Research On AODV Routing Protocol In Ad Hoc Network

With the wide application of Ad Hoc networks in various fields, there have been higher requirements for the routing protocols which are responsible for the data communication between nodes. However, in the traditional routing protocols, due to the random movement of nodes and constraint of energy resource, nodes usually may run out of energy, which leads to the break of links in the process of optimal path, even results in partition of networks. Therefore, this thesis has a deep study on routing in Ad Hoc networks in terms of finding an optimal path and energy optimization of nodes, the main work is as follows:Firstly, to solve the problems of uncertain movement of nodes, and long convergence time in traditional optimization algorithms, the thesis combines the genetic algorithm and ant colony algorithm with the characteristics of AODV routing protocols in Ad Hoc network, and puts forward a new AODV routing protocol based on the improved genetic-ant colony algorithm. First of all, the proposed algorithm takes advantage of the global quickly searching ability of genetic algorithm to obtain the optimization solution set of path and transforms it to the initial pheromone distribution of ant colony algorithm, and then improves the updating rules of pheromone of ant colony algorithm, takes synthetically both the residual energy of nodes and the link delay in the process of searching path into account, and finally picks out an reasonable and effective optimal path in an adaptive way by utilizing the positive feedback characteristics and the capability of rapid searching. Simulation results show that the proposed algorithm has a good effect on the packet delivery ratio and average end-to-end delay and prolongs the network lifetime.Secondly, to solve the problem of network partition which results from the limited energy of nodes and excessive consumption in present Ad Hoc network, the thesis puts forward an improved AODV routing protocol based on energy optimization. The energy optimization of nodes is always taken as the metric standard during the routing process, so that nodes can quickly and efficiently complete the path selection to ensure the reliability of data transmission. The specific method is demonstrated as follows: energy information of nodes and hops of route are considered in the selection of path, and during the process of route establishment, intermediate nodes forward route request in according to delay function which associated with their own energy, thus nodes that have high energy have greater probability to participate in routing request, as much as possible to reduce the participation of low energy nodes; and the destination node has a delay record and waits for the arrival of all request packets, and then selects the best route according to evaluation function. Simulation results show that the improved scheme can balance the energy consumption of the network, and has great advantages in terms of packet delivery ratio and throughput, and prolongs the lifetime of network.