Cross layer congestion aware multi rate multi path routing protocol for ad hoc network

Modern wireless devices, which implement the 802.11b standard, utilizes multiple transmission rates in order to accommodate a varied range of channel conditions. Many rate adaptation algorithms proposed, utilizes the multi data rate, primarily according to the current channel quality. Most algorithms do not consider congestion around the network and proper determinant to identify it. In multi rate Ad hoc network, due to mismatched link rate, the node interface queues get overloaded. Thus causing congestion, which consequently result in packet loss, further reducing effective throughput. In this paper, we propose a novel Cross layer QoS aware Multi Rate routing protocol (CQMR) based on nodes queuing load and link state. CQMR focuses on cross-layer interactions between PHY, MAC and Network layer to utilize these multi-rate supports from 802.11b. CQMR algorithm chooses the optimal path with effective data rate and through a less congested network, which is compatible with existing 802.11 implementations. We have implemented CQMR in the NS-2 simulator and conducted extensive simulation studies over network diversity. Our analysis shows that CQMR protocol significantly increases the network performance in the packet delivery ratio and throughput.