Research And Simulations Of Multicast Routing Protocols For Mobile Ad Hoc Networks

Mobile Ad Hoc Network (MANET) is a multihop provisional autonomy system that is made up of a group of portable terminals with wireless transmitter, in which mobile nodes communicate with each other without the required intervention of any centralized access point or fixed infrastructure. It will be widely used in critical environment such as military or civilian emergency operations because it has many advantages such as it yarely, quickly and absolutely distributed etc. MANET routing protocol has to deal with the dynamic topology, unidirectional link, limited wireless bandwidth and capability-constrained of mobile nodes, etc. So, the MANET routing protocol must play a more important role than others.Multicasting is the transmission of datagrams to a group of hosts identified by a single source address and hence it is intended for group-oriented computing. In a typical MANET, multicasting is very important. On one hand, Ad Hoc users need to cooperate with each other; and on the other hand, it is important means of making the best of limited wireless channel .In view of the feature of MANET, now many kinds of multicast routing protocol are proposed, and some of them have been tested in special wireless network with small scale.In this thesis, firstly we briefly summarize and compare the existing multicast routing protocols based on the characteristic of MANET, and give the analysis of MAODV protocol (Multicast Ad Hoc On-Demand Distance Vector Routing Protocol) in detail. Then the design architecture of MANET multicasting protocol and the solution to the key technologies on OPNET network simulator are presented. Secondly, we describe the improvement and modification about MAODV for scalability. We proposed a protocol named DMAODV-MP (Distensible Multicast Ad Hoc On-Demand Distance Vector Routing Protocol based with Mobility Prediction) that is enhanced the scalability and haleness of protocol,it is effectively solve the question about blindness broadcasting of multicasting control packets on MAODV, it adopts priority-based competitive broadcasting algorithm to send control packets that is greatly reduce the broadcast on networks, at the same time overhead is reduced also. In the new protocol the mobility and link status have been detectected according to the specified algorithm before the node transmits the packet.And it selects a new valid routing to transmit the packet if the link brekage occurs soon.This method improves the performance of the routing protocol greatly. And we conduct plentiful experiments on OPNET simulator about MAODVand DMAODV-MP multicast routing protocols to prove the correctness of our implementation. The simulation shows that the improvement could enhance the performance in the high movement mobile Ad Hoc networks. Finally, we give the conclusion of our work and suggestions for future research direction of Ad Hoc Mobile Networks.