12-04-2011, 03:50 PM
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1. ABSTRACT
ZigBee is a new wireless technology developed by the ZigBee Alliance to overcome the limitations of BLUETOOTH and Wi-Fi. ZigBee is developed on the top of IEEE 802.15.4 standard. It is designed for low-power consumption allowing batteries to essentially last forever. Though we have couple of methods for multimedia applications, till now nothing has been developed for sensor networking and control machines which require longer battery life and continuous working without human intervention. ZigBee devices allow batteries to last up to years using primary cells (low cost) without any chargers (low cost and easy installation).
The ZigBee standard provides network, security, and application support services operating on top of the IEEE 802.15.4.IEEE 802.15.4 standard has two basic layers medium Access Control (MAC) and Physical Layer (PHY) wireless standard. The network layer supports various topologies such star, clustered tree topology and self healing mesh topology. Apart from easy installation and easy implementation ZigBee has a wide application area such as home networking, industrial networking, many more having different profiles specified for each field. The upcoming of ZigBee will revolutionize the home networking and rest of the wireless world.
2. INTRODUCTION
The cellular network was a natural extension of the wired telephony network that became persistent during the mid-20th century. As the need for mobility and the cost of laying new wires increased, the motivation for a personal connection independent of location to that network also increased. Coverage of large area is provided through (1-2km) cells that co-operate with their neighbors to create a seamless network. Cellular standards basically aimed at facilitating voice communications throughout a metropolitan area. During the mid-1980s, it turned out that an even smaller coverage area is needed for higher user densities and the emergent data traffic. The IEEE 802.11 working group for Wireless Local Area Network (WLAN) is formed, to create a wireless local area network standard. Whereas IEEE 802.11 was concerned with features such as Ethernet matching speed, long range(100m), complexity to handle seamless roaming, message forwarding, and data throughput of 2-11Mbps. Wireless personal area networks (WPANs) are used to convey information over relatively short distances. WPANs are focused on a space around a person or object that typically extends up to 10m in all directions. The focus of WPANs is low-cost, low power, short range and very small size. The IEEE 802.15 working group is formed in 1998 to create WPAN standard. This group has currently defined three classes of WPANs that are differentiated by data rate, battery drain and quality of service (QoS).
The high data rate WPAN (IEEE 802.15.3) is suitable for multi-media applications that require very high QoS.
Medium rate WPANs (IEEE 802.15.1/Bluetooth) will handle a variety of tasks ranging from cell phones to PDA communications and have QoS suitable for voice communications.
The low rate WPANs (IEEE 802.15.4/LR-WPAN) is intended to serve a set of industrial, residential and medical applications with very low power consumption, with relaxed needs for data rate and QoS.
3. HISTORY OF ZIGBEE
October 2002
ZigBee Alliance is formed
December 2004
ZigBee 1.0 is released
Current releases
IEEE 802.15.4 standard in 2006
ZigBee specification in 2007
3.1 ZigBee Alliance
The ZigBee Alliance is an association of companies working together to enable reliable, cost-effective, low-power, wirelessly networked, monitoring and control products based on an open global standard.
The goal of the ZigBee Alliance is to provide the consumer with ultimate flexibility, mobility, and ease of use by building wireless intelligence and capabilities into every day devices. ZigBee technology will be embedded in a wide range of products and applications across consumer, commercial, industrial and government markets worldwide. For the first time, companies will have a standards-based wireless platform optimized for the unique needs of remote monitoring and control applications, including simplicity, reliability, low-cost and low-power.
3.2 Why is it called Zigbee?
It has been suggested that the name evokes the haphazard paths that bees follow as they harvest pollen, similar to the way packets would move through a mesh network
Using communication system, whereby the bee dances in a zig-zag pattern, worker bee is able to share information such as the location, distance,
And direction of a newly discovered food source to her fellow colony members. Instinctively implementing the ZigBee Principle, bees around the world actively sustain productive itchiness and promote future generations of Colony members.
3.3 Why do we need Zigbee?
ZigBee is the only standards-based technology that addresses the unique needs of most remote monitoring and control and sensory network applications. The Alliance's members' low cost, low power solutions will enable the broad-based deployment of wireless networks that are able to run for years on standard batteries for a typical monitoring application.