Research On Routing Algorithm Based On Network Coding For Satellite Network

Satellite communication network has played an important role of the Global Communication System with its superiorities over global coverage,scalability and autonomy.As a typical resource-constrained system,the contradiction between high-speed information transmission requirements and restricted network resources brings challenges to the research of satellite network routing mechanism.The application of network coding,especially the combination of coding-aware method and data transmission provides a novel idea for the improvement of the problem.However,the on-off status,length,and connection relationship of inter-satellite links in satellite networks are constantly changing.These dynamic time-varying features affect the feasibility of existing terrestrial solutions in satellite networks.Based on the application of network coding in terrestrial network routing mechanism,this thesis proposes a routing scheme with coding awareness for the satellite network with dynamic spatiotemporal characteristics.Firstly,a coding-aware routing metric(CARM)is explored by introducing the coding graph,so that the measurement problem of coding opportunity is transformed into the problem of calculating the maximum complete subgraph.Then,this thesis analyzes the general coding conditions between data flows and the distributed route discovery procedure with coding awareness.Simulation results show that compared with the traditional network coding-based routing algorithm and minimum hop count routing algorithm,this coding-aware routing scheme can improve the network throughput and decrease the end-to-end delay by detecting coding opportunities along the path actively.Secondly,according to the satellite trajectory equations and the sphere geometry theorem,this thesis establishes an inter-satellite link characteristic model to describe the regular changes of satellite network.Satellite Tool Kit verifies the accuracy of the model.Based on the research above,a link evaluation coefficient is proposed in this thesis to modify CARM to obtain the coding-aware routing metric for satellite network(SCARM).SCARM can realize the rational arrangement of routing paths and coding opportunities while reflecting the characteristics of the satellite network,thereby enhancing the applicability of the coding-aware routing scheme in satellite network.Finally,an adjacency matrix is constructed to describe the topology of the satellite network under the topology control strategy of time virtualization.On the basis of that,a novel routing algorithm based on network coding for satellite network(RANCS)is proposed in this thesis.Through simulation on Walker constellation satellite system,the proposed RANCS algorithm is shown to improve the performance of network throughput,end-to-end delay and invulnerability compared with the routing scheme using CARM and traditional minimum hop count routing algorithm in satellite network.