IEEE-802.15.4 is a wireless standard that specifies the physical (PHY) and media access (MAC) mechanisms for radios operating in the 2.4 GHz frequency band. ZigBee is a networking standard built on top of IEEE-802.15.4 to take care of the higher layers in the networking stack.
Radio networks using just IEEE-802.15.4 are proprietary, adding the ZigBee stack enables interoperability between manufacturers. ZigBee networks can have many configurations: point-to-point, star or mesh are some of the most common, and a network can have up to thousands of nodes. Three types of devices are defined: “End device“, which is in many cases battery operated due to very low power consumption; “Full-function device“, which may also operate as a router to extend the network (this demands that the device is always active), and “Coordinator“, which oversees the entire network.
Bitrate is 250 kbps raw and transmitting power in the range of 1 to 10 mW, enabling distances in the tens of metres. |
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