Research On The Key Technologies Of Mobility Management In Heterogeneous Networks

The main development trend of future mobile communication system is convergence and collaboration of all-IP based heterogeneous networks, in which one of the most important issues is mobility management for heterogeneous networks. The rapid development of heterogeneous networks presents more challenges and requirements for mobility management technology. And at the same time, existing mobility management technologies need to enhance their adaptability, expansibility, accuracy and versatility in the face of the emerging various new technologies, new services and new scenarios. The objective of mobility management is to integrate different wireless access technologies and meet various service requirements of users so as to achieve seamless mobile communication and service quality guarantee, which is also one of the most crucial issues in the development of current mobile communication technology.This thesis focuses on some key technologies related to mobility management for heterogeneous networks, mainly including:mobility management scheme, mobility management algorithm of heterogeneous networks and spot beam handover in satellite mobile communication systems.In terms of mobility management scheme, a new heterogeneous multi-connection communication scenario is considered and a novel multi-connection mobility management scheme is proposed in this thesis. Based on IEEE 802.21 media independent handover standard, a new multi-connection handover framework is proposed, in which some new functional entities and information primitives are introduced. Besides, the new characteristics and corresponding strategies are studied in the multi-connection handover trigger, decision and execution procedure, so as to provide an effective solution for mobility management of heterogeneous multi-connection communications.With respect to mobility management algorithm, this thesis proposes a new mobility management algorithm for network selection of multi-connection and handover management of multi-service. By selecting connected serving networks in priority and introducing Multiple Attribute Decision Making (MADM) theory in candidate network ranking, the proposed algorithm manages to match transmission requirement of multi-service with transmission capability of multi-connection networks. Simulation results show that compared with traditional methods, the proposed algorithm can provide better QoS guarantee and improve the efficiency of network resource utilization.Based on the integration of satellite network and terrestrial network, this thesis focuses on the spot beam handover in GEO satellite mobile communication systems. Taking system features and practical applications of GEO satellite mobile communication into consideration, a complete spot beam handover and channel allocation scheme is proposed, including handover trigger criteria, handover decision and adaptive channel allocation scheme, handover execution and signaling control. System modeling and simulation results show that the proposed scheme can effectively prevents unnecessary handover and has favorable adaptability to emergent application of satellite, which is significant for emergency rescue and disaster relief communication.Finally a summarization is made and the future direction of the study is pointed out.