Low-orbit satellite network structure, networking method, controller and medium

Abstract

The present invention relates to a low-orbit satellite network structure, a networking method, a controller and a medium, wherein the low-orbit satellite network structure comprises a first controller installed on the ground and a plurality of low-orbit satellites distributed in the earth's low-orbit meridian orbit, wherein the low-orbit satellites are connected by physical links, the first controller communicates with overhead satellites among the plurality of low-orbit satellites, and the interconnected low-orbit satellites can communicate with each other. The present invention simplifies the low-orbit satellite network structure, greatly reduces the system deployment cost, and improves the flexibility of the network.

Description

Technical Field

[0001] The present invention relates to the field of low-orbit satellite communication technology, and in particular to a low-orbit satellite network structure, a networking method, a controller and a medium. Background Art

[0002] A low-orbit satellite network refers to a space network composed of a number of low-earth orbit (LEO) satellites, with an orbital altitude of 500km-1000km from the earth. With the success of satellite miniaturization, the manufacturing and launch costs of low-orbit satellites continue to decrease, making it possible to use low-orbit satellites to build a space exchange network. The network operation mode of existing low-orbit satellite networks is that satellites are arranged in a specific orbit. A satellite is usually equipped with a ground station. The ground terminal equipment held by the user sends radio and forwards it through a one-hop forwarding through the satellite currently passing overhead, thereby realizing communication between users or users' access to the Internet, such as the Iridium system, such as Figure 1 shown.

[0003] It can be seen that in the existing low-orbit network system, the management and control of satellites are completed by ground stations. The management and control requires the satellite to pass over the ground station. The rest of the time, the satellite needs to have autonomous capabilities and independently complete network forwarding tasks. There are no or few inter-satellite links between satellites (such as the Iridium system has two experimental inter-satellite links), and there is no networking capability. If ground stations need to interact, they must rent existing ground networks. However, whether it is the global deployment of ground stations or the rental of expensive bandwidth, it will cause huge cost consumption and increase the difficulty of maintenance. Therefore, the traditional satellite network design cannot effectively achieve cost control, and the network flexibility is poor, which in turn affects the network operation income. Summary of the invention

[0004] The purpose of the present invention is to provide a low-orbit satellite network structure, a networking method, a controller and a medium, which simplify the low-orbit satellite network structure, significantly reduce the system deployment cost, and improve the flexibility of the network.

[0005] In order to solve the above technical problems, according to one aspect of the present invention, a low-orbit satellite network structure is provided, comprising a first controller installed on the ground and a plurality of low-orbit satellites distributed in the earth's low-orbit meridian orbits, wherein:

[0006] The low-orbit satellites are connected by physical links, the first controller communicates with overhead satellites among the plurality of low-orbit satellites, and the interconnected low-orbit satellites can communicate with each other.

[0007] Furthermore, the physical link includes a laser link and a radio link.

[0008] Furthermore, the physical topology of the low-orbit satellite network structure is a lattice topology, which is connected end to end and includes multiple rings.

[0009] Furthermore, it includes one or more second controllers installed on the ground, which are used to replace the first controller to communicate with the low-orbit satellite passing overhead when the first controller fails.

[0010] Furthermore, each of the low-orbit satellites is equipped with a network switching module and a space communication module, wherein:

[0011] The network switching module is used to receive the control information of the control plane sent by the first controller and convert it into corresponding control instructions and send it to the space communication module, and receive the data forwarding control information sent by the first controller and convert it into corresponding data forwarding instructions and send it to the space communication module;

[0012] The space communication module is used to forward control information of the control plane to the corresponding satellite according to the received control instruction, and to forward data to the corresponding satellite or ground terminal according to the received data forwarding instruction.

