A Self-Managed Distributed Channel Selection Algorithm for WLANs

In this paper we consider the problem of a wireless LAN selecting a channel to minimise interference with other WLANs. We focus on interfering infrastructure-mode networks, where each access point (AP) or base station has a wired backhaul link. We introduce a new fully distributed and self-managed channel selection algorithm that does not require direct communication between APs nor explicit estimation of the network interference graph. The sole information required by the algorithm is feedback to each WLAN on the presence of interference on a chosen channel; such feedback is already commonly provided by WLAN protocols such as 802.11. We establish that convergence of the distributed algorithm is guaranteed provided that the channel selection problem is feasible. Extensive simulation results are presented that demonstrate rapid convergence under a wide range of network conditions and topologies. While the scope of the present paper is confined to infrastructure networks with static topology, the utility of the proposed algorithm in situations where the network topology is time-varying is briefly discussed.