Design And Research On The Routing Algorithm Base On Network Coding In Satellite Networks

Recently, providing reliable transmission over satellite networks is still achallenging problem due to the dynamic changes of the satellite topology, the largedelay and the high error rate of the satellites’ links. Currently, the design of the efficientand reliable satellite routing protocols has been the research focus of the satellitecommunication system. However, most of the satellite routing protocol has poorrobustness, designing a routing algorithm that can offset this problem become the aimof this paper. Particularly,the emergence of network coding provides an effective way tosolve this problem. But when network codingis appliedforcibly in the satellite networks,a packet will have to wait to be encoded withothers, which may result in large delay andincrease the complexity of each satellite node processing information; if the shortestpath routing is usedonly, which will not adapt to the dynamic changes in the satellitenetwork topology. This paper takes the advantages of network coding on throughput,delay, robustness and so on, and proposes a new coding-aware algorithm.This algorithmcan decrease the large delay and improve the throughput of the satellite networks.This paper proposes an coding-aware routing algorithm based on the satellitenetworks. This algorithm is aimed to select an path or multi-path which have encodingnodes and can make a minimum number of transmissions to transmit data. In the designof the proposed algorithm, firstly, we must determine the set of nodes wich can applynetwork coding. The set is determined by the in-degree and coding opportunity (Codingopportunity is a probability that two virtual buffer are empty). Secondly, we design acoding route metric and take the network coding into consideration. In order to makethe minimal number of the transmission, and the routing metric is optimized by usinglinear programming in this paper. Finally, we implement the proposed routing algorithmin satellite system in NS2and conduct extensive evaluation. Simulation results illustratethat, compared with the traditional satellite routing, the transmission efficiency ofproposed algorithm can be sharply increased in the whole satellite network and achieves5%~20%throughput gains.