CHAMELEON: A Framework for Coexistence of Wireless Technologies in an Unlicensed Band

The recent increase in the number of technologies operating in the 2.4 GHz ISM band has drawn attention towards the impact they can have on each other. In this paper, we have conducted a case study about coexistence of IEEE 802.11 and IEEE 802.15.4 which has led us to discover previously unknown interactions. We show through extensive experiments that CCA method used by a wireless device can significantly change the coexistence scenario. We also highlight the ways in which coexistence can be improved by making runtime adjustments to some MAC/PHY layer parameters and show their effectiveness. Furthermore, we propose a framework which exploits the pervasiveness and ubiquity of Wi-Fi to improve coexistence among wireless technologies in the 2.4 GHz ISM band. Our framework has the capability to detect the presence of wireless technologies operating anywhere in the 2.4 GHz ISM band and also accounts for devices whose signatures do not exist in the database. It facilitates the Wi-Fi AP to make decisions such as changing the channel or making MAC/PHY layer adjustments which are compliant with the configured coexistence policy thus improving the performance of the wireless devices. We have implemented our framework on real hardware and evaluated its performance in the presence of ZigBee.