Satellite communication method and related device

Abstract

Embodiments of the present application provide a satellite communication method and a related device. A satellite-borne base station is deployed on a satellite, the satellite is provided with a satellite-borne network element, the satellite-borne network element comprises the satellite-borne base station or a satellite-borne core network element, and the method is performed by the satellite-borne network element. The method comprises: receiving a data packet sent by a first terminal; and, on the basis of indication information, sending the data packet to a second terminal without passing through a ground core network element.

Description

Satellite communication method and related equipment

[0001] Priority information

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on February 7, 2024, with application number 2024101742905 and application name “Methods and Related Equipment for Satellite Communication”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of communication technology, and in particular to a satellite communication method, satellite-borne network element, communication equipment, computer-readable storage medium, and computer program product. Background Art

[0004] In wireless communication technology research, satellite communications are considered a key future development direction. Satellite communications refers to the technology by which terrestrial wireless communication devices access a network via satellite, or by the technology by which terrestrial wireless communication devices communicate with each other using satellites as relays. Satellite communications offer a wide range and are less susceptible to land-based disasters. As a complementary access method for mobile communications, satellite communications effectively address the limited coverage and high construction costs of mobile communication systems.

[0005] In the future, satellite communication systems will be integrated with terrestrial mobile networks (such as 4G and 5G networks) to form a global, integrated communications network with seamless coverage across land, sea, air, and space, meeting the diverse needs of users everywhere. When all core network functions of a satellite-ground integrated system are located on the ground, communications between terminals must be relayed by satellite back to the ground before data exchange can be achieved. This results in long communication links and significant latency. Summary of the Invention

[0006] The embodiments of the present application provide a satellite communication method and related equipment, which can shorten communication delays and save feedback link transmission resources between satellites and the ground.

[0007] An embodiment of the present application provides a method for satellite communication, wherein a satellite is deployed with an onboard base station, and the satellite has an onboard network element, wherein the onboard network element includes the onboard base station or the onboard core network element. The method is executed by the onboard network element, and the method includes: receiving a data packet sent by a first terminal; and sending the data packet to a second terminal without passing through a ground core network element according to indication information.

[0008] An embodiment of the present application provides a satellite-borne network element, which is located on a satellite. A satellite base station is deployed on the satellite. The satellite-borne network element includes the satellite base station or the satellite core network element. The satellite-borne network element includes: a receiving unit for receiving a data packet sent by a first terminal; and a sending unit for sending the data packet to a second terminal without passing through a ground core network element according to indication information.

[0009] An embodiment of the present application provides a communication device, comprising: one or more processors; and a memory configured to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the communication device implements the satellite communication method described in the embodiment of the present application.

[0010] An embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon. When the computer program is run on a computer, the computer implements the satellite communication method described in the embodiment of the present application.

[0011] An embodiment of the present application provides a computer program product, including a computer program, which, when executed by a computer, implements the satellite communication method described in the embodiment of the present application.

[0012] The satellite communication method provided in the embodiment of the present application deploys an onboard network element on a satellite so that the onboard network element supports local data exchange. After the onboard network element receives a data packet sent by a first terminal, it sends the data packet to a second terminal according to the instruction information without passing through a ground core network element. This enables data transmission between two UEs on the same satellite or between different satellites without the need for forwarding through a ground core network element, thereby shortening the communication delay and saving feedback link transmission resources between the satellite and the ground. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG1 is a schematic diagram of a communication system architecture provided in an embodiment of the present application.

[0014] FIG2 is a system architecture diagram of a 5G network provided in an embodiment of the present application.

[0015] FIG3 schematically shows a network architecture diagram of a transparent forwarding mode according to an embodiment of the present application.

[0016] FIG4 schematically shows a circuitous route and increased delay caused by transferring data through a terrestrial core network.

[0017] FIG5 schematically shows a network architecture diagram of a regeneration mode according to an embodiment of the present application.

[0018] FIG6 schematically shows a network architecture diagram of a regeneration mode according to another embodiment of the present application.

[0019] FIG7 schematically shows a network architecture diagram of a regeneration mode according to another embodiment of the present application.

[0020] FIG8 schematically shows a network architecture diagram of a regeneration mode according to yet another embodiment of the present application.

[0021] FIG9 schematically shows a network architecture diagram of a regeneration mode according to yet another embodiment of the present application.

[0022] FIG10 schematically shows a flow chart of a satellite communication method according to an embodiment of the present application.

[0023] FIG11 schematically shows an interactive diagram of a satellite communication method according to an embodiment of the present application.

[0024] FIG12 schematically shows an interactive diagram of a satellite communication method according to another embodiment of the present application.

[0025] FIG13 schematically shows an interactive diagram of a satellite communication method according to yet another embodiment of the present application.

[0026] FIG14 schematically shows a diagram of a satellite communication method according to an embodiment of the present application.

[0027] FIG15 schematically shows an interactive diagram of a satellite communication method according to yet another embodiment of the present application.

[0028] FIG16 schematically shows an interactive diagram of a satellite communication method according to yet another embodiment of the present application.

[0029] FIG17 schematically shows an interactive diagram of a satellite communication method according to yet another embodiment of the present application.

[0030] FIG18 schematically shows a diagram of a satellite communication method according to an embodiment of the present application.

[0031] FIG19 schematically shows a block diagram of a satellite-borne network element according to an embodiment of the present application.

[0032] FIG20 schematically shows a schematic structural diagram of a communication device according to an embodiment of the present application. DETAILED DESCRIPTION

[0033] To make the objectives, technical solutions, and advantages of the present application more apparent, exemplary embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the accompanying drawings, like reference numerals represent like elements throughout. It should be understood that the embodiments described herein are merely illustrative and should not be construed as limiting the scope of the present application.

[0034] In the embodiments of the present application, the term "module" or "unit" refers to a computer program or a part of a computer program that has a predetermined function and works together with other related parts to achieve a predetermined goal, and can be implemented in whole or in part by using software, hardware (such as processing circuits or memories) or a combination thereof. Similarly, a processor (or multiple processors or memories) can be used to implement one or more modules or units. In addition, each module or unit can be part of an overall module or unit that includes the function of the module or unit.

[0035] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: Global System of Mobile communication (GSM) system, Code Division Multiple Access (CDMA) system, Wideband Code Division Multiple Access (WCDMA) system, General Packet Radio Service (GPRS), Long Term Evolution (LTE) system, LTE Frequency Division Duplex (FDD) system, LTE Time Division Duplex (TDD), Universal Mobile Telecommunication System (UMTS), Worldwide Interoperability for Microwave Access (WiMAX) communication system, 5G system or future evolved mobile communication system, etc.

[0036] For example, a communication system 100 used in an embodiment of the present application is shown in FIG1 . The communication system may be a communication system based on cellular mobile communication technology. The communication system 100 may include a network device 110, which may be a device that communicates with a terminal 120 (or a communication terminal or terminal). The network device 110 may provide communication coverage for a specific geographic area and may communicate with terminals within the coverage area. Optionally, the network device 110 can be a base station (Base Transceiver Station, BTS) in a GSM system or a CDMA system, a base station (NodeB, NB) in a WCDMA system, an evolved base station (Evolutional Node B, eNB or eNodeB) in an LTE (also known as 4G) system, a base station (gNB) in a 5G communication system, or a wireless controller in a cloud radio access network (Cloud Radio Access Network, CRAN), or the network device can be a mobile switching center, a relay station, an access point, a vehicle-mounted device, a wearable device, a hub, a switch, a bridge, a router, a network side device in a 5G network, a network side device in a 5G network and a satellite system fusion system, a network side device in a 5G system with new air interface satellite access technology, a network side device in a 5G network using satellite transmission as base station backhaul, or a network device in a future evolved public land mobile network (Public Land Mobile Network, PLMN), etc.

[0037] Among them, the base station can be provided with a packet data convergence protocol (Packet Data Convergence Protocol, PDCP) layer, a radio link layer control protocol (Radio Link Control, RLC) layer, a media access control (Media Access Control, MAC) layer protocol stack, and a physical (Physical, PHY) layer protocol stack. The embodiment of the present application does not limit the specific implementation method of the base station.

