Performance Evaluation of Varying Contention Window Size for Bandwidth Constrained Routing in Adhoc Networks

Abstract

Providing bandwidth efficient routing in ad hoc networks is a challenging task Available bandwidth of nodes is accurately evaluated before finding route from source to destination Accuracy of available bandwidth is mainly affected by collision and overhead due to the execution of backoff scheme Existing bandwidth constrained routing uses binary exponential backoff which follows serial transmission and causes unfair channel access To overcome these implicit pipelined backoff procedure is proposed to improve the available bandwidth and reduce the overhead associated with the backoff scheme employed in medium access control layer In this when two nodes are sharing the channel the remaining nodes start the channel contention procedure in parallel to transmit next packet Thus the channel waiting time is reduced Each node maintains separate contention window for each phase in pipelined backoff Proper choice of contention window size has great effect on performance of the network This proposed algorithm is combined with a reactive link disjoint multipath routing protocol called AOMDV Adhoc Ondemand Multipath Distance Vector to find the best path based on bandwidth Experimental results show that this algorithm outperforms existing approach in terms of QoS metrics such as delay throughput packet delivery ratio and energy consumption for different contention window size