ZigBee is a communication standard that provides a short-range coast effective networking capability. It has bee developed with the emphasis on low-coast battery powered application such as building automation industrial and commercial control etc. Zigbee has been introduced by the IEEE and the zigbee alliance to provide a first general standard for these applications. The IEEE is the Institute of Electrical and Electronics Engineers. They are a non-profit organization dedicated to furthering technology involving electronics and electronic devices. The 802 group is the section of the IEEE involved in network operations and technologies, including mid-sized networks and local networks. Group 15 deals specifically with wireless networking technologies, and includes the now ubiquitous 802.15.1 working group, which is also known as Bluetooth.
The name "ZigBee" is derived from the erratic zigging patterns many bees make between flowers when collecting pollen. This is evocative of the invisible webs of connections existing in a fully wireless environment. The standard itself is regulated by a group known as the ZigBee Alliance, with over 150 members worldwide.
While Bluetooth focuses on connectivity between large packet user devices, such as laptops, phones, and major peripherals, ZigBee is designed to provide highly efficient connectivity between small packet devices. As a result of its simplified operations, which are one to two full orders of magnitude less complex than a comparable Bluetooth device, pricing for ZigBee devices is extremely competitive, with full nodes available for a fraction of the cost of a Bluetooth node.
ZigBee devices are actively limited to a through-rate of 250Kbps, compared to Bluetooth’s much larger pipeline of 1Mbps, operating on the 2.4 GHz ISM band, which is available throughout most of the world.
ZigBee has been developed to meet the growing demand for capable wireless networking between numerous low-power devices. In industry ZigBee is being used for next generation automated manufacturing, with small transmitters in every device on the floor, allowing for communication between devices to a central computer. This new level of communication permits finely-tuned remote monitoring and manipulation. In the consumer market ZigBee is being explored for everything from linking low-power household devices such as smoke alarms to a central housing control unit, to centralized light controls.
The specified maximum range of operation for ZigBee devices is 250 feet (76m), substantially further than that used by Bluetooth capable devices, although security concerns raised over “sniping” Bluetooth devices remotely, may prove to hold true for ZigBee devices as well.Due to its low power output, ZigBee devices can sustain themselves on a small battery for many months, or even years, making them ideal for install-and-forget purposes, such as most small household systems. Predictions of ZigBee installation for the future, most based on the explosive use of ZigBee in automated household tasks in China, look to a near future when upwards of sixty ZigBee devices may be found in an average American home, all communicating with one another freely and regulating common tasks seamlessly.
Conclusion
The Zigbee solution will be available soon. It will not hit the $10 price point until 2009. The 802.15.4 radio specification has a very poor link budget; 89dB. A Zigbee based solution is not scalable; it will not work reliably with only two end-points separated by the length of a house. It is complicated and requires a significant learning curve from the engineer and significant resources from the protocol controller. The customer must form three supplier relationships; the chip vendor, the software vendor, and the microcontroller vendor.
In addition to cost, reliability, and scalability, Zigbee purports to offer other advantages over proprietary solutions such as Interoperability, Vendor independence and Common platform.There are three separate frequency bands specified for Zigbee. If one manufacturer of heating controls chooses the 900 MHz band, and another chooses the 2.4 GHz band, the products will not operate together. Additionally, it is likely that IC vendors will add proprietary features to their 802.15.4 implementations in an effort to differentiate their product; if the OEM uses these proprietary features, the benefit of interoperability will be negated. In the end, the only way to guarantee interoperability using Zigbee is to design only 2.4GHz products using only Zigbee standard features.
VIJAY
ReplyDeletemail: gtvijay@outlook.com