a second request acceptance response message to the terminal, where the second request acceptance response message carries the data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward. In some embodiments, the forwarding unit is further configured to: If the satellite covers the gateway station, obtain the subscription information of the terminal; if it is determined based on the subscription information that the terminal passes the authentication and the data to be transmitted that meets the data storage quota sent by the terminal is received, forward the data to be transmitted and update the restricted transmission state of the terminal to a non-restricted transmission state. In some embodiments, the apparatus further includes: An update unit, configured to send a status update message to a terminal if it is detected that the terminal obtains satellite coverage, where the status update message indicates that the restricted transmission status of the terminal is updated to an unrestricted transmission status. In some embodiments, the second sending unit is specifically configured to generate a request for temporary storage response message based on the satellite being in a store-and-forward mode, the terminal meeting the conditions for initial access to the satellite, and the terminal's ability to support store-and-forward; return the request for temporary storage response message to the terminal, where the request for temporary storage response message carries a satellite identifier. In some embodiments, the second sending unit is specifically configured to: generate a rejection response message based on the satellite being in a store-and-forward mode, the terminal meeting the conditions for initial access to the satellite, and the terminal's ability to support store-and-forward; return the rejection response message to the terminal, where the rejection response message carries a rejection reason message and a satellite identifier. In some embodiments, the second sending unit is further configured to: send a broadcast message for instructing the terminal to connect to the satellite. It should be noted that the division of units in the embodiments of the present application is illustrative, merely a logical function division. In actual implementation, there may be other division methods. In addition, in each embodiment of the present application, the functional units may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit. The above integrated units may be implemented in the form of hardware or in the form of software functional units. If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it may be stored in a processor-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the related technology, or all or part of the technical solution, may be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) or a processor to execute all or part of the steps of the methods in the embodiments of the present application. It should be noted here that the above device provided in the embodiments of the present application can implement all the method steps implemented in the above method embodiments and can achieve the same technical effects. The same parts and beneficial effects as those in the method embodiments are not specifically described in this embodiment. In an exemplary embodiment, a communication device is provided. The communication device may be a terminal device or a network device, and its internal structure may be as shown in FIG. 12. The communication device includes a memory, a transceiver, and a processor. A transceiver for receiving and sending data under the control of a processor. Among them, in FIG. 12, the bus architecture may include any number of interconnected buses and bridges, specifically, various circuits represented by one or more processors represented by the processor and the memory represented by the memory are linked together. The bus architecture can also link together various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be further described herein. The bus interface provides an interface. The transceiver can be multiple components, that is, including a transmitter and a receiver, and provides a unit for communicating with various other devices on the transmission medium, and these transmission media include wireless channels, wired channels, optical fiber cables and other transmission media. The processor is responsible for managing the bus architecture and general processing, and the memory can store the data used by the processor when executing operations. The processor can be a central processing unit (CPU), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a complex programmable logic device (CPLD), and the processor can also adopt a multi-core architecture. The processor is used to execute any method provided in the embodiments of the present application according to the obtained executable instructions by calling the program stored in the memory. The processor and the memory can also be physically separated. It should be noted here that the above-mentioned device provided in the embodiments of the present disclosure can implement all the method steps implemented in the above-mentioned method embodiments, and can achieve the same technical effects, and the same parts and beneficial effects as those in the method embodiments will not be specifically described herein. The corresponding entity device of the terminal device or the network device is shown in FIG. 12, and can implement all the method steps implemented in the method embodiments on the terminal device or the network device side, and can achieve the same technical effects, and the same parts and beneficial effects as those in the method embodiments will not be specifically described herein. It should be noted here that the above-mentioned device provided in the embodiments of the present application can implement all the method steps implemented in the above-mentioned method embodiments, and can achieve the same technical effects, and the same parts and beneficial effects as those in the method embodiments will not be specifically described herein. In an exemplary embodiment, a network device is provided, including a memory and a processor, and a computer program is stored in the memory, and when the processor executes the computer program, the steps in the above-mentioned method embodiments are implemented. In one embodiment, a processor-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above method embodiments are implemented. In one embodiment, a computer program product is provided, including a computer program. When the computer program is executed by a processor, the steps in the above method embodiments are implemented. The processor-readable storage medium can be any available medium or data storage device accessible by the processor, including but not limited to magnetic memory (such as floppy disks, hard disks, magnetic tapes, magneto-optical disks (MO), etc.), optical memory (such as CDs, DVDs, BDs, HVDs, etc.), and semiconductor memory (such as ROM, EPROM, EEPROM, non-volatile memory (NAND FLASH), solid-state drives (SSD)), etc. Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memory and optical memory, etc.) containing computer-usable program code. The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer-executable instructions. These computer-executable instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for implementing the functions specified in one or more flows in the flowchart and / or one or more blocks in the block diagram. These processor-executable instructions can also be stored in a processor-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the processor-readable memory generate a manufactured product including an instruction device, and the instruction device implements the functions specified in one or more flows in the flowchart and / or one or more blocks in the block diagram. Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these changes and modifications.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be covered within the scope of the claims and the specification of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A communication method, applied to a terminal, includes: Sending a network connection request to a satellite, where the network connection request is used for the terminal to establish a network connection with the satellite; Receiving a target response message returned by a device on the satellite to the terminal.

