Satellite internet high-dynamic distributed routing method based on communication time delay

Abstract

The invention relates to the field of satellite communication, and provides a satellite internet high-dynamic distributed routing method based on communication time delay, which comprises the following steps of: 1, establishing an objective function which minimizes the communication time delay of the satellite internet and is the sum of the total transmission time delay and the total queuing time delay, wherein the total transmission time delay is calculated based on the Euclidean distance between satellites and the light velocity, and the total queuing time delay is calculated based on the average number of data packets and the link bandwidth; 2, constructing a neighbor list of satellites at the current moment, and switching node states, time delays, distances and data packet queuing information by the satellites through broadcast response messages to form a dynamically updated neighbor information matrix; according to the method and the algorithm, the distance between the node selected at the current moment and the target node is considered during node selection, and the communication link is generated by taking the distance as a selection rule, so that the hop count in the data transmission process is reduced, the data transmission direction is ensured, and the stability of the communication link is improved.

Description

Technical Field

[0001] The present invention relates to the field of satellite communications, and in particular to a satellite Internet highly dynamic distributed routing method based on communication delay. Background Art

[0002] In satellite Internet, each network node in the satellite network moves around the earth in a predefined orbit, and the working mode of each satellite switches in real time as the service demand changes. The random on and off of inter-satellite routing links leads to poor stability of the communication topology of satellite Internet, making it difficult to ensure efficient broadcasting of data messages between nodes in different orbits, which brings great difficulties to the development of satellite communication. In satellite Internet, the topological structure between nodes is constantly changing, and there are multiple different communication links for data transmission from the source satellite node to the destination satellite node. How to select nodes with relatively stable transmission capabilities and plan reasonable communication routes for the transmission of inter-satellite information in real time is one of the key issues that need to be solved in the field of satellite communication. Traditional routing generation algorithms generate communication links based on the prediction of inter-satellite dynamic topology. When the working state of the node changes, the re-prediction and generation of the communication topology is time-consuming, the generation time of new communication links is slow, and the algorithm robustness is poor.

[0003] The 54th Institute of China Electronics Technology Group Corporation disclosed a satellite dynamic topology routing method in its patent application "A satellite dynamic topology routing method" (application number: CN202211232283.3 application date: 2022.10.10 application publication number: CN115632692A). The specific steps of this method are: the first step: establish a virtual topology based on the satellite deployment situation and the coverage of its monitoring area; the second step: solve the unicast shortest path from each source node to each target node; the third step: calculate the multicast tree from each source node to the target node group in the virtual topology; the fourth step: solve the broadcast route, broadcast tree, and multicast tree of the data packet according to service requirements. The disadvantage of this method is that more prior information is required to obtain the virtual topology between satellites. When dealing with the routing generation problem of satellite dynamic Internet, the robustness of this method is poor, so this method cannot be applied to the routing generation of satellite dynamic Internet.

