Channel ranking algorithms for cognitive coexistence of IEEE 802.15.4

Widespread proliferation of competitive technologies in licence free Industrial, Scientific and Medical (ISM) radio band is squeezing the room in frequency, temporal and spatial domain for the reliable operation of low power, low cost, IEEE 802.15.4 devices. In this context, providing some intelligence to IEEE 802.15.4 devices to analyze the environment and find the least interfered channel can result in significant improvement in performance and reliability. In this paper we prototyped a test bed that emulate wireless channels in order to evaluate the performance of IEEE 802.15.4 devices under varying IEEE 802.11 activities in different environments. The limiting thresholds for the sustainable operation are determined. Based on the thresholds, two algorithms have been proposed to rank the channels according to interference signal strength and activity level. The effectiveness of the algorithms is also verified by ranking both emulated and real channels.