Research On MAC For Low Earth Orbit Satellite Formation Network

Satellite communication system is an important means to realize communication’sglobalization and personalization, and it attracts greatly concern about its developmentprocess. Compared with geostationary satellite, low-orbiting satellite has the characteristics ofshorter propagation delay and lower transmitting power. Therefore, the Low Earth Orbit(LEO) small satellite formation including multiple satellites and inter-satellite link isbecoming one of the hot topics of satellite communication system presently. This thesis issponsored by NSFC project “Research on networking mechanism of space sensor networkbased on large scale micro small satellite flying in formation”, and mainly studies and designsMAC protocols suitable for LEO small satellites formation network.Firstly, we studied the satellites formation technique and designed the circular formationwhich is one of the special network topology models. Meanwhile, by computer simulationusing STK software, we obtained the important datas such as the max distance of theinter-satellite link.Secondly, we studied the terrestrial wireless communication standard IEEE802.11MACprotocol, and discussed the main factors influencing MAC protocol under the satellitesenvironment. Aiming at the characteristics of inter-satellite link in LEO small satellitesformation network. we adjusted IEEE802.11physical layer and data link layer parameters tosatisfy the requirement of ISL communication. Furthermore, we built the network model inOMNeT++software, in order to simulate and analyze the performance of our designedSSFN-MAC(Small Satellite Flying Network-MAC) protocol using different parameters andthe conditions that satisfy the communication requirements of LEO satellites network.Finally, in view of the problem that the improved802.11SSFN-MAC protocol didn’t fitthe case of high load in LEO small satellites, we proposed the load adaptation mechanismmethod, and designed and realized load adaptation MAC protocol through modifying theoriginal MAC protocol. We also carried out many a feasibility verifications using OMNeT++software.