The Design And Simulation Of Routing Algorithm For LEO Satellite Networks

With the rapid development that Internet applications, the satellite communication systems begin the network era both in civil and military area. LEO satellite system becomes a hot research direction of the satellite communication for it can provide real time multi-media service. In LEO satellite networks, each satellite can be linked with many other satellites via ISLs that is messages can be passed on via many different routings. And for LEO satellite movement and dynamic satellite network topology, routing is always one of key and important problems of LEO satellite networks. Therefore it is so necessary to develop a new routing algorithm, which is tailored just for satellite network as to its special characteristics. And there isn't an international accepted standard about routing algorithm for LEO satellite networks today. The subject of this dissertation is set off for the reasons above.First, this dissertation analyzes the characteristics of the satellite network and discusses the difficulties of routing in LEO satellite network. And a survey of all kinds of routing algorithms is also presented. Then this dissertation discusses how to use NS2 to design the satellite network simulation framework which can be used to verify the performance of satellite network. Focus on possible loops caused by routing table transition between time intervals and link congestions and satellite failures etc., the design of a discrete time based loop-free routing algorithm for LEO satellite networks is discussed. Simulation results show that the algorithm has better end-to-end delay performance and lower packet loss rate. Aiming to the traffic load balancing and congestion controlling and optimizing utilization of costly spatial network resources, carrying on the improvement to the existing routing algorithm, a multi-path routing algorithm based on compressed path information is put forward next. The algorithm can support multi-path routing capability without introducing additional signal overhead by using a distributed hierarchical link state collection policy and a compact path information coding scheme, so as to realize traffic load balancing and optimize utilization of costly spatial network resources. Through the analysis and simulation of the algorithm, it is proved that the performance of congestion controlling and utilization of ISLs are improved notably.