[0038] The communication system 100 also includes at least one terminal 120 located within the coverage area of ​​the network device 110. As used herein, "terminal" includes, but is not limited to, a connection via a wired line, such as via a Public Switched Telephone Network (PSTN), a Digital Subscriber Line (DSL), a digital cable, a direct cable connection; and / or another data connection / network; and / or via a wireless interface, such as for a cellular network, a Wireless Local Area Network (WLAN), a digital television network, a satellite network, a broadcast transmitter; and / or another terminal configured to receive / send communication signals; and / or an Internet of Things (IoT) device. A terminal configured to communicate via a wireless interface may be referred to as a "wireless communication terminal," "wireless terminal," or "mobile terminal." Examples of mobile terminals include, but are not limited to, satellite or cellular telephones; Personal Communications System (PCS) terminals that may combine cellular radiotelephones with data processing, fax, and data communications capabilities; Personal Digital Assistants (PDAs) that may include a radiotelephone, pager, Internet / Intranet access, a web browser, a notepad, a calendar, and / or a Global Positioning System (GPS) receiver; and conventional laptop and / or handheld receivers or other electronic devices that include a radiotelephone transceiver. A terminal may be referred to as an access terminal, user equipment / terminal (UE), a subscriber unit, a subscriber station, a mobile station, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent, or a user device. The access terminal can be a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, a device for an unmanned aerial vehicle, an in-vehicle device (for example, a driving computer with wireless communication capabilities, or a wireless communication device connected to an external driving computer), a wearable device, a terminal in a 5G network or a terminal in a future evolved PLMN, a roadside device (for example, a street lamp, a traffic light or other roadside device with wireless communication capabilities, etc.), etc.

[0039] A wireless connection can be established between the base station and the terminal via a wireless air interface. The wireless air interface can be a wireless air interface based on the 4G standard; or a wireless air interface based on the 5G standard, for example, a new air interface; or a wireless air interface based on the next generation mobile communication network technology standard of 5G.

[0040] In some embodiments, the above-mentioned communication system may further include a network management device (not shown in the figure). One or more (two or more) base stations are respectively connected to the network management device. The network management device may be a core network device (including core network elements) in a wireless communication system. For example, the network management device may be a mobility management entity (MME) in an evolved packet core (EPC), providing non-access stratum (NAS) signaling transmission with the UE (providing encryption and integrity protection for NAS signaling), and processing the UE's ESM (EPS Session Management) and EMM (EPS Mobility Management) transactions through the NAS layer. Alternatively, the network management device may also be other core network devices, such as a serving gateway (S-GW), a public data network gateway (P-GW), a policy and charging rules function (PCRF), or a home subscriber server (HSS). The embodiments of this application do not limit the implementation form of the network management device.

[0041] FIG1 exemplarily shows a network device and two terminals. Optionally, the communication system 100 may include multiple network devices and each network device may include another number of terminals within its coverage area, which is not limited in this embodiment of the present application.

[0042] It should be understood that in the embodiments of the present application, a device having a communication function in a network / system may be referred to as a communication device. Taking the communication system 100 shown in FIG1 as an example, the communication device may include a network device 110 and a terminal 120 having a communication function. The network device 110 and the terminal 120 may be the specific devices described above and will not be described in detail here.

[0043] It should be understood that the terms "system" and "network" are often used interchangeably herein. The term "and / or" is simply a description of an association between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone.

[0044] Figure 2 is a system architecture diagram of the 5G network of an embodiment of the present application. As shown in Figure 2, the equipment involved in the 5G network system includes: terminal (UE), radio access network (Radio Access Network, RAN), user plane function (User Plane Function, UPF) network element, data network (Data Network, DN), access and mobility management function (Access and Mobility Management Function, AMF) network element, session management function (Session Management Function, SMF) network element, policy control function (Policy Control Function, PCF) network element, application function (Application Function, AF) network element, authentication server function (Authentication Server Function, AUSF) network element, unified data management (Unified Data Management, UDM) network element, network slice selection function (Network Slice Selection Function, NSSF).

[0045] In the network architecture shown in Figure 2, network elements can communicate with each other through the interfaces shown in the figure. As shown in Figure 2, the UE and the AMF can interact through the N1 interface, which is used to transmit Quality of Service (QoS) control rules, etc. to the UE. N2 is the interface between the AMF and the RAN, which is used to transmit radio bearer control information, etc., from the core network side to the RAN. The N2 interface can be used to send NAS messages, etc. The RAN and the UPF can interact through the N3 interface, which can be used to transmit user plane data, etc. N4 is the interface between the SMF and the UPF, which is used to transmit information between the control plane and the user plane, including the issuance of forwarding rules, QoS control rules, traffic statistics rules, etc. for the user plane, as well as the reporting of user plane information. The UPF and the DN can interact through the N6 interface, which can be used to transmit user plane data, etc. N7 is the interface between the PCF and the SMF, which is used to issue Protocol Data Unit (PDU) session granularity and service data flow granularity control policies. N15 is the interface between the PCF and the AMF, which is used to issue UE policies and access control-related policies. N5 is the interface between AF and PCF, used for issuing application service requests and reporting network events. N11 is the interface between SMF and AMF, used for transmitting PDU session tunnel information between RAN and UPF, transmitting control messages sent to UE, transmitting radio resource control information sent to RAN, etc. N8 is the interface between AMF and UDM, used for AMF to obtain subscription data and authentication data related to access and mobility management from UDM, and for AMF to register information related to the current mobility management of UE with UDM, etc. N10 is the interface between SMF and UDM, used for SMF to obtain subscription data related to session management from UDM, and for SMF to register information related to the current UE session with UDM, etc. N12 is the interface between AMF and AUSF, used for AMF to initiate an authentication process to AUSF, which can carry SUCI as a subscription identifier. N13 is the interface between UDM and AUSF, used for AUSF to obtain the user authentication vector from UDM to execute the authentication process. N22 is the interface between AMF and NSSF.

[0046] It should be understood that the naming in the embodiments of the present application is only defined to facilitate the distinction between different functions and should not constitute any limitation to the present application.

[0047] This application does not exclude the possibility of adopting other naming in 5G networks and other future networks. For example, in a 6G network, some or all of the above-mentioned network elements may continue to use the terminology in 5G, or may adopt other names, etc. The interface name between the network elements in Figure 2 is only an example. The name of the interface in the specific implementation may be other names, and this application does not specifically limit this. In addition, the name of the message (or signaling) transmitted between the above-mentioned network elements is only an example and does not constitute any limitation on the function of the message itself.

[0048] It is understood that the above-mentioned network elements or functions can be network elements in hardware devices, software functions running on dedicated hardware, or virtualized functions instantiated on a platform (e.g., a cloud platform). For ease of explanation, the following description of this application takes the base station as an example of a radio access network RAN.

[0049] It should be understood that the above-mentioned network architecture applied to the embodiment of the present application is only an example, and the network architecture applicable to the embodiment of the present application is not limited to this. Any network architecture that can realize the functions of the above-mentioned network elements is applicable to the embodiment of the present application.

[0050] The network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Ordinary technicians in this field will know that with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0051] The integration of 5G and satellite networks is an important technical direction for the integrated air-space-ground network, and it begins to transform from the transparent forwarding mode shown in Figure 3 to the regeneration mode shown in Figures 5 to 9.

[0052] As shown in Figure 3, all functions of the core network (such as EPC / 5G core network (5G core network, 5GC)) 33 and the base station (such as eNB in ​​4G or gNB in ​​5G) 34 are deployed on the ground, and the service link (Service link) and feedback link (feeder link) of the satellite 31 are carried as the underlying link of the Uu port to provide support for communication between the base station and the UE. The Uu port is the interface between the base station and the UE, used to transmit signaling and data. The non-terrestrial network gateway (NTN-GW) 32 and the EPC / 5GC 33 are connected through the eNB / gNB 34. The EPC / 5GC 33 is connected to the application server 35. In the transparent forwarding mode shown in Figure 3, the satellite link is only responsible for relaying signals between the UE and the eNB / gNB 34, and the 4G / 5G-related protocol processing is all performed within the 4G / 5G network.

[0053] This transparent forwarding model suffers from high latency because base stations and core network equipment are deployed on the ground. Furthermore, since this model treats satellites only as signal relay links and does not utilize them for signal processing or conversion, communication between satellites cannot be achieved. Therefore, this model does not support inter-satellite links (ISLs), making it difficult to expand coverage of the Earth's surface using satellite constellations. Furthermore, the path between satellites and base stations is long, resulting in high latency.

[0054] The disadvantage of the solution shown in Figure 3 is that it struggles to support flexible and efficient data transmission between UEs. Specifically, when two UEs exchange data via a satellite link, the data must first reach the core network element on the ground before being forwarded to the other UE. This is because satellite links are primarily used for wide coverage and long-distance transmission, while core network elements are responsible for tasks such as data processing, routing, and flow control. Therefore, data forwarding between two different UEs requires both uplink and downlink transmission on both the serving link and the feedback link, increasing latency and wasting resources on the feedback link.

