Game-theoretic analysis for multibandwidth WLAN channel selection by coordinated APs

As the demand for high-throughput communications in wireless LANs increases, the need for expanding channel bandwidth also increases. However, the use of wider band channels results in the decrease of the number of channels available. Therefore, if multiple access points (APs) are in proximity and the cells overlap, it is difficult for each AP to use an orthogonal channel, and competitions thus increase between the APs using the same channel. To cope with this problem, this paper proposes coordinating APs to increase throughputs at Nash equilibria. A centralized controller coordinates the APs, which jointly select multibandwidth channels. To clarify the effect of coordinating APs, we assume a simple scenario where the cells of three APs overlap, and each AP can select multibandwidth channels. In this scenario, we consider two packet length assumptions. In the first case, the data bit amount of each packet is assumed to be the same. Thus, the packet length changes depending on a data rate. The other case assumes that the packet length is the same regardless of the data rate. Through game-theoretic analysis, it can be clarified that the coordinated APs are able to select channels more effectively than if each AP independently selects channels and that the total throughput of the coordinated APs at Nash equilibria is improved by at most 80 % in two packet length assumptions.