Research And Improvement Of AODV Based On NS2

In recent years, of wireless networks with flexibility and simplicity such as WLAN have been applied in more and more places. However, most of these wireless networks rely on wireless access points or wireless routers and other infrastructures. As a network system that composed of a group of wireless mobile nodes which doesn't rely on existing infrastructure and could be quickly initialized, Mobile Ad-Hoc network is being concerned by more and more researchers. In this particular the network, the path used to transmit data is often composed by multiple nodes together, while the routing algorithm must face the problems that the nodes often move and the transmitting distance is limited. At present, many routing algorithms for the Ad Hoc network have been proposed.As the network topology dynamically changes with the movement of each node, Ad Hoc network routing algorithms become a research hot spot. Existing Ad Hoc network routing protocols which focus on different angles on the wireless multi-hop routing problem has been studied and optimized on one or several indicators for different applications. Currently,they can be roughly divided into the priori-type (Proactive) routing protocol, reactive (Reactive) routing protocol and hybrid routing protocols of three. AODV is an on-demand routing protocol with low control of load, low power consumption and low bandwidth overhead.In this paper,we pointed out the limitations of AODV protocol and proposed an improved algorithm through in-depth analysis of the working mechanism of AODV protocol. The routing table in AODV maintains only one route to the specified node. Therefore, the source node needs to re-initiate route discovery process as a route fails. To solve this problem, an improved method is presented in this paper. The proposed scheme suggests that each source node maintains an alternative route to the specified destination node. When the primary route fails, the source node will use the backup route to send packets. Simulation results show that this modification can not only improve the packet delivery fraction but also reduce the average end to end delay, the routing overhead and the route discovery frequency. The main Contribution of this paper as follows:(1)This paper introduces the concept and features of Ad Hoc Network.(2)It analysis the AODV protocol and points out the limitations of AODV protocol.(3)It proposes an improved algorithm for the shortcomings of AODV protocol.(4)Finally,it shows the effectiveness of the improved algorithm through the simulation based on NS2.