Research On Mobility Management In Next Generation Wireless Convergence Networks

Next generation wireless communication system will be an ubiquitous, intelligent and all-IP based convergence network supporting diversification of access methods and different service applications. As the air interface technologies and adopted protocol implementation methods for different wireless systems are incompatible with each other, heterogeneous networks require a generalized and open technology framework to enable cooperation and convergence. This paper investigated mobility management in next generation wireless convergence networks.This paper adopted hybrid research method of theoretic analysis and experiment validation. For every issue, theoretic model is established, algorithms are designed, and finally computer simulations are applied.This paper firstly expatiated technical background and research signification, summarized development and evolution of modern mobile communication systems. This paper also investigated current mobility management schemes in heterogeneous convergence networks, tracked development status and research trend proposed by standards organizations, and analyzed synthetically the issues and challenges to implement.This paper studied the network-layer mobility management in loose-coupling based heterogeneous convergence networks. This paper investigated the important network-layer handover scheme—mobile IP series standards and improved strategies, proposed theoretical analysis for different handover strategies, and implemented corresponding simulations. Besides, by introducing lower-layer trigger events, this paper proposed a novel fast handover scheme. The simulation results show that the proposed handover scheme can obtain better performance for both TCP-based applications and UDP-based applications.This paper proposed a novel handover scenario classification based network-layer handover strategy based on hierarchical mobile IP architecture, and combined fast mobile IP with IEEE 802.21 protocol. This paper designed an improved network architecture based on hierarchical mobile IPv6, introducing a new function entity in the network side, and defined handover management scheme for multimode terminal, referring to module functions and interfaces. Based on this, this paper put forward Handover Scenario Classification (HSC) mechanism, extending the traditional marginal-coverage scenario and overlapped-coverage scenario to four typical kinds of handover scenarios, defining corresponding judgment criteria and application scenarios. This paper proposed different optimized mobility management schemes in different application scenarios. Finally, this paper combined HSC and IEEE 802.21 protocol, proposed a new network handover mechanism in next generation wireless convergence networks. Simulation results showed that the proposed mechanism can decrease packet loss ratio drastically, and apply different optimization strategies according to application scenarios.Besides, this paper proposed a universal network access selection scheme based on multiple objective optimization (MOO) theory. Firstly, a network evaluation mechanism was designed by analyzing the performance attributes from all layers of protocol stack synthetically. This paper abstracted cross layer parameters, classified them, and defined usage rules. Then, MOO theory was introduced. Network evaluation mechanism was applied to describe decision vectors, and corresponding optimization target functions were proposd for next generation wireless convergence networks, so the network access selection issue can be converted to a typical MOO issue. Based on that, efficient access selection algorithm is designed, synthesizing analytical hierarchy process, entropy method, non-dominated sorting genetic algorithm and direct search method, which promoted the efficiency and accuracy of network access selection results. Finally, this paper put forward a novel network architecture for cognitive heterogeneous networks based on the IMS architecture, introducing key entity and cognitive process in hierarchical network, specified cognitive process behavior model, and implemented cognitive terminal function design. This paper investigated cognitive access control issue in cognitive heterogeneous networks, integrating traditional network selection and call admission control. The cognitive access control method can consider service experience for terminal side and performance for network side, achieving self-optimization by dynamic adjustment. This paper also proposed cognitive handover mechanism, modeling networks to hexagon model and circular model, and proposed Motion Classification Assisted Strategy. Simulation results showed that in practical applications, MCAS based cognitive handover mechanism can adjust parameters flexibly, controlled the balance between handover performance and signal cost cognitively.