Message transmission method in satellite-ground network, satellite and satellite network

Abstract

The invention provides a message transmission method in a satellite-ground network, a satellite and a satellite network, and belongs to the technical field of satellite communication. In the method, satellites outside a landing area of target ground receiving equipment perform fuzzy routing forwarding on a second message based on information of a predicted landing satellite, and due to the fact that the predicted landing satellite is in the landing area, the fuzzy routing forwarding can forward the second message to the direction of the landing area; and satellites in the landing area carry out accurate routing forwarding on the second message based on the information of the target ground receiving equipment, and because only the satellites in the landing area know the accurate routing reaching the target ground receiving equipment, when a satellite-ground link between the ground receiving equipment and the satellites is switched, the accurate routing of the target ground receiving equipment is not found. And only satellites in the landing area need to update routes, and all satellites in the whole satellite network do not need to be updated, so that the satellite-to-ground network topology can be converged in time, and the satellite-to-ground network topology synchronization pressure is reduced.

Description

Technical Field

[0001] The present application relates to the field of satellite communication technology, and in particular to a message transmission method, a satellite and a satellite network in a satellite-to-ground network. Background Art

[0002] With the deep integration of satellite communication technology and the Internet, satellite networks have become an important supplement to ground networks. Satellite networks and ground networks constitute a satellite-to-ground network, in which the satellite network includes multiple satellites and the ground network includes multiple ground receiving devices. Satellites and ground receiving devices can communicate with each other. For example, the message sent by the user terminal (UE) can be transmitted to the satellite through the satellite-to-ground link, that is, the access satellite; the access satellite forwards the message through the intersatellite link based on the destination address in the message, so as to forward the message to the satellite directly above the ground receiving device corresponding to the destination address, that is, the landing satellite; and the landing satellite transmits the message to the ground receiving device through the satellite-to-ground link. Among them, when the satellite enters the receiving range of the ground receiving device, the satellite and the ground receiving device can establish a satellite-to-ground connection. Therefore, it is necessary to accurately determine the landing satellite, and then accurately realize the transmission of messages from the access satellite to the ground receiving device.

[0003] In the related technology, based on the concept of dynamic virtual topology (DVT), the regularity and periodicity of satellite network movement are utilized to divide the period of satellite orbital motion into several time slices of unequal length, thereby converting the dynamically changing satellite network topology into multiple static topologies. Then, the Dijkstra algorithm is used to determine the routing table of the satellite in different time slices. By querying the routing table in each time slice, the route from the access satellite to the landing satellite is obtained, thereby realizing the message transmission from the access satellite to the ground receiving device.

[0004] However, in the above method, due to the high-speed movement of the satellite, the switching of the satellite-to-ground link is very frequent, resulting in a shorter duration of the divided time slices and a larger number of time slices corresponding to the same cycle, which leads to a larger number of static topologies. In addition, the routing table needs to be updated frequently, resulting in frequent oscillations of the satellite-to-ground network topology and failure to converge in time, which puts greater pressure on the synchronization of the satellite-to-ground network topology. Summary of the invention

[0005] The embodiment of the present application provides a message transmission method in a satellite-to-ground network, a satellite and a satellite network, which can make the satellite-to-ground network topology converge in time when the satellite-to-ground link is switched, and reduce the pressure of satellite-to-ground network topology synchronization. The technical solution is as follows.

[0006] In a first aspect, a message transmission method in a satellite-to-ground network is provided, which is applied to a satellite in the satellite-to-ground network, wherein the satellite network includes a plurality of satellites, and a ground network in the satellite-to-ground network includes a plurality of ground receiving devices, each of which corresponds to a respective landing area, and the method includes:

[0007] A first message is received, the first message including a destination address, the destination address indicating a destination ground receiving device corresponding to the first message; based on the first message, a second message is sent, the second message carries the first message, information of the destination ground receiving device and information of a predicted landing satellite corresponding to the destination ground receiving device, the predicted landing satellite being a satellite for which a ground receiving device corresponding to the predicted landing satellite may have established a satellite-to-ground connection; wherein the second message instructs satellites among multiple satellites except a landing area corresponding to the destination ground receiving device to forward the second message to the predicted landing satellite, and the second message also instructs satellites within the landing area corresponding to the destination ground receiving device to forward the second message to the destination ground receiving device, the landing area corresponding to the destination ground receiving device including multiple satellites including the predicted landing satellite.

[0008] The ground receiving device may be a ground gateway or a terminal. When the ground receiving device is a ground gateway, the satellite first establishes a satellite-to-ground connection with the ground receiving nodes such as the gateway and antenna corresponding to the ground gateway, and then establishes a connection with the ground gateway through the ground receiving node. The information of the destination ground receiving device may be the device identification (ID) of the destination ground receiving device or the internet protocol (IP) of the destination ground receiving device; similarly, the information of the predicted landing satellite may be the satellite identification of the predicted landing satellite or the IP of the predicted landing satellite.

[0009] In the above method, the satellite outside the landing area of ​​the destination ground receiving device performs fuzzy routing forwarding on the second message based on the information of the predicted landing satellite. Since the predicted landing satellite is within the landing area, the fuzzy routing forwarding will forward the second message in the direction of the landing area; the satellite within the landing area performs precise routing forwarding on the second message based on the information of the destination ground receiving device. Since only the satellite within the landing area knows the precise route to the destination ground receiving device, when the satellite-to-ground link between the ground receiving device and the satellite is switched, only the satellite within the landing area needs to update the route, and there is no need for all satellites in the entire satellite network to update. Therefore, the satellite-to-ground network topology can converge in time and the pressure of satellite-to-ground network topology synchronization can be reduced.

[0010] Optionally, the method further comprises:

[0011] Based on the operation rules of multiple satellites in the satellite network, the positions of the satellites and the position of the destination ground receiving device, the predicted landing satellite corresponding to the destination ground receiving device is predicted.

[0012] Optionally, based on the operating rules of multiple satellites in the satellite network, the positions of the satellites and the position of the destination surface receiving device, the predicted landing satellite corresponding to the destination surface receiving device is predicted, including: determining the relative position difference between the satellite and other satellites in the satellite network based on the operating rules of multiple satellites; determining the distance between each satellite and the destination surface receiving device based on the position of the destination surface receiving device, the position of the satellite and the relative position difference; and determining the satellite with the smallest distance to the destination surface receiving device as the predicted landing satellite corresponding to the destination surface receiving device.

[0013] Optionally, the predicted landing satellite corresponding to the destination ground receiving device is predicted periodically.

[0014] The satellite's operating cycle is divided into n time slices, where n is an integer greater than 0, and the target time slice is any one of the n time slices. Since the satellites in the same satellite network have the same operating speed and altitude, their operating cycles are the same, their relative positions after one operating cycle are fixed, and the divided time slices are also the same. The predicted landing satellite corresponding to the destination ground receiving device is predicted in each time slice.

[0015] Among them, each satellite stores multiple relative position difference tables, each relative position difference table is used to indicate the relative position difference between the satellite and other satellites in the satellite network within a time slice. The relative position difference tables stored in each satellite are different. When the time reaches the satellite's operating cycle, that is, the relative position difference tables corresponding to all time slices are used up, the relative position difference table corresponding to the first time slice is re-polled.

[0016] Optionally, the landing area is determined based on a maximum receiving range corresponding to a receiving device on the destination surface and a maximum number of satellites that may exist within the maximum receiving range.

[0017] The landing area is determined based on the maximum receiving range corresponding to the destination ground receiving device and the maximum number I of satellites that may exist within the maximum receiving range, where I is an integer greater than or equal to 0. In some embodiments, the landing area is centered on the actual landing satellite, and the outermost satellite of the landing area is J hops away from the actual landing satellite, wherein the number of satellites that are J hops away from I is an integer greater than or equal to I. For example, the maximum number of satellites that may exist within the maximum receiving range corresponding to the ground receiving device is I, and the satellite that is farthest from the actual landing satellite among these I satellites is 2 hops away from the actual landing satellite, then the range of the landing area corresponding to the ground receiving device is the satellites within 2 hops centered on the actual landing satellite.

[0018] In the above method, since the satellite is always running at high speed, the ground receiving device may switch the connected satellite multiple times. Therefore, the range of the landing area is determined based on the maximum number of satellites that may exist within the maximum receiving range of the ground receiving device. This can ensure that after multiple switches, the predicted landing satellite is always within the range of the landing area. In addition, since different satellites have different orbits, the orientation of the satellite that the ground receiving node switches to connect to each time is not necessarily the same. Therefore, the landing area is centered on the actual landing satellite, which can ensure that all switched connected satellites are located in the landing area, thereby ensuring the effectiveness of the selected landing area.

