一种适于LEO卫星网络的动态源路由算法

Dynamic source routing algorithm for LEO satellite networks

针对低轨(LEO)卫星网络拓扑变化有规律、可预知的特点,提出了一种适于LEO卫星网络的动态源路由算法,即自适应路由选择(ARS)算法.它引入逻辑位置的思想屏蔽了卫星移动性对路由选择的影响,使得源卫星只需自身和目的卫星的逻辑位置信息便可以进行路由计算获得最小传播时延路径,避免了收集路由信息所带来的交换开销;同时,根据最小传播时延路径的分布特点提出了一种高效的路径表示方法,用于在IP数据报头中存储所获得的最小传播时延路径,中转卫星可以根据该路径信息转发数据报直至目的卫星,和其他各类源路由算法相比大大降低了路由开销;另外,该算法还针对可能发生的链路拥塞和卫星失效情况提供了保证数据报正常传输的处理方法.最后,将所提出的算法与最小传播时延数据报路由算法(DRA)和Bellman最短路径(SP)算法进行了仿真比较.仿真结果表明,ARS算法在降低路由计算开销和交换开销的同时,保证了数据报的端到端传输时延要求.

Based on the regular and predictable features of topology changes in low earth orbit （LEO） satellite networks, a dynamic source routing algorithm, namely adaptive route-selection （ARS） algorithm, was presented for LEO satellite networks. In the algorithm, logical location is adopted to hide satellite mobility from the routing algorithm so that a source satellite can compute the path with minimum propagation delay between source and destination satellites by only knowing their logical locations, which avoids the exchange overhead of collecting route information from other intermediate satellites. An efficient metric was proposed to denote the path with minimum propagation delay on the basis of its distribution properties. Then the path is designated by source satellite in packet header and according to the path the packet is forwarded to its destination satellite by intermediate satellites, which can greatly decrease the route overhead compared with other dynamic source routing algorithms. The algorithm can also deal with packet routing issues in case of link congestion or satellite failure. The performance comparison of the ARS algorithm with datagram routing algorithm （DRA） and Bellman＇s shortest path （SP） algorithm was evaluated by simulation. The simulation results show that the proposed algorithm can guarantee the demand of end-to-end transmission delay for data packets with lower computation and exchange overhead.