Research Of On-demand Multicast Routing Protocol Based On The Stability Of Path In Ad Hoc Networks

Mobile Ad Hoc network is an autonomous and temporary multi-hop system, which iscomposed of a group of mobile terminals with wireless communication transceiver. Due to therandom mobility behavior of all nodes in Ad Hoc network, its topology changes frequently,which cause a significant impact on network performances. Besides, with the rapiddevelopment of various applications, people’s requirements of the quality of service becomemore and more urgent. Therefore, there is a extremely vital significance to design a multicastrouting protocol based on the stability of path in Ad Hoc network, in order to reduce therouting interruption and improve its adaptability to dynamic topology.This paper firstly introduced the topology structure, characteristics and applicationscenarios of the Ad Hoc network, and made the classification and analysis on the currentresearch status of the stability of path about routing protocols in Ad Hoc network. Thenthrough the in-depth study of all kinds of typical multicast routing protocols, and according totheir respective advantages and shortcomings, a greedy stable routing protocol based onODMRP whose comprehensive performance is better called GS-ODMRP is proposed.ODMRP is improved by GS-ODMRP mainly on the following optimized measures:1. To deal with the problem of the performance degradation due to the request floodingduring the routing establishment of ODMRP, GS-ODMRP set up the primary routing bygreedy forwarding to limit the flooding and make the route length approximately equal to theshortest path, which reduces the protocol overhead and transmission delay.2. Considering the stability of routing, the robust mechanism is used based on theprediction of link lifetime to ensure the backup routing is still available when the primaryrouting fails, so as to prolong the average route lifetime and improve the stability of routing.3. In order to reduce the adverse effect on the failure of routing, the routing ismaintained before its failure, which makes it active and adaptive to the dynamic changes of network topology. The method of maintenance effectively improves the overall performanceof the protocol.In the latter of thesis, GS-ODMRP and ODMRP were realized on the simulation platformcalled NS2, and compared through the four performance index of average route lifetime,packet delivery ratio, control overhead and end-to-end delay, which verified the effectivenessand optimization of GS-ODMRP.