A specification from the ZigBee Alliance for a set of high-level communications protocols based on the IEEE 802.15.4 standard for a low-data-rate wireless personal area network (WPAN) comprising devices of low complexity and long battery life. ZigBee is designed for connecting devices in ad hoc networks over very short distances with very low power consumption. ZigBee specifies star, peer-to-peer and mesh network topologies, with mesh being the preferred approach for reasons of redundancy and resiliency. ZigBee runs in the ISM band using direct sequence spread spectrum (DSSS) transmission. A ZigBee Coordinator (ZC) initializes the network, coordinates its operation, and is responsible for security. ZigBee End Devices (ZEDs) are terminal devices that are very limited in function, and can communicate only with ZigBee Routers (ZRs), which function to pass messages to other ZRs or to the ZC. In beacon enabled networks, ZigBee Routers (ZRs) periodically beacon their presence and, therefore, need power up only during the beaconing cycle, which conserves battery life. In non
A wireless network used for home, building and industrial control. It conforms to the IEEE 802.15.4 wireless standard for low data rate networks. With a maximum speed of 250 Kbps at 2.4 GHz, ZigBee is slower than Wi-Fi and Bluetooth, but is designed for low power so that batteries can last for months and years. The typical ZigBee transmission range is roughly 50 meters, but that can vary greatly depending on temperature, humidity and air quality. Zigzag Like a Bee Although ZigBee networks can be configured in star, peer-to-peer and mesh topologies, it is the mesh network from which ZigBee was named. A ZigBee mesh provides multiple pathways from device to device (like the Internet) and eliminates a single point of failure. If nodes go down or are removed, ZigBee devices can "zig" and "zag" through the network to their destination like a bumblebee. Lots of Bees ZigBee networks are simple control networks that periodically send small packets from sensors to regulate lights, motors and other equipment. A large building can have tens of thousands of ZigBee nodes; a home could have a hundred or more. In fact, ZigBee can address more than a thousand quadrillion devices (surely enough for the gadget fanatic's apartment!). Reduced Function and Full Function ZigBee uses two types of devices. Reduced-function devices (RFDs) are sensors that communicate with full-function devices (FFDs). FFDs are complex nodes that conform to the full 802.15.4 standard and can serve as routers. All devices can be implemented with low-cost, 8-bit microcontrollers (MCUs) that derive their power from two AAA batteries. For more information, visit the ZigBee Alliance at www.zigbee.org.