Most everyone is familiar with Wi-Fi (IEEE 802.11 standards) and most are likely also familiar with Bluetooth wireless. Far fewer are familiar with some of the standard wireless technologies used for Internet of Things applications. These technologies include Bluetooth Low Energy (Bluetooth LE), Zigbee and others.
This post is about Zigbee.
Zigbee is a low power, very short range wireless technology that has been around for more than a decade, although it has continually evolved to support new requirements. Zigbee 3.0 is the current version of the specification.
Source – Zigbee standards group.
Zigbee is a set of protocols that sit on top of the IEEE 802.15.4 specification. 802.15.4 specifies a short range (less than 10 meters), low speed (up to 250 kbps maximum) wireless link operating in the 2.4 Ghz band (or alternatively the 868 Mhz band in Europe and the 902-928 Mhz band in North America and potentially in other forms including Ultra Wide Band).
While used for peer to peer communications, protocols add support for mesh networking, where nodes in the network can forward packets on to others in the network. In this way, a message can be delivered over a much greater distance than the few meters of a specific link. Zigbee specifies how devices join the network, plus how security is implemented.
Key to Zigbee is its design for extreme low power operation. This means a device can be powered by a small battery for very long periods of time (such as a year or many years) or the device can even use “energy harvesting” to obtain sufficient energy from a wireless field (similar to how RFID works). A Zigbee device might operate on 1/100,000 to 1/1,000,000 the power required for a typical WiFi connection.
Zigbee’s design is oriented towards applications of Zigbee, such as a switch remote controlling a light bulb, or a dimmer controlling a light. Zigbee devices are intended to be easily installed “plug and play”. Contrast that with setting up an Internet connection just a few years ago – where end users had to enter router and DNS addresses and possibly specify a subnet mask. The complexity was absurd in terms of the the end consumer. The consumer just wants to purchase a solution, plug it in, and it works.
The device should automatically discover its surrounding support network, plus, automatically adapt in the event the environment changes. In other words, each device may be part of a mesh network that forwards packets – but if devices within the mesh go offline or are blocked, a new path can be automatically identified.
As you can see, Zigbee is a low power, wireless communications standard that is designed for a world of small, battery powered, Internet of Things devices. Zigbee is not the only standard available – but it is certainly an important one.