The Research And Improvement Of AODV Routing Protocol In Wireless Ad Hoc Network

Ad Hoc network is an open, multiple nodes together to form a non-human intervention,non-pre-self-organizing network infrastructure.It can be achieved within the framework of a limited number of mobile terminals being connected. Because of flexible networking, fast and efficient characteristics,it is widely used in civilian,military, disaster relief and other fields. In order to support the Ad Hoc network,we must have appropriate routing protocols.Now, Ad Hoc network routing protocols include on-demand routing protocols and table-driven routing protocols.There are differences between the performance.We can quantitatively compare and measure these protocols.Therefore,how to improve the performance of routing protocols has become a research hotspot in Ad Hoc Networks.This dissertation focuses on demand routing protocols for Ad Hoc Networks such as the AODV protocol. In the Ad Hoc network, the nodes will join or leave the network randomly, resulting in the network topology constantly changes.Also making the routing's disconnection happen frequently. Thus, the nodes repairing the routing becomes very important.By analysing the characteristics of the AODV protocol as well as specific operational processes, then summarize the advantages and disadvantages of AODV protocol performance.We base on the disadvantages, then discuss the redundant control messages'issues of AODV protocol and put forward an improved D-AODV protocol with the combination of the source node's repairing routing and the local node's repairing routing. The new protocol has the following characteristics:(1) introducing the concept of pre-detection group.(2) when the mobile nodes move with high speed, effective in reducing the production of redundant control messages.(3) increasing the overall network packet transmission rate, also improving the transmission delay and reducing the routing finding time with high-speed mobile node.Finally,we test the D-AODV protocol and the AODV protocol within the use of network simulation software NS2. Experimental results show that the improvement of the AODV protocol is successful.