Research On Mobility Management In Wireless Heterogeneous IP Networks

Future wireless communication network is an all-IP based heterogeneous networks, need to serve more high-density, high-mobility users and support roaming between different access networks and core networks, which will produce an effect on service quality and plenty of systemic resource depletion. Mobility management (MM) means the ability to provide constant service during the mobile node (MN) move within the whole network coverage, that is to say, communication and service access is independent from the position of MN and the access technology. That is the most challengeable critical technology for future ubiquitous and heterogeneous networks. Research on finding a reasonable, effective and optimized mobility management scheme is one prerequisite of always-on-line and 5W telecommunication, which will also promotes other related information technologies and brings great economic and social benefits.This thesis focuses on the some key technologies related to mobility management of wireless heterogeneous IP networks, mainly including: location management of link layer mobility management, host-based network layer mobility management, network-based network layer mobility management and the policy-based mobility management architecture of heterogeneous networks.In terms of link layer mobility management, this thesis deduces the relation between failure and success call status under location update failure rate and analyzes the effect on call failure rate from main network parameters, which provide the basic theory for optimizing call performance under location update failure. A new location update scheme is introduced, in which the location update failure rate is considered.Then the thesis focuses on the MM technology of network layer in heterogeneous network. Hierarchical mobile IPv6 (HMIPv6) protocol is a regional mobility management protocol for MN, which is also an expansion and optimization for MIPv6 through dividing region to reduce signaling cost produced by MN moving within a region. But when MN migrates from one region to another, HMIPv6 can not reduce the binding update cost, the switching delay, the packet lost rate and so on. To reduce the high cost of binding update, the paper proposes a new HMIPv6 binding update and paging policy based on pointer forwarding, which can effectively improve network performance through controlling the length of pointer to reduce signaling cost when idle MN is moving between different regions.Proxy MIPv6 is a low-complicated, easy-run regional mobility management method of the network layer. In proxy MIPv6, a new functional entity instead of MN is in charge of update binding information. The functional entity will provide transparent MM to home agent and correspondent node, and lower the cost at the same time. However, proxy MIPv6 relays data flow to MN service access router through tunnel, packet forwarding cost is increased. Comparing the expenses between above two IPv6 schemes, the thesis gives a decision function on how to choose the proper one, named self-adaptive MM scheme, so as to minimize the system cost.After that, a policy-based mobility management architecture is proposed, which can not only describe behavior a mobility management entity should have under different protocols, services, mobility schemes according to subscribers, networks and so on, but also choose management process under different conditions. That will make management entity more flexible so as to deal with system extension when there is new demand of technology or upgrading on mobility management system.Finally, summarize the discussion and future step on this field.