Leo Satellite Mobile Communication System User Location Management Strategy

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 find (or search/locate). Associated with each one of these operations there is a certain cost. For instance, frequent updates cause high power consumption at the mobile units and load the network, increasing one cost leads to a decrease in the other one. We should find a trade-off between these two problems. In this paper, I mainly propose three strategies for location management in LEO satellite network. In chapter 2, I propose an one-step pointer forwarding strategy for location registration in LEO satellite network which reduces the expensive home location register(HLR) access. Simulation results indicate that our strategy significantly decreases the location update cost, particularly for the satellite network where there exit frequent flip-flop effects. In chapter 3, I propose a Cell Identification Code method to realize the distance-based location update strategy in LEO Satellite Communication System, which performs best among the three dynamic location update strategy and I analyze the result of different distance threshold. In chapter 4, a satellite selection strategy for the MT to register its location is presented, as MTs are always covered by more than one satellite simultaneously. I consider both the elevation angle factor and the time during which the MT remain covered by the same satellite. Performance of the strategy indicates that it reduces the MT location update rate and the probability of paging MT in the condition of lower elevation angles.