Cooperative Opportunistic Routing based on ETX metric to get better performance in MANET

The key objective of routing protocols in Wireless Mobile Adhoc Networks is to discover optimal path based on highest routing progress. This can be achieved by minimum HOP count routings metric. The quality of links also directly influence on the efficiency of data transmission. The best probable quality and efficiency of data transmission can be achieved by optimizing several performance metrics as delay, routing overhead, delay variance, packet loss, which are directly effects on the ratio of successful transmission of data. The recently proposed opportunistic routing paradigm takes the decision on route selection by considering the quality of links on account. In this paper, we addressed the problem of best forwarder selection in Cooperative Opportunistic Routing in Mobile Adhoc Network (CORMAN) protocol. Expected transmission count (ETX) based transmission scheme is proposed and implemented using NS-2 simulator for CORMAN protocol. Simulation and comparative analysis shows that ETX-based-CORMAN outperforms both HOP-based-CORMAN and AODV in terms of throughput, delay and delay variance under varying network size and speed.