Research On Distributed Topology Control Algorithm And Protocol For Mobile Ad Hoc Networks

Mobile Ad Hoc Networks (MANETs) are comprised of a collection of wireless mobile nodes communicating with each other without any support of fixed communication facilities. MANET are self-organized, which are very useful in such applicants where temporary, fast and on-demand communication needed to be built.Topology control is an important research field in mobile Ad hoc networks. Existing research results show that as a network supporting technology, topology control can maintain the network connectivity while reduce the transmission power and then enhance channel spatial reuse, thus prolonging the network lifetime and improving the network performance by adjusting the node's singnal range to estabilish an appropirate neighboring relations.The main work of this paper are as follows:(1)By analysis of the characteristics of Mobile Ad hoc networks, we study the significance of topology control and research issues. A novel Media Access Control protocol with topology control for Ad hoc network is proposed. The characteristics of the topology control algorithm are considered. Through the RTS/CTS handshake mechanism the distance of neighbors can be computed while the transmission power of data packet can be adjusted according to the topology control algorithm. In order to ensure the integrity of the information collected, a self-active algorithm is presented. Simulation results show that the new protocol can effectively support the application of topology control and provides higher space division of the network then higher network throughput and lower end-to-end delay.(2)Analyse the impaction of mobility on exsisting topology control algorithm, then advance a distributed topology control algorithm-LTETMTC(Local Topology Expire Time-based Topology Control for MANET). Through the prediction of neighbor-hood expire time, node can determines the stability of neighbors then chooses the proper ones as the logic neighbors. Theoretic provement of the high-probability connected properties of the LTETMTC-generated topology is given. As a distributed algorithm, in LTETMTC only local information of neighbors is in need for a node. Experiment results show that the proposed algorithm significantly reduces the average link broken counts, and improves the routing protocal performances by supporting a stable topology.(3)In order to adding the function of topology control to network protocol, we extended the standard MAC processing module of the OPNET simulator, add the module of topology control to it and verify the effectiveness by experiments. On the Extension of mobility models interface of OPNET simulatior, a mobile network platform is built to analyse the double influence of mobility and signal interferance on the performance of network transmission and routing protocol.