The Location Area Design In Leo Satellite Communications And Switching Algorithm

LEO satellite communication systems are intended to play an important role in the next generation of mobile communication system. An important research spot of LEO satellite communication system is mobility management. In this paper, I propose a mixed location area (LA) design strategy to reduce the cost of location management in LEO satellite communication system. And I also propose tow handoff strategies, one is just for voice services, the other is for multimedia services.Chapter 1 gives brief introduction of satellite communication system and the main work of this paper.Chapter 2 describes current development of location area design and handoff technologies for LEO satellite communication systems.In Chapter 3, a mixed LA design strategy is proposed for LEO satellite network from two existed strategies. This scheme is based on the speed of the users and simulation results show that this scheme improves the system performance. Chapter 4 mainly studies handoff technology LEO satellite communication systems which just support voice service, and proposes a dynamic channel reservation scheme. In addition, it adopts self-adjustment measures to be adaptive to varying traffic loads and makes the blocking probability decrease. The results by analysis and simulation in grade of service prove the better performance of this scheme.The trend of wireless communication must be multimedia services, so it is another research spot on handoff scheme for multi-service. Chapter 5 proposes a new call admission algorithm, the dynamic channel thresholds and preemptive priority scheme for integrated voice and data LEO satellite mobile communication systems. According to the queuing strategy and a Guard Channel scheme based on dynamic channel thresholds, this scheme reduces the blocking probability of all kinds of calls, moreover, it gives handoff voice calls a higher priority by permitting them to preempt handoff data calls channels in preemptive channel. Through simulation and comparison with other schemes, it can be clearly seen that the proposed handoff scheme improves the system performance.The dissertation is summarized in the chapter 6.