[0013] Furthermore, the network switching module includes a control plane management interface, a data plane management interface, a management process unit and a control agent unit, wherein:

[0014] The control plane management interface is connected to the first controller and the management process unit respectively, and is used to receive control information of the control plane sent by the first controller and send it to the management process unit;

[0015] The data plane management interface is connected to the first controller and the management process unit respectively, and is used to receive data forwarding control information sent by the first controller and send it to the management process unit;

[0016] The management process unit is used to generate or rewrite the control information flow table according to the received control information of the control plane, generate or rewrite the data forwarding flow table according to the received data forwarding control information, and forward the control information of the control plane and the data forwarding control information to the control agent unit;

[0017] The control agent unit is connected to the management process unit and the soft switch channel unit respectively, and is used to parse the control information of the control plane, convert it into a control instruction, and forward the control information of the control plane to the corresponding satellite according to the control information flow table and the control instruction, and parse the data forwarding control information, convert it into a data forwarding instruction, and send it to the hardware unit corresponding to the space communication module through the software switch channel according to the data forwarding flow table;

[0018] The soft switch path unit is connected to the network card device and the control agent unit respectively, and is used to parse the data message received from the network card device and match the data forwarding flow table.

[0019] Furthermore, the space communication module includes an antenna, a conversion unit, a baseband and a network card device connected in sequence, wherein:

[0020] The network card device is used to convert the data format of the data to be forwarded and support the required access function, and the access function includes a TDMA function;

[0021] The baseband is used to perform coding modulation in the digital domain on the data to be sent and send it to the digital / analog conversion subunit, and is also used to demodulate and decode the digital signal received from the analog / digital conversion subunit and send it to the network card device;

[0022] The conversion unit includes a digital / analog conversion subunit and an analog / digital conversion subunit, wherein the digital / analog conversion subunit is used to convert a digital signal into an analog signal, and the analog / digital conversion subunit is used to convert an analog signal into a digital signal;

[0023] The antenna is used to receive and transmit modulated radio waves.

[0024] Furthermore, the network switching module also includes:

[0025] The fault recovery unit is used to rewrite the control information flow table and make a recovery decision when a network fault occurs.

[0026] Furthermore, the network switching module also includes:

[0027] System management interface, used to monitor, manage and restore the health status of the operating system;

[0028] Core network management interface, used to exchange user management information with the core network module;

[0029] A user management unit, used for authenticating and charging users during network operation, and sending QOS control information to the management process unit;

[0030] The management process unit is further used to generate or rewrite a QOS policy according to the QOS control information.

[0031] According to another aspect of the present invention, a low-orbit satellite network networking method is provided, comprising:

[0032] The low-orbit satellites are connected by physical links to establish a physical topology structure of the low-orbit satellite network, wherein all the low-orbit satellites in the physical topology structure can communicate with the same first controller located on the ground;

[0033] Establishing a logical topology structure of a control channel based on the physical topology structure, wherein the logical topology structure can traverse all low-orbit satellites without any logical loop;

[0034] The overhead satellite receives the control information of the control plane sent by the first controller, and forwards the control information of the control plane to the corresponding satellite based on the logical topology structure;

[0035] The overhead satellite receives the data forwarding control information sent by the first controller, and forwards the data based on the satellite or ground terminal corresponding to the physical topology structure.

[0036] Further, the overhead satellite receives the control information of the control plane sent by the first controller, and forwards the control information of the control plane to the corresponding satellite based on the logical topology structure, including:

[0037] Receiving control information of the control plane sent by the first controller;

[0038] Generate or rewrite a control information flow table according to the control information received from the control plane;

[0039] Parsing the control information of the control plane and converting it into control instructions;

[0040] The control information of the control plane is forwarded to the corresponding satellite in the logical topology structure according to the control information flow table and the control instruction.

[0041] Further, the overhead satellite receives the data forwarding control information sent by the first controller, and forwards the data based on the satellite or ground terminal corresponding to the physical topology structure, including:

[0042] receiving data forwarding control information sent by the first controller;

[0043] Generate or rewrite a data forwarding flow table according to the received data forwarding control information;

[0044] Parse data forwarding control information and convert it into data forwarding instructions;

[0045] Data forwarding is performed based on the satellite or ground terminal corresponding to the physical topology structure according to the data forwarding flow table and the data forwarding instruction.

