Research On The Architecture And Key Technologies Of Mobility Management In Next Generation Wireless Networks

A higher data rate, greater system capacity, broader network coverage and more rational resource allocation are the main trends and evolution goals of the future mobile communications.As the increasing demands on new kinds of services, wide bandwidth and high mobility support, heterogeneous networks converging is being considered as the trend of next generation communication system. In the meantime, mobile satellite networks,as an important complementation to terrestrial wireless networks,is becoming another hot direction for next generation networks. A critical problem for wireless networks, no matter in homogeneous or heterogeneous networks,is mobility management. Adaptive and seamless mobility management architecture and mechanism without users' participation and consciousness have greatly interested of both academe and industry.This thesis mainly focuses on some key issues of mobility management for next generation networks, including mobility management framework, vertical handover algorithm in heterogeneous networks and admission control strategy in mobile satellite networks.Firstly, new mobility management Function Entities and modules are designed in response to the challenge of multi-connection scenario in future wireless application, in which each mobile user could have several communication connections with different wireless networks simultaneously through a multi-mode mobile terminal.Besides, comprehensive mobility management trigger criteria in multi-connection scenario and a toolbox with various flexible connection management strategies are designed to help the new framework provide seamless and effective mobility management.And then, based on ranking with median value theory, a novel vertical handover algorithm in heterogeneous networks is proposed. The key character of this algorithm is that it helps solve the problem of target network selection when some decision parameters are missing or inaccurate.Moreover, median based algorithm is extended for multi-traffic scenario in which traffics with different QoS requirements coexist.With the respect to mobile satellite networks, based on Markov Queue theory, two novel admission control strategies are proposed separately for Low Earth Orbit (LEO) and Geostationary Earth Orbit (LEO) satellite networks,while the mobility characteristic of mobile terminals vary according to the type of satellites in those two networks.In LEO satellite networks, mobile terminals have to take handover between two spot beams frequently because of the high velocity of LEO satellite. Oppositely, the frequency of inter-spotbeam handover in GEO satellite network is low because of relative low speed of terrestrial mobile terminals in large spot beam. And the key problem of admission control strategy in GEO satellite network is to provide high QoS experience for users with guaranteed mobility management.Both theoretical and numerical simulation results show that these two strategies effectively help satisfy the QoS requirements of mobile users in satellite networks.A summarization is made in the end of this thesis in which the future direction of the study is pointed out.