Wifi Interference-avoidance In ZigBee Networks Using Multi-channel

In recent years, with the development of wireless communication technology and the decrease of hardware cost, more and more wireless devices have been emerging in people's daily lives. More wireless devices work in the same location, resulting in increasingly serious cross technology interference. In the foreseeable future, due to the convenience of no wiring, WiFi will become more popular. 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. Therefore, how to avoid interference from WiFi and improve the link performance of ZigBee will become an important issue.It is observed that WiFi interference changes over time and space, demonstrating the different interference characteristics. On this basis, this paper proposes an interference avoiding approach based on multi-channel for ZigBee networks called MuZi, which can effectively avoid WiFi interference in the local region and improve the performance of ZigBee networks. MuZi consists of three basic mechanisms: 1) interference assessment, unlike traditional approaches that depend only on interference intensity, the proposed interference assessment approach jointly considers the degree of intensity and denseness, and then can achieve a much actual relationship between WiFi interference and link quality; 2) target channel selection, based on the proposed interference assessment approach, choose the quietest channel available, meanwhile take into account the neighbor's channel selection to minimize the number of channels that all nodes used; 3) connectivity maintenance, ensure that the nodes working in the different channels can deliver data to the sink successfully.Finally, the performance evaluations of the proposed interference assessment approach and MuZi are conducted separately. The results show that: 1) new interference assessment methods can effectively distinguish the different levels of interference; 2) under the existence of WiFi interference, MuZi can achieve 3.3 times throughput than the traditional single-channel method.