The Big Zee
February 3, 2008
This blog is actually first in a series of introductory articles on the emerging wireless technologies.
The first one I want to cover is called the ZigBee standard. This is a high-level communications protocol using small, low-power digital radios based on the IEEE 802.15 .4 specifications. This new standard is fast being deployed in Home Automation systems and is in direct competition with other WPANs , such as Bluetooth.
WPAN, which stands for Wireless Personal Area Network, is a small network which comprises of mobile devices which are close to one person. Unlike LAN networks, which are spread out over the a complete office or university campuses, WPANs usually cover a few meters only.
Although Bluetooth is a fairly popular means of wireless communication, what with the advent of mobile phones having Bluetooth chips, I will cover this technology in more detail in the coming days.
The ZigBee standard operates in the unlicensed 2.4Ghz band. Although it also operates at other frequencies like 915Mhz and 868Mhz, 2.4Ghz seems to be the most popular frequency usage. The 2.5 Ghz band has about 16 Zigbee channels , with each channel requiring 5 Mhz bandwidth. The raw, over-the-air data rate is 250 kbits/sec per channel. Transmission range is about 10-75 meters (30-250 feet). The maximum output power is generally 0 dBm (1mW).
As you can see, the principle characteristics of the ZigBee specifications are low data rate, low power and hence long battery life and secure networking. Thus, although Zigbee supports low data rates compared to other WPAN, the low power consumption makes it a very viable option , especially for Home networking deployment.
In an attempt to support this specification and make it easy for mass adoption, a small number of companies have formed the ZigBee alliance. Members of this alliance are some of the big names in the industry including Samsung, Freescale, Texas Instruments, etc.
I hope I have covered enough in this article to introduce this technology to the absolutely unaware.
More to come in this series is introductory articles on Bluetoth, MoCA,UWB, wireless USB and many more.