Research On Mobility Management In Hierarchical Multi-hop Mobile Wireless Networks

With the increasing requirement of mobile communication, the mobile communication system has been widespread deployed. However, because of the centralized management and control, the operation of the mobile communication network is relied on preexisted fixed network infrastructure. This makes it unsuitable for several special situations, such as the expanding and propelling of armies in battlefield, the management of rescue work after disasters like earthquake or flood happened. So networks of special structure are introduced which can be rapidly deployed without relying on any preexisted fixed network infrastructure and can also be automatically configured as well as adapted themselves to the dynamic changing of node location. One of these networks is the Hierarchical Multi-hop Mobile Wireless Networks (HMWN), as researched in this dissertation.HMWN contains two kinds of nodes, mobile users and mobile switches. Only mobile users can be sources and destinations of user data traffic, and only switches can perform the functions of routing and forwarding, as well as the organization of the network. The architecture of mobile switches forms as Ad hoc networks while the architecture between mobile switches and mobile users is similar to that of the cell mobile communication system. So HMWN inherits the advantages of both Ad hoc networks and the cell mobile communication systems. In general, the mobility management is the set of mechanisms providing time-varying mapping between the identifier of mobile users and their addresses (i.e., where the users are located with respect to the network structure). The main function of mobility management is to effectively support the seamless roam of mobile users, equipments and serviceswithin the whole service network. These characters of HMWN make it very important of mobility management. However, there are still several problems existed without any proper solutions. This dissertation studies mobility management in HMWN and pays attention to macro mobility management, micro mobility management, and user handoff management as well as the route handoff management.In Chapter 2, according to the battlefield and emergent status of the environment mainly in use of HWMN, a macro management method is proposed, which uses a few agents to compose a logical home agent to obtain high survivability. Compared with other strategies of macro mobility management, its main advantage is that the physical counterpart relationship between user and home network, user and home agent, home network and home agent is released. Based on the logical home agent composed of several physical distributed management entities, the macro mobile management obtains its high reliability and survivability and increases the update velocity of node location at the same time. It also solves the problem in traditional mobile IP that the HA must be located in the home network and the frangibility caused by single HA.In order to solve the problem of the user location management, Chapter 3 proposes a user micro mobility management algorithm combined with the advantages of HMWN, the traffic characters, user location management and route discovery. This decreases the user management overhead. Compared with other strategies, its main creativity is that the algorithm needs no special packets for location update and remarkably decreases the location overhead when the user traffic load is relatively low. So it is suitable for highly dynamic environment.Chapter 4 proposes a switch selection algorithm during user handoff. It aims to solve the selection problem when user switches to another...