An Improved Connection-Oriented Routing in LEO Satellite Networks

LEO (Low-Earth-Orbit) satellite constellation networks are expected to play a significant role in the future satellite communications. LEO system provides global communication with shorter end-to-end delays. One of the challenges in LEO network is development of specialized and efficient routing algorithm. In this paper, an improved routing algorithm including inter-satellite-link (ISL) and up-down-link (UDL) parts is proposed. Time-variant coverage and handoff models of LEO constellation are presented firstly. Based on the Dijkstra Shortest Path algorithm, a new link-cost considering dynamic distance and traffic distribution is developed for UDLs´ and ISLs´ respectively. It successfully makes our algorithm more reliable. Snapshot determination and kinds of routing filters are also proposed for improving algorithm efficiency. Finally, an Iridium system simulates on OPNET platform. The performances of the algorithm are evaluated through simulations. It shows that our algorithm takes great advantage of dynamic characteristics of LEO system and results are valid and correct. Building up correct LEO satellite networks simulation system in this work is also an important foundation for further studies of cross-layer protocols in LEO satellite networks.