Queue-based contention control for congested multihop wireless networks

In multihop wireless networks, packets from a source node are relayed by intermediate nodes (relay nodes) toward their destination node along a multihop wireless path. However, if a relay node simultaneously receives a large number of packets and fails to forward them at the same rate as they are received, the end-to-end throughput performance of the network degrades due to packet losses at the bottleneck relay node. In this paper, we propose an adaptive contention control algorithm that adjusts the channel access probability depending on the level of congestion at each relay node in order to improve the end-to-end throughput performance in multihop wireless networks. In this algorithm, a bottleneck relay node is granted permission to increase its channel access probability by reducing its contention window size, thus enabling it to forward packets more aggressively. Through a series of simulations, we show that the end-to-end throughput is improved by about 60% in a chain topology.