Research On Routing Technology In LEO Satellite Networks

With the fast progress of mobile communications and the continuous innovation of science and technology,creating a globally interconnected wireless network is the future direction of the expand of the communications scope.The low-earth-orbit satellite communication system will be a powerful supplement to the terrestrial network by virtue of its short delay,low packet loss rate and the ability to achieve global coverage.As one of the important technologies in the satellite communication network,routing strategy determines the overall network performance.However,the low-earth-orbit satellite network also has problems such as complex operating environment,large number of satellite nodes,frequent topology changes and unbalanced load.In order to solve these problems,it is of great significance to conduct in-depth research on routing selection technology in low-earth-orbit satellite networks.First of all,in order to solve the problems of frequent topology change,variable inter satellite link state and unbalanced load in low-earth-orbit satellite network,a load balancing routing strategy based on ant colony optimization algorithm is proposed.By introducing the delay jitter factor and the queuing delay factor into the probabilistic routing formula of ant colony optimization,the routing algorithm is guided to select a link which with a smaller delay and a more stable link state to forward data.In order to prevent the routing algorithm from converging prematurely,the final path is selected in combination with the roulette method,which can effectively avoid the dilemma of local optimality.In order to further expand the pathfinding range of routing,the pheromone volatilization factor suitable for the update of the entire network link and the pheromone legacy factor for the update of the local network link are introduced to simulate the self-organization and positive feedback characteristics of ants,so as to find the global optimum.By using the classic low-earthorbit satellite constellation model for simulation,the results show that when most of the links in the network are busy,the proposed algorithm has lower latency and lower packet loss rate and greater throughput,which is better than the improved snapshot sequence algorithm and the improved ant colony optimization algorithm.Then,in view of the problem that the previous algorithms did not fully consider the uncertainty of the operating environment of the low-earth-orbit satellite network,the applicability of routing is not high,a fuzzy logic-based satellite network routing algorithm is proposed.The proposed algorithm is based on the idea of fuzzy logic and uses different membership functions to characterize the transmission delay,propagation delay and queuing delay that affect communication performance,and defines the function for evaluating the superiority of the link.Finally,based on the idea of the shortest path algorithm combined with the rerouting mechanism to optimize the network topology.The simulation results indicate that the proposed algorithm can effectively improve network performance.