[0055] For example, as shown in Figure 4, a first terminal (UE1) first sends data to satellite 31 via a service link between UE1 and satellite 31. Satellite 31 then transmits the data received from UE1 to a base station (e.g., eNB / gNB) 34 via a feedback link between NTN-GW 32 and satellite 31. Base station 34 then transmits the data received from NTN-GW 32 to a terrestrial core network element (e.g., EPC / 5GC) 33 via the terrestrial network. EPC / 5GC 33 processes and forwards the data. For example, core network element 33 can encrypt, decrypt, filter, and screen the data to ensure data security and privacy. Furthermore, core network element 33 can perform access control and traffic management based on user authentication, authorization, and billing information to ensure normal communication. EPC / 5GC 33 then transmits the processed data to UE2 via the service link between eNB / gNB 34, NTN-GW 32, satellite 31, and between satellite 31 and a second terminal (UE2). As can be seen from Figure 4, redundant transmission leads to increased delay and waste of link resources.

[0056] To this end, the industry is developing another approach, namely the regeneration mode, which places the base station (optionally, at least part of the 4G / 5G core network) on the satellite. This can shorten the link processing delay and realize satellite networking through ISL.

[0057] To this end, an embodiment of the present application provides a method and device for supporting on-board local data exchange in a satellite Internet, which can realize UE1-satellite-UE2 communication, so that the data transmission between two UEs under the same satellite or between different satellites does not need to be forwarded through the core network elements on the ground, thereby shortening the communication delay and saving feedback link transmission resources between the satellite and the ground.

[0058] The method provided in the embodiment of the present application can be based on the network architecture of the regeneration mode shown in Figures 5 to 9 below, which can be oriented to 5G systems and can also be applicable to 4G systems.

[0059] In the network architecture shown in FIG5 , a base station (e.g., eNB / gNB) 511 is deployed on a satellite 51 and is referred to as a satellite-borne base station 511. The functional entities of the core network are deployed on the ground and are referred to as ground-based core network elements (e.g., EPC / 5GC) 53. When no core network equipment / core network elements are deployed on the satellite 51, in order to enable communication between UE1, the satellite, and UE2, the satellite-borne base station 511 has local data forwarding capabilities. That is, data transmission between different UEs can be achieved through the satellite-borne base station 511 without passing through the ground-based core network element 53, thereby optimizing data routing and saving transmission resources. Specifically, data sent by UE1 is transmitted to the satellite 51 via the service link between UE1 and the satellite 51. The satellite-borne base station 51 sends the data to UE2 based on the service link between the satellite 51 and UE2, without the need for uplink and downlink transmission between the NTN-GW 52 and the satellite 51. In the embodiment of FIG5 , the EPC / 5GC 53 is in communication with the application server 55.

[0060] In the network architecture shown in Figure 6, base station 611 and some core network functional entities are deployed on satellite 61, while other core network functional entities are deployed on the ground. That is, the functional entities of the core network (e.g., EPC / 5GC) can be distributed on both the satellite and the ground. The core network functional entities deployed on the ground are referred to as ground core network elements (EPC / 5GC-ground part, i.e., the core network functional entities deployed on the ground) 631, and the core network functional entities deployed on the satellite are referred to as onboard core network elements (EPC / 5GC-onboard part, i.e., the core network functional entities deployed on the satellite) 632. When both the onboard base station 611 and the onboard core network element 632 are deployed on satellite 61, the onboard core network element 632 has local data forwarding capabilities. That is, data transmission between different UEs (e.g., UE1 and UE2) can be achieved through the onboard core network element 632 instead of the ground core network element 631, optimizing data routing and saving transmission resources. Specifically, data sent by UE1 is transmitted to satellite 61 via the service link between UE1 and satellite 61. Onboard core network element 632 transmits the data to UE2 based on the service link between satellite 61 and UE2, eliminating the need for uplink and downlink transmission via the feedback link between NTN-GW 62 and satellite 61. In the embodiment of FIG6 , ground EPC / 5GC 631 is in communication with application server 65.

[0061] In the network architecture shown in Figure 7, the base station 711 and the functional entities of the core network (such as EPC / 5GC) are deployed on the satellite 71. The functional entity of the core network deployed on the satellite is called the onboard core network element 712. At this time, the satellite 71 may also be deployed with a corresponding application server (Application Server, abbreviated as AS). Optionally, another core network functional entity and corresponding application server may be deployed on the ground. For the sake of distinction, the core network element deployed on the satellite 71 and the corresponding application server are respectively marked as the first core network element (EPC / 5G 5GC 1) 712 and the first application server (Application Server 1, AS1) 713, and the core network element deployed on the ground and the corresponding application server are respectively marked as the second core network element (EPC / 5G 5GC 2) 74 and the second application server (Application Server 2, AS2) 75. EPC / 5G 5GC 1 has local data forwarding capabilities, that is, data transmission between different UEs (such as UE1 and UE2) can be achieved through EPC / 5G5GC 1, which optimizes data routing and saves transmission resources. Specifically, the data sent by UE1 is transmitted to satellite 71 through the service link between UE1 and satellite 71, and the onboard core network element 712 sends the data to UE2 based on the service link between satellite 71 and UE2, without the need for uplink and downlink transmission between the feedback link between NTN-GW 72 and satellite 71. In the embodiment of Figure 7, the ground EPC / 5GC 2 is connected to its corresponding AS2. Optionally, in the embodiment of Figure 7, UE1 and / or UE2 can also exchange data through EPC / 5G 5GC 2 and AS2, that is, local data exchange and the path for exchanging data through the ground core network can exist at the same time.

[0062] In the network architecture shown in Figure 8 , UE1 and UE2 are located under different satellites. For example, UE1 is located under first satellite 81, i.e., UE1 accesses the network or transmits data through first satellite 81; UE2 is located under second satellite 86, i.e., UE2 accesses the network or transmits data through second satellite 86. A base station 811 is deployed on first satellite 81, and a base station may or may not be deployed on second satellite 86. The functional entities of the core network (e.g., EPC / 5GC) 83 are deployed on the ground. Base station 811 deployed on first satellite 81 has local data forwarding capabilities. That is, when base station 811 on first satellite 81 receives data sent by UE1 via the service link between first satellite 81 and UE1, it first transmits the data to second satellite 86 via the ISL between first satellite 81 and second satellite 86. The data is then transmitted to UE2 via the service link between second satellite 86 and UE2, without having to transmit the data to ground core network element 83 via the feedback link between NTN-GW 82 and second satellite 86. This enables data transmission between UE1 and UE2, optimizes data routing, and conserves transmission resources. In the embodiment of FIG8 , ground core network element 83 is in communication with application server 85.

[0063] It should be noted that although FIG8 only shows the ISL between the first satellite 81 and the second satellite 86, the present application is not limited thereto. Local data exchange between UE1 and UE2 can also be achieved through multiple ISLs between multiple satellites.

[0064] In the network architecture shown in Figure 9, UE1 is located under a first satellite 91, and UE2 is located under a second satellite 96. A base station 911 and at least a portion of the core network's functional entities (e.g., onboard EPC / 5GC) 932 are deployed on the first satellite 91. The second satellite 96 may or may not have a base station and at least a portion of the core network's functional entities deployed. The functional entities of the remaining portion of the core network (e.g., EPC / 5GC) 931 may be deployed on the ground. Onboard core network element 932 deployed on first satellite 91 has local data forwarding capabilities. That is, when onboard core network element 932 receives data sent by UE1 via the service link between first satellite 91 and UE1, it first sends the data to second satellite 96 via the ISL between first satellite 91 and second satellite 96. The data is then sent to UE2 via the service link between second satellite 96 and UE2, without having to be sent to terrestrial core network element 931 via the feedback link between NTN-GW 92 and second satellite 96. This enables data transmission between UE1 and UE2, optimizes data routing, and conserves transmission resources. In the embodiment of FIG9 , terrestrial core network element 931 is in communication with application server 95.

[0065] Similarly, although FIG9 only shows the ISL between the first satellite 91 and the second satellite 96 , the present application is not limited thereto. Local data exchange between UE1 and UE2 may also be achieved through multiple ISLs between multiple satellites.

[0066] As shown in Figure 10, an embodiment of the present application provides a satellite communication method. In the embodiment of Figure 10, a satellite is deployed with an onboard base station, and the satellite has onboard network elements, which include onboard base stations or onboard core network elements.

[0067] In an exemplary embodiment, the onboard network element stores a terminal-related context, and the terminal-related context includes instruction information, where the instruction information is used to instruct the first terminal and the second terminal to perform local data exchange through the onboard network element.

[0068] In the embodiments of the present application, a satellite-based network element refers to a network element deployed on a satellite. It can be a base station deployed on a satellite, i.e., a satellite-based base station; or a core network element deployed on a satellite, i.e., a satellite-based core network element. The satellite-based core network element can have at least some core network functional entities.

[0069] In an embodiment of the present application, the onboard network element has a local data exchange capability, that is, it can realize data forwarding between different UEs without passing through the ground core network element. In order to enable the onboard network element to support local data exchange, a terminal-related context (UE context) is stored in the onboard network element, and the terminal-related context refers to a context stored in the onboard network element and related to the UE. The terminal-related context indicates that the onboard network element supports local data exchange. When the onboard network element receives a data packet sent by a UE (for example, UE1) that supports local data exchange and is contained in the terminal-related context, the onboard network element can transmit the received data packet to another UE (for example, UE2) according to the terminal-related context without passing through the ground core network element.

