A Distributed QoS MAC Protocol for Wireless Mesh

Abundant hidden node collisions and correlated channel access due to multi-hop flows degrade QoS in wireless mesh networks. QoS in nearby WLANs operating on a single channel is also affected. We propose using wider contention windows for backoff to lower the risk of repeated hidden-node collisions, a spatial extension of the TXOP concept called ´express forwarding´ to clear multi-hop flows sooner, and a new mechanism called ´express re-transmission´ to reduce collisions on retransmission. Simulation results show the potential benefit of the proposed enhancements and impact on fairness.