Research On Clustering Algorithm And Routing Protocol In MANET

Mobile Ad Hoc networks formed by a collection of mobile nodes through radio links are multi-hop and temporary autonomous systems. They are typically characterized by their un-center, self-organization, dynamically reconfigurable network topology and limited resource. With the hierachical structure, the Cluster Head take charge of the routing not only between the nodes in the local cluster but also between the nodes in the local cluster and in the other clusters, therefore, how to select the most reasonable nodes to be Cluster Heads is the pivotal problem in clustering algorithm. In addition, because the nodes can move freely into or out of a cluster, the links may break at any time, and the service of routing will be affected. So how to build and maintain the links to supply a better service is very important.The paper analyzes and compares many typical clustering algorithms, and then brings forward a new AOW clustering algorithm by use of mobility prediction model, which is called MP_AOW clustering algorithm. In the clustering algorithm, each mobile node is learning from its own mobile history, and dynamically forming a mobile tree. Then, the mobile node can predict how long itself will stay in the virtual cluster, and which virtual cluster it will visit with how much probability, and how long it will stay in the virtual cluster. MP_AOW clustering algorithm weighs the mobility, the capability of management, the transmission ability and the power, and then selects the most appropriate nodes as Cluster Heads. The result of simulation shows that, compared with the LOWID clustering algorithm and the HIGHD clustering algorithm, MP_AOW clustering algorithm have more stable clusters.Based on the stable cluster structure of MP_AOW clustering algorithm, the paper brings forward SC_AODV routing protocol. By use of the mobile tree, each mobile node can predict how long itself will stay in the virtual cluster. So we can predict the shortest staying time in a corresponding link, which is the life time of the corresponding link. Before the link breaks, a new link is built up. If the source node (or the destination node) leaves the virtual cluster A to virtual cluster B, it must tell the destination node (or the source node) to set up a new link which can arrive to B's Cluster Head. The result of simulation shows that, in the same situation, the packet delivery ratio and the data packet delivery fraction of SC_AODV are higher than AODV's.