[0070] The method provided in the embodiment of Figure 10 is executed by a satellite-borne network element. As shown in Figure 10, the method provided in the embodiment of the present application may include the following steps.

[0071] In S10, a data packet sent by the first terminal is received.

[0072] In S20, according to the instruction information, the data packet is sent to the second terminal without passing through the ground core network element.

[0073] In an embodiment of the present application, the terminal-related context stored in the onboard network element includes indication information that the first terminal and the second terminal are performing local data exchange through the onboard network element. For example, the indication information may include a mapping relationship between an identifier of the first terminal as the source address and an identifier of the second terminal as the destination address. When the onboard network element receives a data packet sent by the first terminal, the onboard network element determines, based on the mapping relationship, that local data exchange can be performed between the first terminal and the second terminal. Therefore, the onboard network element can directly send the data packet to the second terminal without forwarding it through the ground core network element.

[0074] The satellite communication method provided in the embodiment of the present application deploys on-board network elements on the satellite, so that the on-board network elements support local data exchange, thereby enabling data transmission between two UEs on the same satellite or between different satellites without the need for forwarding through the core network elements on the ground. That is, a method for supporting on-board local data exchange in the satellite Internet is disclosed, which can realize UE-1 satellite-UE2 communication, thereby shortening the communication delay and saving feedback link transmission resources between the satellite and the ground.

[0075] In an exemplary embodiment, the method provided in the embodiment of the present application may further include: during the process of establishing a session or connection between the first terminal and the second terminal respectively through the satellite base station and the core network element, the satellite network element obtaining a terminal-related context. The core network element includes at least one of a terrestrial core network element and a satellite core network element.

[0076] In an embodiment of the present application, when the first terminal and the second terminal establish a session or connection through the onboard base station and the core network network element, if the core network network element determines that both the first terminal and the second terminal support local data exchange, the core network network element can provide the onboard network element with signaling interaction and corresponding configuration so that it has the ability to locally exchange data transmitted between the first terminal and the second terminal, that is, the onboard network element obtains a terminal-related context containing indication information that the first terminal and the second terminal perform local data exchange through the onboard network element.

[0077] In some embodiments, the signaling interaction and corresponding configuration of the local data exchange on the satellite can be retained in the ground core network element, and the satellite network element obtains the signaling interaction and corresponding configuration of the local data exchange from the ground core network element. After the ground core network element performs the signaling interaction and corresponding configuration of the local data exchange based on the satellite network element, the satellite network element can process the input provided by the ground core network element and derive the context related to the terminal. However, the present application is not limited to this. In other embodiments, the satellite network element can also obtain the signaling interaction and corresponding configuration of the local data exchange from the onboard core network element. In this case, the terminal-related context can be established through the interaction between the satellite core network element and the ground core network element.

[0078] In an exemplary embodiment, the terminal-related context includes a first key of the first terminal and a second key of the second terminal. Accordingly, according to the indication information, the data packet is sent to the second terminal without passing through the ground core network element. Specifically, the data packet is decrypted using the first key of the first terminal, the decrypted data packet is encrypted using the second key of the second terminal, and the data packet encrypted using the second key of the second terminal is sent to the second terminal. In the embodiment of the present application, the key of UE1 and the key of UE2 are different. Therefore, before sending the data packet to the onboard network element, UE1 will first encrypt the data packet using the key of UE1. When the onboard network element receives the data packet sent by UE1 through the service link between the satellite and UE1, it first decrypts the data packet using the first key of UE1, and then encrypts the decrypted data packet using the second key of UE2. Then, the data packet encrypted with the second key of UE2 is sent to UE2 through the service link between UE2 and the satellite, thereby achieving the security of local data exchange between UE1 and UE2.

[0079] In an exemplary embodiment, the terminal-related context also includes satellite parameters. Based on the indication information, a data packet is sent to the second terminal without passing through the ground core network element. Specifically, the following may be performed: determining whether the first terminal and the second terminal are located under the same satellite based on the satellite parameters; if the first terminal and the second terminal are located under the same satellite, the data packet is sent to the second terminal via the satellite's onboard network element; if the first terminal and the second terminal are located under a first satellite and a second satellite, respectively, and the first satellite and the second satellite are different, the onboard network element of the first satellite sends the data packet to the second terminal located under the second satellite via the intersatellite link between the first and second satellites. That is, in this embodiment of the present application, the terminal-related context stored on the onboard network element may also include the parameters of the satellite. For example, if UE1 is located under the first satellite and UE2 is located under the second satellite, the interspatial link (ISL) between the first and second satellites can be determined, and local data exchange between UE1 and UE2 can be achieved via the ISL between the first and second satellites. For another example, if UE1 and UE2 are both located under the same satellite, local data exchange between UE1 and UE2 can be achieved directly through the onboard network element on the satellite.

[0080] In an exemplary embodiment, when all core network elements are deployed on the ground, the satellite-borne network element is a satellite-borne base station.

[0081] In an exemplary embodiment, the indication information includes a local data exchange index (index), a source address (source) corresponding to the local data exchange index includes a first data radio bearer (DRB) of the first terminal, and a destination address (dest) corresponding to the local data exchange index includes a second data radio bearer (DRB) of the second terminal. That is, in the embodiment of the present application, local data exchange (also known as local switching) between different UEs is implemented through an onboard network element, which can be DRB-granular. That is, when the onboard network element detects that a data packet transmitted by UE1 through the first DRB is transmitted to UE2 through the second DRB of UE2, the onboard network element can transmit the data packet to UE2 through the second DRB based on the indication information.

[0082] In an exemplary embodiment, the indication information includes a local data exchange index, the source address corresponding to the local data exchange index includes multiple (including part or all) data radio bearers of the first terminal, and the destination address corresponding to the local data exchange index includes at least one data radio bearer of the second terminal. In some embodiments, local data exchange between different UEs is implemented through an onboard network element, which can be UE-granular, that is, the indication information can indicate that all data packets of UE1 are transmitted to UE2 via local data exchange (local switch), that is, at this time, the source address corresponding to the local data exchange index includes all data radio bearers of the first terminal, and the destination address corresponding to the local data exchange index includes one or more data radio bearers of the second terminal.

[0083] In an exemplary embodiment, the terminal-related context also includes information indicating that the first terminal and the second terminal exchange data via the onboard network element and the terrestrial core network element. That is, while the onboard network element supports local data exchange between different UEs, it can also support a path for data exchange between different UEs via the terrestrial core network element, thereby further improving the reliability of data transmission.

[0084] In an exemplary embodiment, when at least part of the core network elements are deployed on a satellite, the onboard network element is a satellite-based core network element. In an embodiment of the present application, when there are satellite-based core network elements and satellite-based base stations on a satellite, local data exchange between different UEs is achieved through the satellite-based core network elements.

[0085] In an exemplary embodiment, the indication information includes a local data exchange index, the source address corresponding to the local data exchange index includes the first tunnel identification information of the first terminal, and the destination address includes the second tunnel identification information of the second terminal. In some embodiments, when local data exchange is implemented through an onboard core network element, the indication information stored by the onboard core network element includes a mapping relationship between the first tunnel identification information of UE1 and the second tunnel identification information of UE2. In this way, when the onboard core network element receives a data packet sent by UE1 through the tunnel indicated by the first tunnel identification information, it can send the data packet to UE2 through the tunnel corresponding to the second tunnel identification information according to the indication information.

[0086] In an exemplary embodiment, the indication information includes a local data exchange index, the source address corresponding to the local data exchange index includes the first evolved radio access bearer (E-UTRAN Radio Access Bearer, E-RAB) of the first terminal, and the destination address corresponding to the local data exchange index includes the second evolved radio access bearer of the second terminal. In other embodiments, when local data exchange is implemented through an onboard core network element, the indication information stored in the onboard core network element includes a mapping relationship between the first E-RAB of UE1 and the second E-RAB of UE2, so that when the onboard core network element receives a data packet sent by UE1 through the first E-RAB, it can send the data packet to UE2 through the second E-RAB according to the indication information. That is, in the embodiment of the present application, local data exchange between different UEs is implemented through the onboard core network element, which can be at the E-RAB granularity, but the present application is not limited to this, and can also be at the UE granularity, that is, the indication information can indicate that all data packets of UE1 are transmitted to UE2 through local data exchange.

[0087] The method provided in the embodiments of the present application enables on-board local data exchange in the satellite internet, enabling UE1-satellite-UE2 communication. Data transmission between two UEs on the same or different satellites does not need to be forwarded through the core network elements on the ground, thereby shortening communication latency and saving feedback link transmission resources between the satellite and the ground. At the same time, it can also support flexible conversion between local forwarding and ground forwarding modes, supporting communication between UEs and cloud-edge-end collaboration between UEs, the onboard "edge cloud", and the ground "central cloud".

