SIMULATION STUDY OF ODMRP WITH MOBILITY PREDICTION IN AD HOC NETWORKS

Abstract

On-Demand Multicast Routing Protocol (ODMRP) is a reactive, multicast protocol for Mobile Ad hoc Networks (MANET) that delivers packets to destination(s) on a mesh topology using scoped flooding of data. ODMRP adopts the shortest path approach to deliver packets to the receivers. However, the shortest path may fail quickly, because some of the wireless links on the shortest path may be broken shortly after the path is established due to mobility of nodes. Further, multicast sources periodically broadcast the query packets to refresh the routes and group membership. This excessive data flooding and rediscovering of routes leads to substantial data loss and communication overhead. In this thesis, a mobility prediction scheme for ODMRP using GPS location information has been proposed. This mobility information is used to anticipate the Route Expiry Time and to initiate the route discovery process in advance. The proposed scheme selects stable routes as compared to shortest routes used in basic ODMRP. In this work, several entity, group and scenario based mobility models have been used to model much more realistic and practical movements of mobile nodes in real scenarios. Reference point group model, Manhattan mobility model and Freeway mobility model ' are used to evaluate the performance. Techniques to improve transmission reliability and eliminate route acquisition latency have also been introduced. The proposed scheme has been evaluated and compared with the basic ODMRP for different performance metrics. The simulation study shows that the proposed scheme is better in terms of average number of control bytes transmitted per data byte delivered and average number of packets transmitted per data packet delivered. The packet delivery ratio is high and end-to-end delay is low as compared to basic ODMRP. The simulation study has been done using NS-2 discrete event network simulator. The simulation is written in TCL & C++ and runs under LINUX on a Pentium 4 machine. iii