Moving away from the Crowd: Channel selection in uncoordinated unplanned dense wireless LANs

Networks using WiFi continue to proliferate which has contributed to increased levels of crowding in the unlicensed bands in which these networks operate. Given the limited number of channels available in these bands, a key problem that arises is how to avoid / minimise conflicting channel assignment among neighbouring networks. This is particularly challenging in uncoordinated, unplanned deployments wherein Access Points (APs) belonging to different administrative entities may be operating in isolation in the vicinity of each other. Given the difficulty of planning conflict free channel allocation in such deployments, it is highly desirable to devise mechanisms such that the APs themselves become radio neighbourhood aware and adapt their operation (channel switching on the fly) so as to mitigate interference issues. In this paper, we propose two distributed channel selection algorithms for accomplishing the above mentioned objective. In particular, we show that these algorithms are practical from an implementation perspective, accomplish their objective without requiring any changes to the hardware, the existing infrastructure and the WLAN standard, and highlight findings from a simulation based study. Findings indicate that the proposed algorithms significantly outperform the typical random selection approach commonly employed by low cost commercial off-the-shelf hardware.