A low-orbit satellite signaling interaction method based on a heterogeneous communication network

Abstract

The present application relates to low-orbit satellite signaling interaction technical field, specifically to a kind of low-orbit satellite signaling interaction method based on heterogeneous communication network, comprising the following steps: S1, low-orbit satellite A is initiated by multiple heterogeneous communication networks and as the responding party low-orbit satellite B cooperates to complete connection establishment process, and agrees on signaling interaction available time window set;S2, select available one or more communication networks in signaling interaction available time window set to send signaling service package, during connection persistence, both sides realize signaling interaction by the sending and receiving of signaling service package;S3, after the end of all time periods included in signaling interaction available time window set, connection is automatically invalid, this signaling interaction ends;If signaling interaction time needs to be extended, any party reinitiates next connection establishment before this connection invalidation.The present application significantly improves the success rate of signaling interaction connection establishment, meets the requirements of high-reliability transmission for signaling interaction task, and effectively reduces transmission delay.

Description

Technical Field

[0001] This invention relates to the field of low-Earth orbit satellite signaling interaction technology, specifically a low-Earth orbit satellite signaling interaction method based on heterogeneous communication networks. Background Technology

[0002] With the rapid increase in the scale and types of low-Earth orbit constellations, and the continuous improvement in the requirements for the integrated application of heterogeneous giant constellations and autonomous survivability, different types of low-Earth orbit satellites need to have real-time, reliable, and efficient low-speed communication interconnection capabilities across the entire airspace, so as to realize the automatic interaction of control and signaling information (hereinafter referred to as signaling) on ​​demand, and support functions such as on-board autonomous mission coordination and autonomous collision avoidance.

[0003] In the field of aerospace telemetry and control, some research has proposed using communication networks with wide coverage and multi-user access capabilities, such as the BeiDou global short message system, to achieve telemetry and remote control signaling interaction between fixed ground satellite telemetry and control centers and mobile low-Earth orbit satellites across the entire airspace by installing short message communication terminals on low-Earth orbit satellites and ground telemetry and control centers, with both connected to the BeiDou satellite short message system. However, this method of achieving two-way signaling interaction by installing single-mode communication terminals and then connecting to a wide-area communication network has the following problems for achieving two-way signaling interaction between low-Earth orbit satellites in the complex heterogeneous constellation: First, the coverage of a single communication network is insufficient: existing and planned communication networks mainly achieve global surface or hotspot coverage. Due to the elevation of low-Earth orbit satellites, the coverage of a single communication network in the orbital space of low-Earth orbit satellites may have gaps; and second, due to the influence of the low-Earth orbit satellite communication terminal's location... First, limitations in installation location and coverage area, along with the impact of attitude maneuvering on low-Earth orbit (LEO) satellite platforms, make it difficult for LEO satellites to achieve 100% visibility to a single communication network, further worsening coverage. Second, the service capacity of a single communication network is insufficient: the access frequency and transmission rate provided by a single communication network are limited, making it difficult to meet the high-frequency and diverse signaling interaction needs between a large number of satellites. Third, unlike ground satellite control centers which manage LEO satellites, LEO satellites are on equal footing. When one party initiates communication, it cannot know the other party's position, attitude, health status, etc., and therefore cannot know whether the other party can access the communication network for communication, which can easily lead to communication failure. Fourth, signaling service transmission reliability requirements are high. Even if the communication timing between the sender and receiver has been agreed upon, the insufficient reliability of some communication networks, such as the packet loss rate of satellite communication networks reaching 5%, still cannot meet the needs of signaling service interaction. Summary of the Invention

[0004] The purpose of this invention is to provide a low-Earth orbit satellite signaling interaction method based on heterogeneous communication networks to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A low-Earth orbit satellite signaling interaction method based on heterogeneous communication networks includes the following steps: S1. Low-Earth orbit satellite A, as the initiator, collaborates with low-Earth orbit satellite B, as the responder, through multiple heterogeneous communication networks to complete the connection establishment process and agree on a set of available time windows for signaling interaction. S2. Select one or more available communication networks within the set of available signaling interaction time windows to send signaling service packets. During the connection period, both parties realize signaling interaction through the sending and receiving of signaling service packets. S3. Once all time periods included in the available time window for signaling interaction have ended, the connection will automatically expire, and the current signaling interaction will end. If it is necessary to extend the signaling interaction time, either party may re-initiate the next connection establishment before the current connection expires.

