Analysis And Improvement Of AODV Routing Performance In Manets

Hoc Ad network is a network which has no fixed equipment support. Users need to use its own network. It usually consists of tens to hundreds of thousands of nodes. It is usually used in wireless communication. It has a dynamic network of multi hop mobility, because each node can transmit data, so each node has the function of routing.The mobile node in the network has both router and host function. The fast moving node, dynamically changing topology and unstable link as well as the unreliable wireless channel in the ad hoc network is the main problems need to be considered in the design of routing algorithm. The design goal of the routing protocol should not only minimize network overhead, but also and improve overall network performance on the basis of satisfying the addressing function.In mobile ad hoc network protocols, On-demand distance vector routing protocol has better performances compared to other protocols and is also a hot area of research at present. This paper analyzes the route discovery process and route maintenance process in detail and discusses the problems in the route discovery process, that is AODV protocol establishes route only according to the smallest hops, taking little route survival time and stability into consideration. In the light of shortcomings mentioned above, this paper proposes an improved protocol named O-AODV on the basis of the traditional AODV, which gives a new way to build a much stable route with a longer survival time. This new protocol takes into account the impact of node motion and edge effect on link availability and takes the volatility of time lag between the neighbor node sends out a hello packet and the node receives it as the standard of node stability. Stability value is calculated when the node forwards the RREQ packet and this information is added to the RREQ packet, accumulating with the successive forwarding until it reaches the destination node. The destination node creates the best route from the source to the destination in accordance with the stability information carried by the RREQ packets received.At last the article presents the performance comparison between O-AODV and AODV protocol with the help of the NS-2 network simulation platform. From the two scenarios of different node mobility and node number, it can be seen from the experimental results that the improved O-AODV protocol has a better performance in packet delivery rate, routing overhead and route discovery frequency.