MuZi: Multi-channel ZigBee Networks for Avoiding WiFi Interference

In Cyber-Physical system (CPS), different wireless technologies are used, which results in cross-technology communication interference. Specifically, ZigBee networks share the 2.4GHz ISM band with WiFi but have much lower transmission power. Thus, the ZigBee networks inevitably suffer the interference from WiFi Networks. This paper focuses on the locality of WiFi interference and proposes an interference avoiding approach based on multi-channel for ZigBee networks called MuZi. MuZi has three basic mechanisms: interference assessment, channel switch and connectivity maintenance. The proposed interference assessing approach jointly considers the degree of intensity and density and achieves a much actual relationship between WiFi interference and link quality. Based on this finding, the better working channel for each node is determined. A connectivity maintenance approach is also proposed to ensure the connectivity of the nodes to the sink. Our extensive experiments on a test bed of 802.11 embedded nodes and 802.15.4 TelosB motes show that, under the existence of WiFi interference, MuZi can achieve 3.3 times throughput than the traditional single-channel method.