Zigbee utilize the 2.4 GHz radio frequency band. The 2.4 GHz radio frequency band is a crowded frequency as many device use this frequency. Devices like WiFi routers, microwave oven, and many other smart home devices utilize the 2.4 GHz radio frequency band.
Since so many devices use the 2.4 GHz radio frequency band, the signal from Zigbee can experience interference from these devices. If the signals from Zigbee experience interference, the Zigbee network will experience slow communication and potentially become unreliable. To avoid these issues with the Zigbee network, it is crucial to understand the frequency layout of Zigbee to avoid interference from other device and build a reliable Zigbee network.
Pick the Best Zigbee Channel to Avoid WiFi Interference
Zigbee use a mesh network design that allows the devices to relay the signal to other devices in the network. The mesh network design allow the devices to act as repeaters for the signal. The 2.4 GHz radio frequency band is only 100 MHz in width.
Furthermore, many protocols share this bandwidth. WiFi uses a much wider bandwidth then Zigbee. WiFi channels are 20 MHz in width, while Zigbee channels are only 2 MHz in width.
Due to the number of devices using the 2.4 GHz radio frequency band being so crowded, it is essential to find the quiet pockets in the radio frequency wherein no WiFi signals are present. By doing this, you can place the Zigbee channels in areas where they will not interfere with other devices using the 2.4 GHz band. If you place Zigbee channels too close to the WiFi channels, the WiFi channels will create interference for the Zigbee channels.
For example, lower Zigbee channels may overlap with WiFi channel 1. The middle Zigbee channels may overlap with the frequencies used by WiFi channel 6. Additionally, Zigbee channels may overlap with the frequencies used by WiFi channel 11.
To avoid interference between these two network, Zigbee channels should be selected to sit in the gaps between the WiFi channels. By placing the Zigbee channels in these gaps, the Zigbee coordinator will have more breathing room to communicate with the low-power sensor without noise in the signal. By reducing the noise in the signal, there will be fewer instances of packet loss.
By reducing packet loss, the Zigbee network will have to work less to relay data, thus allowing the network to function more efficiently. Many people use the factory default Zigbee channel. However, this default channel may be a frequency that many WiFi network use.
The solution to this problem is to perform an energy scan on the Zigbee coordinator to reveal which frequencies are causing the most interference to the Zigbee signals. In houses where people use WiFi channels 1, 6, and 11, there will be gaps between these frequencies where the Zigbee network can be placed. By placing the Zigbee channel in these areas, the Zigbee network will experience less interference from the WiFi network.
If you place the Zigbee channel in the same frequencies as the WiFi channels, there will be instance of latency and higher battery consumption of Zigbee devices. High latency cause the Zigbee devices to attempt to retransmit their data, which drains their batteries faster. Changing the channel on your Zigbee devices can be complex, depending on the type of coordinator that you use for your Zigbee network.
With some coordinators, you can broadcast a channel change for your devices so that the devices follow the coordinator to the new channel. However, with other types of coordinators, you will have to reset each Zigbee device. Resetting a device require you to join the device to the network again.
If you do not change the channel for your Zigbee devices correctly, they will drop off the network due to the battery drain. However, if you manage the change of channel correctly, you can utilize the full range that the Zigbee devices can provide for indoor properties. Each Zigbee device can act as a repeater, allowing them to weave through wall to extend the coverage of the network.
There are various other wireless protocol you can use instead of Zigbee for your smart home. Z-Wave uses sub-gigahertz frequencies that do not interfere with the 2.4 GHz radio frequency band that many devices use. However, Z-Wave has fewer devices that can connect to its network and has slower data speeds than Zigbee.
Thread use the same 2.4 GHz frequency band as Zigbee but uses the Matter protocol. WiFi offers high data speeds but uses more power and has data congestion issues. Lastly, Zigbee uses less power than other protocols and works best for smart home sensor that are in sleep mode most of the time.
There are several other adjustments you can use to improve your Zigbee network. If you use multiple Zigbee coordinators, place the coordinators at least two meter from each other and provide each coordinator with its own unique ID. Add Zigbee repeaters in locations where you find weak WiFi signals to bridge the gap between the WiFi signal and your Zigbee devices.
After you change the channel for your Zigbee devices, walk through your home and test the signal of each Zigbee device. If you find any weak signal, relocate the Zigbee plug. Do not guess the channel that you will use for your Zigbee network.
Always use a scan to find the best channel for your Zigbee devices. The hardware that you use can also have an impact on your Zigbee network. Make sure to use Zigbee chips that support all the channels and transmit signals of power.
Use a USB extension cable for your Zigbee dongle to move it away from your WiFi router. This will reduce the interference between the two device. Finally, do not allow the Zigbee network to transmit signals that interfere with other device in the airwaves.
Master the frequency gap in the airwaves and scan the airwaves to find the best Zigbee channel for your devices.