The Research Of Hierarchical Routing Protocol Based On Link Stability Prediction

A Mobile Ad Hoc network is a distributed wireless multi-hop network, which doesn’t depend on any fixed infrastructure. It has many advantages, such as flexible networking, quick deployment so that Ad Hoc network has wide application in the military and civilian fields. So, many routing protocols have been proposed, for example, on-demand routing protocol like AODV and DSR which choose the shortest path as routing metric. Compared to AODV, DSR is more stable to choose path, but it only applies to a small network. So, a hierarchical routing protocol is proposed, in which a number of intermediate nodes are selected as up-nodes including the source and the destination, and others are down-nodes. They run different routing protocols each other. So far, domestic and foreign scholars have proposed various hierarchical routing protocols, such as CGSR, ZRP and so on, but they only run a unique route protocol. In this paper, up-nodes run DSR and down-nodes run AODV, which is named as DSR over AODV (DOA routing protocol). Its main characteristic is to combine the respective advantages of DSR and AODV and to make up for the inadequacies. At the same time, in the routing repair mechanism, DOA reduces the number of global routing repair and increases the proportion of local routing repair so as to reduce the overhead greatly.The significance of DOA is to reduce the overhead in the wireless transmission and to quickly repair the interrupt path to maintain reliable persistent transmission status. However, when link interrupt occurs because of node damage and node moving, whether global repair or local repair(including interrupt notification, route discovery, data forwarding and route reply) succeeds, it will result in buffered packets in the period of time. So, in order to avoid transmission interruption, the prediction of link stability is hoped. In this paper, the solution is to combine Two-Ray ground reflection propagation model and Friis to calculate link stability, and set a threshold value. When the link stability is less than the threshold value, a warning will be issued and the node starts route discovery to find a new route which is used to replace the upcoming interrupt link. Therefore, LSP-DOA routing protocol is proposed, and its simulation is described in the MATLAB Simulator.The simulation and performance analysis of LSP-DOA routing protocol is described in MATLAB simulation platform. Then compare the performance of LSP-DOA, DOA, AODV and DSR by changing network size and the number of CBR flow. Simulation results show that LSP-DOA reduces control overhead and end-to-end delay, improves packet delivery ratio, route repair success and average route length, maintains a stable efficient route for a long time, and then improves the network performance.