Research On Self-Adaptive Routing Algorithms For Mobile Ad Hoc Network

With the accelerating of social informationization, wireless mobile communication networks have become an irreplaceable component of daily life, and the development of relative researches has promoted the process towards"information world and the digital earth". As an important branch, the strong points of infrastructureless, rapid networking and flexible to carry out of mobile Ad Hoc network make it adaptable and survivable, and it can meet special needs such as battlefield deployment and disaster relief. It is these advantages, however, that brings new challenges for mobile Ad Hoc network research. Besides the bandwidth and energy limit, weak wireless connection and so on, mobile Ad Hoc network has to meet more than topology frequent changes, multihop forwarding and lack of central scheduling, which restrict the development greatly.The characteristics of centerless control and topology frequent changes, make routing problem one of the most important technical keys. The former means multihop style needs to be adopted, and the latter indicates each link of the route is unstable and unreliable. As a field that carried out earliest and achieved most, routing design has many issues to be addressed. This dissertation will mainly focus on the deficiency of network adaptability from routing algorithm of mobile Ad Hoc network, and carry out from node neighborhood state update, transmission balancing and local repair after link invalidation to make the routing algorithm be able to react with dynamic environment through setting up mapping relationship between environment variables and routing factors by the loop control algorithm and optimal exploration theory, so as to improve traffic transmission efficiency and service quality.Firstly, this dissertation will analyze and expatiate on the causes and impacts of the neighborhood maintenance, the traffic balancing and the link repair around routing technology in mobile Ad Hoc network. With an introduction on representative solutions from different points of view, the achievements and problems remained will go into details. The design of dynamic environment-oriented typical routing algorithms has been taken apart, and the essence of routing issues as well as relationship between network environment and algorithms devising will be presented, based on which the ideological line of this dissertation will be mapped out. Secondly, the neighborhood state maintenance and update problems in routing issues will be addressed. The impacts of fixed updating cycle in neighborhood state maintenance will be analyzed. Local topology flapping measurement will be devised to judge the stability of neighborhood state. The control model of state updating cycle and its relationship with LTFM will be established based on loop control theory. The neighborhood state self-adaptive updating algorithm will be proposed to ensure that the updating cycle will be set and adjusted dynamically according to network environment so as to reduce the control overhead and improve traffic transmitting efficiency.Moreover, the issue of transmission balancing when the traffic concentrates on some links or nodes will be studied. Impacts of long time usage about some certain paths according to reactive routing protocol on the network life time and transmission efficiency will be analyzed in detail. The traffic load measurement will be devised to judge the busy degree. The self-adaptive traffic balancing routing algorithm will be proposed to make nodes balance the transmission according to the value of load measurement. Besides, considering some individual nodes may refuse to forward to save energy in balancing process, a self-adaptive traffic balancing fairness auxiliary algorithm will be proposed to detect the selfish nodes quickly and exactly to compel them to join in balancing process in order to prolong the network life time.Finally, the local link repair problem caused by relative motion or environment changing will be presented. The exploring model and corresponding state functions from the local node to the next hop will be established by the optimal exploration theory, so as to convert the optimal exploration problem into the local repair one. A route quality inspection approach based on traffic packets received power will be adopted to alleviate the delay cause by repair process initialed after the link invalid and establish the relationship between network and route repair. Combining route inspection result and radial solution from the optimal exploring model, a local link self-adaptive repair algorithm will be proposed by restricting the flooding region to repair the route with less cost and higher probability. Furthermore, an optimizing algorithm will be supplemented to solve the problem of more than one solution obtained so as to ensure the shortest route with stability.