[0006] Preferably, the plurality of heterogeneous communication networks in step S1 includes: Multiple space-based or ground-based communication network infrastructures of different types, with wide-area coverage, multi-user, and ubiquitous access capabilities, work together to achieve full-area and multi-layer coverage of low-orbit satellites through multiple heterogeneous communication networks, without interconnection between the multiple heterogeneous communication networks.

[0007] Preferably, step S3 includes: Low Earth Orbit (LEO) satellite A and LEO satellite B are the main entities for signaling interaction, including: In-satellite modules are used to generate and use signaling; The transmission adaptation module is used to determine the network status of both parties in the signaling interaction, establish a connection, select the access mode for heterogeneous communication networks, and convert multiple communication network protocol formats. Multimode communication terminals are used to select access nodes and perform frequency compensation, transmit and receive radio frequency signals, encode and decode, and modulate and demodulate signals in heterogeneous communication networks, and have the ability to work in parallel under different communication modes.

[0008] Preferably, step S1 includes: S11. The initiator selects at least one communication network from its available communication networks according to the sending strategy and sends at least one connection establishment request to the responder. The connection establishment request includes at least the identifiers of both signaling interaction parties.<A,B> The table includes the planned signaling interaction period (T0, T1), the latest start time of signaling interaction T0', and the network status table of low-Earth orbit satellite A during the planned signaling interaction period (T0, T1). Here, T0 represents the initiation time, T1 represents the end time of the signaling interaction, T0 < T0' ≤ T1, and the communication network available to the initiator refers to the communication network available to the initiator at the initiation time, which the initiator obtains by querying the network status of low-Earth orbit satellite A. S12. Upon receiving the connection establishment request, the responder obtains the network status of low-Earth orbit satellite A, calculates the set of available time windows for signaling interaction, and confirms the signaling interaction plan. S13. The responder selects at least one communication network from its available communication networks according to the sending strategy and sends at least one connection establishment response to the initiator. The connection establishment response shall at least include the identifiers of both signaling interaction parties.<A,B> The set of available time windows for signaling interaction; wherein, the communication network available to the responder itself is obtained by querying the set of available time windows for signaling interaction. S14. If the initiator receives a connection establishment response from the responder before the latest start time T0' of the signaling interaction, the initiator determines that the connection establishment is successful; if the initiator does not receive a connection establishment response from the responder before the latest start time T0' of the signaling interaction, the initiator determines that the connection establishment has failed and the initiator's process ends. S15. When the responder receives the signaling service packet from the initiator for the first time, the responder determines that the connection has been successfully established.

[0009] Preferably, step S12 specifically includes: S121. If the responder does not receive the connection establishment request from the initiator, the low-Earth orbit satellite B procedure will not be triggered. S122. If the responder receives the connection establishment request from the initiator, it determines whether the receiving time T0'' is later than the latest start time T0' of the signaling interaction. If so, the responder determines that the connection establishment has failed and the responder's process ends. S123. If the responder receives the connection establishment request from the initiator, and the receiving time T0'' is not later than the latest start time T0' of the signaling interaction, the responder calculates the time window set V; If the time window set V is empty or the earliest start time of the time window set V is later than the latest start time T0' of the signaling interaction, the responder determines that the connection establishment has failed and the responder's process ends; otherwise, the time window set V is the set of available time windows for signaling interaction.

[0010] Preferably, the calculated time window set V specifically includes: Based on the network status of LEO satellite A and LEO satellite B during the remaining time period (T0'', T1) of the signaling interaction plan, and based on the transmission constraint models of each communication network, plus the constraints imposed by LEO satellite B itself on this signaling interaction, the types and time periods of communication networks that can be used for data transmission between LEO satellite A and LEO satellite B during the remaining time period (T0'', T1) of the signaling interaction plan are calculated. This yields the time window set V={Ts,Te,Net}, where Ts is the start time of the time window, Te is the end time of the time window, and Net is the set of communication network numbers that are continuously available within the time window.

