A novel congestion control algorithm by exploiting cross-layer information in multihop wireless networks

In multi-hop wireless networks, TCP performs poorly due to the difficulty in distinguishing congestion problem from error transmission caused by MAC layer link error and collision. To solve this problem, the paper proposes a novel cross-layer congestion control algorithm based on coordination of TCP and IEEE 802.11 MAC protocols. In this work, each node can monitor the contention degree of the wireless channel in MAC layer, as a basis to determine the network congestion. And this MAC congestion information will be sent to the TCP sender using the cross-layer techniques, under which, TCP sender can dynamically adjust the congestion window size to keeping the network load at a reasonable level. Also due to the cross-layer information, TCP will know the reason of the packet loss and avoid starting congestion control mechanism incorrectly. Simulation results show that this algorithm could provide a more efficient solution for frequent transmission losses, and thus result in a significant improvement of the network throughput.