Research On Modified Routing Algorithms Based On AODV

Ad Hoc network possesses the characteristics of no centre, self-organization, temporary self-government and so on, which makes it suitable for establishing communications network in a variety of urgent and temporary environments. Ad Hoc network broadens the application field of mobile communications, which has a bright future. For its particularities differing from the existing wireless communication systems, Ad Hoc network addresses many special problems which have not been effectively solved, with research focus on routing protocols, energy issues, QoS security and management of wireless bandwidth resources.Ad Hoc network is a kind of multi-hop network, which has limited bandwidth resources and limited energy of nodes. Routing cost and energy saving become the two important issues. Most of the existing classic routing protocols such as AODV and DSR choose minimum hop as metric, considering neither the routing cost of sending packets nor energy saving of nodes. Thus, it is urgent to design a high-performance routing algorithm to meet the requirements of the Ad Hoc networks. This paper focuses on researches around these two issues, including following three parts.Firstly, having an in-depth study of the AODV protocol based on minimum hop routing algorithm. Including its route process of discovery and maintenance, its modeling on OPNET simulation platform, and analysis of its performance based on different packet transmission rate, different motion speed, different transmission power and different size of network.Secondly, researching on the limited bandwidth resources of Ad Hoc network, and proposing a minimum cost of routing algorithm based on the AODV routing. That is, route cost items are added to the RREQ and RREP and the minimum hop of AODV routing is changed into the minimum cost routing. Then, the optimized algorithm in a simple network is simulated, including analyzing and comparing delay time of network and statistical data of throughput.Finally, analyzing limited energy problem of Ad Hoc network. Under the guidance of learning and summarizing the two main algorithms, that is, minimizing the energy consumed for each packet and maximizing lifetime of the network. We proposed an EAODV algorithm (Energy-saving Ad Hoc On-demand Distance Vector routing algorithm) based on AODV routing Algorithm, considering shortage of these two algorithms, combined ideas of the two energy-saving routing algorithms and characteristics of wireless links. The algorithm selects routing according to the dynamic priority factor, and adopts back up routing mechanism. In EAODV, the route which spends lower energy and owns larger dynamic priority factor is selected by synthetic analysis. As a consequence, it can save more energy. This algorithm is under a theoretical analysis and computer simulation validation, which is feasible and effective. It provides a certain reference value for the research and realization of energy-saving algorithm in mobile Ad Hoc networks.