[0046] According to yet another aspect of the present invention, a controller is provided, comprising a memory and a processor, wherein the memory stores a computer program, and the program can implement the steps of the method when executed by the processor.

[0047] According to yet another aspect of the present invention, there is provided a computer-readable storage medium for storing a computer program, wherein the program implements the steps of the method when executed by a computer or a processor.

[0048] Compared with the prior art, the present invention has obvious advantages and beneficial effects. By means of the above technical solution, the low-orbit satellite network structure, networking method, controller and medium of the present invention can achieve considerable technical advancement and practicality, and have wide industrial utilization value, and have at least the following advantages:

[0049] The present invention does not require global ground station deployment or leasing of ground networks. A low-orbit satellite network can be established by establishing links between low-orbit satellites and communicating with the same ground station, thereby simplifying the low-orbit satellite network structure, greatly reducing system deployment costs, and improving network flexibility. In addition, the control plane and data plane of the present invention are separated, achieving controllable in-band control of the control plane and enhancing the fault tolerance and coordination capabilities of the low-orbit satellite network.

[0050] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following specifically cites the preferred embodiments and describes them in detail with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a schematic diagram of the traditional low-orbit satellite network structure;

[0052] Figure 2 A schematic diagram of a low-orbit satellite network structure provided by an embodiment of the present invention;

[0053] Figure 3 A schematic diagram of a low-orbit satellite network structure service process provided by an embodiment of the present invention;

[0054] Figure 4 (a) is a physical topology diagram of a low-orbit satellite network provided in an embodiment of the present invention;

[0055] Figure 4 (b) a logical topology diagram of a low-orbit satellite network provided by an embodiment of the present invention;

[0056] Figure 4 (c) is a schematic diagram of a data flow path of a low-orbit satellite network provided in one embodiment of the present invention;

[0057] Figure 5 A schematic diagram of the structure of a low-orbit satellite network and a ground gateway 4 provided in one embodiment of the present invention.

[0058]

Explanation of symbols

[0059] 1: First controller 2: Low-orbit satellite

[0060] 3: Mobile terminal 4: Ground gateway

[0061] 21: Network switching module 22: Space communication module

[0062] 211: Control plane management interface 212: Data plane management interface

[0063] 213: Management process unit 214: Control agent unit

[0064] 215: Fault recovery unit 216: System management interface

[0065] 217: Core network management interface 218: User management unit

[0066] 221: Antenna 222: Conversion unit

[0067] 223: Baseband 224: Network card device DETAILED DESCRIPTION

[0068] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following is a detailed description of the specific implementation methods and effects of a low-orbit satellite network structure, networking method, controller and medium proposed in accordance with the present invention, in combination with the accompanying drawings and preferred embodiments.

[0069] The embodiment of the present invention provides a low-orbit satellite network structure, such as Figure 2 As shown, it includes a first controller 1 installed on the ground and a plurality of low-orbit satellites 2 distributed in the earth's low-orbit meridian orbit, wherein the low-orbit satellites 2 are connected by physical links, the first controller 1 communicates with the overhead satellites among the plurality of low-orbit satellites 2, and the interconnected low-orbit satellites 2 can communicate with each other. The physical link can be a laser link and a radio link.

