1: ZigBee Essential Facts and Features > Wireless Networks

Wireless Networks

A wireless network consists of nodes that are not connected by cables, but communicate with each other via radio, infra-red or other electromagnetic radiation. Therefore, each node is able to transmit and receive messages through the relevant medium. In addition, most nodes run one or more applications to perform their function in the network - for example, temperature and humidity measurement.

Motivation for ZigBee

ZigBee is a worldwide open standard for wireless radio networks in the monitoring and control fields. The standard was developed by the ZigBee Alliance (an association of international companies) to meet the following principal needs:

• low cost
• ultra-low power consumption
• use of unlicensed radio bands
• cheap and easy installation
• flexible and extendable networks
• integrated intelligence for network set-up and message routing

Some of the above requirements are related - for example, the need for extremely low power consumption is motivated by the use of battery-powered nodes which can be installed cheaply and easily, without any power cabling, in difficult locations.

Some of the application areas that benefit from this type of network are described below.

Typical Application Areas

Application areas that are suitable for ZigBee networks are likely to have the following characteristics or requirements:

• low data rates (less than 250kbps)
• nodes which are idle (not transmitting/receiving) for long periods
• node locations where cables would be difficult or expensive to install
• a need to modify the network (add, remove or move nodes) while in service

The following are typical application areas in which ZigBee provides a low-cost solution (this is not an exhaustive list):

Commercial Building and Home Automation: Electronic control within a building or home can be implemented through wireless networks - example applications are HVAC (heating, ventilation and air-conditioning), lighting, curtains/blinds, doors, locks and home entertainment systems.

Security: Another important application within commercial buildings and the home is security – both intruder and fire detection.

Healthcare: This field employs sensors and diagnostic devices that can be networked by means of a wireless network. Applications include monitoring during healthcare programmes such as fitness training, in addition to medical applications such as patient monitoring.

Vehicle Monitoring: Vehicles usually contain many sensors and diagnostic devices, and provide ideal applications for wireless networks. A prime example is the use of pressure sensors in tyres, which cannot be connected by cables.

Agriculture: Wireless networks can help farmers monitor land and environmental conditions in order to optimise their crop yields. Such networks may require wide geographical coverage, but ZigBee addresses this issue by offering network topologies that allow the relaying of messages from node to node across the network.

Move the cursor over the above images to see which application areas they represent

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