[0004] Nanjing University of Posts and Telecommunications disclosed a low-orbit satellite network routing strategy in its patent application "Low-orbit satellite network routing strategy based on membership function" (application number: CN201910682419.2 application date: 2019.07.26 application publication number: CN110336751A). The specific steps of this method are: the first step: construct a directed graph of the satellite network based on the relative position of the satellite and the earth's surface area; the second step: calculate the membership function of the link delay, packet loss rate, and available bandwidth; the third step: construct a comprehensive evaluation index of the link based on the membership function between nodes; the fourth step: construct a routing model for the satellite network. The fifth step: use the gray wolf algorithm to solve the satellite routing model and calculate the optimal path. The disadvantage of this method is that when solving the satellite routing, satellite nodes with computing power are required to receive global information and make routing decisions in a centralized manner. The overall algorithm complexity is high, and there is a certain demand for the communication and computing power of the central node satellite. Therefore, this method cannot be applied to the distributed routing generation problem of satellite dynamic Internet. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a highly dynamic distributed routing method for satellite Internet based on communication delay, which solves the problem that the traditional flooding algorithm has a large amount of calculation and is easy to cause satellite network congestion. The specific idea of ​​implementing the present invention is to construct an objective function that minimizes the communication delay of the low-orbit satellite network. Each satellite broadcasts data containing its own node information to form its own neighbor list. The source satellite node broadcasts a routing application message. When the satellite receives the application message, it compares the Euclidean distance between the previous satellite and itself from the target satellite. If the distance is greater, the routing application message is discarded. Otherwise, after waiting for a fixed time interval, if the satellite distance remains the minimum, the routing application message is forwarded. Repeat the above process until the target satellite receives the routing application message, and then reply to the optimal routing application message link to determine the generation of the communication route and forward the data message. The present invention optimizes the traditional flooding algorithm, sets a fixed waiting time to ensure that the link delay is small, and uses the distance as the selection criterion when selecting the routing node, ensuring the direction of data transmission, and solving the optimal route generation problem in the satellite dynamic Internet in real time, overcoming the difficulty of high computational complexity in the prior art.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: a satellite Internet highly dynamic distributed routing method based on communication delay, comprising the following steps: Step 1: Establish an objective function that minimizes the satellite Internet communication delay, where the objective function is the sum of the total transmission delay and the total queuing delay, where the total transmission delay is calculated based on the Euclidean distance between satellites and the speed of light, and the total queuing delay is calculated based on the average number of data packets and the link bandwidth; Step 2: Construct the neighbor list of the satellite at the current moment. Each satellite exchanges node status, delay, distance and data packet queuing information through broadcast response messages to form a dynamically updated neighbor information matrix. Step 3: The source satellite broadcasts a routing request message to neighboring satellites. The satellite receiving the message calculates the forwarding energy consumption and compares the weighted sum of the Euclidean distance with the target satellite, and selects the path with the smallest delay to forward the message until the target satellite receives and confirms the optimal link. Step 4: The source satellite transmits data through the confirmed optimal link. When the link is interrupted, the dynamic routing reconstruction mechanism is triggered, and step 3 is re-executed with the previous hop satellite of the failed node as the new source node.

[0007] Preferably, the objective function in step 1 is: ,in is the total delay of data transmission over the communication link, is the total propagation delay, is the total queuing delay.

[0008] Preferably, the total propagation delay calculation formula is: ,in, is the set of satellite nodes with available communication links between the source satellite and the target satellite, Indicates satellite and satellite The Euclidean distance between Represents the speed of light.

[0009] Preferably, the total queuing delay calculation formula is: ,in, Indicates the average number of packets being transmitted. Satellite node and satellite nodes The bandwidth between Representation Node To Node The average size of the data packets that have been used when transmitting data.

[0010] Preferably, the construction of the neighbor list in step 2 includes the following steps: a. The satellite periodically broadcasts a response message containing node status, location and resource information; b. The satellite receiving the response message replies with a confirmation message and verifies link connectivity; c. Generate a dynamically updated neighbor information matrix by exchanging delay, distance and queuing information.

[0011] Preferably, the forwarding conditions of the routing application message in step 3 include: a. The remaining energy meets the forwarding energy consumption threshold: in, For Node To Node The forwarding energy consumption, Receive for the node The energy consumed by data, is the total number of bits of data sent and received by the node; The energy consumed by node data transmission and reception to meet the signal-to-noise ratio; b. The weighted sum of the Euclidean distances between the current node and the target satellite is less than the previous hop node, otherwise the message is discarded; c. If no better path is received after waiting for a fixed period of time, the message is forwarded.

[0012] Preferably, the remaining energy is calculated as follows: ,in, is the remaining energy after the satellite node completes the transmission, is the total energy of the node.

[0013] Preferably, in step three, the target satellite compares the total delays of multiple paths and selects a link with the smallest delay to send a route to receive the message.

[0014] Preferably, the dynamic routing reconstruction mechanism includes: a. Real-time monitoring of link status and detection of relay node failure; b. Use the previous hop satellite of the failed node as the new source node and rebroadcast the routing application message; c. Generate a new path within the maximum hop count constraint to ensure data transmission continuity.

[0015] The present invention provides a highly dynamic distributed routing method for satellite Internet based on communication delay. It has the following beneficial effects: 1. The present invention adopts a highly dynamic distributed routing algorithm based on communication delay to perform satellite Internet route planning. When generating routes, satellite nodes autonomously select nodes with the smallest delay to build communication links, which overcomes the problems of network congestion and large amount of calculation caused by indiscriminate broadcasting when performing route planning in the prior art. The route generation speed of the present invention is fast, which helps to reduce the time of low-orbit satellite Internet data transmission and optimize the utilization rate of communication resources.

