ZigBee can be a great way of handling smart home communication, without putting additional load on your existing WiFi network. Having the network separated, also means additional resilience for your smart home network, at times when your WiFi is under heavy load. Conversely, it also prevents heavy load on the ZigBee side from affecting WiFi throughput.
ZigBee works alongside 2.4Ghz WiFi, operating at the same frequency.
As such, it is important to bear in mind the coexistence of WiFi and ZigBee and set your channels accordingly, so that interference is minimised.
The diagram below demonstrates well how the channels overlap.
My WiFi broadcasts on channel 1. This was easy information for me to obtain, as I set this channel myself.
The WiFi analyser mobile app is a great tool for establishing on which channels your local WiFi networks are broadcasting.
As you can see from the screenshots below, my neighbours WiFi networks are primarily on channels 5 & 11, with some distant networks also broadcasting on 6.
Cross referencing this information with the ZigBee/WiFi diagram earlier in this post, we can see that we want to aim for channels 18 to 20. This should place our ZigBee network just in the gap between the purple and green WiFi networks sat around channels 5 and 11.
Test results
15 – Unreliable results immediately from battery powered devices
18 – Reliable on initial testing, further tests to be completed
19 – Unreliable results immediately from battery powered devices and no neutral devices
25 – Reliable for a few hours, then interference caused dropouts
26 – Some devices refused to use this channel entirely
Channel 18 final result with additional testing to be completed
Edit: channel 18 is unreliable over a period of days, with battery powered and no neutral device suffering the most disconnections
Next channel to test: 20