ZigBee and WiFi interference

In doubt regarding interference between ZigBee and WiFi? Check out our explanation below.

Interference free Zigbee and WiFi

Wireless systems are being introduced in industries, buildings and hospitals at a rapid pace. A growing concern is the possible interference between these wireless systems. This document outlines how Rmoni avoids this risk in its wireless sensor networks. 

About Zigbee 

Zigbee is a wireless technology developed by an international consortium of companies. It is developed specifically for Wireless Sensor Networks. It can be compared to Bluetooth, developed for audio connections, and Wifi developed for internet connectivity. Zigbee uses the IEEE802.15.4 standard, in the license-free spectrum around 2,4GHZ dedicated for Industrial, Scientific and Medical applications. 

Zigbee and Wifi 

Wifi is currently deployed in many environments, such as buildings, offices and even hospitals. Wifi also operates at the 2,4GHz frequency, so what is the risk of interference between Wifi and Zigbee systems? 

To look further into this, it should be noted that Wifi is built upon another standard, the often-cited IEEE802.11.x. This 11.x standard slices the spectrum into 11 so-called channels, which can be selected to form a local Access point cell. The 15.4 standard has a slightly different channel plan, and slices the same spectrum into 16 channels. This can be seen below in Figure1 

As can be seen, there are a number of channels in Zigbee which do not interfere with the Wifi channels. Channel 25 and 26 are preferred because they are outside of the Wifi channel plan. But also channel 15 and 20 are good candidates because they are nested at frequencies which are not touched by the Wifi channels. 

Conclusion 

Rmoni avoids interference between its RmoniWeb Wireless Sensor Network and the existing WiFi systems. This is done using one of the so called Clear Channels , which do not interfere with Wifi by design. This channel plan is to be discussed with the customer’s IT department