[0016] 2. The method algorithm of the present invention takes into account the distance between the node currently selected and the target node when selecting nodes, and uses this as the selection rule to generate a communication link, which reduces the number of hops in the data transmission process, ensures the direction of data transmission, and improves the stability of the communication link. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a flow chart of the present invention; Figure 2 A node scene simulation diagram provided by an embodiment of the present invention; Figure 3 A routing generation result graph of a highly dynamic distributed routing algorithm based on communication delay provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Example: Please see attached Figure 1 - Attachment Figure 3 The embodiment of the present invention provides a satellite Internet highly dynamic distributed routing method based on communication delay, comprising the following steps: Step 1: Establish an objective function to minimize the communication delay of satellite Internet ,in is the total delay of data transmission over the communication link, is the total propagation delay, is the total queuing delay. The total propagation delay is calculated as: ,in, is the set of satellite nodes with available communication links between the source satellite and the target satellite, Indicates satellite and satellite The Euclidean distance between Represents the speed of light. The total queue delay calculation formula is: ,in, Indicates the average number of packets being transmitted. Satellite node and satellite nodes The bandwidth between Representation Node To Node The average size of the data packets that have been used when transmitting data.

[0020] Step 2: Build the neighbor list of the satellite at the current moment: Each satellite broadcasts a message containing its own information, and builds its own neighbor information matrix based on the information messages received from other satellites. The specific steps are: a. Send response message: The satellite node broadcasts a response message to initiate communication.

[0021] b. Receive response message: When other satellites receive the response message, they send a response reply message to confirm the link.

[0022] c. Check the connection: Check whether the satellite that sent the response message can receive the response reply message to verify whether the connection has been established and is operating normally.

[0023] d. Exchange information: After the connection is established, the satellite nodes exchange information, specifically the node operation status, the delay between satellite nodes, the distance, and the packet queuing status.

[0024] e. Constructing neighbor information matrix: Based on the exchanged information of other satellites, satellites form their own neighbor information matrix.

[0025] Step 3: Generate a communication route from the source satellite to the target satellite using a highly dynamic distributed routing algorithm based on communication delay: a. According to the neighbor information matrix, the source satellite broadcasts the routing request message to its neighbor satellites; the neighbor satellites broadcast the routing request message.

[0026] b. When the remaining satellites receive the routing request message, they first calculate the forwarding energy consumption. If the remaining energy of the satellite is less than the forwarding energy consumption of the data message, the routing request message is discarded. Otherwise, go to step (c). The forwarding energy consumption is calculated as follows: ; For Node To Node The forwarding energy consumption, Receive for the node The energy consumed by data, is the total number of bits of data sent and received by the node; The energy consumed by node data transmission and reception to meet the signal-to-noise ratio. The current calculation method of the satellite's remaining energy is: , in, is the remaining energy after the satellite node completes the transmission, is the total energy of the node, c. Calculate the Euclidean distance between the satellite and the previous hop satellite of the data request message and the target satellite respectively; if the weighted sum of the delay and distance of the previous hop is greater, go to (d), otherwise discard the routing request message.

[0027] d. Wait for a fixed time. If no route request message with a smaller weighted sum is received, the message will be forwarded until the route request message reaches the target satellite.

[0028] e. The target satellite selects a communication link with the smallest delay from the multiple communication links generated to send the route receiving message.

[0029] Step 4: After the source satellite receives the route receiving message, it indicates that the source satellite and the target satellite have established an available route connection. The source satellite sends data to the target satellite along the communication link: Step 5: When an emergency occurs and causes the relay satellite on the route to fail, the previous hop satellite is used as the new source satellite, and the satellite Internet highly dynamic distributed routing algorithm based on communication delay is used to rebuild the node communication link from the new source node to the target node to complete the forwarding of the data message. The following simulation experiment further illustrates the satellite Internet highly dynamic distributed routing algorithm based on communication delay of the present invention.

[0030] During the simulation experiment of this embodiment, 100 satellite communication nodes are randomly generated within the range of , and any two of them are selected as the source node and the target node respectively. The communication range between each satellite node is set to a random number within (1,30), that is, for a certain node, it can only communicate with other nodes within its own communication range. Assume that the maximum number of hops for message data transmission is 8, that is, data transmission is completed within 8 hops. If the number of hops of the selected communication link is greater than 8, it is considered that the data transmission has failed, and the generated routing link 1 is an invalid link. Assume that after the source node and the target node are selected, the address of the target node is known to the source node.

