Research On Routing Algorithm In LEO Satellite Communication Network

Satellite communication has become the current research hotspot with its wide coverage,large capacity,large-scale characteristics,etc.It can meet the communication needs of contemporary users regardless of geographic environment and location.Routing problem is the key issue in the satellite communication network,which is of great significance to improve the real-time and reliability of data transmission.However,LEO satellite network has the characteristics of dynamic topology changes and frequent switching of communication links,which makes the routing design face a great challenge.This article focuses on the in-depth study of the routing algorithm in satellite time-varying networks.The detailed research works are as follows:Firstly,the development of satellite communication and the characteristics of satellite network are briefly summarized,and the current research status of the existing routing algorithms are described in this paper.Based on the dynamic topology control strategies of satellite time-varying network,the characteristics of the routing algorithms proposed in the existing literature and the key problems to be solved are analyzed and summarized.Secondly,in the research of satellite routing algorithm,the topology structures of the time-varying satellite networks are analyzed in the perspective of satellite routing algorithm.In order to solve the problem that the traditional ant colony optimization(ACO)will lead to congestion when the optimal path is overload,we propose a probabilistic routing algorithm based on ant colony optimization(ACO-PRA).Firstly,the algorithm divides the topology period into several time slices and forms the topology connectivity graph,and then establishing the objective function to minimize the delay to meet the requirements of the link capacity in line with the topology connectivity graph;finally,the next hop node is selected by means of the node probability function of the ant colony algorithm,and the optimum signal transmission path can be found to meet the requirements of link capacity.Compared with the traditional ant colony algorithm,the algorithm can not only reduce the average end-to-end delay and packet loss rate,but also effectively improve network throughput and balance network load.Finally,aiming at the problem that the genetic algorithm(GA)cannot always ensure the optimal path results in intermittent connection of links by the dynamic changes of the satellite network topology,we proposed a Markov space-time graph based Markov Space-time Graph based Delay Optimization Routing(MSG-DOR)algorithm.The space-time graph model based on Markov chain is constructed,and the transition time probability and sojourn time probability of satellite nodes are calculated.Secondly,the GA algorithm is used to establish the time delay minimization objective function to meet the requirements of bandwidth;then through the process of selection,crossover and mutation,we find a global optimal path that meets the minimum transmission time.Finally,by comparing with the traditional GA and ACO-PRA algorithm,MSG-DOR algorithm can reduce the loss rate of data packets and improve the network throughput.