Location Management In LEO Satellite Network

LEO satellite communication systems are an important part of the future global personal communication infrastructures. An important aspect of the LEO satellite network is to manage the location of both users and satellites. Many network signal flows and database updates and queries are required to accomplish such a task. There are two basic operations that are elemental to tracking mobile users: update and paging (or search/locate). Associated with each one of these operations there is a certain cost. A trade-off should be found between these two problems.First, in this paper, several locating methods are presented. Three structures of database used in location management are discussed. Location management strategies are explained based on the classification of the characteristics. Especially, three location area division strategies are analyzed.Then, a dual-location update strategy based on two kinds of location areas is proposed. Mobile terminals should operate the location update procedure only when both the two location area boundaries are crossed. Simulation results are presented based on three kinds of mobile terminals with different motilities to indicate the location update performances of the three proposed location area division strategies and the dual-location update strategy.At last, a two-step paging strategy corresponding to the dual-location update strategy is proposed. Mobile terminals are first paging under the registered satellite, then paging within the FES (Fix Earth Station) location area as the second step. The paging bandwidth and paging delay performances are analyzed based on mathematic algorithm.Results show that based on low location update cost the dual-location update strategy performs better in paging bandwidth performance, while the paging delay will be a little increased.