Abstract: This paper proposes an asymmetric discrete time based routing algorithm (A-DTRA) for LEO satellite networks. To the links state among each consecutive time intervals, this algorithm realizes links detection for satellite networks by central node broadcasting message twice, and each node has the knowledge of its direct 1-hop neighbors and the neighbors of its neighbors. So the directional virtual typology network can be obtained to every consecutive time intervals. The backup routing and routing table compression mechanism are used in routing algorithm, which can realize the reliability of the packet forwarding on asymmetric link, the timeliness of failure node disposal and the low consumption of satellite nodes overhead. Simulation results show that the connectivity of the network can be improved by A-DTRA, and the packet delivery ratio and the average end-to-end delay are superior to those by DTRA. It is well suitable for LEO satellite networks with asymmetric links.

Key words: LEO satellite networks, asymmetric, routing algorithm, link detection

摘要： 提出了一种基于分时的LEO卫星网络非对称路由算法A-DTRA（asymmetric discrete time based routing algorithm）。针对网络节点在各时间片内的链路连接状态，该算法通过中心节点两次广播来获取一跳邻节点信息及其邻节点的邻居节点信息，从而完成了链路检测，得到每个时间片内的有向虚拟拓扑图。通过使用备份路由和路由表压缩机制实现了非对称链路上分组转发的可靠性，失效节点处理的及时性以及星上节点开销的低耗性。通过仿真分析可知，该算法具有较好的数据包转发率和端到端时延性能。此外，利用非对称链路可提高网络的连通性能，该算法适用于存在非对称链路的LEO卫星网络。

关键词: LEO卫星网络, 非对称, 路由算法, 链路检测