[0088] The following examples illustrate the protocol flow design for implementing local data forwarding using satellite-borne base stations, combined with the architecture of 4G and 5G network integration with satellite networks. Examples of local data forwarding by different network elements in different scenarios are as follows, with reference to Figures 11 to 14.

[0089] Figures 11 to 14 show scenarios where the base station is located on the satellite and the core network is entirely located on the ground.

[0090] FIG11 is a flowchart showing the main steps for realizing local data exchange for satellite-borne base stations.

[0091] In S11, the terminal initiates PDU session / PDN connection establishment and service initiation, obtains signaling interaction and corresponding configuration of the core network, and can perform local switching.

[0092] In S12, after obtaining signaling interaction and corresponding configuration from the core network, the satellite-borne base station eNB / gNB establishes a local interaction context and key. The local interaction context may include a terminal-related context indicating that the satellite-borne base station can support local data exchange.

[0093] In S13, local data exchange is performed through the base station. For example, the satellite-borne base station eNB / gNB performs local data exchange between UE1 and UE2 based on the local exchange context and key.

[0094] Specifically, the GS in Figure 11 stands for ground station (e.g., NTN-GW). UEs (including UE1 and UE2) establish a PDU session or public data network (PDN) connection through a 4G or 5G satellite base station (eNB / gNB) and ground-based core network equipment (CN). During service request initiation and connection establishment, the satellite-based eNB / gNB obtains signaling interaction and corresponding configuration from the core network, enabling local data exchange.

[0095] Among them, PDU session and PDN connection are used for 5G and 4G systems respectively.

[0096] In order to realize local data exchange, it is explicitly indicated in the terminal-related context of the satellite base station eNB / gNB that local exchange can be performed.

[0097] The terminal-related context stored in the satellite base station eNB / gNB includes user information, terminal information, bearer information, etc., which is used to establish and maintain a communication connection with the UE. For example, it may include at least one of the following information:

[0098] User identifier: includes Subscription Permanent Identifier (SUPI), Subscription Concealed Identifier (SUCI), Permanent Equipment Identifier (PEI), etc., used to uniquely identify a user;

[0099] Mobility management restrictions and terminology: including registration area, prohibited area, service-restricted area, etc., used to restrict user mobility and access rights.

[0100] For example, in a converged 4G and satellite network, the terminal-related context of the satellite base station eNB includes information such as UE status information, security information, UE capability information, the association between the UE and the S1 logical connection, the association between the UE and the X2 logical connection, and information related to roaming and access restrictions. This is used to maintain the services provided by the E-UTRAN to active UEs. This information is used to establish and maintain communication connections with the UE to ensure normal communication. For another example, in a converged 5G and satellite network, the terminal-related context of the satellite base station gNB includes information such as UE status information, security information, UE capability information, the association between the UE and the N2 / N3 logical connection, the association between the UE and the Xn logical connection, and information related to roaming and access restrictions. This is used to maintain the services provided by the RAN to active UEs. This information is used to establish and maintain communication connections with the UE to ensure normal communication.

[0101] In this embodiment of the present application, the local data exchange supported by the satellite base station eNB / gNB itself needs to obtain relevant parameters, including security parameters (such as various keys), from the ground core network element (CN element) such as MME / AMF. The relevant parameters can be included in the terminal-related context.

[0102] Specifically, since the 4G and 5G base station eNB / gNB itself needs to support protocol layer processing such as the SDAP layer and the PDCP layer from the perspective of the protocol stack, and the PDCP key needs to be configured by the ground core network elements such as MME / AMF, the base station that supports the local forwarding function on the satellite must maintain a connection with the ground core network elements such as MME / AMF. This connection can be used to derive the key.

[0103] The key acquisition process includes: generating NAS layer keys, including IK (Integrity Key) and CK (Cipher Key), from the MME / AMF and UE NAS layers, and generating AS layer keys at the AS layer of the eNB / gNB and UE. Both steps involve the core network elements (CN elements) located on the ground. When configuring PDCP keys, it is necessary to first generate NAS layer keys and AS layer keys. NAS layer keys are mainly used to protect the confidentiality and integrity of NAS signaling, while AS layer keys are used to protect the confidentiality and integrity of RRC signaling, as well as the confidentiality of user plane data. Generating these keys before configuring PDCP keys can ensure that PDCP data transmission is carried out in a secure environment.

[0104] The process of obtaining the base station's PDCP keys from the MME / AMF is achieved through security context exchange. After the UE successfully accesses the base station, the base station obtains the UE's security context from the MME / AMF, which includes the keys used for PDCP encryption and decryption. In this way, the base station can use these keys to encrypt and decrypt data to ensure the security of communications. This process involves certain specific protocols and processes, such as NAS security context and the NAS security context exchange process. These protocols and processes ensure that the base station can securely obtain PDCP keys from the MME / AMF, thereby achieving secure communications. PDCP layer keys are mainly used to encrypt and decrypt user plane data and provide integrity protection for data. These keys are generated at the RRC layer and configured for the PDCP layer when AS layer security is activated.

[0105] In the embodiment of the present application, NAS security is designed to securely transmit signaling information between the wireless link UE and the CN network element (such as MME / AMF, etc.), and is used to perform integrity check and encryption of NAS signaling messages. For example, it may include the integrity key K NASint and encryption key K NASenc NAS-layer keys are generated during the security context exchange process between the MME / AMF and the UE. When the UE successfully accesses the network, the MME / AMF and the UE exchange a security context, including the NAS security context. During this process, the MME / AMF and the UE jointly generate NAS-layer keys.

[0106] AS security is used to ensure the security of data transmission between the UE and the satellite base station eNB / gNB on the radio link. Integrity checking and encryption are performed on the control side for RRC signaling messages, and encryption is performed on the user side for IP (Internet Protocol) data packets (such as the above data packets). Different keys are used for integrity checking / encryption of RRC signaling messages and encryption of IP data packets. AS security keys, such as K RRCint , K RRCenc and K UPenc , which is generated by UE and satellite base station eNB / gNB from K eNB Derived from K RRCint and K RRCenc Used for integrity checking and encryption of control plane data, K UPenc Used for encryption of user plane data. Optionally, the AS security key may also include K UPint . Integrity check and encryption can be performed at the PDCP layer. UE can ASME K is derived from eNB , K ASME It is not transmitted to the satellite base station eNB / gNB, but is transmitted from K ASME K is derived from eNB , which is then passed to the onboard base station, the eNB / gNB. AS-layer keys are generated between the eNB / gNB and the UE through the security context exchange process. These keys are jointly generated by the eNB and UE and are used to encrypt and decrypt RRC signaling and user plane data.

[0107] For example, in a 5G network, after the UE receives the terminal-related context from the 5GC, the RAN uses the initial radio access AS security activation procedure to activate AS security (encryption and integrity protection). After the RRC message (command and successful response) for activating AS security is integrity protected, the RAN initiates DRB establishment. In 5G wireless networks, all RRC reconfiguration messages used to establish DRBs are encrypted and integrity protected.

[0108] As shown in Figure 12, it is a flowchart of the main steps for the satellite-borne base station eNB to implement local data exchange in the scenario of 4G network and satellite network integration.

[0109] In S11a, the terminal initiates PDN connection establishment and service initiation, obtains signaling interaction and corresponding configuration of functional entities such as MME / P-GW in the ground core network, and can perform local switching.

[0110] In S12a, after obtaining the signaling interaction and corresponding configuration of the MME / P-GW and other functional entities in the core network, the satellite base station eNB establishes a local interaction context and key. The local interaction context may include a terminal-related context indicating that the satellite base station eNB can support local data exchange.

[0111] In S13a, local data exchange is performed through the satellite-borne base station eNB. For example, the satellite-borne base station eNB performs local data exchange between UE1 and UE2 based on the local exchange context and key.

[0112] For other contents of the embodiment of FIG12 , reference may be made to the other embodiments described above.

[0113] As shown in Figure 13, this is a flowchart of the main steps for the satellite-borne base station gNB to implement local data exchange in the scenario of 5G network and satellite network integration.

[0114] In S11b, the terminal initiates PDU session establishment and service initiation, obtains signaling interaction and corresponding configuration of functional entities such as AMF / SMF / UPF in the ground core network, and can perform local switching.