[0019] In a second aspect, a message transmission method in a satellite-to-ground network is provided, wherein a ground network in the satellite-to-ground network includes a plurality of ground receiving devices, each ground receiving device corresponds to a respective landing area, and is applied to a satellite in a satellite network in the satellite-to-ground network except for a landing area corresponding to a destination ground receiving device, the method comprising:

[0020] Receive a second message carrying the first message, information of the destination ground receiving device and information of the predicted landing satellite corresponding to the destination ground receiving device, and forward the second message to the predicted landing satellite; wherein the predicted landing satellite is a satellite for which the destination ground receiving device may have established a satellite-to-ground connection.

[0021] Optionally, the satellite stores a first routing table and does not store a second routing table, the first routing table includes routes from the satellite to other satellites in the satellite network, the second routing table includes routes from the satellite to a receiving device on the destination ground, and forwarding the second message to the predicted landing satellite includes: forwarding the second message to the predicted landing satellite based on information about the predicted landing satellite and the first routing table.

[0022] After receiving the second message, the satellite forwards the second message to the next-hop satellite indicated by the first routing table to the predicted landing satellite. It should be noted that the next-hop satellite indicated by the first routing table to the predicted landing satellite may be located outside the landing area of ​​the destination ground receiving device, or may be located within the landing area. If the next-hop satellite is located outside the landing area, after receiving the second message, the satellite forwards the second message in the same manner as the satellite.

[0023] In the above method, the satellite stores a second routing table indicating the route to the ground receiving device when and only when the satellite exists within the landing area corresponding to the ground receiving device, so that when the satellite connected to the ground receiving device is switched, only the satellite within the landing area needs to update the second routing table, and there is no need to update all satellites in the entire satellite network. Therefore, when the satellite-to-ground link switches frequently, the satellite-to-ground network topology can converge in time, reducing the pressure of satellite-to-ground network topology synchronization.

[0024] Optionally, the satellite stores a third routing table, the third routing table includes a first route to a host corresponding to a destination address in the second message, the first route indicates a predicted landing satellite and does not indicate a destination ground receiving device, and forwarding the second message to the predicted landing satellite includes: forwarding the second message to the predicted landing satellite based on the first route in the third routing table.

[0025] The second message is forwarded by an IP forwarding mechanism (IPv4 or IPv6). In the method, each satellite in the satellite network stores a third routing table, which includes a first route to the host corresponding to the destination address in the second message. The first route corresponding to the satellite outside the landing area corresponding to the destination surface receiving device includes the information of the predicted landing satellite corresponding to the destination surface receiving device, but does not include the information of the destination surface receiving device. For example, the first route is XXXX.SID.0.0 / 96, where SID indicates the satellite identifier of the predicted landing satellite; the first route corresponding to the satellite within the landing area includes the information of the predicted landing satellite and the information of the destination surface receiving device. For example, the first route is XXXX.SID.GID.0 / 104, where SID indicates the satellite identifier of the predicted landing satellite, and GID indicates the device identifier of the destination surface receiving device.

[0026] In the above method, satellites outside the landing area and inside the landing area generate forwarding entries with prefixes of different lengths, thereby achieving compatibility of the two sets of routing tables under the existing IP forwarding mechanism without changing the forwarding plane.

[0027] In a third aspect, a message transmission method in a satellite-to-ground network is provided, wherein a ground network in the satellite-to-ground network includes a plurality of ground receiving devices, each ground receiving device corresponds to a respective landing area, and is applied to a satellite within a landing area corresponding to a destination ground receiving device in a satellite network in the satellite-to-ground network, the method comprising:

[0028] Receive a second message carrying the first message, information of a destination surface receiving device, and information of a predicted landing satellite corresponding to the destination surface receiving device, and forward the second message to the destination surface receiving device.

[0029] Among them, the predicted landing satellite is a satellite for which the destination ground receiving equipment may have established a satellite-to-ground connection.

[0030] Optionally, the satellite stores a second routing table, which includes a route from the satellite to the destination surface receiving device, and forwarding the second message to the destination surface receiving device includes: forwarding the second message to the destination surface receiving device based on information of the destination surface receiving device and the second routing table.

[0031] Optionally, the satellite stores a fourth routing table, the fourth routing table includes a second route to a host corresponding to the destination address in the second message, the second route indicates the predicted landing satellite and the destination surface receiving device, and forwarding the second message to the destination surface receiving device includes: forwarding the second message to the destination surface receiving device based on the second route in the fourth routing table.

[0032] In a fourth aspect, a message transmission method in a satellite-to-ground network is provided, which is applied to a satellite in a satellite network in the satellite-to-ground network, where the satellite network includes a plurality of satellites, and a ground network in the satellite-to-ground network includes a plurality of ground receiving devices, each of which corresponds to a respective landing area, and the method includes:

[0033] A satellite in a satellite network receives a first message, and based on the first message, sends a second message, wherein the first message includes a destination address, the destination address indicates a destination ground receiving device corresponding to the message, and the second message carries the first message, information about the destination ground receiving device, and information about a predicted landing satellite corresponding to the destination ground receiving device, wherein the predicted landing satellite is a satellite for which a ground receiving device corresponding to the predicted landing satellite may have established a satellite-to-ground connection;

[0034] Satellites other than the landing area corresponding to the destination ground receiving device in the satellite network receive the second message, and forward the second message to the predicted landing satellite;

[0035] A satellite within the landing area corresponding to the destination ground receiving device in the satellite network receives the second message and forwards the second message to the destination ground receiving device.

[0036] In a fifth aspect, a satellite is provided, comprising an onboard base station and an onboard router, the onboard base station being used to receive messages, and the onboard router being used to forward messages so that the satellite executes the message transmission method in a satellite-to-ground network provided by the first aspect or any possible implementation method of the first aspect.

[0037] In a sixth aspect, a satellite network is provided, characterized in that it includes at least one satellite, each satellite includes a satellite-borne base station and a satellite-borne router, and the satellite-borne base station includes a transceiver and a controller;

[0038] The onboard base station of at least one satellite is used to receive messages, and the onboard router of at least one satellite is used to forward messages so that the satellite network executes the message transmission method in the satellite-to-ground network provided by the first aspect or any possible implementation method of the first aspect.

[0039] In the seventh aspect, a computer program product comprising instructions is provided. When the instructions are executed by a satellite network, the satellite network executes the message transmission method in the satellite-to-ground network provided by the first aspect or any possible implementation method of the first aspect.

[0040] In an eighth aspect, a computer-readable storage medium is provided, which includes computer program instructions. When the computer program instructions are executed by a satellite network, the satellite network executes the message transmission method in the satellite-to-ground network provided by the first aspect or any possible implementation method of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of an implementation environment of a message transmission method in a satellite-to-ground network provided in an embodiment of the present application;

[0042] Figure 2 It is a flowchart of a method for determining a predicted landing satellite corresponding to a ground gateway provided in an embodiment of the present application;

[0043] Figure 3 This is a schematic diagram of the relative position of a satellite after one cycle of operation provided by an embodiment of the present application;

[0044] Figure 4 is a schematic diagram of a method for predicting a landing satellite provided in an embodiment of the present application;

[0045] Figure 5 It is a flow chart provided by an embodiment of the present application for spreading the route from a satellite to a ground gateway to a landing area;

[0046] Figure 6 It is a flow chart of a method for spreading a route to a ground gateway provided in an embodiment of the present application;

[0047] Figure 7 It is a flow chart of a message transmission method in a satellite-to-ground network provided by an embodiment of the present application;

[0048] Figure 8 It is a schematic diagram of a method for packaging a gateway identifier and a satellite identifier provided in an embodiment of the present application;

[0049] Fig. 9 It is a flow chart of a message transmission method in a satellite-to-ground network provided by an embodiment of the present application;

[0050] Fig.10 It is a flow chart of a message transmission method in a satellite-to-ground network provided by an embodiment of the present application;

[0051] Fig.11 A schematic diagram of adding a segment routing extension header to an IPv6 address provided in an embodiment of the present application;

[0052] Fig.12 This is a schematic diagram of the format of an SRH provided in an embodiment of the present application;

[0053] Fig.13 This is a schematic diagram of an encapsulation format of a second message provided in an embodiment of the present application;

[0054] Fig.14 is a schematic diagram of a first route of a satellite within a landing area provided in an embodiment of the present application;

[0055] Fig.15 It is a flow chart of a message transmission method in a satellite-to-ground network provided by an embodiment of the present application;

[0056] Fig.16 It is a flow chart of a message transmission method in a satellite-to-ground network provided by an embodiment of the present application;

[0057] Fig.17 It is a schematic diagram of a message transmission method in a satellite-to-ground network provided in an embodiment of the present application;

[0058] Fig.18 It is a structural schematic diagram of a message transmission device in a satellite-to-ground network provided in an embodiment of the present application. DETAILED DESCRIPTION

[0059] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0060] In order to facilitate understanding of the technical solution of the present application, several technical terms involved in the embodiments of the present application are introduced below.

