Centralized Channel Assignment for IEEE 802.11 WLANs: Utilization MinMax-Sum

The ubiquitous wireless local area networks (WLANs) have been deployed almost everywhere imaginable including homes, offices, cafes, shopping malls, universities, airports and even cities. While this can potentially increase capacity and coverage, the problem of increased interference and contention can severely degrade its performance. With increased deployment density and the limited number of channels available, it is imperative that an effective channel assignment scheme is employed. In one of the earlier prominent work, the centralized channel assignment problem was formulated with the objective function of minimizing the effective channel utilization at the access point (AP) with the highest utilization or bottleneck AP. However, the scheme does not consider any channel changes that do not lower the utilization of the bottleneck AP, even if they can lower the utilization of other APs. Therefore, in this paper, a channel assignment scheme that considers the utilization of other APs without compromising the utilization at the bottleneck APs is proposed. Simulation results show that the proposed scheme not only can lower the sum utilization of all APs but also can minimize the utilization at the bottleneck APs.