[0115] For example, a UE (including UE1 and UE2) sends an RRC Connection Establishment Request to the gNB, carrying the initial terminal identifier and establishment reason. The gNB replies with an RRC Connection Establishment Response, carrying the complete configuration information for the signaling channel between the UE and the gNB. The UE then sends an RRC Connection Establishment Complete message to the gNB, carrying an uplink NAS message, i.e., a Registration Request. The gNB selects an appropriate CN (core network) and forwards the Registration Request message. The CN initiates an authentication process with the terminal through the gNB, performing mutual authentication between the UE and CN. After authentication is complete, the UE and CN perform a NAS security mode activation (security mode command) process, initiating NAS signaling encryption, decryption, and integrity protection. The CN sends an Initial Context Establishment Request to the gNB, carrying a Registration Success NAS message. The gNB initiates an AS security mode control process to the terminal, initiating AS signaling encryption, decryption, and integrity protection. The gNB then sends an RRC Connection Reconfiguration Request to the UE and forwards the Registration Success NAS message. The UE sends a response to the gNB: RRC Connection Reconfiguration Complete. The service channel between the UE and the gNB is now established. The gNB sends an Initial UE Context Setup Response to the CN. The UE has now joined the network and established a PDU session.

[0116] In some embodiments, UE1 initiates a request to the CN to establish a local data exchange path to UE2. The CN reviews the local data exchange service capabilities of UE1 and UE2 and assigns keys to them respectively. The CN retrieves the base station locations of UE1 and UE2, allocates an inter-satellite path for the local data exchange service, and initiates a PDU Session Modify request to the satellite base station gNB (if UE1 and UE2 are on different satellites, the request is sent to the first satellite base station on the first satellite corresponding to UE1 and the second satellite base station on the second satellite corresponding to UE2) to establish a local data exchange path between UE1 and UE2. If UE1 and UE2 are on different satellites, the satellite base stations gNB send each other service direct transmission channel establishment messages based on the inter-satellite path to establish a service transmission tunnel between the satellite base stations gNB.

[0117] In other embodiments, the CN may perform route optimization and establish local data exchange between UE1 and UE2 via the satellite-borne base station gNB.

[0118] In S12b, after obtaining signaling interaction and corresponding configuration from the AMF / SMF / UPF functional entities in the core network, the gNB establishes a local interaction context and key. The local interaction context may include a terminal-related context indicating that the gNB can support local data exchange.

[0119] For example, the ground CN network element obtains an identification list, which includes identification information of one or more UEs that support local data exchange under the satellite and access the satellite. The identification list corresponds to the relevant information of the satellite. The identification information of the UE can be the IP address of the UE, or the identification information of the UE can also be other types of identification, such as the UE's SUPI / cell radio network temporary identifier (Cell-Radio Network Temporary Identifier, C-RNTI), etc., which is not limited in this application.

[0120] In an embodiment of the present application, the ground CN network element can determine whether to allow the UE to perform local data exchange under the satellite based on the UE's contract information or policy information, for example, the contract information or policy information indicates that the UE can perform local data exchange, thereby generating the above-mentioned identification list.

[0121] The relevant information (or parameters) of the satellite may refer to any information associated with the satellite. For example, the relevant information of the satellite may be any one of the following information: the data network access identifier corresponding to the satellite, the identifier of the satellite, etc., which is not limited in this application.

[0122] As an example, the ground CN network element determines the satellite-related information based on the UE's location information. Optionally, the satellite-related information may be determined in combination with other information. For example, the satellite-related information may be determined based on the UE's location information, the satellite type (e.g., high orbit, low orbit, etc.), and the satellite return type information. For another example, the satellite-related information may be determined based on the UE's location information, the satellite return type information, and the satellite's constellation information.

[0123] The ground CN network element configures a local interaction context and key with the gNB on the satellite. This local interaction context is used to forward data packets whose destination address contains the address of a UE corresponding to the identifier list to that UE. For example, UE1 accesses the network via satellite. Assume that the identifier list corresponding to the satellite's relevant information includes UE2. UE1 sends a data packet to UE2, whose destination address is UE2's IP address. When the gNB receives the data packet, it determines, based on the local interaction context, that the destination address is included in the identifier list. The gNB then forwards the data packet to UE2. Data packets destined for terminals on the identifier list can be sent directly from the gNB on the satellite to the corresponding terminals, without passing through the ground core network equipment. This shortens the data transmission path and reduces transmission latency.

[0124] In S13b, local data exchange is performed via the gNB. For example, the gNB performs local data exchange between UE1 and UE2 based on the local exchange context and key.

[0125] For other contents of the embodiment of FIG13 , reference may be made to the other embodiments described above.

[0126] In an exemplary embodiment, the onboard eNB / gNB supports local data exchange while also supporting mapping with the GTP-u tunnels of the S1-u and N3 interfaces of the terrestrial core network. The GTP-u tunnels of the S1-u and N3 interfaces of the core network are primarily used to transmit user data.

[0127] Specifically, as shown in Figure 14, UE1, UE2 and the satellite base station eNB / gNB use their own DRBs to transmit data. The satellite base station eNB / gNB that supports local switching can support <ue1-drbx>and <ue2-drby>(In FIG14 , x=1, y=3 is used as an example, but the present application is not limited thereto) data exchange can also be supported with S1-u / GTP-u tunneling. For example, assuming that UE1 corresponds to GTP-u tunneling x (first tunnel identification information) and UE2 corresponds to GTP-u tunneling y (second tunnel identification information). In other words, in the embodiment of the present application, data paths for local on-board switching and switching through the terrestrial core network can coexist.

[0128] Figure 14 shows an example mapping table for implementing local switching in an eNB / gNB, also illustrating switching through the core network. This mapping table can be part of the established local interaction context. For example, assuming that the direction corresponding to index = 1 is local switching, the source address is UE1-DRB1, and the destination address is UE2-DRB3, based on this indication, when the eNB / gNB receives a data packet from UE1 via DRB1, the eNB / gNB uses the mapping table shown in Figure 14. If the mapping table entry contains an entry such as index = 1, the eNB / gNB can first decrypt the data packet from UE1's DRB1 and then, according to the entry with index = 1, encrypt the data packet and transmit it to UE2 via DRB3 established between the eNB / gNB and UE2. In this case, the eNB / gNB does not determine whether to perform local data switching based on the destination IP address carried in the data packet sent by UE1. In this case, the data packet sent by UE1 does not need to carry UE2's IP address as the destination IP address. For another example, assuming that the direction corresponding to index=2 is uplink, the source address is UE1-DRB1, and the destination address is the first tunnel identification information, then when the satellite base station eNB / gNB receives a data packet from UE1 through DRB1, it can also transmit it to the ground CN network element through the first tunnel identification information. For another example, assuming that the direction corresponding to index=3 is downlink, the source address is UE2-DRB3, and the destination address is the second tunnel identification information, then when the satellite base station eNB / gNB receives a data packet from UE2 through DRB3, it can transmit it to the ground CN network element through the second tunnel identification information. For another example, assuming that the direction corresponding to index=4 is downlink, the source address is the first tunnel identification information, and the destination address is UE1-DRB1, then when the satellite base station eNB / gNB receives a data packet from the ground CN network element through the first tunnel identification information, it can transmit it to the ground UE1 through DRB1.

[0129] In some embodiments, local data exchange is performed based on the context on the satellite base station eNB / gNB, and the exchange can be composed of mutual mapping of DRBs. For example, in a local data exchange between UE1-satellite-UE2, the uplink data of a corresponding DRB is first decrypted and then encrypted into another DRB (the AS keys of different UEs are different). That is, the AS keys of different UEs are stored in the satellite base station eNB / gNB, such as the AS key (first key) of UE1 and the AS key (second key) of UE2. When a data packet transmitted by UE1 through DRBx is received, the data packet is first decrypted with the AS key of UE1, and then encrypted with the AS key of UE2, and then transmitted to UE2 through DRBy.

[0130] It can be understood that the mapping table stored on the satellite base station in Figure 14 is only for illustration, and is not used to limit the representation method of the indication information, and is not limited to DRB granularity, but can also be UE granularity.

[0131] Using an onboard base station for forwarding requires enhancements to the AS layer protocol stack and is not the only solution. This application also proposes another embodiment, in which local forwarding is performed by an onboard core network functional entity (an onboard core network element or an onboard core network device). This is illustrated below with reference to Figures 15 to 18 . In the embodiments of Figures 15 to 18 , it is assumed that some core network functional entities are located on the satellite (denoted by CN-NT) and others are located on the ground (denoted by CN-T).

[0132] The protocol flow shown in Figure 15, combined with the architecture of 4G and 5G network integration with satellite network, is a flowchart of the main steps for the onboard core network element (CN-NT) to realize local data exchange.

[0133] In S21, the terminal initiates PDU session / PDN connection establishment and service initiation, obtains signaling interaction and corresponding configuration of the core network (which can be CN-T, CN-NT and CN-T), and can perform local switching.

[0134] UEs (including UE1 and UE2) establish PDU sessions or PDN connections through 4G or 5G satellite base stations and onboard and terrestrial core network equipment. During the service request and connection establishment process, they obtain signaling interaction and corresponding configuration from the core network, enabling local data exchange, which is completed by the onboard core network functional entity (CN-NT). To achieve local data exchange, it is necessary to explicitly indicate that local exchange is possible in the terminal-related context of the CN-NT.