[0061] Satellite: refers to an artificial satellite, that is, a device built by humans, launched into space by space flight vehicles such as rockets and space shuttles, and orbiting the earth or other planets like a natural satellite.

[0062] Satellite constellation: refers to a group of artificial satellites working together as a system. Unlike a single satellite, a satellite constellation can provide permanent global or near-global coverage, so that at any time, there is at least one satellite visible from anywhere on Earth. Multiple satellites in a satellite constellation are placed on a set of complementary orbital planes and connected to ground receiving nodes distributed around the world. Multiple satellites in a satellite constellation communicate with each other using inter-satellite communications (also known as inter-satellite links).

[0063] Satellite-to-ground link: The connection between a satellite and a ground receiving station or user terminal, which can be microwave or laser.

[0064] Low earth orbit (LEO): Located in an orbit at an altitude of 500-2000 kilometers (km), it has a fast movement speed and small delay in inter-satellite communication and satellite-to-ground communication.

[0065] The implementation environment of the embodiments of the present application is introduced below.

[0066] Figure 1 is a schematic diagram of an implementation environment of a message transmission method in a satellite-to-ground network provided by an embodiment of the present application, such as Figure 1 As shown, the implementation environment includes multiple satellites 101 and ground receiving equipment 102. Multiple satellites 101 communicate with each other through inter-satellite links (ISL), and satellites 101 and ground receiving equipment 102 communicate with each other through satellite-to-ground links.

[0067] The satellite 101 includes a satellite-generation node B (S-gNB) and a satellite-router (S-Router). The satellite-generation node B is used to receive messages, for example, to receive messages sent by a user equipment (UE), and to transmit the received messages to the satellite-based router through a virtual private network (VPN) sub-interface; the satellite-based router is used to receive messages transmitted by the satellite-based base station, forward the received messages, receive messages forwarded by other satellites 101, and forward the messages to a ground receiving device 102. In some embodiments, among multiple satellites 101, for a message transmission in a satellite-to-ground network, the satellite that receives the message from the ground is called an access satellite, and the satellite that forwards the message to the ground receiving device is called a landing satellite.

[0068] The ground receiving device 102 is used to receive the message forwarded by the satellite 101.

[0069] In some embodiments, the ground receiving device 102 is a ground gateway, which is used to receive messages forwarded by ground receiving nodes, forward the received messages to the core network (that is, the user plane function (UPF)), and forward the messages from the core network to the ground receiving nodes, etc. The ground gateway is also called a serving gateway (SGW), and the ground gateway can be connected to one or more ground receiving nodes. Among them, the ground receiving node can be an antenna or a gateway station, etc. The ground receiving node and the ground gateway can be separately or jointly set up, and the embodiments of the present application do not limit this. Among them, the satellite 101 first establishes a satellite-to-ground connection with a ground receiving node such as an antenna or a gateway station, and the ground receiving node then establishes a connection with the ground gateway through the ground network in a wired or wireless manner, thereby establishing a satellite-to-ground connection between the satellite 101 and the ground gateway.

[0070] In some embodiments, the ground receiving device 102 is a user terminal capable of establishing a satellite-ground connection with the satellite 101. The user terminal may be at least one of a smart phone, a smart watch, a desktop computer, a laptop computer, a virtual reality terminal, an augmented reality terminal, a wireless terminal, and a laptop computer, and the user terminal has a communication function and can communicate with the satellite 101.

[0071] In some embodiments, in the ground network, the wired network or the wireless network uses standard communication technology and / or protocol. The network is usually the Internet, but it can also be any network, including but not limited to any combination of a local area network (LAN), a metropolitan area network (MAN), a wide area network (WAN), a mobile, wired or wireless network, a dedicated network or a virtual private network. In some embodiments, the data exchanged through the network is represented using technologies and / or formats including hypertext markup language (HTML), extensible markup language (XML), etc. In addition, conventional encryption technologies such as secure socket layer (SSL), transport layer security (TLS), virtual private network (VPN), and Internet protocol security (IPsec) can be used to encrypt all or some links. In other embodiments, customized and / or dedicated data communication technologies can also be used to replace or supplement the above-mentioned data communication technologies.

[0072] The implementation environment of the embodiment of the present application is introduced above, and the following is a message transmission method in a satellite-to-ground network provided by the embodiment of the present application. The method is applied to a satellite in a satellite network in a satellite-to-ground network, the satellite network includes multiple satellites, and the ground network in the satellite-to-ground network includes multiple ground receiving devices, each ground receiving device corresponding to its own landing area. In the method, the satellite regularly predicts the predicted landing satellites corresponding to each ground receiving device according to the position of the ground receiving device and the satellite operation law; if any satellite establishes a satellite-to-ground connection with any ground receiving device, the satellite diffuses the route to the ground receiving device to the satellite within the landing area of ​​the destination ground receiving device, so that each satellite in the landing area knows the route to the ground receiving device; when any satellite receives a first message from the ground network, based on the destination address in the first message, the information of the destination ground receiving device and the information of the predicted landing satellite are encapsulated into the first message to obtain a second message; during the transmission of the second message, the satellite outside the landing area of ​​the destination ground receiving device forwards the second message to the predicted landing satellite based on the above route, and the satellite within the landing area of ​​the destination ground receiving device forwards the second message to the destination ground receiving device based on the above route.

[0073] In the above method, firstly, the satellite outside the landing area of ​​the destination ground receiving device performs fuzzy routing forwarding on the second message based on the information of the predicted landing satellite. Since the predicted landing satellite is within the landing area, the second message will be forwarded in the direction of the landing area during the fuzzy routing forwarding process; secondly, the satellite within the landing area performs precise routing forwarding on the second message based on the information of the destination ground receiving device. Since only the satellite within the landing area knows the precise route to the destination ground receiving device, when the satellite-to-ground link between the ground receiving device and the satellite is switched, only the satellite within the landing area needs to update the route, and there is no need for all satellites in the entire satellite network to be updated. Therefore, when the satellite-to-ground link is frequently switched, the satellite-to-ground network topology can converge in time, reducing the pressure of satellite-to-ground network topology synchronization.

[0074] The above describes the basic process of the embodiment of the present application, and the following describes the process of the embodiment of the present application in detail. In the embodiment of the present application, the message transmission process involves satellite A, satellite B and satellite C, wherein satellite A is a satellite that receives the first message from the ground network; satellite C is a satellite within the landing area corresponding to the destination ground receiving device, and the satellite C includes the actual landing satellite C1; satellite B is a satellite that transmits messages between satellite A and satellite C, that is, a satellite other than satellite A outside the landing area corresponding to the destination ground receiving device.

[0075] The following first introduces the method for determining the predicted landing satellite corresponding to the ground receiving device in the embodiment of the present application. In this method, taking any ground receiving device as an example, based on the operation rules of multiple satellites in the satellite network, the positions of the satellites and the position of the destination ground receiving device, the predicted landing satellite corresponding to the destination ground receiving device is predicted. The following is an introduction taking the ground receiving device as a ground gateway as an example. Figure 2 is a flowchart of a method for determining a predicted landing satellite corresponding to a ground gateway provided in an embodiment of the present application, such as Figure 2 As shown, taking the method executed by satellite A in a satellite network as an example, the method includes the following steps 201 to 203.

[0076] 201. Satellite A queries the relative position difference table corresponding to each satellite in the satellite network in the target time slice, and obtains the relative position difference between satellite A and other satellites in the satellite network in the target time slice.

[0077] The time slice is determined based on the satellite operation law. In some embodiments, the satellite operation cycle is divided into n time slices, where n is an integer greater than 0, and the target time slice is any time slice among the n time slices. Since the satellites in the same satellite network have the same operation speed and altitude, the operation cycle is the same, the relative position after one operation cycle is fixed, and the divided time slices are also the same. Figure 3 As shown, Figure 3 is a schematic diagram of the relative position of a satellite after one cycle of operation provided by an embodiment of the present application, Figure 3 In the figure, satellite S1 and satellite S2 have the same running speed and altitude. The position of satellite S1 is (lat1', lon1'), and the position of satellite S2 is (lat2', lon2'). After one cycle of operation, the position of satellite S1 is (lat1", lon1"), and the position of satellite S2 is (lat2", lon2"), but the relative position difference between satellite S1 and satellite S2 has not changed.

