Research And Simulation Of Multi-layer Satellite Network Routing Mechanism

With the development of communication technology,satellite network has gradually plays an important role in the communication industry.Multi-layer satellite network has become the research object of scholars all over the world because of its excellent coverage and onboard computing ability.Among them,the double-layer satellite network composed of GEO satellite and LEO satellite stands out.However,the inter-layer connections of GEO/LEO double-layer satellite network is complex.The satellite coverage of GEO satellite to polar region and the frequent topology changes are the focus of research.Aiming at the problems of high topology complexity,frequent link switching,the high packet loss rate and delay,and the limited management of polar satellites,we propose a routing solution based on clustering and clustering.Firstly,the basic knowledge of satellite network is introduced,and then the existing multi-layer satellite network routing algorithms are compared to analyze the problems existing in the algorithms.Then we analyze the disadvantages of the traditional inter layer connection relationship in the double-layer satellite network.Meanwhile we analyze the consequences caused by the relatively highspeed movement of the satellite.The thesis studies the packet management mode of the satellite network,so as to lay the foundation for the design of the subsequent routing algorithm.Finally,combined with the design of two different satellite constellations,and the problems existing in the scenes,a routing strategy based on GEO/LEO double-layer satellite network is proposed.The algorithm in this paper includes four solution mechanisms: time slice division mechanism,link fault detection mechanism,grouping and packet management mechanism and routing update mechanism.The time slice division mechanism proposes a suitable time slice merging mechanism to solve the problem that the improper selection of time slice length in existing algorithms leads to the complexity of routing calculation,the increase of overhead,the increase of link packet loss rate and the degradation of network performance;The link fault detection mechanism aims to detect nodes and link states between nodes,detect link faults regularly,and provide accurate topology connection for routing updates;In the existing research,there is a mechanism for the grouping and grouping management of near polar orbit satellite constellation,but the application in the tilted orbit is not given.In this paper,a grouping and grouping mechanism suitable for the tilted orbit is proposed according to the characteristics of the tilted orbit;The routing update mechanism aims at the problem that the link state information of the satellite can be transmitted to the group head faster and more reliably when the link in the packet fails in the grouping mechanism,and proposes a mechanism for forwarding the link state information of the node to the adjacent orbit.Next,STK and OPNET software are used to set different scenarios to simulate the algorithm,and compared with the classical VLRA algorithm and SORA algorithm to evaluate the performance of this algorithm.After simulation analysis,we take into account the complex connection relationship of network topology,the combination of time slices,different grouping methods for different constellations and the link information processing mode in case of link failure.Compared with SORA algorithm and VLRA algorithm,the performance in average delay,throughput and packet loss rate is improved under relevant circumstances.In the near polar and inclined orbit constellations,the average delay decreases by at least 24.3% and 13.5%,the throughput increases by at least 11.7% and 7.65%,and the packet loss decreases by at least 16.7% and 6.3%.