Wireless local area networks (WLANs) are pervasive but crowded nowadays. It is of great importance for access points (APs) to adapt to the changing traffic conditions. Exiting approaches for channel selection largely rely on local channel assessment and adopt greedy selection strategies. They suffer a major limitation that an AP fail to take various traffic demands of clients into account. We have witnessed that wireless sensor networks are increasingly deployed everywhere. A ZigBee sensor operates on the 2.4G radio spectrum which overlaps the spectrum used by most WiFi APs. As a result, a ZigBee sensor is able to sense the traffic of different AP channels. Motivated by this important observation, we present the design, implementation and evaluation of OutSence, a system that enables APs to takes traffic volumes of clients into account. It makes use of channel utilization sensed by ZigBee sensors and allows an AP to select a channel of good performance. The salient feature of OutSence is that it exploits in-situ ZigBee sensors for APs to quickly adapt to short-term traffic variations (e.g., order of minutes). We have fully implemented OutSence on Telos B sensor nodes and off-the-self APs. Extensive experiments have been conducted and conclusive results demonstrate that OutSence effectively improves overall WLAN performance.
['Yanmin Zhu', 'Lubin Liu', 'Juan Li', 'Jiadi Yu', 'Chengnian Long']
OutSense: Out-of-Band Sensing with ZigBee Sensors for Channel Adaptation in Wireless LANs