Research On The Key Technologies Of Mobility Management In Heterogeneous Convergence Networks

Wireless communication technology recenetlly gets the gaint development, various wireless technology provide ubiquitous and heterogeneous network environment for users. Future heterogeneous convergence wireless networks include infrastructure (single-hop) and infrastructureless (ad hoc or multi-hop) wireless network. If we take full advantage of the complementary characteristics of different types of networks to achieve real integration of networks, mobility management technology are the key issues that need urgent solutions.In heterogeneous convergence network environment, mobility management technology couldn't meet requirments coverging seamless handoff and roam, location management, cooperation of mobile hosts due to network heterogeneity and differences. Currently, research workes in this field mainly focue on mobility management of infrastructure heterogeneous networks. And the vertical handoff technology has been a challenging issue. In addition, in heterogeneous infrastructure networks, the vertical handoff technology and joint radio resource management are in close relationship, they are intertwined. On the condition that bandwidth allocation of various services areas is fair and reasonable, optimizing radio resource management with vertical handoff technique to improve call admission rate, network load balancing and improve customer satisfaction. This has always been a hot issue. In heterogeneous infrastructure and infrastructureless networks, the study of handoff and location management supporting cooperation of mobile hosts is little. This paper focues on these outstanding issues and key technologies, the study conducted in the following four aspects:(1) A utility-based vertical handoff decision-making method is proposed. It is mainly to resolve the issue of vertical handoff decision-making in heterogeneous infrastructure networks. Performance metrics of networks are denoted by a reward function. Overhead of switching, signaling and blocking rate are depicted by a loss function. Net reward of networks gaining in the process of handoff is presented by profit function. Based on analysis of characteristics of different traffics, we take into account the issue of distribution of weights for various decision-making properties. In the process of vertical handoff decision-making, the target is to find the network obtaining maximum profit. The algorithm takes into account the cost of switching from the view of operators. It lays the foundation for optimizing joint radio resource mangment with vertical handoff technology. In addition, switching triggered rules are designed and implementation details of the method are discussed. Through real-time and non real-time simulation of the two traffices, the results show that the decision-making method is effective to avoid unnecessary switching and optimal performance. And comparing with other vertical handoff decision methods, it can achieve better performance.(2) The issue of bandwidth allocation in heterogeneous wireless network environment is studied. We proposed a theoretical model for distribution of bandwidth and connections of different radio resource based on non-cooperative game theory. Combined with utility fuction of network connections, we demonstrated that the Nash equilibrium point of non-cooperative game radio resource allocation is existent and exclusive. On this basis, we further discuss the issue of vertical handoff cost and achieve the optimization of joint radio resource management using vertical handoff technology. The experimental results show that game theory-based wireless network resource allocation mechanism that can effectively solve the bandwidth allocation and distribution of the number of connections, and can ensure the distribution of the overall rationality and fairness. According to the distribution of connections and bandwidth of different service areas, vertical handoff technology can further optimizes joint radio resource management in the aspects of load balancing, access rates, user satisfaction and etc.(3) A handoff mechanism supporting cooperation of mobile hosts is proposed. It mainly resolves the handoff managemen issue of the cooperation solution access terminal has switched network infrastructure management. It established a multi-hop connection mechanism and an estimation method of quality of connections based on AHP and fuzzy theory. In the heterogeneous convergence infrastructure and infrastructureless networks, the fuzzy estimation method overall takes into account metrices of networks and terminals and resolves the issue to chose optimal connection. On this basis, we further propose a handoff decision-making algorithm supporting for multi-hop connections to access seamlessly. The experimental results show that comparing with existing mechanisms, the connection option and handoff mechanism can achieve better performance in the aspect of arrival rate of packets, transmission delay, control packet overhead and the switching frequency. (4) A location management mechanism supporting cooperation of mobile hosts is proposed. It supports a mobile host in the coverage of base stations or access points (BS/AP) single-hop accesses infrastructure networks, and a mobile host outside the coverage of BS/AP multi-hop cooperation accesses infrastructureless networks. It designs a registration architecture in order to support for accessing of multi-hop cooperation. And a dynamic location update and query mechanism is proposed. Theoretical analysis and experimental results show that the location management mechanism solves the problem of registration, update and query of multi-interface terminals. And it is able to improve call arrive rate.