[0011] Preferably, the sending strategy includes: Starting from time T, every Δt, the initiator or responder randomly selects n available communication networks from its own available communication networks, and sends a connection establishment request or connection establishment response to the other party using the n available communication networks respectively, where n=min(n0,m), m is the number of available communication network types, and n0≥1 and is a preset integer; n0=1 represents sending using any available communication network, n0≥N represents sending using all available communication networks, and N is the total number of heterogeneous communication network types.

[0012] Preferably, the sending strategy further includes: For the initiator, if time T is the initiation time T0, the process ends when any of the following conditions are met: The latest start time of signaling interaction is T0'; Upon receiving a connection establishment response from the responder; For the responder, if time T is the earliest start time of the available time window in the set of signaling interaction time windows, the process ends when any of the following conditions are met: The latest start time of signaling interaction is T0'; Received signaling service packet from the initiator; The cumulative number of connection establishment responses sent exceeds the predetermined number.

[0013] Preferably, step S2 specifically includes: S21. In a single connection, the satellite modules of both signaling interaction parties assign a unique label to the same signaling service packet sent by their respective parties. The transmission adaptation module of the sending party processes the signaling service packet into data frames of the protocol format of each communication network, wherein the destination address is filled in as the destination address of the receiving party in the corresponding communication network, and then sends them to the corresponding communication network through the multi-mode communication terminal. S22. Each communication network completes data reception and routing forwarding until the data frame is sent to the destination node at a certain exit. S23. The receiving multi-mode communication terminal receives data frames from each communication network, splits the frames to obtain signaling service packets, and deduplicates the signaling service packets based on tags.

[0014] Compared with the prior art, the beneficial effects of the present invention are: (1) Based on the autonomous calculation of network status and the connection establishment mechanism of two-end interaction, this invention can realize the autonomous detection of network status and connection establishment between any two low-orbit satellites in the complex heterogeneous giant constellation. Without ground assistance or changes in the communication network technology status, it can significantly improve the success rate of signaling interaction task initiation and the reliability of transmission process. (2) This invention realizes signaling interaction between low-orbit satellites based on heterogeneous communication networks, which can effectively solve the problems of insufficient orbital coverage, insufficient coverage multiple, and insufficient service capacity of single communication networks for low-orbit satellites. It utilizes the existing and continuously developing various space-ground communication network resources to effectively support on-demand, reliable, and real-time cross-network signaling interaction between low-orbit satellites of different orbital types in the complex heterogeneous constellation with a lower construction cost. (3) This invention supports the parallel transmission of service data using multiple communication networks, which can significantly improve the transmission success rate, meet the requirements of high reliability transmission for signaling interaction tasks, and effectively reduce transmission latency. Attached Figure Description

[0015] Figure 1 A schematic diagram of the architecture of a low-Earth orbit satellite signaling interaction method based on a heterogeneous communication network provided for an embodiment of the present invention; Figure 2 A flowchart of a low-Earth orbit satellite signaling interaction method based on a heterogeneous communication network provided for an embodiment of the present invention;

[0016] Figure 3 The flowchart illustrates the connection establishment process between the signaling interaction initiator and responder in the low-Earth orbit satellite signaling interaction method based on heterogeneous communication networks provided for embodiments of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Figure 1 This invention provides an overall flowchart of a low-Earth orbit satellite signaling interaction method based on a heterogeneous communication network. Figure 1 As shown, low-Earth orbit satellite A and low-Earth orbit satellite B are the main entities for signaling interaction, including: In-satellite modules are used to generate and use signaling; The transmission adaptation module is used to determine the network status of both parties in the signaling interaction, establish a connection, select the access mode for heterogeneous communication networks, and convert multiple communication network protocol formats. Multimode communication terminals are used to select access nodes and perform frequency compensation, transmit and receive radio frequency signals, encode and decode, and modulate and demodulate signals in heterogeneous communication networks, and have the ability to work in parallel under different communication modes.