[0070] The satellites in the low-orbit satellite network structure of the embodiment of the present invention can form intersatellite links with neighboring satellites, and any two satellites on the entire network can communicate by relying on one or more intersatellite links. On this basis, a globally logically unique first controller 1 is set up on the ground. The first controller 1 is located at the ground station. The controller is connected to the satellite that passes over the top at a certain moment, and is connected to each satellite in the entire network through the intersatellite link, and exchanges control information. Before the first controller 1 is out of the coverage range of the current satellite, the first controller 1 will complete the connection with the next satellite that passes over the top, that is, complete the switch, and use the new satellite that passes over the top to realize the control information exchange, so as to realize the full-time and full-network management and control. As an example, the low-orbit satellite network structure also includes one or more second controllers installed on the ground, which are used to replace the first controller 1 to communicate with the low-orbit satellite 2 that passes over the top when the first controller 1 fails, so as to improve the stability and reliability of the low-orbit satellite network structure.

[0071] The low-orbit satellite network structure described in the embodiment of the present invention has a logically unique network controller in the entire network, namely, the first controller 1. It does not require global ground station deployment or leasing of a ground network. A low-orbit satellite network can be formed by establishing links between low-orbit satellites 2 and communicating with the same ground station. This simplifies the low-orbit satellite network structure, greatly reduces system deployment costs, and improves network flexibility.

[0072] Figure 3 The figure shows the service mode of the low-orbit satellite network structure of the embodiment of the present invention. Similar to the mobile network, the mobile terminal 3 (which can be deployed on a vehicle, a mobile device, etc.) can communicate with the overhead satellite via radio. After the information is connected to the overhead satellite, it can reach the ground gateway 4 through one or more hops of inter-satellite links. The ground gateway 4 forwards the information to the Internet or aggregates the information and forwards it to the user terminal via the satellite network. It can be seen that the low-orbit satellite network structure of the embodiment of the present invention is compatible with the existing network system.

[0073] like Figure 4 (a)- Figure 4 (c) shows the networking mode of the low-orbit satellite network of an embodiment of the present invention, Figure 4(a) is the physical topology of the low-orbit satellite network. The physical topology is a lattice-like network, connected end to end, with multiple rings. The characteristic of this physical topology is that the routes between the same pair of nodes are extremely rich, and the transmission of business flows in the network can choose different paths because of the flexible adjustment capability. The network control and network forwarding on the satellite of the low-orbit satellite network structure of the embodiment of the present invention are separated, that is, the satellite node only receives the forwarding instruction and completes the forwarding according to the instruction, and the generation of the forwarding instruction (forwarding strategy) is completed by the first controller 1. The advantage of doing so is that in addition to the first controller 1 being able to collect information from the entire network to form a better decision, it can also avoid frequent broadcasts caused by the traditional "self-learning" process as much as possible. This also enables all satellites to operate in a layer 2 switching state, without the need to set network segments and routing domains, thereby further improving the forwarding speed and reducing the control complexity.

[0074] There is also a technology of separating control and forwarding in the existing ground commercial network, which is characterized by the fact that control information needs to be exchanged through an independent control network. However, in space networks such as low-orbit satellite networks, due to resource constraints, it is difficult to physically set up a separate management network or add management channels. This is because it is necessary to add new transceivers, which may cause serious interference in space on the one hand, and increase system load and management costs on the other hand. Therefore, the existing inter-satellite links can be used to multiplex control information and data information together, and a logical channel is reserved for control information to form a plane for the flow of control information. This implementation method is also called in-band control. In traditional in-band control, the information flow of the control plane is uncontrolled, and the forwarding of control information depends on traditional self-learning, which requires full network broadcasting. Since there are a large number of loops in the physical topology of low-orbit satellite networks, self-learning through full network broadcasting will inevitably form a network storm, and further cause port blocking, affecting data communication, which is intolerable. Therefore, it is necessary to redesign the in-band control. The core principle of this design is to make the control plane (i.e., the entire control channel) controlled by the first controller 1, and the control result of the first controller 1 on the control plane does not affect the data forwarding function at all. Figure 4 Based on the physical topology of the low-orbit satellite network shown in (a), the control channel forms a tree-shaped control plane by designing a forwarding flow table for control information for each node, such as Figure 4 As shown in (b), the control plane topology remains basically unchanged during normal operation, but when the network scale changes or a network failure occurs, the control plane will be adjusted. Figure 4 (c) A unified controller is used to control the routing between any two points, which can complete the optimal path configuration without forming loops or network storms.

