QoS Research Of AODV Routing Protocol Based On The Small World Theory

Ad Hoc network is a kind of temporary, multi-hop, self-organizing network. It can be deployed quickly and don’t need infrastructure in the environment which is very harsh. It has a wide range of applications both in military and civilian. In order to guarantee the accuracy of the multimedia, real-time application, the high demand of the users for the energy of the nodes, transmission delay and so on, provide quality of service(Qo S) support for Ad Hoc network.Broadcast method for routing of AODV protocol consumes a large amount of network resources, the success rate is very small and it is inefficient. AODV protocol just uses the hop as a standard of selecting routing and doesn’t take into account the energy. If the energy of a node use up, it will make the whole route stop, affecting the network life cycle. Ad Hoc network topology dynamically changes and it often appear link break. If you choose the unstable nodes, it can also cause secondary repair.In order to improve the network life cycle, reduce the times of the link break and reduce routing overhead, in this paper, AODV protocol is improved. In the process of routing discovery, predict the nodes which will send data and route discovery process will be in advance. Use the small world theory and control the scope of broadcast message. In order to support for Qo S, when looking for a route, take remaining energy of the nodes into consideration. Local repair process is applied in the process of routing maintenance. According to the current direction of movement, the speed of the mobile nodes and the speed of the use of energy, node predict the time of the link break. Choose the nodes which keep connection for a long time to transmit data and reduce the times of the link break. In routing discovery and local repair process, the node receives the RREQ packets, at first, the node check the direction, try to choose the mobile node in the same direction, and reduces the likelihood of the link break.Simulation experiments show that compared with AODV, Modified- AODV, the improved protocol has better performance in the life cycle of the network, average hops and the routing overhead and reduces the times of routing interrupts. The improved protocol is more suitable for the network in which energy is not enough and the network in which the routing often interrupt.