29-05-2012, 05:04 PM
Zigbee Protocol
Zigbee Protocol.doc (Size: 863.5 KB / Downloads: 63)
Abstract
ZigBee is a wireless network protocol which isspecifically designed for low-rate sensor and industrial controlnetwork. It is widely used in many fields including building automation network, building security system, industrial control networks, remote meter reading, PC peripherals, etc.This paper discusses the CC2420-based ZigBee wireless network systems. In the implementation of the system,MSP430F135, the MCU and the Chipcon’s CC2420 RF chip are used. The hardware circuitry is designed by Aye-Tech Electronics Inc. The system realized a ZigBee wireless network application. It had showed flexible and highly efficient in practical applications. It can also be combined with The Internet of Things in practical applications.
(Keywords-Internet of Things,IEEE 802.15.4,ZigBee,MSP430)
Introduction
ZigBee is a new technology of a short-range, low complexity, low-power consumption, low-data-rate, low-cost and duplex wireless communication. It is applied on the lowdata- rate wireless data communication between various electronic equipments within a short distance. The physical layer and link layer protocol of ZigBee technology applied mainly IEEE802.15.4 standard, and the ZigBee Alliance that was set up in August 2002 is responsible for the development of network layer and application layer and so on. IEEE802.15.4 ZigBee standards were approved in the May 2003[1]. The wireless sensor network is a special Ad-Hoc network.
Local Area Network
LAN connects networking devices with in short spam of area, i.e. small offices, home, internet cafes etc. LAN uses TCP/IP network protocol for communication between computers. It is often but not always implemented as a single IP subnet. Since LAN is operated in short area so It can be control and administrate by single person or organization.
WAN - Wide Area Network
As “word” Wide implies, WAN, wide area network cover large distance for communication between computers. The Internet it self is the biggest example of Wide area network, WAN, which is covering the entire earth. WAN is distributed collection of geographically LANs. A network connecting device router connects LANs to WANs. WAN used network protocols like ATM, X.25, and Frame Relay for long distance connectivity.
. ZIGBEE CHARACTERISTICS
The focus of network applications under the IEEE 802.15.4 / ZigBee standard include the features of low power consumption, needed for only two major modes (Tx/Rx or Sleep), high density of nodes per network, low costs and simple implementation. These features are enabled by the following characteristics,
• 2.4GHz and 868/915 MHz dual PHY modes. This represents three license-free bands: 2.4-2.4835 GHz, 868-870 MHz and 902-928 MHz. The number of channels allotted to each frequency band is fixed at sixteen (numbered 11-26), one (numbered 0) and ten (numbered 1-10) respectively. The higher frequency band is applicable worldwide, and the lower band in the areas of North America, Europe, Australia and New Zealand .
DEVICE TYPES
These devices have 64-bit IEEE addresses, with option to enable shorter addresses to reduce packet size, and work in either of two addressing modes – star and peer-to-peer.
ZigBee networks use three device types:
• The network coordinator maintains overall
network knowledge. It's the most sophisticated of the three types and requires the most memory and computing power.
• The full function device (FFD) supports all
802.15.4 functions and features specified
by the standard. It can function as a network coordinator. Additional memory and computing power make it ideal for network router functions or it could be used in network-edge devices (where the network touches the real world).
• The reduced function device (RFD) carries
limited (as specified by the standard)
functionality to lower cost and complexity.
It's generally found in network-edge
Devices
CONLUSION
It is likely that ZigBee will increasingly play an important role in the future of computer and communication technology. In terms of protocol stack size, ZigBee's 32 KB is about one-third of the stack size necessary in other wireless technologies (for limited capability end devices, the stack size is as low as 4 KB). The IEEE 802.15.4–based ZigBee is designed for remote controls and sensors, which are very many in number, but need only small data packets and, mainly, extremely low power consumption for (long) life. Therefore they are naturally different in their approach to their respective application arenas. The ZigBee Alliance targets applications "across consumer, commercial, industrial and government markets worldwide". Unwired applications are highly sought after in many networks that are characterized by numerous nodes