2. The method according to claim 1, wherein The network connection request includes the ability to support store-and-forward and a terminal identifier.

3. The method according to claim 2, wherein, The receiving the target response message returned by the device on the satellite to the terminal includes: Receiving a first request acceptance response message returned by the device on the satellite to the terminal, where the first request acceptance response message carries the data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward, and the first request acceptance response message is generated by the satellite after determining that the terminal is in an accessible network state based on the terminal identifier and the ability to support store-and-forward.

4. The method according to claim 1, wherein The network connection request includes the ability to support store-and-forward and a terminal identifier; the receiving the target response message returned by the device on the satellite to the terminal includes: Receiving a second request acceptance response message returned by the device on the satellite to the terminal, where the second request acceptance response message carries the data retention period of on-board store-and-forward and the data storage quota of on-board store-and-forward, and the second request acceptance response message is generated by the satellite after determining that the terminal is in a restricted transmission state based on a second configuration policy, the terminal identifier, and the ability to support store-and-forward.

5. The method according to claim 1, wherein The network connection request includes the ability to support store-and-forward; the receiving the target response message returned by the device on the satellite to the terminal includes: Receiving a request staging response message returned by the device on the satellite to the terminal, where the request staging response message is generated by the device on the satellite based on the satellite being in store-and-forward mode, the terminal meeting the conditions for initially accessing the satellite, and the ability of the terminal to support store-and-forward; the request staging response message carries a satellite identifier.

6. The method according to claim 1, wherein, The network connection request includes the ability to support store-and-forward; the receiving the target response message returned by the device on the satellite to the terminal includes: Receiving a rejection response message returned by the device on the satellite to the terminal, where the rejection response message is generated by the device on the satellite based on the satellite being in store-and-forward mode, the terminal meeting the conditions for initially accessing the satellite, and the ability of the terminal to support store-and-forward; the rejection response message carries a rejection reason message and a satellite identifier.

7. The method according to any one of claims 1 to 4, wherein The target response message also carries a satellite identifier and a bearer session identifier.

8. The method according to claim 5 or 6, wherein The target response message also carries a satellite flyback time.

9. The method according to claim 1, wherein Before the step of sending the network connection request to the satellite, the method further includes: Receiving a satellite broadcast message.

10. The method according to claim 9, wherein, The satellite broadcast message carries store-and-forward characteristics and / or a satellite identifier.

11. The method according to claim 3 or 4, further includes: Sending data to be transmitted that meets the data storage quota to the satellite.

12. A communication method, applied to a satellite, includes: Receive a network connection request sent by a receiving terminal, where the network connection request is used to instruct the terminal to establish a network connection with the satellite; Generate a target response message based on the network connection request, and return the target response message to the terminal.

13. The method according to claim 12, wherein, The network connection request carries a terminal identifier and the ability to support store-and-forward.