[0019] Multiple space-based or ground-based communication network infrastructures of different types possess wide-area coverage, multi-user, and ubiquitous access capabilities, such as the BeiDou global short message system and various high, medium, and low orbit satellite communication systems. Each communication network has the functions of rapid access, mobility management, and data forwarding for massive numbers of communication terminals. Each communication network has a certain coverage area and access capacity, and the full-area, multi-layered coverage of low orbit satellites is achieved through the joint efforts of multiple heterogeneous communication networks. There is no interconnection or interoperability between the multiple heterogeneous communication networks.

[0020] Figure 2 This is a flowchart of a low-Earth orbit satellite signaling interaction method based on heterogeneous communication networks. Figure 2 As shown, an embodiment of the present invention provides a low-Earth orbit satellite signaling interaction method based on a heterogeneous communication network, comprising the following steps: S1. Low-Earth orbit satellite A, as the initiator, collaborates with low-Earth orbit satellite B, as the responder, through multiple heterogeneous communication networks to complete the connection establishment process and agree on a set of available time windows for signaling interaction. S2. Select one or more available communication networks within the set of available signaling interaction time windows to send signaling service packets. During the connection period, both parties realize signaling interaction through the sending and receiving of signaling service packets. S3. Once all time periods included in the available time window for signaling interaction have ended, the connection will automatically expire, and the current signaling interaction will end. If it is necessary to extend the signaling interaction time, either party may re-initiate the next connection establishment before the current connection expires.

[0021] This invention enables signaling interaction between low-Earth orbit (LEO) satellites based on heterogeneous communication networks. It can effectively solve problems such as insufficient orbital coverage, coverage overlap, and service capacity of single communication networks for LEO satellites. By utilizing existing and continuously developing space-ground communication network resources, it can effectively support on-demand, reliable, and real-time cross-network signaling interaction between LEO satellites of different orbital types in the complex heterogeneous constellation at a relatively low construction cost.

[0022] Furthermore, Figure 3 A flowchart illustrating the connection establishment between the signaling interaction initiator and responder in a low-Earth orbit satellite signaling interaction method based on heterogeneous communication networks, provided as an embodiment of the present invention, is shown in one embodiment of the present invention. Figure 3 As shown, step S1 includes: S11. The initiator selects at least one communication network from its available communication networks according to the sending strategy and sends at least one connection establishment request to the responder. The connection establishment request includes at least the identifiers of both signaling interaction parties.<A,B> The table includes the planned signaling interaction period (T0, T1), the latest start time of signaling interaction T0', and the network status table of low-Earth orbit satellite A during the planned signaling interaction period (T0, T1). Here, T0 represents the initiation time, T1 represents the end time of the signaling interaction, T0 < T0' ≤ T1, and the communication network available to the initiator refers to the communication network available to the initiator at the initiation time, which the initiator obtains by querying the network status of low-Earth orbit satellite A. S12. Upon receiving the connection establishment request, the responder obtains the network status of low-Earth orbit satellite A, calculates the set of available time windows for signaling interaction, and confirms the signaling interaction plan. S13. The responder selects at least one communication network from its available communication networks according to the sending strategy and sends at least one connection establishment response to the initiator. The connection establishment response shall at least include the identifiers of both signaling interaction parties.<A,B> The set of available time windows for signaling interaction; wherein, the communication network available to the responder itself is obtained by querying the set of available time windows for signaling interaction. S14. If the initiator receives a connection establishment response from the responder before the latest start time T0' of the signaling interaction, the initiator determines that the connection establishment is successful; if the initiator does not receive a connection establishment response from the responder before the latest start time T0' of the signaling interaction, the initiator determines that the connection establishment has failed and the initiator's process ends. S15. When the responder receives the signaling service packet from the initiator for the first time, the responder determines that the connection has been successfully established.

