Summary: Multicast is a fundamental routing service in wireless mesh networks (WMNs) due to its many potential applications such as video conferencing, online games, and webcast. Recently, researchers proposed using link-quality-based routing metrics for finding high-throughput paths for multicast routing. However, the performance of such link-quality-based multicast routing is still limited by severe unfairness. Two major artifacts that exist in WMNs are fading which leads to low quality links, and interference which leads to unfair channel allocation in the 802.11 MAC protocol. These artifacts cause the multicast application to behave unfairly with respect to the performance achieved by the multicast receivers.
In this paper, we design a MAC layer solution to improve the fairness of multicast service in WMNs. Our proposed MAC layer takes into account the interference among multicast forwarding nodes and assigns them transmission time slots while maximizing the spatial reuse for high throughput. Detailed simulations and testbed experiments show that our solution significantly increases fairness as well as throughput compared to the 802.11 protocol.