Research And Improvement Of AdHoc Routing Protocol Based On Local Topology Stability

Mobile network (Ad hoc network) is a non-center, self-organizing wireless mobile communication network, which includs a highly efficient self-organization, dynamic transformation of the network topology, multi-hop forward technology, the robustness of non-central node and survivability features. So it is widely used in military tactical environment, scene of urgent accidents and field of civil wireless data communication.However, because of the transmission characteristic of wireless channel and node position of uncertainty, the network topology is always in an unstable state, which results in a link is easy to be broken. So traditional routing protocols can not adapt to these features of mobile network. Right now, the existing Ad Hoc routing protocols such as DSR, DSDV, AODV, TORA, also have their own limitation and still in the research stage. So the purpose of this paper is to optimize the existing routing protocols to improve the robustness of the network, ensure the stability and reliability of network transmission in a variety of harsh conditions and provide a higher quality of service.Firstly, I will give an overview of the Ad Hoc network in brief including the background of Ad Hoc network development, routing protocols existing right now and its shortcomings. I also will introduce some methods of protocol improvement currently. And AODV routing protocol will be introduced in detail.Secondly, through researching the factors that influence the stability of network topology and the impact of stability of network topology to the link state and based on AODV routing protocol, a topology stability routing protocol AODV-TS (AODV-based on Topology Stability) is proposed. In the improvement routing protocol, AODV-TS,1add a node energy model and take full advantage of the residual energy of nodes and nodes’neighbors information to optimize the router discovery and local repair of original AODV routing protocol.Finally, according to the NS2network simulation platform, I simulate both AODV-TS and AODV routing protocol, With the result of simulation, I compare and analysis two protocols in three aspects which represents the performance of network, including packet delivery ratio, end to end delay and routing overhead. According to analysis, we can conclude that network performance of optimized protocol is better than the original AODV protocol.