[0031] See also Figure 1 , Figure 2 This is a node scenario simulation diagram provided by an embodiment of the present invention; the total number of communication nodes in the diagram is 100, including source nodes and target nodes. The source nodes and target nodes are represented by black dots, and the remaining blue nodes are central relay nodes. Figure 2 It can be seen that the source node and the target node are far apart, and there are a large number of relay nodes, which makes the problem more complex.

[0032] See also Figure 2 , Figure 3 is a routing result diagram of a satellite Internet highly dynamic distributed routing algorithm based on communication delay provided by an embodiment of the present invention; Figure 3 It can be seen that the generated communication link completes data forwarding from the source node to the target node through two relay nodes, which meets the constraint that the maximum number of hops of the data message is 8, and the generated communication link path cost is low, and the communication path is feasible.

[0033] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A highly dynamic distributed routing method for satellite Internet based on communication delay, characterized in that: The following steps are involved: Step 1: Establish an objective function that minimizes the satellite Internet communication delay, where the objective function is the sum of the total transmission delay and the total queuing delay, where the total transmission delay is calculated based on the Euclidean distance between satellites and the speed of light, and the total queuing delay is calculated based on the average number of data packets and the link bandwidth; Step 2: Construct the neighbor list of the satellite at the current moment. Each satellite exchanges node status, delay, distance and data packet queuing information through broadcast response messages to form a dynamically updated neighbor information matrix. Step 3: The source satellite broadcasts a routing request message to neighboring satellites. The satellite receiving the message calculates the forwarding energy consumption and compares the weighted sum of the Euclidean distance with the target satellite, and selects the path with the smallest delay to forward the message until the target satellite receives and confirms the optimal link. Step 4: The source satellite transmits data through the confirmed optimal link. When the link is interrupted, the dynamic routing reconstruction mechanism is triggered, and step 3 is re-executed with the previous hop satellite of the failed node as the new source node.

2. According to claim 1, a satellite Internet highly dynamic distributed routing method based on communication delay is characterized in that: The objective function in step 1 is: ,in is the total delay of data transmission over the communication link, is the total propagation delay, is the total queuing delay.

3. According to claim 2, a satellite Internet highly dynamic distributed routing method based on communication delay is characterized in that: The total propagation delay calculation formula is: ,in, is the set of satellite nodes with available communication links between the source satellite and the target satellite, Indicates satellite and satellite The Euclidean distance between Represents the speed of light.

4. According to claim 2, a satellite Internet highly dynamic distributed routing method based on communication delay is characterized in that: The total queuing delay calculation formula is: ,in, Indicates the average number of packets being transmitted. Satellite node and satellite nodes The bandwidth between Representation Node To Node The average size of the data packets that have been used when transmitting data.

5. According to claim 1, a satellite Internet highly dynamic distributed routing method based on communication delay is characterized in that: The construction of the neighbor list in step 2 includes the following steps: a. The satellite periodically broadcasts a response message containing node status, location and resource information; b. The satellite receiving the response message replies with a confirmation message and verifies link connectivity; c. Generate a dynamically updated neighbor information matrix by exchanging delay, distance and queuing information.

6. The satellite Internet highly dynamic distributed routing method based on communication delay according to claim 1 is characterized in that: The forwarding conditions of the routing application message in step 3 include: a. The remaining energy meets the forwarding energy consumption threshold: in, For Node To Node The forwarding energy consumption, Receive for the node The energy consumed by data, is the total number of bits of data sent and received by the node; The energy consumed by node data transmission and reception to meet the signal-to-noise ratio; b. The weighted sum of the Euclidean distances between the current node and the target satellite is less than the previous hop node, otherwise the message is discarded; c. If no better path is received after waiting for a fixed period of time, the message is forwarded.

7. A satellite Internet highly dynamic distributed routing method based on communication delay according to claim 6, characterized in that: The calculation method of the residual energy is: ,in, is the remaining energy after the satellite node completes the transmission, is the total energy of the node.

8. The satellite Internet highly dynamic distributed routing method based on communication delay according to claim 1 is characterized in that: In step 3, the target satellite compares the total delays of multiple paths and selects the link with the smallest delay to send the route to receive the message.

9. The satellite Internet highly dynamic distributed routing method based on communication delay according to claim 1 is characterized in that: The dynamic routing reconstruction mechanism includes: a. Real-time monitoring of link status and detection of relay node failure; b. Use the previous hop satellite of the failed node as the new source node and rebroadcast the routing application message; c. Generate a new path within the maximum hop count constraint to ensure data transmission continuity.

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