14. The method according to claim 13, wherein, The generating a target response message based on the network connection request and returning the target response message to the terminal includes: Based on the terminal identifier and the ability to support store-and-forward, determine that the terminal is in an accessible network state, and determine the data retention period of on-board store-and-forward data and the data storage quota of on-board store-and-forward data based on the available satellite coverage time; Return a first request acceptance response message to the terminal, where the first request acceptance response message carries the data retention period of on-board store-and-forward data and the data storage quota of on-board store-and-forward data.

15. The method according to claim 13, further comprising: If the satellite covers the gateway station and receives the data to be transmitted sent by the terminal that meets the data storage quota, forward the data to be transmitted.

16. The method according to claim 15, wherein, The if the satellite covers the gateway station and receives the data to be transmitted sent by the terminal that meets the data storage quota, forward the data to be transmitted includes: If the satellite covers the gateway station and receives the data to be transmitted sent by the terminal that meets the data storage quota, perform an authentication process on the terminal; If it is determined that the terminal passes the authentication, forward the data to be transmitted.

17. The method according to claim 12, wherein, The network connection request carries a terminal identifier and the ability to support store-and-forward. The generating a target response message based on the network connection request and returning the target response message to the terminal includes: Based on a second configuration policy, the terminal identifier, and the ability to support store-and-forward, determine that the terminal is in a restricted transmission state, and determine the data retention period of on-board store-and-forward data and the data storage quota of on-board store-and-forward data based on the available satellite coverage time; Return a second request acceptance response message to the terminal, where the second request acceptance response message carries the data retention period of on-board store-and-forward data and the data storage quota of on-board store-and-forward data.

18. The method according to claim 17, further comprising: If the satellite covers the gateway station, obtain the subscription information of the terminal; If it is determined based on the subscription information that the terminal passes the authentication and receives the data to be transmitted sent by the terminal that meets the data storage quota, forward the data to be transmitted and update the restricted transmission state of the terminal to a non-restricted transmission state.

19. The method according to claim 18, further comprising: If it is detected that the terminal obtains the coverage of the satellite, send a status update message to the terminal, where the status update message indicates that the restricted transmission state of the terminal is updated to a non-restricted transmission state.

20. The method according to claim 13 or 17, wherein, The target response message further carries a satellite identifier and a bearer session identifier.

21. The method according to claim 12, wherein, The generating a target response message based on the network connection request and returning the target response message to the terminal includes: Generate a request for temporary storage response message based on the satellite being in the store-and-forward mode, the terminal meeting the condition for initially accessing the satellite, and the store-and-forward support capability of the terminal; Return the request for temporary storage response message to the terminal, where the request for temporary storage response message carries the satellite identifier.

22. The method according to claim 12, wherein, The generating a target response message based on the network connection request and returning the target response message to the terminal includes: Generate a rejection response message based on the satellite being in the store-and-forward mode, the terminal meeting the condition for initially accessing the satellite, and the store-and-forward support capability of the terminal; Return the rejection response message to the terminal, where the rejection response message carries a rejection reason message and the satellite identifier.

23. The method according to claim 12, further comprising: Send a broadcast message for instructing the terminal to connect to the satellite.

24. The method according to claim 23, wherein, The broadcast message includes the store-and-forward characteristic and / or the satellite identifier.

25. The method according to claim 21 or 22, wherein, The target response message further carries the satellite flyback time.

26. A communication device, applied to a terminal, comprising: A first sending unit, configured to send a network connection request to a satellite, where the network connection request is used to instruct the terminal to establish a network connection with the satellite; A first receiving unit, configured to receive a target response message returned by a device on the satellite to the terminal.

27. A communication device, applied to a satellite, comprising: A second receiving unit, configured to receive a network connection request sent by a terminal, where the network connection request is used to instruct the terminal to establish a network connection with the satellite; A second sending unit, configured to generate a target response message based on the network connection request and return the target response message to the terminal.

28. A communication device, comprising a memory, a transceiver, and a processor: A memory for storing a computer program; The transceiver is configured to transmit and receive data under the control of the processor; The processor is configured to read a computer program in the memory and execute the method according to any one of claims 1 to 25.

29. A computer-readable storage medium having a computer program stored thereon, wherein, When the computer program is executed by the processor, the steps of the method according to any one of claims 1 to 25 are implemented.

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