[0075] In order to achieve the above-mentioned separation of the control plane and the data plane, control the control plane to control the in-band, and on this basis realize a low-orbit satellite network with high flexibility, strong fault tolerance and strong coordination ability, the satellite must be equipped with corresponding module support. Figure 5 The detailed structure of the satellite node and the ground gateway in the low-orbit satellite network is described. The following is a detailed description of the various parts of the satellite node:

[0076] As an example, each of the low-orbit satellites 2 is equipped with a network switching module 21 and a space communication module 22. It should be noted that in order to illustrate the multiple satellites included in the low-orbit satellite network structure, Figure 5 Multiple space communication modules 22 are shown in the figure, and each space communication module 22 corresponds to a satellite. However, since there are many components in the network switching module 21, all components in each network switching module 21 are not shown one by one. However, it can be understood that each low-orbit satellite structure includes a network switching module 21 and a space communication module 22. The network switching module 21 is used to receive the control information of the control plane sent by the first controller 1 and convert it into corresponding control instructions and send it to the space communication module 22, and receive the data forwarding control information sent by the first controller 1 and convert it into corresponding data forwarding instructions and send it to the space communication module 22; the space communication module 22 is used to forward the control information of the control plane to the corresponding satellite according to the received control instructions, and forward data to the corresponding satellite or ground terminal according to the received data forwarding instructions.

[0077] The network switching module 21 includes a control plane management interface 211, a data plane management interface 212, a management process unit 213 and a control agent unit 214, wherein the control plane management interface 211 is respectively connected to the first controller 1 and the management process unit 213, and is used to receive the control information of the control plane sent by the first controller 1 and send it to the management process unit 213; the data plane management interface 212 is respectively connected to the first controller 1 and the management process unit 213, and is used to receive the data forwarding control information sent by the first controller 1 and send it to the management process unit 213; the management process unit 213 has a globally unique and fixed IP address, and is used to generate or rewrite the control information flow table according to the received control information of the control plane, generate or rewrite the data forwarding flow table according to the received data forwarding control information, and send the control information of the control plane to the data forwarding control unit 213. The control information and data forwarding control information are forwarded to the control agent unit 214, etc.; the control agent unit 214 is respectively connected to the management process unit 213 and the soft switching path unit, and is used to parse the control information of the control plane, convert it into a control instruction, and forward the control information of the control plane to the corresponding satellite according to the control information flow table and the control instruction, and parse the data forwarding control information, convert it into a data forwarding instruction, and send it to the hardware unit corresponding to the space communication module 22 through the software switching path according to the data forwarding flow table, wherein the control instruction and the data forwarding instruction are hardware instructions, which can coordinately control the hardware devices in the space communication module 22; the soft switching path unit is respectively connected to the network card device 224 and the control agent unit 214, and is used to parse the data message received from the network card device 224 and match the data forwarding flow table. Among them, the flow table refers to the forwarding table of a business flow, which usually includes the field for identifying the flow and the corresponding action to which port, etc.

[0078] As an example, the network switching module 21 also includes a fault recovery unit 215, which is used to rewrite the control information flow table and make recovery decisions when a network failure occurs, and is not controlled by the first controller 1. The network switching module 21 may also include a system management interface 216, a core network management interface 217 and a user management unit 218, wherein the system management interface 216 is used to monitor and manage the health status of the operating system; the core network management interface 217 is used to exchange user management information with the core network module; the user management unit 218 is used to authenticate and bill users during network operation, and send quality of service (QOS) control information to the management process unit 213; the management process unit 213 is also used to generate or rewrite QOS policies based on the QOS control information.

