Research On Topology Structure Of Beidou Laser Link Network

The Beidou-3 navigation system has carried out the experimental scheme design of laser intersatellite link,and according to the characteristics of laser intersatellite link,the conception of spatial backbone network is put forward.Taking this backbone network as a breakthrough point,this paper analyzes the network throughput of the existing Beidou-3 inter-satellite link,and points out that the main bottleneck restricting the network performance lies in the transmission capacity of the inter-satellite link.Aiming at the problem of high-speed inter-satellite link network topology optimization,aiming at matching the network throughput between satellite-ground link and intersatellite transmission link,the design of laser inter-satellite link topology and satelliteground link allocation scheme in spatial information network is studied,and a Beidou laser link allocation scheme based on network throughput optimization is proposed.The scheme aims at maximizing the throughput of the inter-satellite link network and establishes the laser inter-satellite link network model with the minimum hop count as the constraint.On this basis,considering the visibility between MEO and ground base station,LEO,IGSO and other MEOs,select suitable nodes to establish links with ground base stations,and search through a minimum hop count Dijkastra algorithm based on the longest visibility to realize link allocation.Simulation results show that the link allocation scheme based on this algorithm can match the data throughput between satellite-ground link and inter-satellite link,solve the bottleneck problem of satellite-ground transmission and improve the network throughput.The main content of the paper is summarized as follows:1.This paper analyzes the current situation of navigation satellite inter-satellite link system,studies the working principle of laser inter-satellite link system,and studies the topology of inter-satellite network,which lays a foundation for formulating and evaluating laser inter-satellite link network.2.Analyzed the navigation constellation link construction constraints and backbone network design,focusing on inter-satellite and satellite-to-ground visibility,taking into account the inter-satellite distance,inter-satellite azimuth,and elevation angles,and proposed designing laser inter-satellite links.Finally,two network topologies are proposed for the future laser link between Beidou satellites,and their advantages and disadvantages are analyzed based on the number of hops and delay between satellites.3.The idea of the next-generation Beidou system space network is proposed.The inter-satellite high-speed laser link is used as the backbone network.Through the combination of low,medium and high hybrid constellations,the advantages of the Beidou inter-satellite laser link are fully utilized.First,IGSO was used as an information routing transfer node to transmit MEO business data to the ground station,but the simulation results were not ideal;then an improvement plan was proposed to connect some MEO satellites to the ground station,and the simulation was performed with two topological structures and analyzed separately In order to improve its throughput,it is proposed that the main bottleneck restricting network performance is the transmission capacity of the satellite-to-earth link,and corresponding solutions have been proposed.The method of inter-satellite congestion control is proposed and simulated,and the conclusion that different congestion control methods are used according to different requirements is given.