[0023] The low-Earth orbit satellite signaling interaction method based on heterogeneous communication networks provided by the embodiments of the present invention is based on the autonomous calculation of network status and the connection establishment mechanism of two-end interaction. It can realize the autonomous detection of network status and connection establishment between any two low-Earth orbit satellites in the complex heterogeneous giant constellation. It can significantly improve the success rate of signaling interaction task initiation and the reliability of transmission without ground assistance or changes in communication network technology status.

[0024] In the above process, the low-Earth orbit (LEO) satellite is aware of its own network status in order to realize the sending of the connection establishment request by the initiator and the calculation of the time window set of the responder during the connection establishment process. Here, network status refers to the types and time periods of heterogeneous communication networks that the LEO satellite can use. Each LEO satellite in the complex heterogeneous constellation periodically and autonomously calculates the types and time periods of communication networks that it can use, based on its own GNSS, attitude, antenna coverage, and the coverage and access constraint models of the various heterogeneous communication networks, forming and maintaining its own network status table. An example of the key elements of the network status table is shown in Table 1 below: Table 1 Examples of Key Elements in the Network Status Table

[0025] Specifically, in one embodiment of the present invention, step S12 specifically includes: S121. If the responder does not receive the connection establishment request from the initiator, the low-Earth orbit satellite B procedure will not be triggered. S122. If the responder receives the connection establishment request from the initiator, it determines whether the receiving time T0'' is later than the latest start time T0' of the signaling interaction. If so, the responder determines that the connection establishment has failed and the responder's process ends. S123. If the responder receives the connection establishment request from the initiator, and the receiving time T0'' is not later than the latest start time T0' of the signaling interaction, the responder calculates the time window set V; If the time window set V is empty or the earliest start time of the time window set V is later than the latest start time T0' of the signaling interaction, the responder determines that the connection establishment has failed and the responder's process ends; otherwise, the time window set V is the set of available time windows for signaling interaction.

[0026] In one embodiment of the present invention, calculating the time window set V specifically includes: Based on the network status of LEO satellite A and LEO satellite B during the remaining time period (T0'', T1) of the signaling interaction plan, and based on the transmission constraint models of each communication network, plus the constraints imposed by LEO satellite B itself on this signaling interaction, the types and time periods of communication networks that can be used for data transmission between LEO satellite A and LEO satellite B during the remaining time period (T0'', T1) of the signaling interaction plan are calculated. This yields the time window set V={Ts,Te,Net}, where Ts is the start time of the time window, Te is the end time of the time window, and Net is the set of communication network numbers that are continuously available within the time window.

[0027] In one embodiment of the present invention, the sending strategy includes: Starting from time T, every Δt, the initiator or responder randomly selects n available communication networks from its own available communication networks, and sends a connection establishment request or connection establishment response to the other party using the n available communication networks respectively, where n=min(n0,m), m is the number of available communication network types, and n0≥1 and is a preset integer; When n0=1, the value of n is 1, which means that any one of the communication networks can be used to send the message. When n0≥N, it means that all available communication networks are used for transmission. N is the total number of heterogeneous communication network types. The total number of heterogeneous communication network types N is a known and fixed number. The number of available communication network types m is a randomly changing number. Since 1≤m≤N, when n0≥N, we know that n0≥m. At this time, the value of n is m.

[0028] Furthermore, in one embodiment of the present invention, the transmission strategy further includes: For the initiator, if time T is the initiation time T0, the process ends when any of the following conditions are met: The latest start time of signaling interaction is T0'; Upon receiving a connection establishment response from the responder; For the responder, if time T is the earliest start time of the available time window in the set of signaling interaction time windows, the process ends when any of the following conditions are met: The latest start time of signaling interaction is T0'; Received signaling service packet from the initiator; The cumulative number of connection establishment responses sent exceeds the predetermined number.

[0029] In one embodiment of the present invention, step S2 specifically includes: S21. In a single connection, the satellite modules of both signaling interaction parties assign a unique label to the same signaling service packet sent by their respective parties. The transmission adaptation module of the sending party processes the signaling service packet into data frames of the protocol format of each communication network, wherein the destination address is filled in as the destination address of the receiving party in the corresponding communication network, and then sends them to the corresponding communication network through the multi-mode communication terminal. S22. Each communication network completes data reception and routing forwarding until the data frame is sent to the destination node at a certain exit. S23. The receiving multi-mode communication terminal receives data frames from each communication network, splits the frames to obtain signaling service packets, and deduplicates the signaling service packets based on tags.

