QoS for Wireless Mesh: MAC Layer Enhancements

Date Added: Jun 2010
Format: PDF

Wireless mesh networks present MAC design challenges beyond those of WLANs. Abundant hidden nodes increase the number of collisions. This, combined with the correlated access needed when forwarding a multi-hop flow, degrades QoS. MAC enhancements for meshes are presented in this paper that reduce latency for mesh traffic while promoting co-existence with nearby WLANs. Wider contention windows for backoff lower the risk of repeated hidden-node collisions, a spatial extension of the TXOP concept called 'express forwarding' clears multi-hop flows sooner, and a new mechanism called 'express retransmission' reduces collisions on retransmission.