Research On Mobility Management And Security In Heterogeneous Networks

With the rapid development of communication technology, the mobile communication system represented by 3G/4G and the wireless broadband access technology with representative of the IEEE 802 family of standards, continue to evolve toward their own direction, will jointly offer mobile users the diversificated and personalized network services. A variety of these wireless networks, can provide different system characteristics and service type. Future wireless communication networks will be the coexistence of various wireless access technologies, and developed together, which form the heterogeneous network environment.In the heterogeneous network environment, the mobile node can be moved from their home network to external networks, when the connection should be maintained uninterrupted. In this case, the existing mobility management mechanisms need to be improved. At the same time, because there exist a variety of secure access technology, the mobile users should be authenticated to ensure data transmission between the two kinds of network security while doing handoff. In this paper, these two major issues affecting integration of heterogeneous networks had been in-depth studied and discussed. The main work and innovation points of this dissertation are as follows:MAP-controlled load balancing scheme (MCBL): as the frequently used micro-mobility management protocol in IP networks, HMIPv6 can be also used in the 3GPP network as mobility management mechanism. The existing HMIPv6 load balancing schemes are based on the properties of mobile nodes. Because mobile node is difficult to accurately obtain the real-time load of MAP, network-based schemes are better to complete MAP load balancing procedure. In this paper, a MAP-controlled load balancing scheme is proposed, which includes two algorithms: probability-based MAP selection algorithm and the MAP-based load adjustment algorithm. Through the quantification of MAP load, mobile node can obtain the real-time load information, and then can select the appropriate MAP based on the probability. When MAP was found overloading, it can notify MN to select candidate MAP. Experimental results show that this scheme can maintain the load-balancing state with the heavy load in HMIPv6 network.Mobility management mechanism with traffic characteristics: mobile node will take place vertical handoff when moving between heterogeneous networks. Various factors containing networks and terminals should be considered in vertical handoff decision making. This paper proposes a traffic-based vertical handoff decision scheme, with comprehensive consideration of QoS parameters in the various networks. Then the handoff target network is selected by the first-fit algorithm. At the same time, as the most important systems in the future mobile communication networks, LTE network can adjust handoff parameter to complete mobility load balancing function. This paper also presents a traffic-based mobility load balancing scheme to adjust handoff parameters according to the specific traffic characteristics in user equipment. Simulation results show that the mobility management mechanisms based on traffic characteristics can effectively reduce the number of invalid handoff, and improve the stability of the network system.A Diameter-based secure context transfer mechanism (DSCT): As the heterogeneous network contains many types of network, which led to mobile nodes cannot guarantee the security of context transfer while handover to another network. In this paper, a diameter-based secure context transfer mechanism is proposed, which can applied to Mobile IPv6 and 3GPP networks. Before context transfer, the Diameter servers can used to guarantee the safety of context related messages. Through the security service view model, DSCT is suitable for heterogeneous network environments to provide security.Also, a process-based paradigm of LTE system-level simulation platform prototype implementation is introduced. As event-based paradigm and activity-based paradigm are mostly used in the existing network simulation platform, which makes the network scalability and the module relationship very complicated. The simulation platform focus on achieving the SON and related functionality, which can used to guide the design of handoff parameter adjustment. The experiences in designing and implementing of the simulation platform are of high value of SON proposals selection.