Research And Improvement Of Repair Procession Of AODV Protocol

Mobile Ad Hoc network is an autonomous system of mobile hosts connected by wireless links. Such networks are useful in military and other Special applications, e.g., army's quick spread and advance in the battlefield, emergency rescue or exploration missions after earthquake and flood, where cellular infrastructure is unavailable or unusable. In such networks, each mobile node operates not only as a host but also as a router. This network has a series of the strengths, for example, Ad Hoc can be built rapidly and easily, and it is not restrained by wired network, and so on. Because of constantly changing topology, Ad Hoc networks can not adopt traditional routing protocols, node's dynamic change causes the probability of the route break in Ad Hoc network occurs higher than the common network. AODV protocol is used as the main protocol in Ad Hoc network, therefore the research and improvement of AODV repair routing becomes the most important Part of the application of AODV protocol in the Ad Hoc network. This thesis consists of two separate parts.The first part is a research and illustration of the Ad Hoc network and the basic principle of AODV protocol. Firstly, the situation of current research, application and the development prospects of Ad Hoc network are elaborate, as well as the current routing protocols used in Ad Hoc network. Then the research emphasis AODV protocol is introduced, including its basic principle, the formate of main message frames and the related data structures, as well as its routing mechanism and working procedure of each step. The second part presents the research on the routing repair of AODV protocol and the improvement for it. Firstly, the principle of the AODV routing repair is elaborated. Then the analysis and comparation of current routing repair methods and the main improvements are given. After pointing out the problems of the current methods, an improved AODV break-link routing repair protocol is presented, that is OLR-AODV (Optimized Local Repair AODV). OLR-AODV resolves the break-link repair problems of AODV protocol in a better way, enhanced the efficiency of AODV. Finally, based on the research of the main functions of routing repair procedure, the network model of OLR-AODV and the coding methods for the main protocol parts are presented.