[0078] Among them, each satellite stores multiple relative position difference tables, each relative position difference table is used to indicate the relative position difference between the satellite and other satellites in the satellite network within a time slice, and the relative position difference tables stored by each satellite are different. When the time reaches the satellite's operating cycle, that is, the relative position difference tables corresponding to all time slices are used up, the relative position difference table corresponding to the first time slice is re-polled. As shown in Table 1 and Table 2 below, Table 1 is the relative position difference table corresponding to satellite S1 in time slice 1, and Table 2 is the relative position difference table corresponding to satellite S1 in time slice M, wherein the relative position difference is represented by the latitude and longitude difference. The relative position difference table can be determined by a ground computing device and then annotated to each satellite, or it can be determined by each satellite itself, or it can be determined by a certain satellite and then synchronized by other satellites. As long as the division standard of the operating cycle of each satellite and the calculation standard of the relative position difference are consistent, the embodiment of the present application does not limit this.

[0079] Table 1

[0080] Satellite ID Relative position difference (Δα, Δβ) S1 <![CDATA[(Δα 11 ,Db 11 )]]> S2 <![CDATA[(Δα 12 ,Db 12 )]]> … … <![CDATA[S n-1 ]]> <![CDATA[(Δα 1(n-1) ,Db 1(n-1) )]]> <![CDATA[S n ]]> <![CDATA[(Δα 1n ,Db 1n )]]>

[0081] Table 2

[0082] Satellite ID Relative position difference (Δα, Δβ) S1 <![CDATA[(Δα M1 ,Db M1 )]]> S2 <![CDATA[(Δα M2 ,Db M2 )]]> … … <![CDATA[S n-1 ]]> <![CDATA[(Δα M(n-1) ,Db M(n-1) )]]> <![CDATA[S n ]]> <![CDATA[(Δα Mn ,Db Mn )]]>

[0083] It should be noted that the above Tables 1 and 2 are described by taking the latitude and longitude differences corresponding to satellites as an example to represent the relative position difference. In some embodiments, the relative position difference is represented based on other methods, which is not limited in the embodiments of the present application.

[0084] 202. Satellite A determines the distance between each satellite and the ground receiving node based on the position of the ground receiving node corresponding to the ground gateway, the position of satellite A in the target time slice, and the relative position difference between satellite A and other satellites.

[0085] Among them, the position of each ground receiving node can be reported to the satellite A separately by each ground receiving node, or can be reported to the satellite A uniformly by a certain ground receiving node. The embodiment of the present application does not limit this.

[0086] The process of satellite A determining the distance between each satellite and the ground receiving node includes: the position of the ground receiving node corresponding to the ground gateway is (α', β'), and satellite A determines its own position in the target time slice as (α k , β k ); Satellite A determines the position difference between itself and the ground receiving node (Δα', Δβ') = (α k -α', β k-β'); Satellite A determines the distance (Δα", Δβ") between each satellite and the ground receiving node based on the relative position difference (Δα, Δβ) between satellite A and other satellites = (Δα-Δα', Δβ-Δβ').

[0087] 203. Satellite A determines the satellite with the shortest distance from the ground receiving node as the predicted landing satellite of the ground gateway within the target time slice.

[0088] Among them, the satellite with the shortest distance to the ground receiving node is also the satellite with the smallest (Δα”, Δβ”). Figure 4 As shown, Figure 4 is a schematic diagram of a method for predicting a landing satellite provided in an embodiment of the present application, Figure 4 In the figure, the relative position difference between satellite A and satellite S is (Δα, Δβ), the position difference between satellite A itself and the ground receiving node G is (Δα', Δβ'), and the distance between satellite S and the ground receiving node G is (Δα", Δβ"). If the distance (Δα", Δβ") between satellite S and the ground receiving node G is the smallest among all satellites, then satellite S is the predicted landing satellite of the ground gateway within the target time slice.

[0089] It should be noted that the above is explained by taking the example of determining the predicted landing satellite corresponding to the ground gateway within the target time slice. Satellite A periodically determines the predicted landing satellite corresponding to the ground gateway, that is, the predicted landing satellite corresponding to the ground gateway is predicted in multiple time slices of each operation cycle, wherein the process of satellite A determining the predicted landing satellite each time is the same as the above steps 201 to 203, which will not be repeated. In the above method, satellite A predicts the predicted landing satellite corresponding to the ground gateway within multiple time slices of each operation cycle, thereby ensuring that the accuracy of the prediction result can be guaranteed when the position of the ground gateway or the ground receiving node corresponding to the ground gateway is updated.

[0090] In some embodiments, satellite A stores the satellite identifiers of the predicted landing satellites corresponding to each ground gateway predicted in each time slice in a predicted landing satellite identifier table, so as to obtain the satellite identifiers of the predicted landing satellites corresponding to each ground gateway by looking up the table later.

[0091] The above embodiment is illustrated by taking satellite A determining the predicted landing satellite corresponding to the ground gateway as an example. In the embodiment of the present application, each satellite determines the predicted landing satellite corresponding to each ground gateway in each time slice. The process of other satellites determining the predicted landing satellite is the same as the process of satellite A determining the predicted landing satellite, and will not be repeated.

[0092] It should be noted that the above steps 201 to 203 are described using the example of the ground receiving device being a ground gateway. In some embodiments, the ground receiving device is a terminal, and the process of determining the predicted landing satellite corresponding to the terminal will be introduced in subsequent embodiments and will not be repeated here.

[0093] It should be noted that the above steps 201 to 203 are based on the operating rules of multiple satellites to determine the relative position difference between the satellite and other satellites in the satellite network, and based on the position of the destination ground receiving device, the position of the satellite and the relative position difference, determine the distance between each satellite and the destination ground receiving device, and determine the satellite with the smallest distance to the destination ground receiving device as an implementation method of the predicted landing satellite corresponding to the destination ground receiving device. In some embodiments, the process is also implemented based on other methods, which is not limited to the embodiments of the present application.

[0094] The following describes the process of spreading the route from the satellite to the ground receiving device to the landing area corresponding to the ground receiving device in the embodiment of the present application. Taking the ground receiving device as a ground gateway as an example, Figure 5 This is a flow chart of an embodiment of the present application providing a method of spreading the route from a satellite to a ground gateway to a landing area, such as Figure 5 As shown, the method includes the following steps 501 to 503.

[0095] 501. The satellite C1 establishes a satellite-to-ground connection with a ground receiving node, and determines a route from the satellite C1 to a ground gateway corresponding to the ground receiving node.

[0096] Among them, satellite C1 is the actual landing satellite corresponding to the ground gateway. After satellite C1 establishes a satellite-to-ground connection with the ground receiving node, a route connection from the satellite C1 to the ground gateway corresponding to the ground receiving node is established through the link discovery protocol, that is, the route from the satellite C1 to the ground gateway is determined.

[0097] 502. Satellite C1 diffuses the route from satellite C1 to the ground gateway to satellites within the landing area corresponding to the ground gateway.

[0098] The landing area is determined based on the maximum receiving range corresponding to the destination ground receiving node and the maximum number I of satellites that may exist within the maximum receiving range, where I is an integer greater than or equal to 0. In some embodiments, the landing area is centered on the actual landing satellite C1, and the outermost satellite of the landing area is J hops away from the actual landing satellite, wherein the number of satellites that are J hops away from I is an integer greater than or equal to I. For example, the maximum number of satellites that may exist within the maximum receiving range corresponding to the ground receiving node is I, and the satellite that is farthest from the actual landing satellite among these I satellites is 2 hops away from the actual landing satellite, then the range of the landing area corresponding to the ground gateway is the satellites within 2 hops centered on the actual landing satellite C1.

[0099] In the above method, since the satellite is always running at high speed, the ground receiving node may switch the connected satellite multiple times. Therefore, the range of the landing area is determined based on the maximum number of satellites that may exist within the maximum receiving range of the ground receiving equipment. This can ensure that after multiple switches, the predicted landing satellite is always within the range of the landing area. In addition, since different satellites have different orbits, the orientation of the satellite that the ground receiving node switches to connect to each time is not necessarily the same. Therefore, the landing area is centered on the actual landing satellite C1, which can ensure that all switched connected satellites are located in the landing area, thereby ensuring the effectiveness of the selected landing area.

[0100] 503. The satellite within the landing area corresponding to the ground gateway establishes a second routing table to reach the ground gateway based on the route from the satellite C1 to the ground gateway.

[0101] The second routing table is used to indicate the next hop from the current satellite to the ground gateway.

[0102] In some embodiments, when satellite C1 is disconnected from the ground receiving node, satellite C1 sends a route withdrawal message to satellites in the landing area. After receiving the route withdrawal message, the satellites in the landing area withdraw the stored route to the ground gateway.

