Research On Routing Algorithm Of Low Orbit Satellite Constellation

With the rapid development of mobile communication technology,ground communication technology has gradually been unable to meet people's requirements for wireless communication.Therefore,the development of satellite communications and satellite networks is a very important part of the next generation of network construction.Compared with terrestrial networks,satellite networks have many advantages,such as large communication range,long communication distance,large communication capacity,and wide coverage.However,the satellite equipment itself has the problem of limited storage and computing resources,and the satellite has been moving around the earth at a high speed,resulting in frequent changes in the satellite network topology,making satellite network routing more difficult than ground routing.Based on the above problems,this article conducts research on routing algorithms based on the Low Earth Orbit(Low Earth Orbit,LEO)satellite constellation.The main research contents are as follows.(1)First,a semi-dynamic topology is proposed,and on the basis of this topology,a shortest path routing algorithm based on port addressing(Port Address Shortest Routing,PASR)is proposed.This algorithm is different from the traditional Dijkstra algorithm.The operation of the Dijkstra algorithm needs to store the topology of the entire satellite network.Therefore,the overhead on the satellite is relatively large and increases exponentially with the increase of network nodes.This overhead is unacceptable.For the above problems,the PASR algorithm also takes the minimum number of hops into consideration,calculates the shortest distance in the minimum number of hops grid,and applies a forwarding method based on port addressing,which effectively reduce the storage and computing overhead on the satellite.(2)A low-cost shortest path routing algorithm based on port addressing(Port Address Low-Cost Shortest Routing,PALSR)is proposed.This algorithm is an improvement based on the PASR algorithm.It is hoped that when the path length is close to the shortest distance,further reduce the storage and computing overhead of satellites.The algorithm still considers the shortest path selection based on the minimum number of hops,and makes full use of the regularity of the topology and the regularity of the link connection.The algorithm is carried out in two steps,direction estimation and direction selection.The direction estimation stage determines the minimum space to be searched by the routing algorithm.The principle of the direction selection stage is to perform horizontal link jumps at high latitudes as much as possible.Since the algorithm does not need to store and calculate the satellite node information and link information in the search space during operation,and the algorithm complexity is only O(n),the overall efficiency of the algorithm is greatly improved.(3)Using STK and Python experimental simulation tools,the proposed PASR and PALSR algorithms were compared and analyzed experimentally.The experimental results show that the PASR and PALSR algorithms proposed in this paper can effectively reduce the on-board storage and calculation overhead,and reduce the end-to-end average delay and bit error rate.They are suitable for various LEO oblique orbit satellite constellations,especially large-scale constellations with limited satellite performance.