What is the standard used by Zigbee networks? Describe its characteristics.

Zigbee What is it?

In the wireless world, the terms Bluetooth and WIFI have become a household names in recent years. They find wide acceptance in applications using mobile sensors.

Zigbee is born out of huge demand arising from industry and others for wireless DAS (Data acquiition system) applications that use lower data rate, longer battery life, simpler design and low cost solutions.

Zigbee Applications
Zigbee technology is based on IEEE 802.15.4 industry standard. . It supports all network topologies namely STAR, MESH and CLUSTER tree. project Developers need only have to focus on application while the hard ware and networking parts are taken care off.

There are 3 types data collection methods used by Zigbee networks.
a Data on demand
An example of this traffic is a wireless sensor to read the water meter. The sensor is programmed to wake up at certain interval to transmit the information needed and goes back to sleep after this is done.

b) Asychronous data
An example of this traffic is a wireless light switch operation. Here command circuit is triggered by external input and wakes up on receipt of the message from master controller . When action is over, it is local unit is disconnected from the network and hence saves energy.

c) Repetitive data
An example of this traffic is security monitoring.Time multiplexed monitoring devices are to return their status to the network. This type use consumes more energy.

Popular Zigbee applications include metering gas/water/electricity readings. Here readings are automatically send to utility headquarters for further action. This saves time and money. In the area of warehousing/inventory management , the wireless technology will enable accurate and hassle free management of goods. Security and access control, and lighting control are other applications that can be implemented with ease.Home automation system to control lightings, blinds, air conditioning, security system, remote control and appliances can be implemented eassily.


IEEE 802.15.4 standard

IEEE 802.15.4 is a simple standard that specifies the Media Access Control (MAC) and Physical (PHY) networking layers for packet data protocol. Its license free frequency bands are:

2.4 GHz (16 channels with baud rate of 250 kps)
902 MHz - 928 MHz (10 channels with baud rate of 40 kps)
868 MHz - 870 MHz (1 channel with baud rate of 20 kps)

North America, Europe, Australia and New Zealand use the sub 1 GHz bands whereas the rest of the world uses 2.4 GHz bands.

It uses Carrier Sense Multiple Access with Collison Avoidance for Channel Access.

The security method used is AES-128.

Has message acknowledgement and a host of other features.