[0103] Below Figure 6 Taking as an example, the process shown in the above steps 501 to 503 is illustrated. Figure 6 : is a flow chart of a method for spreading a route to a ground gateway provided in an embodiment of the present application, such as Figure 6As shown, satellite S7 has established a satellite-to-ground connection with a ground gateway (i.e., a ground receiving node), and satellite S7 is the actual landing satellite. The ground receiving gateway corresponding to the ground gateway is SGW1, and the landing area corresponding to SGW1 is the satellites within a 2-hop range centered on satellite S7 (satellite S1 to satellite S13). Satellite S7 establishes a second routing table 601 to reach SGW1, and the second routing table 601 indicates that the next hop satellite for satellite S7 to reach SGW1 is itself (self); satellite S7 diffuses the route to reach SGW1 to each satellite within one hop range of satellite S7 (satellite S3, satellite S6, satellite S8 and satellite S11). After each satellite within one hop range of satellite S7 establishes a second routing table to reach SGW1, the route to reach SGW1 is diffused to each satellite within two hops range of satellite S7 (satellite S1, satellite S2, satellite S4, satellite S5, satellite S9, satellite S10, satellite S12 and satellite S13). Each satellite within two hops range of satellite S7 establishes a second routing table to reach SGW1. For example, satellite S5 establishes a second routing table 602 to reach SGW1, and the second routing table indicates that the next hop satellite for satellite S5 to reach SGW1 is S6. The second routing tables of other satellites within the landing area are the same and will not be repeated.

[0104] It should be noted that the above steps 501 to 503 are described using the example of the ground receiving device being a ground gateway. In some embodiments, the ground receiving device is a terminal, and the process of spreading the route from the satellite to the terminal to the landing area will be introduced in subsequent embodiments and will not be repeated here.

[0105] In the above method, the satellite stores a second routing table indicating the route to the ground gateway only when and only when the satellite exists within the landing area corresponding to the ground gateway. Therefore, when the satellite connected to the ground gateway is switched, only the satellite within the landing area needs to update the second routing table, and there is no need for all satellites in the entire satellite network to update the route to the ground gateway. Therefore, when the satellite-to-ground link switches frequently, the satellite-to-ground network topology can converge in time, reducing the pressure of satellite-to-ground network topology synchronization.

[0106] The following describes a method for transmitting messages in a satellite-to-ground network provided by an embodiment of the present application. Taking the ground receiving device as a ground gateway as an example, Figure 7 is a flow chart of a message transmission method in a satellite-to-ground network provided by an embodiment of the present application, such as Figure 7 As shown, the method includes the following steps 701 to 704.

[0107] 701. Satellite A receives a first message, where the first message includes a destination address, and the destination address indicates a destination ground gateway corresponding to the first message.

[0108] The first message comes from the ground network, and the first message may come from a user terminal or a core network in the ground network, etc., which is not limited in the embodiment of the present application. The satellite A is a satellite that receives the first message from the ground network, and the satellite A is also an access satellite, and may also be called a head node satellite or a source node satellite.

[0109] 702. Satellite A sends a second message to satellite B based on the first message. The second message carries the first message, the gateway identifier of the destination ground gateway, and the satellite identifier of the predicted landing satellite corresponding to the destination ground gateway. The predicted landing satellite is a satellite for which the ground gateway corresponding to the predicted landing satellite may have established a satellite-to-ground connection.

[0110] The satellite B refers to one or more satellites other than satellite A outside the landing area corresponding to the destination ground gateway. The satellite B generates a second message based on the first message and sends the second message to satellite B. The process of satellite B generating the second message based on the first message includes: determining the gateway identifier of the destination ground gateway and the satellite identifier of the predicted landing satellite corresponding to the destination ground gateway; encapsulating the gateway identifier and satellite identifier into the outer layer of the first message, so as to use the gateway identifier and satellite identifier as part of the destination address. For example, Figure 8 As shown, Figure 8 It is a schematic diagram of a method for encapsulating a gateway identifier and a satellite identifier provided in an embodiment of the present application.

[0111] The satellite B obtains the satellite identifier of the predicted landing satellite corresponding to the destination ground gateway by looking up the table. The process of determining the predicted landing satellite corresponding to the destination ground gateway is the same as the above. Figure 2 The same is true for the embodiment shown, which will not be described in detail.

[0112] 703. After receiving the second message, satellite B forwards the second message to the predicted landing satellite within the landing area of ​​the destination ground gateway based on the satellite identifier of the predicted landing satellite and the first routing table.

[0113] The satellite B stores a first routing table but does not store a second routing table, wherein the first routing table includes a route from the satellite B to the predicted landing satellite of the destination ground gateway, and the second routing table includes a route from the satellite B to the destination ground gateway. It should be noted that each satellite in the satellite network stores the first routing table, and according to the above Figure 5 It can be seen from the illustrated embodiment that the satellite stores the second routing table only when the satellite is within the landing area corresponding to the destination ground gateway.

[0114] After receiving the second message, satellite B forwards the second message to the next-hop satellite indicated by the first routing table to the predicted landing satellite. It should be noted that the next-hop satellite indicated by the first routing table to the predicted landing satellite may be located outside the landing area of ​​the destination ground gateway, or may be located within the landing area. If the next-hop satellite is located outside the landing area, after receiving the second message, the satellite forwards the second message in the same manner as satellite B; if the next-hop satellite is located within the landing area, the satellite forwards the second message in the manner shown in the following step 704.

[0115] 704. After receiving the second message, satellite C forwards the second message to the destination ground gateway based on the gateway identifier of the destination ground gateway and the second routing table.

[0116] The satellite C generally refers to one or more satellites within the landing area corresponding to the destination ground gateway. The satellite C may be the actual landing satellite corresponding to the destination ground gateway, or the predicted landing satellite corresponding to the destination ground gateway, or other satellites other than the actual landing satellite and the predicted landing satellite within the landing area. As described in step 703, the satellite C within the landing area stores the first routing table and the second routing table at the same time. After receiving the second message, the satellite C forwards the second message to the next hop satellite indicated by the second routing table that reaches the destination ground gateway.

[0117] It should be noted that the above description of satellite C is illustrated by taking the actual landing satellite and the predicted landing satellite as different examples. In some embodiments, the actual landing satellite and the predicted landing satellite are the same, and the embodiments of the present application do not limit this.

[0118] It should be noted that the above steps 701 to 704 are explained by taking the example of satellite A receiving the first message, forwarding the second message to satellite B, and satellite B forwarding the second message to satellite C. That is, satellite A and satellite C need to communicate through other satellites. In some embodiments, the next-hop satellite of satellite A is located in the landing area, that is, the next-hop satellite of satellite A is satellite C, and there is no need to communicate through other satellites B. The embodiments of the present application are not limited to this.

[0119] Below through Fig. 9 and Fig.10 The process shown in the above steps 701 to 704 is described with an example. Fig. 9 is a flow chart of a message transmission method in a satellite-to-ground network provided in an embodiment of the present application, Fig.10 FIG. 1 is a flow chart of a message transmission method in a satellite-to-ground network provided by an embodiment of the present application. Fig.10As shown, after receiving the first message, satellite A determines the satellite identifier S6 of the predicted landing satellite corresponding to the ground gateway SGW1 through the query table 1001; satellite A encapsulates the satellite identifier (SID) and the gateway identifier (GID) into the outer layer of the first message to obtain the second message; satellite A forwards the second message to satellite B; after receiving the second message, satellite B forwards the second message to the predicted landing satellite (S6) based on the satellite identifier (SID); after S5 (that is, satellite C) in the landing area receives the second message, it determines that the next-hop satellite is S6 based on the gateway identifier (GID) through the second routing table 1002, and forwards the second message to satellite S6; after receiving the second message, satellite S6 determines that the next-hop satellite is S7 based on the gateway identifier (GID) through the second routing table, and forwards the second message to satellite S7; after receiving the second message, satellite S7 determines that the next-hop is itself (self) based on the gateway identifier (GID) through the second routing table 1003, and forwards the second message to the ground gateway SGW1.

[0120] It should be noted that the above steps 701 to 704 are explained by taking the gateway identifier of the destination ground gateway and the satellite identifier of the predicted landing satellite as an example. In some embodiments, the information carried in the second message is the IP of the destination ground gateway and the IP of the predicted landing satellite. The message is transmitted based on the IP of the predicted landing satellite and the IP of the ground receiving device. This process is the same as the message transmission process in the above steps 701 to 704. The similarities will not be repeated here. The difference is that the encapsulation format of the second message is different. Taking IPv6 as an example, Fig.11 As shown, Fig.11 A schematic diagram of adding a segment routing extension header (SRH) to an IPv6 address is provided in an embodiment of the present application. Satellite A adds a new extension header in IPv6, or borrows an existing segment routing IPv6 (segment routing IPv6, SRv6) message header to carry the IP of the predicted landing satellite. Fig.12 is a schematic diagram of the format of an SRH provided in an embodiment of the present application, Fig.13 This is a schematic diagram of the encapsulation format of a second message provided in an embodiment of the present application.