[0079] As an example, the space communication module 22 includes an antenna 221, a conversion unit 222, a baseband 223 and a network card device 224 connected in sequence, wherein the network card device 224 is used to convert the data format of the data to be forwarded and support the required access function, and the access function includes time division multiple access (TDMA) technology; the baseband 223 is used to encode and modulate the data to be sent in the digital domain and send it to the digital / analog conversion subunit, and is also used to demodulate and decode the digital signal received from the analog / digital conversion subunit and send it to the network card device 224; the conversion unit 222 includes a digital / analog conversion subunit and an analog / digital conversion subunit, the digital / analog conversion subunit is used to convert the digital signal into an analog signal, and the analog / digital conversion subunit is used to convert the analog signal into a digital signal; the antenna 221 is used to receive and send modulated radio waves.

[0080] The ground gateway node 4 has an air-to-air antenna 221 for interacting with overhead satellites. The main difference from the satellite node is that, in order to be compatible with the ground network, the switching equipment in the ground gateway node 4 can directly use commercial switches, reflecting the compatibility of the low-orbit satellite network structure described in the embodiment of the present invention with the existing network.

[0081] based on Figure 5 The satellite node structure shown in the figure takes video service as an example to illustrate an embodiment of the network operation process step by step:

[0082] (1) A user requests a video service. The video server sends the content to the corresponding gateway. The gateway completes user authentication and performs rate limiting based on the user's payment standard.

[0083] (2) The gateway sends the video stream forwarding intention to the first controller 1. The first controller 1 designs the video transmission path and QoS strategy, and sends control information to the relevant satellite (forwarded through the control plane). After the configuration is successful, the gateway sends it to the overhead satellite through the air antenna;

[0084] (3) In the overhead satellite, the radio waves carrying the video stream are received by the antenna 221 and then pass through the analog / digital conversion unit 222, the baseband 223 and the network card device 224 to reach the soft switch path;

[0085] (3) In the operating system, before the video stream arrives, the data forwarding control information has been received by the data forwarding management interface, and the data forwarding flow table has been added or rewritten; and through the control agent unit 214, the antenna angle, analog / digital and digital / analog conversion rate, baseband encoding and decoding method and modulation format, and the QoS policy of the network card are coordinated and controlled to ensure high reliability of data transmission and reception; thus, after the video stream arrives, it can be forwarded to the specified network card device 224 according to the data forwarding flow table;

[0086] (4) The network card device 224 queues and forwards the video stream according to the priority level according to the QoS policy, sends the video stream to the baseband 223 and the digital / analog conversion unit 222, and then sends it to the nearby satellite or ground terminal via the antenna 221.

[0087] An embodiment of the present invention further provides a low-orbit satellite network networking method, comprising:

[0088] Step S1: connecting the low-orbit satellites with physical links to establish a physical topology structure of the low-orbit satellite network, wherein all the low-orbit satellites in the physical topology structure can communicate with the same first controller located on the ground;

[0089] Step S2: establishing a logical topology structure of a control channel based on the physical topology structure, wherein the logical topology structure can traverse all low-orbit satellites without any logical loop;

[0090] Step S3: The overhead satellite receives the control information of the control plane sent by the first controller, and forwards the control information of the control plane to the corresponding satellite based on the logical topology structure;

[0091] Step S4: The overhead satellite receives the data forwarding control information sent by the first controller, and forwards the data based on the satellite or ground terminal corresponding to the physical topology structure.

[0092] As an example, step S3 includes:

[0093] Step S31, receiving control information of the control plane sent by the first controller;

[0094] Step S32: Generate or rewrite a control information flow table according to the received control information of the control plane;

[0095] Step S33, parsing the control information of the control plane and converting it into control instructions;

[0096] Step S34: forward the control information of the control plane to the corresponding satellite in the logical topology structure according to the control information flow table and the control instruction.