[0030] This invention supports a wide range of transmission strategies. When using multiple communication networks for transmission, it can significantly improve transmission reliability. For example, if a signaling service packet is transmitted as a single packet in each heterogeneous communication network and the packet loss rate of each communication network is high (e.g., 5%), then the transmission success rate using a single communication network is 95%, the transmission success rate using two communication networks is 99.75%, and the transmission success rate using four communication networks is better than 99.999%.

[0031] The low-Earth orbit satellite signaling interaction method based on heterogeneous communication networks provided by the embodiments of the present invention supports the parallel transmission of service data using multiple communication networks, which can significantly improve the transmission success rate, meet the high reliability transmission requirements of signaling interaction tasks, and effectively reduce transmission latency.

[0032] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A low-Earth orbit satellite signaling interaction method based on heterogeneous communication networks, characterized in that, Includes the following steps: S1. Low-Earth orbit satellite A, as the initiator, collaborates with low-Earth orbit satellite B, as the responder, through multiple heterogeneous communication networks to complete the connection establishment process and agree on a set of available time windows for signaling interaction. S2. Select one or more available communication networks within the set of available signaling interaction time windows to send signaling service packets. During the connection period, both parties realize signaling interaction through the sending and receiving of signaling service packets. S3. Once all time periods included in the available time window for signaling interaction have ended, the connection will automatically expire, and the current signaling interaction will end. If it is necessary to extend the signaling interaction time, either party may re-initiate the next connection establishment before the current connection expires.

2. The low-Earth orbit satellite signaling interaction method based on a heterogeneous communication network according to claim 1, characterized in that, The multiple heterogeneous communication networks mentioned in step S1 include: Multiple space-based or ground-based communication network infrastructures of different types, with wide-area coverage, multi-user, and ubiquitous access capabilities, work together to achieve full-area and multi-layer coverage of low-orbit satellites through multiple heterogeneous communication networks, without interconnection between the multiple heterogeneous communication networks.

3. The low-Earth orbit satellite signaling interaction method based on a heterogeneous communication network according to claim 2, characterized in that, Step S3 includes: Low Earth Orbit (LEO) satellite A and LEO satellite B are the main entities for signaling interaction, including: In-satellite modules are used to generate and use signaling; The transmission adaptation module is used to determine the network status of both parties in the signaling interaction, establish a connection, select the access mode for heterogeneous communication networks, and convert multiple communication network protocol formats. Multimode communication terminals are used to select access nodes and perform frequency compensation, transmit and receive radio frequency signals, encode and decode, and modulate and demodulate signals in heterogeneous communication networks, and have the ability to work in parallel under different communication modes.

4. The low-Earth orbit satellite signaling interaction method based on a heterogeneous communication network according to claim 3, characterized in that, Step S1 includes: S11. The initiator selects at least one communication network from its available communication networks according to the sending strategy and sends at least one connection establishment request to the responder. The connection establishment request includes at least the identifiers of both signaling interaction parties.<A,B> The table includes the planned signaling interaction period (T0, T1), the latest start time of signaling interaction T0', and the network status table of low-Earth orbit satellite A during the planned signaling interaction period (T0, T1). Here, T0 represents the initiation time, T1 represents the end time of the signaling interaction, T0 < T0' ≤ T1, and the communication network available to the initiator refers to the communication network available to the initiator at the initiation time, which the initiator obtains by querying the network status of low-Earth orbit satellite A. S12. Upon receiving the connection establishment request, the responder obtains the network status of low-Earth orbit satellite A, calculates the set of available time windows for signaling interaction, and confirms the signaling interaction plan. S13. The responder selects at least one communication network from its available communication networks according to the sending strategy and sends at least one connection establishment response to the initiator. The connection establishment response shall at least include the identifiers of both signaling interaction parties.<A,B> The set of available time windows for signaling interaction; wherein, the communication network available to the responder itself is obtained by querying the set of available time windows for signaling interaction. S14. If the initiator receives a connection establishment response from the responder before the latest start time T0' of the signaling interaction, the initiator determines that the connection establishment is successful; if the initiator does not receive a connection establishment response from the responder before the latest start time T0' of the signaling interaction, the initiator determines that the connection establishment has failed and the initiator's process ends. S15. When the responder receives the signaling service packet from the initiator for the first time, the responder determines that the connection has been successfully established.