[0121] In the above method, after receiving the first message, satellite A encapsulates the satellite identifier of the predicted landing satellite and the gateway identifier of the destination ground gateway into the second message, so that satellite B outside the landing area of ​​the destination ground gateway can perform fuzzy routing forwarding on the second message based on the satellite identifier of the predicted landing satellite. Since the predicted landing satellite is within the landing area, the second message will be forwarded in the direction of the landing area during the fuzzy routing forwarding process; secondly, the satellite within the landing area performs precise routing forwarding on the second message based on the gateway identifier of the destination ground gateway. Since only the satellite within the landing area knows the precise route to the destination ground gateway, when the satellite-to-ground link between the ground gateway and the satellite is switched, only the satellite within the landing area needs to update the route, and there is no need for all satellites in the entire satellite network to update. Therefore, when the satellite-to-ground link is frequently switched, the satellite-to-ground link is only flooded in a small range, which can effectively reduce the pressure of frequent flooding of the entire routing network caused by the switching of the satellite-to-ground link, and can make the satellite-to-ground network topology converge in time, reducing the pressure of satellite-to-ground network topology synchronization.

[0122] Above Figure 5 and Figure 7 The illustrated embodiment is explained by taking the example of determining the next-hop satellite by querying the first routing table or the second routing table. In some embodiments, the second message is forwarded by an Internet Protocol (IP) forwarding mechanism (IPv4 or IPv6). In this method, a satellite outside the landing area of ​​the destination surface receiving device stores a third routing table, and the third routing table includes a first route to the host corresponding to the destination address in the second message, and the first route includes the information of the predicted landing satellite corresponding to the destination surface receiving device, but does not include the information of the destination surface gateway. For example, the first route is XXXX.SID.0.0 / 96, where SID indicates the satellite identifier of the predicted landing satellite; the satellite within the landing area of ​​the destination surface receiving device stores a fourth routing table, and the fourth routing table includes a second route to the host corresponding to the destination address in the second message, and the second route includes the information of the predicted landing satellite and the information of the destination surface gateway. For example, the second route is XXXX.SID.GID.0 / 104, where SID indicates the satellite identifier of the predicted landing satellite, and GID indicates the gateway identifier of the destination surface gateway. For example, Fig.14 As shown, Fig.14 It is a schematic diagram of a second route of a satellite within a landing area provided in an embodiment of the present application, wherein the second route includes a satellite identifier of a predicted landing satellite, a device identifier of a receiving device on the destination surface, and a host address.

[0123] The generation process of the second route corresponding to the satellite within the landing area includes: after the actual landing satellite establishes a connection with the destination surface receiving device, a second route (XXXX.SID.GID.0 / 112) is generated, and the generated second route is diffused to the satellites within the landing area; after the satellite within the landing area receives the second route, the second route is added to the fourth routing table. When the satellite connected to the destination surface receiving device is switched, the second route corresponding to the satellite is revoked from the entry in the fourth routing table.

[0124] Among them, the process of forwarding the second message through the IP forwarding mechanism includes: after receiving the second message, any satellite queries the entry in the stored routing table according to the longest matching mechanism to obtain the entry that longest matches the encapsulated destination address of the second message; and forwards the second message based on the entry. In the above method, each satellite forwards the second message based on the longest matching mechanism. If the entry matched by the satellite through the longest matching mechanism does not include the information of the destination ground receiving device, it means that the satellite is outside the landing area, and the satellite forwards the second message based on the information of the predicted landing satellite in the entry; if the entry matched by the satellite through the longest matching mechanism includes the information of the destination ground receiving device, it means that the satellite is within the landing area, and the satellite forwards the second message based on the information of the destination ground receiving device in the entry.

[0125] In the above method, satellites outside the landing area and inside the landing area generate forwarding entries with prefixes of different lengths, thereby achieving compatibility of the two sets of routing tables under the existing IP forwarding mechanism without changing the forwarding plane.

[0126] Above Figure 5 and Figure 7 The illustrated embodiment introduces the message transmission method in the satellite-to-ground network provided by the present application by taking the scenario in which the satellite receives a message from the ground network and forwards the message to the destination ground receiving device as an example. The method can also be applied to the scenario in which the satellite receives a message from the ground gateway, forwards the message to the destination ground gateway, the destination ground gateway sends a response message corresponding to the message to the satellite, and the satellite network returns the response message, that is, the scenario of communication between ground gateways and ground gateways. The method can also be applied to the scenario of communication between terminals and terminals or between terminals and ground gateways.

[0127] The following introduces the method by taking the 5G non-terrestrial network (NTN) mobile rotation scenario in the terminal and ground gateway communication scenario as an example.

[0128] The 5G NTN mobile turnaround scenario includes two message transmission processes: from the user terminal (UE) to the core network (UPF) and from the UPF to the UE. Fig.15 and Fig.16 , and the two message transmission processes are introduced respectively.

[0129] The first process: from UE to UPF. Fig.15 is a flow chart of a message transmission method in a satellite-to-ground network provided by an embodiment of the present application, such as Fig.15 As shown, the UE accesses the satellite-borne base station (S-gNB) of satellite S0, communicates with satellite S0 via messages, and sends message 1501 (i.e., the first message) to satellite S0; the S-gNB of satellite S0 encapsulates the message with the general packet radio service tunneling protocol (GTP) to obtain message 1502, and sends the encapsulated message to the sub-interface corresponding to the satellite-borne router (S-Router) of satellite S0 according to the user VPN; the S-Router of S0 determines the destination ground gateway SGW and the S-Router address of the satellite directly above it (i.e., the S-Router address of the predicted landing satellite) according to the destination address of the GTP tunnel and the VPN, encapsulates the on-board tunnel (tunnel), and obtains the encapsulated message 1503 (i.e., the second message), wherein the destination address in message 1503 includes the satellite identifier of the predicted landing satellite and the destination ground gateway gateway identifier; satellites S1 and S2 in non-landing areas forward message 1503 based on the longest matching mechanism; satellites S10 and S11 in the landing area forward message 1503 based on the longest matching mechanism to send the message to the actual landing satellite; the actual landing satellite transparently transmits the message 1503 to the destination ground gateway SGW according to the VPN identifier (VPNID); after receiving the message 1503, the destination ground gateway SGW strips off the outer tunnel of the message 1503, encapsulates the ground tunnel according to the VPNID and UPF address, and finds the outbound interface forwarding to forward the message 1501 to the UPF.

[0130] The second process: from UPF to UE. Fig.16 is a flow chart of a message transmission method in a satellite-to-ground network provided by an embodiment of the present application, such as Fig.16As shown, UPF encapsulates the message according to the user to reach the GTP tunnel of the S-gNB of satellite S11, and obtains message 1601; the ground gateway strips off the outer encapsulation of message 1601, and encapsulates the onboard tunnel according to the sub-interface and the S-gNB address to obtain message 1602, wherein the destination corresponding to the gateway identifier GID of the ground gateway is the S-Router of satellite S0; the ground gateway SGW sends message 1602 to the S-Router of satellite S11; each satellite searches for the next-hop satellite based on the longest matching mechanism, and forwards the message 1602 to satellite S0; after receiving the message 1602, satellite S0 strips off the outer encapsulation of message 1602 to obtain message 1601, matches the S-gNB address segment of satellite S0 based on the destination address in the message 1601, and sends the message 1601 to the S-gNB; the S-gNB of satellite S0 dismantles the GTP tunnel in message 1601 to obtain message 1603, and sends the message 1603 to the UE.

[0131] The following takes the user terminal and user terminal communication scenario as an example to introduce the message transmission method in the satellite-to-ground network provided by the embodiment of the present application. In this scenario, the ground is divided into several ground partitions according to the distribution characteristics of the satellite constellation. User terminals located in the same ground partition have the same routing prefix, and different user terminals with the same prefix have their own host numbers. The satellite can determine the ground partition where the user terminal is located based on the routing prefix of the user terminal. It should be noted that since the shape of the satellite beam cannot be distributed completely like the ground partition, it is inevitable that the satellite beam will overlap at the edge of the ground partition. However, in the embodiment of the present application, the routing prefix confusion caused by the overlapping ground partition coverage due to the irregular shape of the satellite beam will not affect the solution.

