Coexistence with WiFi for a Home Automation ZigBee product

Abstract

Home Automation (HA) products based on IEEE 802.15.4 and ZigBee, both low power wireless communication standards, are starting to appear on the market. Most of these products use the 2.4GHz Industrial Scientific Medical (ISM) band, sharing the wireless spectrum with several other ubiquitous technologies such as Bluetooth, cordless phones, microwaves ovens and WiFi. The potential for cross technology interference exists and it is a looming threat to the success of new HA products based on the IEEE 802.15.4 standard. We developed a ZigBee Home Automation line of products for the Belgium market and therefore decided to evaluate the robustness of our products in the face of cross technology interference in the crowded 2.4 GHz band. We exposed our product, in a controlled laboratory setting, to increasing levels of WiFi interference and measured its performance. This paper summarizes our findings and presents recommendations and a methodology to measure and avoid WiFi interference while deploying and installing ZigBee based products in a home setting. While ZigBee products can successfully withstand interference from microwave ovens and Bluetooth devices, they are still vulnerable to high load WiFi traffic. ZigBee and WiFi can peacefully coexist in the home environment as long as certain basic precautions are taken.