[0097] As an example, step S4 includes:

[0098] Step S41, receiving data forwarding control information sent by the first controller;

[0099] Step S42: Generate or rewrite a data forwarding flow table according to the received data forwarding control information;

[0100] Step S43, parsing the data forwarding control information and converting it into a data forwarding instruction;

[0101] Step S44: forwarding data based on the satellite or ground terminal corresponding to the physical topology structure according to the data forwarding flow table and the data forwarding instruction.

[0102] An embodiment of the present invention also provides a controller, which includes a memory and a processor, wherein the memory stores a computer program, and when the program is executed by the processor, it can implement the steps of the low-orbit satellite network networking method.

[0103] An embodiment of the present invention also provides a computer-readable storage medium for storing a computer program, which, when executed by a computer or a processor, implements the steps of the low-orbit satellite network networking method.

[0104] The low-orbit satellite network structure and networking method described in the embodiments of the present invention do not require global ground station deployment or leasing of ground networks. A low-orbit satellite network can be established by establishing links between low-orbit satellites and communicating with the same ground station, thereby simplifying the low-orbit satellite network structure, greatly reducing system deployment costs, and improving network flexibility. In addition, the control plane and data plane are separated in the low-orbit satellite network structure and networking method of the present invention, thereby achieving controllable in-band control of the control plane and enhancing the fault tolerance and coordination capabilities of the low-orbit satellite network.

[0105] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A low-orbit satellite network structure, characterized in that: The invention comprises a first controller installed on the ground and a plurality of low-orbit satellites distributed in the low-orbit meridian orbit of the earth, wherein: The low-orbit satellites are connected by physical links to establish a physical topology of the low-orbit satellite network, and a logical topology of the control channel is established based on the physical topology, wherein the logical topology can traverse all low-orbit satellites without any logical loops; the first controller communicates with the overhead satellites among the plurality of low-orbit satellites, and the interconnected low-orbit satellites can communicate with each other; The first controller is connected to the overhead satellite, and is connected to all satellites in the entire network through an intersatellite link to exchange control information. Before the first controller is out of the coverage of the current satellite, the first controller completes the connection with the next overhead satellite, completes the switching, and uses the new overhead satellite to realize control information exchange; Each of the low-orbit satellites is equipped with a network switching module and a space communication module, wherein: The network switching module is used to receive control information of the control plane sent by the first controller and convert it into corresponding control instructions and send it to the space communication module, and receive data forwarding control information sent by the first controller and convert it into corresponding data forwarding instructions and send it to the space communication module; The space communication module is used to forward control information of the control plane to the corresponding satellite according to the received control instruction, and to forward data to the corresponding satellite or ground terminal according to the received data forwarding instruction.

2. The low-orbit satellite network structure according to claim 1, characterized in that: The physical link includes a laser link and a radio link.

3. The low-orbit satellite network structure according to claim 1, characterized in that: The physical topology of the low-orbit satellite network structure is a lattice topology, which is connected end to end and includes multiple rings.

4. The low-orbit satellite network structure according to claim 1, characterized in that: It also includes one or more second controllers installed on the ground, which are used to replace the first controller to communicate with the low-orbit satellite passing overhead when the first controller fails.

5. The low-orbit satellite network structure according to claim 1, characterized in that: The network switching module includes a control plane management interface, a data plane management interface, a management process unit and a control agent unit, wherein: The control plane management interface is connected to the first controller and the management process unit respectively, and is used to receive control information of the control plane sent by the first controller and send it to the management process unit; The data plane management interface is connected to the first controller and the management process unit respectively, and is used to receive data forwarding control information sent by the first controller and send it to the management process unit; The management process unit is used to generate or rewrite the control information flow table according to the received control information of the control plane, generate or rewrite the data forwarding flow table according to the received data forwarding control information, and forward the control information of the control plane and the data forwarding control information to the control agent unit; The control agent unit is connected to the management process unit and the soft switch path unit respectively, and is used to parse the control information of the control plane, convert it into a control instruction, and forward the control information of the control plane to the corresponding satellite according to the control information flow table and the control instruction, and parse the data forwarding control information, convert it into a data forwarding instruction, and send it to the hardware unit corresponding to the space communication module through the soft switch path unit according to the data forwarding flow table; The soft switch path unit is connected to the network card device and the control agent unit respectively, and is used to parse the data message received from the network card device and match the data forwarding flow table.