[0132] Among them, each satellite stores ephemeris information, and the ephemeris information is used to indicate the position of each satellite at different times. The process of satellite A determining the predicted landing satellite corresponding to the user terminal includes: based on the stored ephemeris information, the longest coverage time and the maximum elevation angle of each satellite, predicting the predicted landing satellite corresponding to the ground partition where the user terminal is located. It should be noted that the above method is described by taking the determination of the predicted landing satellite based on the longest coverage time and the maximum elevation angle of each satellite as an example. In some embodiments, the predicted landing satellite is also determined based on other information, which is not limited in the embodiments of the present application. In some embodiments, each satellite stores the prediction results in a satellite-to-ground position mapping relationship table, and periodically updates the satellite-to-ground position mapping relationship table. The satellite-to-ground position mapping relationship table is used to store the mapping relationship between the ground partition and the predicted landing satellite.

[0133] Each satellite stores a user access information table, which is used to store the access information of the user terminal in real time. Whenever a user terminal is connected or disconnected, the satellite with the user terminal connected or disconnected will update the stored user access information table. If a user terminal is connected to any satellite, the satellite will diffuse the access information of the user terminal to the satellites within the landing area corresponding to the user terminal; after receiving the access information, the satellite within the landing area will update the stored routing table based on the access information. In the above method, since the synchronization of the entire access information adopts a distributed diffusion form, the entire diffusion process will not generate a large amount of centralized control interaction information, which can greatly avoid the single-point performance bottleneck of centralized control; in addition, since the synchronization of the access information adopts a local synchronization method, it can avoid the problems of large synchronization overhead and routing oscillation caused by the diffusion of routes to the entire network by distributed routing protocols such as open shortest path first (OSPF). In some embodiments, if the satellite accessed by the user terminal is not the predicted landing satellite corresponding to the ground partition where the user terminal is located, the satellite will also synchronize the access information of the user terminal to the predicted landing satellite corresponding to the ground partition. Since the predicted landing satellite will definitely synchronize all access information in the corresponding partition, even if all the intermediate satellites on the forwarding path of the second message do not synchronize the access information of the destination user terminal, after the second message reaches the predicted landing satellite, the forwarding route of the second message will still be redirected by the predicted landing satellite to the actual landing satellite of the destination user terminal. Therefore, the second message will eventually be sent to the actual landing satellite, thereby ensuring 100% accessibility of the destination user terminal.

[0134] The process in which, after receiving a first message from a user terminal, a satellite generates a second message based on the first message, and forwards the second message to a destination user terminal includes: satellite A receives a first message, the first message includes a destination address, and the destination address indicates a ground partition where the destination user terminal corresponding to the first message is located; satellite A sends a second message to satellite B based on the first message, and the second message carries the first message, information about the destination user terminal, and information about a predicted landing satellite corresponding to the ground partition; after receiving the second message, satellite B queries a routing table stored in satellite B based on the destination address, and if the access information corresponding to the destination user terminal does not exist in the routing table, the predicted landing satellite is used as the destination satellite, and the second message is sent to the next-hop satellite; after receiving the second message, satellite C queries a user access information table based on the information of the destination user terminal in the second message, obtains the access information of the destination user terminal, and performs routing redirection on the second message based on the access information, so as to forward the second message to the actual landing satellite indicated by the access information, and then transmit the message to the destination user terminal. In the process of redirecting the second message, since the redirected route may pass through a satellite that has not synchronized the access information of the destination user terminal, in order to avoid the occurrence of a routing loop, the route of the second message is redirected to the actual landing satellite in a tunnel manner.

[0135] Below through Fig.17 The above embodiments are described by way of example. Fig.17 is a schematic diagram of a message transmission method in a satellite-to-ground network provided by an embodiment of the present application, such as Fig.17 As shown, the ground is divided into N ground partitions Net1-N, where N is an integer greater than 0. Among them, the predicted landing satellite corresponding to the ground partition Net1 is S4, and there are two user terminals U1 and U2 in the ground partition Net1, where U2 is the destination user terminal. When satellite S2 receives the second message, it queries the S2 forwarding table based on the information of the destination user terminal in the second message, and obtains that the actual landing satellite of U2 is S5. Satellite S2 forwards the second message to satellite S5 in a tunneling manner, and then forwards the second message to the destination user terminal U2. Among them, since S3 is located outside the access information diffusion area (that is, the landing area) of the actual landing satellite S5 of U2, S3 does not synchronize the access information of S5, so the predicted landing satellite S4 corresponding to U2 is used as the destination satellite, and the second message is forwarded to satellite S2; since satellite S2 is located in the access information diffusion area (that is, the landing area) of the actual landing satellite S5 of U2, S2 synchronizes the access information of S5, so it can redirect the route of the second message and directly forward the second message to S5 without forwarding it according to the route of S2-S1-S4-S5, thereby avoiding the occurrence of loops.

[0136] Fig.18 A satellite is provided in an embodiment of the present application, and the satellite includes a satellite base station 1801 and a satellite router 1802.

[0137] The satellite-borne base station 1801 is configured to receive a first message, and send a second message based on the first message, wherein the first message includes a destination address, the destination address indicates a destination ground gateway corresponding to the message, and the second message carries the first message, a gateway identifier of the destination ground gateway, and a satellite identifier of a predicted landing satellite corresponding to the destination ground gateway, wherein the predicted landing satellite is a satellite for which a ground gateway corresponding to the predicted landing satellite may have established a satellite-to-ground connection;

[0138] The satellite-borne router 1802 is used to receive the second message, forward the second message to the predicted landing satellite, and forward the second message to the destination ground gateway.

[0139] Optionally, the satellite further comprises:

[0140] The prediction module is used to predict the predicted landing satellite corresponding to the destination ground gateway in each time slice based on the position of the ground receiving node corresponding to the destination ground gateway, the position of each satellite in the time slice and the relative position difference of each satellite.

[0141] Optionally, the prediction module is used to:

[0142] Query the relative position difference table corresponding to each satellite in the target time slice to obtain the relative position difference between each satellite and other satellites in the satellite network in the target time slice;

[0143] Based on the position of the ground receiving node, the position of each satellite in the target time slice and the relative position difference, the distance between each satellite and the ground receiving node is determined;

[0144] The satellite with the shortest distance to the ground receiving node is determined as the predicted landing satellite of the destination ground gateway within the target time slice.

[0145] Optionally, the landing area is determined based on the maximum number of satellites that a ground receiving node corresponding to the destination ground gateway may switch within a time slice.

[0146] Optionally, the satellite stores a first routing table and does not store a second routing table, the first routing table includes routes from the satellite to other satellites in the satellite network, the second routing table includes routes from the satellite to a destination ground gateway, and the onboard router 1802 is used to:

[0147] Based on the satellite identifier and the first routing table, the second message is forwarded to the predicted landing satellite.

[0148] Optionally, the satellite stores a third routing table, the third routing table includes a first route to a host corresponding to the destination address in the second message, the first route indicates a predicted landing satellite and does not indicate a destination ground gateway, and the onboard router 1802 is used to:

[0149] Based on the first route in the third routing table, the second message is forwarded to the predicted landing satellite.

[0150] Optionally, the satellite stores a second routing table, the second routing table including a route from the satellite to a destination ground gateway, and the onboard router 1802 is used to:

[0151] Based on the gateway identifier and the second routing table, the second message is forwarded to the destination plane gateway.

[0152] Optionally, the satellite stores a fourth routing table, the fourth routing table includes a second route to a host corresponding to the destination address in the second message, the second route indicates the predicted landing satellite and the destination ground gateway. The onboard router 1802 is used to:

[0153] Based on the second route in the fourth routing table, the second message is forwarded to the predicted landing satellite.

[0154] The present application implements a computer program product including instructions, which may be software or a program product including instructions that can be run on a satellite or stored in any available medium. When the computer program product is run on a satellite, the satellite implements the message transmission method in the satellite-to-ground network provided in the above embodiment.

[0155] The embodiment of the present application provides a computer-readable storage medium, which can be any available medium that can be stored by a satellite in a satellite network or a data storage device such as a data center containing one or more available media. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state hard disk). The computer-readable storage medium includes instructions, and when the instructions are executed by a satellite, the satellite executes the message transmission method in the satellite-to-ground network provided in the above embodiment.

[0156] Those of ordinary skill in the art will appreciate that the various method steps and units described in the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the steps and components of each embodiment have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Those of ordinary skill in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0157] Those skilled in the art can 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.

[0158] In the several embodiments provided in the present application, it should be understood that the disclosed satellite network, satellite and method can be implemented in other ways. For example, the satellite embodiments described above are only schematic. For example, the division of the unit is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, or it can be an electrical, mechanical or other form of connection.