[0135] In S22, after obtaining the signaling interaction and corresponding configuration of the core network, the onboard core network device establishes a local interaction context and key. The local interaction context may include a context related to a terminal indicating that the onboard core network device can support local data exchange.

[0136] In S23, local data exchange is performed through the onboard core network device. For example, the onboard core network device performs local data exchange between UE1 and UE2 based on the local exchange context and key.

[0137] In an exemplary embodiment, the local data exchange supported by CN-NT itself needs to obtain relevant parameters, including security parameters, from the ground core network element CN-T (such as AMF / MME).

[0138] The CN-NT that supports local forwarding on board maintains a connection with the ground core network element CN-T (such as AMF / MME) (assuming that the key acquisition function is anchored in the ground core network entity CN-T, but this application is not limited to this). This connection can be used for key acquisition. The key acquisition process includes first generating NAS layer keys, including IK and CK, from the AMF / MME and UE NAS layer, and generating AS layer keys at the AS layer of the eNB / gNB and UE. Both steps need to involve (involve) core network elements located on the ground and on board.

[0139] For other contents of the embodiment of FIG15 , reference may be made to the above contents.

[0140] The protocol flow shown in Figure 16, combined with the architecture of 4G network and satellite network integration, is a flowchart of the main steps for the onboard core network element (CN-NT) to realize local data exchange.

[0141] In S21a, the terminal initiates PDN connection establishment and service initiation, obtains signaling interaction and corresponding configuration of the core network (which can be the core network functional entities such as the satellite MME / P-GW, or the core network functional entities such as the satellite MME / P-GW and the ground MME / P-GW), and can perform local switching.

[0142] UEs (including UE1 and UE2) establish PDN connections through 4G satellite base stations (eNBs) and onboard and terrestrial core network equipment (MME / P-GW, etc.). During the service request and connection establishment process, they receive signaling interaction and corresponding configuration from the core network, enabling local data exchange, which is completed by the onboard core network functional entities (MME / P-GW, etc.). To enable local data exchange, the terminal-related context of the onboard core network functional entities (MME / P-GW, etc.) must explicitly indicate that local exchange is possible.

[0143] In S22a, after obtaining the signaling interaction and corresponding configuration of the core network, the onboard core network device (MME / P-GW, etc.) establishes a local interaction context and key. The local interaction context may include a terminal-related context indicating that the onboard core network device (MME / P-GW, etc.) can support local data exchange.

[0144] In S23a, local data exchange is performed through the onboard core network equipment (MME / P-GW, etc.). For example, the onboard core network equipment (MME / P-GW, etc.) performs local data exchange between UE1 and UE2 based on the local exchange context and key.

[0145] For other contents of the embodiment of FIG16 , reference may be made to the above contents.

[0146] The protocol flow shown in Figure 17, combined with the architecture of 5G network and satellite network integration, is a flowchart of the main steps for the onboard core network element (CN-NT) to realize local data exchange.

[0147] In S21b, the terminal initiates PDU session establishment and service initiation, obtains signaling interaction and corresponding configuration from the core network, and can perform local switching. The core network that provides signaling interaction and corresponding configuration here can be the satellite AMF / SMF and other core network functional entities, or the satellite AMF / SMF and other core network functional entities and the terrestrial AMF / SMF and other core network functional entities.

[0148] In the embodiment of the present application, the UPF network element on the satellite is a local UPF (local UPF), and the UPF network element deployed on the ground is a PSA (PDU session anchor) UPF.

[0149] UEs (including UE1 and UE2) establish PDU sessions through the 5G gNB and onboard and terrestrial core network equipment (such as the AMF and SMF). During service request initiation and connection establishment, they receive signaling interaction and corresponding configuration from the core network, enabling local data exchange, which is accomplished by the onboard core network functional entities (such as the AMF, SMF, and local UPF). Local data exchange requires explicit indication of local exchange within the terminal-related context of the onboard core network functional entities (such as the AMF, SMF, and local UPF).

[0150] In S22b, after the on-board core network device obtains the signaling interaction and corresponding configuration of the core network, it establishes a local interaction context and a key. The local interaction context can be a context related to the terminal that indicates that the on-board core network device (AMF / SMF / local UPF, etc.) can support local data exchange.

[0151] In S23b, local data exchange is performed through the on-board core network device. For example, the on-board core network device performs local data exchange between UE1 and UE2 based on the local exchange context and the key.

[0152] For other contents of the embodiment in FIG. 17, reference may be made to the above contents.

[0153] In an exemplary embodiment, while the CN-NT supports local data exchange, it can also support mapping with the GTP-u tunnels of the S1-u and N3 interfaces of the core network. That is to say, the data paths for local exchange through the on-board core network and for exchange through the terrestrial core network can exist simultaneously.

[0154] For example, as shown in FIG. 18, UE1 and UE2 use their respective DRBs to transmit data to and from the on-board base station eNB / gNB. When the on-board base station eNB / gNB receives a data packet from UE1 through DRB1, it transmits it to the on-board core network functional part (i.e., the on-board core network element) through S1-u / the first tunnel identification information. The on-board core network element can support data exchange between <UE1 - the first tunnel identification information> and <UE2 - the second tunnel identification information>, and can also support data exchange with the terrestrial core network element.

[0155] FIG. 18 is an example of a mapping table for implementing local exchange in an on-board core network element. Assume that the direction corresponding to index =  1 in this mapping table is local exchange, the source address is UE1 - the first tunnel identification information, and the destination address is UE2 - the second tunnel identification information.

[0156] In an exemplary embodiment, local data exchange is performed based on the context on the CN-NT, and the exchange is carried out through the mapping between E-RABs (in the EPS case). In the 5G case, it is the mapping between N3 GTP-u tunnels. That is, for the local data exchange of one UE1 - satellite - UE2, the data on one GTP-u tunnel is mapped to another GTP-u. In the 4G case, an E-RAB is composed of a concatenation of a S1 bearer (GTP-u tunneling) and a data radio bearer DRB on the air interface.

[0157] In scenarios where local UPF / UPF ULCL (Uplink Classifier) ​​is deployed on a satellite for local data exchange, it can be different from the deployment of a base station on a satellite for local data exchange. The on-board UPF can route the data packet sent by UE1 to UE2 according to the source IP address and destination IP address carried by the data packet. That is, the source address in the entry indicating local data exchange in the mapping table can be the IP address of UE1, and the destination address can be the IP address of UE2. Therefore, using the on-board UPF to implement local data exchange between different UEs is more flexible because the UPF has the processing capabilities of the IP layer and above.

[0158] As shown in FIG19 , an embodiment of the present application further provides an onboard network element 1900. Onboard network element 1900 is located on a satellite, on which an onboard base station is deployed. Onboard network element 1900 includes an onboard base station or an onboard core network element. Onboard network element 1900 stores terminal-related context, which includes indication information indicating that a first terminal and a second terminal are exchanging local data via onboard network element 1900. Onboard network element 1900 includes a receiving unit 1910 and a sending unit 1920.

[0159] The receiving unit 1910 is configured to receive a data packet sent by a first terminal. The sending unit 1920 is configured to send the data packet to a second terminal without passing through a network element of a ground core network according to the instruction information.

[0160] In an exemplary embodiment, the receiving unit 1910 is further configured to, during a process in which the first terminal and the second terminal establish a session or connection through the onboard base station and the core network element respectively, the onboard network element obtains the terminal-related context from the core network element.

[0161] In an exemplary embodiment, the onboard network element obtains the terminal-related context from the ground core network element.

[0162] In an exemplary embodiment, the terminal-related context includes a first key of a first terminal and a second key of a second terminal. Onboard network element 1900 further includes a processing unit configured to decrypt a data packet using the first key of the first terminal and encrypt the decrypted data packet using the second key of the second terminal. Transmitting unit 1920 is further configured to transmit the data packet, encrypted using the second key of the second terminal, to the second terminal.

[0163] In an exemplary embodiment, the terminal-related context also includes satellite parameters. Onboard network element 1900 further includes a processing unit configured to determine, based on the satellite parameters, whether the first terminal and the second terminal are located under the same satellite. Transmitting unit 1920 is further configured to: if the first terminal and the second terminal are located under the same satellite, transmit the data packet to the second terminal via the satellite's onboard network element; if the first terminal and the second terminal are located under a first satellite and a second satellite, respectively, transmit the data packet to the second terminal located under the second satellite via the intersatellite link between the first and second satellites.

[0164] In an exemplary embodiment, when all core network elements are deployed on the ground, the satellite-borne network element is a satellite-borne base station.

[0165] In an exemplary embodiment, the indication information includes a local data exchange index, a source address corresponding to the local data exchange index includes a first data radio bearer of the first terminal, and a destination address includes a second data radio bearer of the second terminal.