6. The low-orbit satellite network structure according to claim 5, characterized in that: The space communication module includes an antenna, a conversion unit, a baseband and the network card device connected in sequence, wherein: The network card device is used to convert the data format of the data to be forwarded and support the required access function, and the access function includes a TDMA function; The baseband is used to perform coding modulation in the digital domain on the data to be sent and send it to the digital / analog conversion subunit, and is also used to demodulate and decode the digital signal received from the analog / digital conversion subunit and send it to the network card device; The conversion unit includes a digital / analog conversion subunit and an analog / digital conversion subunit, wherein the digital / analog conversion subunit is used to convert a digital signal into an analog signal, and the analog / digital conversion subunit is used to convert an analog signal into a digital signal; The antenna is used to receive and transmit modulated radio waves.

7. The low-orbit satellite network structure according to claim 5, characterized in that: The network switching module also includes: The fault recovery unit is used to rewrite the control information flow table and make a recovery decision when a network fault occurs.

8. The low-orbit satellite network structure according to claim 5, characterized in that: The network switching module also includes: System management interface, used to monitor, manage and restore the health status of the operating system; Core network management interface, used to exchange user management information with the core network module; A user management unit, used for authenticating and charging users during network operation, and sending QOS control information to the management process unit; The management process unit is further used to generate or rewrite a QOS policy according to the QOS control information.

9. A low-orbit satellite network networking method, characterized in that: Applied to the low-orbit satellite network structure according to any one of claims 1 to 8, the method comprises: Connecting the low-orbit satellites with physical links to establish a physical topology structure of the low-orbit satellite network, wherein all the low-orbit satellites in the physical topology structure can communicate with the same first controller located on the ground; Establishing a logical topology structure of a control channel based on the physical topology structure, wherein the logical topology structure can traverse all low-orbit satellites without any logical loop; The overhead satellite receives the control information of the control plane sent by the first controller, and forwards the control information of the control plane to the corresponding satellite based on the logical topology structure; The overhead satellite receives the data forwarding control information sent by the first controller, and forwards the data based on the satellite or ground terminal corresponding to the physical topology structure.

10. The low-orbit satellite network networking method according to claim 9, characterized in that: The overhead satellite receives the control information of the control plane sent by the first controller, and forwards the control information of the control plane to the corresponding satellite based on the logical topology structure, including: Receiving control information of the control plane sent by the first controller; Generate or rewrite a control information flow table according to the control information received from the control plane; Parsing the control information of the control plane and converting it into control instructions; The control information of the control plane is forwarded to the corresponding satellite in the logical topology structure according to the control information flow table and the control instruction.

11. The low-orbit satellite network networking method according to claim 9, characterized in that: The overhead satellite receives the data forwarding control information sent by the first controller, and forwards the data based on the satellite or ground terminal corresponding to the physical topology structure, including: receiving data forwarding control information sent by the first controller; Generate or rewrite a data forwarding flow table according to the received data forwarding control information; Parse data forwarding control information and convert it into data forwarding instructions; Data forwarding is performed based on the satellite or ground terminal corresponding to the physical topology structure according to the data forwarding flow table and the data forwarding instruction.

12. A controller comprising a memory and a processor, characterized in that , the memory stores a computer program, which, when executed by the processor, can implement the steps of the method described in any one of claims 9 to 11.

13. A computer-readable storage medium for storing a computer program, characterized in that When the program is executed by a computer or a processor, the program implements the steps of the method according to any one of claims 9 to 11.

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