DL Rate (Peak)
UL Rate (Peak)
ZigBee is a specification developed by the ZigBee Alliance based on the IEEE 802.15.4 standard for wireless personal area networks (WPANs). ZigBee operates in the ISM radio bands, and it defines a general-purpose, inexpensive, self-organizing, mesh network for industrial control, embedded sensing, medical data collection, smoke and intruder warning, building automation, home automation, and domotics, etc.
ZigBee differs substantially from many other IoT protocols as it has been designed specifically for operation within 10 to 100 metres (radio line of sight). It is not designed for deployment by mobile network operators.
IEEE 802.15.4 was developed with lower data rate, simple connectivity and battery application in mind. The 802.15.4 standard specifies that communication can occur in the 868 to 868.8 MHz, 902 to 928 MHz or 2.400 to 2.4835 GHz Industrial Scientific and Medical (ISM) bands. While any of these bands can technically be used by 802.15.4 devices, the 2.4 GHz band is more popular as it is open in most of the countries worldwide.
ZigBee is a protocol that uses this 802.15.4 standard as a baseline and adds additional routing and networking functionality. ZigBee is designed to add mesh networking to the underlying 802.15.4 radio. Mesh networking is used in applications where the range between two points may be beyond the range of the two radios located at those points, but intermediate radios are in place that could forward on any messages to and from the desired radios.
Devices in the ZigBee specification can either be used as End Devices, Routers, or Coordinators.
- Coordinator (Master): Only one coordinator exists in each ZigBee network. Its function is to store information about the network and to determine the optimum transmission path between any two points of the network.
- Full function device (Router, Repeater): Routers act as an intermediate repeater that passes data from other devices.
- Reduced Function Device (End Device): This device contains a minimal amount of functionality to enable it to talk to its parent node (either the coordinator or a router); it cannot relay data directly from other devices.
Since the ZigBee protocol uses the 802.15.4 standard to define the PHY and MAC layers, the frequency, signal bandwidth and modulation techniques are identical.