Achieving Fair Throughput in Infrastructure-Based IEEE 802.11 Mesh Networks

This paper studies throughput fairness among different basic service sets (BSSs) in infrastructure-based IEEE 802.11 mesh networks, where inter-BSS interference is unavoidable because of the difficulty in frequency and coverage planning and the limited number of non-overlapping frequency channels available for IEEE 802.11 networks. An analytical model is first developed to find the aggregated BSS transmission throughput in a mesh environment. Two approaches are studied for achieving fair throughput among the co-channel BSSs: (i) NAV-blocking which uses network allocation vectors (NAVs) to temporarily stop transmissions in some BSSs in order to control the inter-BSS interference, and (ii) forced handoff (FHO) which forces mobile stations (MSs) to handoff between neighboring BSSs in order to balance the traffic load among the BSSs. An optimization problem is formulated for each of the approaches for achieving the required throughput fairness while keeping high transmission throughput in the BSSs. Our results show that (i) using NAV-blocking can always achieve the required throughput fairness and its performance does not depend on coverage overlapping between the BSSs; and (ii) performance of throughput fairness using FHO depends on coverage overlapping between the BSSs, and when there is strong coverage overlapping among the BSSs, this approach can achieve throughput fairness among the BSSs.