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Definition
Zigbee is a rather new wireless technology that looks to have applications in a variety of fields. Zigbee is a technological standard based on the IEEE 802.15.4 specification for low data rates technology allows for devices to communicate with one another with very low power consumption, allowing the devices to run on simple batteries for several years. Zigbee is targeting various forms of automation, as the low data rate communication is ideal for sensors, monitors, and the like. Home automation is one of the key market areas for Zigbee, with an example of a simple network .

A concern that could arise may be related to the specific frequency band that ZigBee uses - that is, the 2.4 GHz band, which is the same band used by IEEE 802.11 and WiFi. A cursory reading of the previous sentence may seem to imply that ZigBee could not co-exist with these other technologies without interfering with one another. However, ZigBee-based products can access up to 16 different 5 MHz channels within the 2.4 GHz band, several of which do not overlap those of 802.11 and WiFi; data packets are automatically retransmitted in case interference does happen to occur; and very few data packets are transmitted anyway, further reducing the probability that data will be lost. Thus, ZigBee, with its specific application focus, is not generally affected by other similar wireless technologies, but fits nicely into a field of ever-increasing technological innovations.

ZigBee is designed for wireless controls and sensors. It could be built into just about anything you have around your home or office, including lights,switches, doors and appliances. These devices can then interact without wires,
and you can control them all . . . from a remote control or even your mobile phone.Although ZigBee's underlying radio-communication technology isn't revolutionary, it goes well beyond single-purpose wireless devices, such as
garage door openers and "The Clapper" that turns light on and off. It allows wireless two-way communications between lights and switches, thermostats and furnaces, hotel-room air-conditioners and the front desk, and central command posts. It travels across greater distances and handles many sensors that can be linked to perform different tasks.

ZigBee works well because it aims low. Controls and sensors don't need to send and receive much data. ZigBee has been designed to transmit slowly. It has a data rate of 250kbps (kilobits per second), pitiful compared with WiFi,which is hitting throughput of 20Mbps or more. But because ZigBee transmits slowly, it doesn't need much power, so batteries will last up to 10 years. Because ZigBee consumes very little power, a sensor and transmitter that reports whether a door is open or closed, for example, can run for up to five years on a single double-A battery. Also, operators are much happier about adding ZigBee to their phones than faster technologies such as Wi-Fi; therefore, the phone will be able to act as a remote control for all the ZigBee devices it encounters.

ZigBee basically uses digital radios to allow devices tocommunicate with one another. A typical ZigBee network consists of several types of devices. A network coordinator is a device that sets up the network, is aware of all the nodes within its network, and manages both the information about each node as well as the information that is being transmitted/received within the network. Every ZigBee network must contain a network coordinator. Other Full Function Devices (FFD's) may be found in the network, and these devices support all of the 802.15.4 functions. They can serve as network coordinators, network routers, or as devices that interact with the physical world.The final device found in these networks is the Reduced Function Device (RFD), which usually only serve as devices that interact with the physical world.

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