The impact of IEEE 802.11 MAC strategies on multi-hop wireless mesh networks

This paper analyzes the impact of different MAC (medium access control) and transmission rate adaptation schemes on wireless mesh networks. The considered protocols include three different MAC protocols specified in IEEE 802.11 standards, i.e., 802.11, 802.11e, and 802.11n, and three rate adaptation schemes, i.e., ARF (automatic rate fallback), RBAR (receiver-based auto rate), and 802.11n rate adaptation. We also study the interactions of these MAC strategies with the state-of-the-art routing metric ETT (expected transmission time). Through comparative simulation evaluations, we investigate the effectiveness of these protocols when they coexist on both single-hop and multi-hop wireless mesh network environments. As these MAC strategies are designed for single-hop WLANs, we observed their limitations on multi-hop wireless mesh networks. We analyze their performances and suggest solutions for improvements. Based on our simulation results, we also argue for the need of a new routing metric that takes advantage of the new emerging MAC features.