[0159] The unit described as a separate component may or may not be physically separated, and the component displayed as a unit may or may not be a physical unit, that is, it may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiment of the present application.

[0160] In addition, each unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or software unit.

[0161] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including several instructions for enabling a satellite to execute all or part of the steps of the method in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk and other media that can store program code.

[0162] In this application, the term "at least two" means two and more than two, and the term "plurality" means two or more than two, for example, a plurality of satellites means two or more than two satellites. In this document, the terms "network" and "system" are often used interchangeably.

[0163] It should also be understood that the term "if" may be interpreted to mean "when" or "upon" or "in response to determining" or "in response to detecting." Similarly, the phrase "if it is determined that ..." or "if [a stated condition or event] is detected" may be interpreted to mean "upon determining that ..." or "in response to determining that ..." or "upon detecting [a stated condition or event]" or "in response to detecting [a stated condition or event]," depending on the context.

[0164] The above description is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0165] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware, or any combination thereof. When implemented by software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer program instructions. When the computer program instructions are loaded and executed on the satellite, all or part of the processes or functions in the embodiments of the present application are generated.

[0166] The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer program instructions may be transmitted from one website, computer, server or data center to another website, computer, server or data center by wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a satellite or a data storage device such as a server or data center that includes one or more available media integrated therein. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a digital video disc (DVD), or a semiconductor medium (e.g., a solid-state drive)), etc.

[0167] A person skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware or by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0168] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A message transmission method in a satellite-to-ground network, characterized in that: Applied to a satellite in a satellite network in the satellite-to-ground network, the satellite network includes a plurality of satellites, the ground network in the satellite-to-ground network includes a plurality of ground receiving devices, each of the ground receiving devices corresponds to a respective landing area, and the method includes: receiving a first message, where the first message includes a destination address, and the destination address indicates a destination plane receiving device corresponding to the first message; Based on the first message, a second message is sent, where the second message carries the first message, information of the destination ground receiving device, and information of a predicted landing satellite corresponding to the destination ground receiving device, where the predicted landing satellite is a satellite for which a ground gateway corresponding to the predicted landing satellite may have established a satellite-to-ground connection; Among them, the second message instructs the satellites among the multiple satellites except the landing area corresponding to the destination surface receiving device to forward the second message to the predicted landing satellite, and the second message also instructs the satellites within the landing area corresponding to the destination surface receiving device to forward the second message to the destination surface receiving device, and the landing area corresponding to the destination surface receiving device includes at least one satellite including the predicted landing satellite.

2. The method according to claim 1, characterized in that The method further comprises: Based on the operation rules of multiple satellites in the satellite network, the positions of the satellites and the position of the destination surface receiving device, the predicted landing satellite corresponding to the destination surface receiving device is predicted.

3. The method according to claim 2, characterized in that The predicting the predicted landing satellite corresponding to the destination surface receiving device based on the operation rules of the multiple satellites in the satellite network, the positions of the multiple satellites and the position of the destination surface receiving device includes: Determining a relative position difference between the satellite and other satellites in the satellite network based on the operation rules of the multiple satellites; Determine the distance between each of the satellites and the destination surface receiving device based on the position of the destination surface receiving device, the position of the satellites and the relative position difference; The satellite having the shortest distance from the destination surface receiving device is determined as the predicted landing satellite corresponding to the destination surface receiving device.

4. The method according to claim 3, characterized in that The predicted landing satellite corresponding to the destination ground receiving device is periodically predicted.

5. The method according to any one of claims 1 to 4, characterized in that: The landing area is determined based on a maximum receiving range corresponding to the destination surface receiving device and a maximum number of satellites that may exist within the maximum receiving range.

6. A message transmission method in a satellite-to-ground network, characterized in that: The ground network in the satellite-to-ground network includes a plurality of ground receiving devices, each of which corresponds to a respective landing area, and is applied to satellites in the satellite network in the satellite-to-ground network except for the landing area corresponding to the destination ground receiving device, and the method includes: receiving a second message, wherein the second message carries the first message, information of the destination ground receiving device, and information of a predicted landing satellite corresponding to the destination ground receiving device, wherein the predicted landing satellite is a satellite with which the destination ground receiving device may have established a satellite-to-ground connection; Forward the second message to the predicted landing satellite.

7. The method according to claim 6, characterized in that The satellite stores a first routing table and does not store a second routing table, the first routing table includes routes from the satellite to other satellites in the satellite network, the second routing table includes routes from the satellite to the destination ground receiving device, and forwarding the second message to the predicted landing satellite includes: Based on the information of the predicted landing satellite and the first routing table, the second message is forwarded to the predicted landing satellite.

8. The method according to claim 6, characterized in that The satellite stores a third routing table, the third routing table includes a first route to a host corresponding to a destination address in the second message, the first route indicates the predicted landing satellite and does not indicate the destination ground receiving device, and forwarding the second message to the predicted landing satellite includes: Based on the first route in the third routing table, the second message is forwarded to the predicted landing satellite.

9. A message transmission method in a satellite-to-ground network, characterized in that: The ground network in the satellite-to-ground network includes a plurality of ground receiving devices, each of which corresponds to a respective landing area, and is applied to a satellite within a landing area corresponding to a destination ground receiving device in a satellite network in the satellite-to-ground network, and the method includes: receiving a second message, wherein the second message carries the first message, information of the destination ground receiving device, and information of a predicted landing satellite corresponding to the destination ground receiving device, wherein the predicted landing satellite is a satellite with which the destination ground receiving device may have established a satellite-to-ground connection; Forward the second message to the destination plane receiving device.

10. The method according to claim 9, characterized in that The satellite stores a second routing table, the second routing table includes a route from the satellite to the destination surface receiving device, and forwarding the second message to the destination surface receiving device includes: Based on the information of the destination plane receiving device and the second routing table, the second message is forwarded to the destination plane receiving device.

11. The method according to claim 9, characterized in that The satellite stores a fourth routing table, the fourth routing table includes a second route to a host corresponding to a destination address in the second message, the second route indicates the predicted landing satellite and the destination surface receiving device, and forwarding the second message to the destination surface receiving device includes: Based on the second route in the fourth routing table, the second message is forwarded to the destination plane receiving device.

12. A message transmission method in a satellite-to-ground network, characterized in that: Applied to a satellite in a satellite network in the satellite-to-ground network, the satellite network includes a plurality of satellites, the ground network in the satellite-to-ground network includes a plurality of ground receiving devices, each of the ground receiving devices corresponds to a respective landing area, and the method includes: The satellite in the satellite network receives a first message, and based on the first message, sends a second message, wherein the first message includes a destination address, the destination address indicates a destination ground receiving device corresponding to the message, and the second message carries the first message, information of the destination ground receiving device, and information of a predicted landing satellite corresponding to the destination ground receiving device, wherein the predicted landing satellite is a satellite for which a ground receiving device corresponding to the predicted landing satellite may have established a satellite-to-ground connection; The satellites in the satellite network other than the landing area corresponding to the destination ground receiving device receive the second message, and forward the second message to the predicted landing satellite; A satellite in the satellite network within the landing area corresponding to the destination surface receiving device receives the second message and forwards the second message to the destination surface receiving device.

13. A satellite, characterized in that: The satellites include: A satellite-borne base station, configured to receive a first message, and send a second message based on the first message, wherein the first message includes a destination address, the destination address indicates a destination ground receiving device corresponding to the message, and the second message carries the first message, information of the destination ground receiving device, and information of a predicted landing satellite corresponding to the destination ground receiving device, wherein the predicted landing satellite is a satellite for which a ground receiving device corresponding to the predicted landing satellite may have established a satellite-to-ground connection; The satellite-borne router is used to receive the second message, forward the second message to the predicted landing satellite, and forward the second message to the destination ground receiving device.

14. A satellite network, characterized in that: The invention comprises at least one satellite, each of which comprises a satellite-borne base station and a satellite-borne router, and the satellite-borne base station comprises a transceiver and a controller; The onboard base station of at least one satellite is used to receive messages, and the onboard router of at least one satellite is used to forward the messages so that the satellite network executes the message transmission method in the satellite-to-ground network as described in any one of claims 1 to 12.

15. A computer program product comprising instructions, characterized in that When the instruction is executed by the satellite network, the satellite network executes the message transmission method in the satellite-to-ground network as described in any one of claims 1 to 12.

16. A computer-readable storage medium, characterized in that: It comprises computer program instructions. When the computer program instructions are executed by a satellite network, the satellite network executes the message transmission method in a satellite-to-ground network as described in any one of claims 1 to 12.

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