5. A low-Earth orbit satellite signaling interaction method based on a heterogeneous communication network according to claim 4, characterized in that, Step S12 specifically includes: S121. If the responder does not receive the connection establishment request from the initiator, the low-Earth orbit satellite B procedure will not be triggered. S122. If the responder receives the connection establishment request from the initiator, it determines whether the receiving time T0'' is later than the latest start time T0' of the signaling interaction. If so, the responder determines that the connection establishment has failed and the responder's process ends. S123. If the responder receives the connection establishment request from the initiator, and the receiving time T0'' is not later than the latest start time T0' of the signaling interaction, the responder calculates the time window set V; If the time window set V is empty or the earliest start time of the time window set V is later than the latest start time T0' of the signaling interaction, the responder determines that the connection establishment has failed and the responder's process ends; otherwise, the time window set V is the set of available time windows for signaling interaction.

6. The low-Earth orbit satellite signaling interaction method based on a heterogeneous communication network according to claim 5, characterized in that, The calculated time window set V specifically includes: Based on the network status of LEO satellite A and LEO satellite B during the remaining time period (T0'', T1) of the signaling interaction plan, and based on the transmission constraint models of each communication network, plus the constraints imposed by LEO satellite B itself on this signaling interaction, the types and time periods of communication networks that can be used for data transmission between LEO satellite A and LEO satellite B during the remaining time period (T0'', T1) of the signaling interaction plan are calculated. This yields the time window set V={Ts,Te,Net}, where Ts is the start time of the time window, Te is the end time of the time window, and Net is the set of communication network numbers that are continuously available within the time window.

7. A low-Earth orbit satellite signaling interaction method based on a heterogeneous communication network according to claim 6, characterized in that, Sending strategies include: Starting from time T, every Δt, the initiator or responder randomly selects n available communication networks from its own available communication networks, and sends a connection establishment request or connection establishment response to the other party using the n available communication networks respectively, where n=min(n0,m), m is the number of available communication network types, and n0≥1 and is a preset integer; n0=1 represents sending using any available communication network, n0≥N represents sending using all available communication networks, and N is the total number of heterogeneous communication network types.

8. A low-Earth orbit satellite signaling interaction method based on a heterogeneous communication network according to claim 7, characterized in that, The sending strategy also includes: For the initiator, if time T is the initiation time T0, the process ends when any of the following conditions are met: The latest start time of signaling interaction is T0'; Upon receiving a connection establishment response from the responder; For the responder, if time T is the earliest start time of the available time window in the set of signaling interaction time windows, the process ends when any of the following conditions are met: The latest start time of signaling interaction is T0'; Received signaling service packet from the initiator; The cumulative number of connection establishment responses sent exceeds the predetermined number.

9. A low-Earth orbit satellite signaling interaction method based on a heterogeneous communication network according to claim 8, characterized in that, Step S2 specifically includes: S21. In a single connection, the satellite modules of both signaling interaction parties assign a unique label to the same signaling service packet sent by their respective parties. The transmission adaptation module of the sending party processes the signaling service packet into data frames of the protocol format of each communication network, wherein the destination address is filled in as the destination address of the receiving party in the corresponding communication network, and then sends them to the corresponding communication network through the multi-mode communication terminal. S22. Each communication network completes data reception and routing forwarding until the data frame is sent to the destination node at a certain exit. S23. The receiving multimode communication terminal receives data frames from each communication network, splits the frames to obtain signaling service packets, and deduplicates the signaling service packets based on tags.

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