[0166] In an exemplary embodiment, the indication information includes a local data exchange index, a source address corresponding to the local data exchange index includes all data radio bearers of the first terminal, and a destination address includes all data radio bearers of the second terminal.

[0167] In an exemplary embodiment, the terminal-related context further includes indication information that the first terminal and the second terminal exchange data via the onboard network element and the ground core network element.

[0168] In an exemplary embodiment, when at least part of the core network elements are deployed on a satellite, the onboard network elements are onboard core network elements.

[0169] In an exemplary embodiment, the indication information includes a local data exchange index, the source address corresponding to the local data exchange index includes first tunnel identification information of the first terminal, and the destination address includes second tunnel identification information of the second terminal.

[0170] In an exemplary embodiment, the indication information includes a local data exchange index, a source address corresponding to the local data exchange index includes a first evolved radio access bearer of the first terminal, and a destination address includes a second evolved radio access bearer of the second terminal.

[0171] For other contents of the satellite-borne network element provided in the embodiment of FIG19 , reference can be made to the other embodiments described above.

[0172] Figure 20 schematically shows a schematic structural diagram of a communication device 2000 according to an embodiment of the present application. The communication device can be a terminal such as a UE, or a network device such as a base station, or an AMF and / or UPF and / or PCF and / or NEF and / or AF and / or SMF network element and / or MME and / or P-GW and / or S-GW and / or HSS. The communication device 2000 shown in Figure 20 includes a processor 2010, which can call and execute a computer program from a memory to implement the method in the embodiment of the present application.

[0173] Optionally, as shown in FIG20 , the communication device 2000 may further include a memory 2020. The processor 2010 may call and execute a computer program from the memory 2020 to implement the method in the embodiment of the present application.

[0174] The memory 2020 may be a separate device independent of the processor 2010 , or may be integrated into the processor 2010 .

[0175] Optionally, as shown in FIG20 , the communication device 2000 may further include a transceiver 2030 , and the processor 2010 may control the transceiver 2030 to communicate with other devices, specifically, to send information or data to other devices, or to receive information or data sent by other devices.

[0176] The transceiver 2030 may include a transmitter (which may be used as the transmitting unit in the above embodiment) and a receiver (which may be used as the receiving unit in the above embodiment). The transceiver 2030 may further include an antenna, and the number of antennas may be one or more.

[0177] Optionally, the communication device 2000 may specifically be various network elements of the embodiments of the present application, and the communication device 2000 may implement the corresponding processes implemented by each network element in each method of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0178] Optionally, the communication device 2000 may specifically be a mobile terminal / terminal of an embodiment of the present application, and the communication device 2000 may implement the corresponding processes implemented by the mobile terminal / terminal in each method of the embodiment of the present application. For the sake of brevity, they will not be repeated here.

[0179] Optionally, the processor 2010 , the memory 2020 , and the transceiver 2030 may implement bidirectional communication with each other via the communication bus 2040 .

[0180] It should be understood that the processor of the embodiment of the present application may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method embodiment may be completed by hardware integrated logic circuits in the processor or software instructions.

[0181] The above-mentioned processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component. The various methods, steps, and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor. The steps of the method disclosed in the embodiments of the present application can be directly embodied as being executed by a hardware decoding processor, or can be executed by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium mature in the art, such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above-mentioned method in combination with its hardware.

[0182] It is understood that the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct RAM bus random access memory (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory. It should be understood that the above-mentioned memory is by way of example and not limitation.

[0183] An embodiment of the present application also provides a computer-readable storage medium for storing a computer program.

[0184] Optionally, the computer-readable storage medium can be applied to each network element in the embodiments of the present application, and the computer program enables the computer to execute the corresponding processes implemented by each network element in the various methods of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0185] Optionally, the computer-readable storage medium can be applied to the mobile terminal / terminal in the embodiments of the present application, and the computer program enables the computer to execute the corresponding processes implemented by the mobile terminal / terminal in the various methods of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0186] An embodiment of the present application also provides a computer program product, including computer program instructions.

[0187] Optionally, the computer program product can be applied to each network element in the embodiments of the present application, and the computer program instructions enable the computer to execute the corresponding processes implemented by each network element in the various methods of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0188] Optionally, the computer program product can be applied to the mobile terminal / terminal in the embodiments of the present application, and the computer program instructions enable the computer to execute the corresponding processes implemented by the mobile terminal / terminal in the various methods of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0189] The embodiment of the present application also provides a computer program.

[0190] Optionally, the computer program can be applied to each network element in the embodiments of the present application. When the computer program runs on a computer, the computer executes the corresponding processes implemented by each network element in the various methods of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0191] Optionally, the computer program can be applied to the mobile terminal / terminal in the embodiments of the present application. When the computer program runs on the computer, the computer executes the corresponding processes implemented by the mobile terminal / terminal in the various methods of the embodiments of the present application. For the sake of brevity, they are not repeated here.

[0192] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0193] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0194] The above content is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A satellite communication method, characterized in that: The satellite is deployed with an onboard base station, and the satellite has an onboard network element, the onboard network element includes the onboard base station or an onboard core network element, and the method is performed by the onboard network element, and the method includes: receiving a data packet sent by the first terminal; According to the instruction information, the data packet is sent to the second terminal without passing through the ground core network element.

2. The method according to claim 1, characterized in that The onboard network element stores a terminal-related context, and the terminal-related context includes indication information that the first terminal and the second terminal perform local data exchange through the onboard network element.

3. The method according to claim 2, characterized in that The method further comprises: During the process of establishing a session or connection between the first terminal and the second terminal through the onboard base station and the core network element respectively, the onboard network element obtains context related to the terminal; The core network element includes at least one of the ground core network element and the satellite core network element.

4. The method according to claim 2, characterized in that The terminal-related context includes a first key of the first terminal and a second key of the second terminal, and sending the data packet to the second terminal without passing through a terrestrial core network element according to the instruction information includes: decrypting the data packet using a first key of the first terminal; encrypting the decrypted data packet using a second key of the second terminal; The data packet encrypted by using the second key of the second terminal is sent to the second terminal.

5. The method according to claim 2, characterized in that The terminal-related context further includes parameters of the satellite, and sending the data packet to the second terminal without passing through a ground core network element according to the instruction information includes: determining, based on parameters of the satellite, whether the first terminal and the second terminal are located under the same satellite; If the first terminal and the second terminal are located under the same satellite, sending the data packet to the second terminal through an onboard network element of the satellite; If the first terminal and the second terminal are located under a first satellite and a second satellite respectively, the onboard network element of the first satellite sends the data packet to the second terminal via an interstellar link, where the interstellar link is an interstellar link between the first satellite and the second satellite.

6. The method according to any one of claims 2 to 5, characterized in that: When all core network elements are deployed on the ground, the satellite-borne network element is the satellite-borne base station.

7. The method according to claim 6, characterized in that The indication information includes a local data exchange index, a source address corresponding to the local data exchange index includes a first data radio bearer of the first terminal, and a destination address corresponding to the local data exchange index includes a second data radio bearer of the second terminal.

8. The method according to claim 6, characterized in that The indication information includes a local data exchange index, a source address corresponding to the local data exchange index includes multiple data radio bearers of the first terminal, and a destination address corresponding to the local data exchange index includes at least one data radio bearer of the second terminal.

9. The method according to claim 6, characterized in that The terminal-related context also includes indication information of the first terminal and the second terminal exchanging data through the onboard network element and the ground core network element.

10. The method according to claim 1, characterized in that When at least part of the core network elements are deployed on the satellite, the onboard network element is the onboard core network element.

11. The method according to claim 10, characterized in that The indication information includes a local data exchange index, a source address corresponding to the local data exchange index includes first tunnel identification information of the first terminal, and a destination address corresponding to the local data exchange index includes second tunnel identification information of the second terminal.

12. The method according to claim 10, characterized in that The indication information includes a local data exchange index, a source address corresponding to the local data exchange index includes a first evolved radio access bearer of the first terminal, and a destination address corresponding to the local data exchange index includes a second evolved radio access bearer of the second terminal.

13. A satellite-borne network element, characterized in that: The onboard network element is located on a satellite, a satellite base station is deployed on the satellite, the onboard network element includes the onboard base station or the onboard core network element, and the onboard network element includes: a receiving unit, configured to receive a data packet sent by the first terminal; The sending unit is used to send the data packet to the second terminal without passing through the ground core network element according to the indication information.

14. A communication device, characterized in that: include: one or more processors; The memory is configured to store one or more programs, and when the one or more programs are executed by the one or more processors, the communication device implements the method according to any one of claims 1 to 12.

15. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is run on a computer, the computer is caused to execute the method according to any one of claims 1 to 12.

16. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the method according to any one of claims 1 to 12 is implemented.

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