Launch Platform Communications Systems Mobility Management

The High Attitude Platform Station Communication System is an important component of the space-based information system, And it may become the third wireless communication system after the ground communications system and satellite communications system, it is the information superhighway ground to space, fixed terminals to the extension of mobile terminals.It synthesized the technical superiority of the ground wireless system and satellite system, such as broad cover, the low time delay, the low path loss and the low system construction cost and the run cost. So it is very suitable in emergency communication.Mobility management can make the network to locate mobile users and reserve the connection between the network and the mobile users when the users moved to a new areas.It includes location management and handover management. And the location management mainly realizes the user location registration and the location renewal, so that when the uesr calls another user, it can be possible fast query the called user's positional information promptly. The handover is most complex and the most important process for the High Attitude Platform Station Communication System. The goal of handover management is to provide a seamless connection when the mobile terminals move from one area to another while they are communicating. Through handover management, the mobile terminals can get the on-line connection and services so as to realize the seamless roaming.When considered the High Attitude Platform Station Communication System's own characteristic and many limits, the mobility management method at present used in the ground network and the satellite network is unable to use directly by it. Thus needs to study and to design a suitable mobility management method for the High Attitude Platform Station Communication System. In the present paper, we introduce one mobility management strategy based on the SIP protocol in the application layer. The present paper mainly research the location management based on the SIP protocol, and expected that can realize user's localization and query the user quickly.Simultaneously we have also studied the handover management. When the user is far away from the platform, it may long latency and great expenses when the user handover from one platform to another. For this case, in this paper a solution is introduced that reduces the handover delay by sharing the registration information and call states between the new platform and old one.It can reduce the delay and the network expenses, and can optimize the performance of the network.In this article, the simulation models are built in the OPNET simulation environment and the mobility management mechanism is realized based on the basic floor I buit. According to a series of simulation data and curves produced in the scenario, it is proved that this mobility management mechanism has achieved the design goal and is effective to realize the seamless handover. This mobility management mechanism also provides a reference model and a reference data for the design and layout of the practical system.