Research And Simulation Of LEO Constellation Routing Protocol

The terrestrial communication system cannot realize communication anytime and anywhere.As an important technology to fill this gap,low earth orbit(LEO)satellite communication has always been valued by researchers.LEO satellites have been moving at high speed in their orbits,and their network topology is constantly changing,making it impossible to communicate using the routing technology already available in terrestrial networks.Therefore,routing technology is a difficult point in LEO satellite communication.Due to the different traffic requirements of each area in the network,uneven traffic distribution often occurs.This may lead to excessive traffic in some areas of the network,exceeding the link capacity and causing congestion;the traffic in some areas is less,resulting in a waste of network resources.With the development of satellite technology,the satellite network scenarios are gradually diversified,and the dependence of human production activities on satellite communication networks has gradually increased.In the future,there will be more and more traffic in satellite networks,which also highlights the problem of uneven traffic distribution in the network and leads to more serious congestion.In order to make full use of limited network resources,satellites need to use load balancing technology when routing,so that the traffic in the network is distributed as evenly as possible and the congestion in the network is reduced.On the basis of in-depth analysis of the composition and networking characteristics of LEO satellite network,we focus on the study of load balancing routing in satellite network,fully consider the characteristics of traffic distribution when congestion occurs in the network,and judge link status and provide information feedback.A new routing algorithm is designed and implemented by simulation.Compared with the existing routing algorithm,its overall performance is analyzed.Firstly,the operation mode and service characteristics of LEO satellite network are introduced,the existing routing algorithms are discussed and their advantages and disadvantages are summarized,and the design principles and performance evaluation indicators of routing algorithms are studied.Then,combined with the characteristics of the LEO satellite constellation,a load balancing routing algorithm based on accurate link status feedback(LBR-AF)is designed to solve the problem of unbalanced traffic distribution in the satellite network and the possible congestion caused by it.The algorithm regularly detects the specific conditions of the link,and when the link is congested,it accurately feeds back the congestion status of the link to the neighbor nodes,and diverts the traffic that is about to enter the congested link,so as to accurately handle the congestion and avoid unnecessary detours of the traffic;when the link fails,accurate link feedback and traffic detours are performed to ensure the survivability of the algorithm.The LBR-AF algorithm includes four key mechanisms: routing table update,link state detection,congestion handling and fault handling.The routing table update mechanism divides time slices,selects the combination of propagation delay and queuing delay as the measure of link cost,and periodically updates the routing table;the link status detection mechanism regularly detects the congestion and connectivity status of the link;the congestion processing mechanism accurately notifies the neighbor nodes of the congestion information when the link is congested,and conducts shunting process in time;the fault handling mechanism accurately announces the fault information when the link fails,so that the neighbors can open the detour mechanism.Finally,the LBR-AF algorithm is simulated and realized by STK and OPNET software,the congestion and fault handling functions of the LBR-AF algorithm are tested,and the overall performance of the LBR-AF algorithm is simulated and analyzed by comparing the SPF algorithm and the ELB algorithm.The simulation results verify the effectiveness of the LBR-AF algorithm.It is shown that the LBR-AF algorithm can effectively improve the performance of the network in terms of delay,packet loss,and throughput by balancing the load.