ZigBee may be a new wireless technology.Technological Standard Created for Control and Sensor Networks.It is supported the IEEE 802.15.4 Standard.Created by the ZigBee Alliance; Philips, Motorola, Intel,HP are all members of the alliance.It is basically designed for low power consumption allowing batteries to essentially last for ever.ZigBee makes possible completely networked homes where all devices are ready to communicate and be controlled by one unit.It provides network security and application support services operating on the highest of IEEE.
ZigBee, like Bluetooth, features a large installed base of operation, although perhaps traditionally more in industrial settings. ZigBee PRO and ZigBee remote (RF4CE), among other available ZigBee profiles, are supported the IEEE802.15.4 protocol, which is an industry-standard wireless networking technology operating at 2.4GHz targeting applications that need relatively infrequent data exchanges at low data-rates over a restricted area and within a 100m range like during a home or building.
WHAT IS ZIGBEE ?
ZigBee may be a Ad-hoc networking technology for LRWPAN. Technological Standard Created for Control and
Sensor Networks. supported IEEE 802.15.4 standard that defines the PHY and Mac Layers for ZigBee. it’s Low in cost ,complexity & power consumption as compared to competing technologies. Data rates touch 250Kbps for two .45Ghz ,40 Kbps 915Mhz and 20Kbps for 868Mhz band.
ZigBee is targeted at radio-frequency (RF) applications which require a coffee rate , long battery life, and secure networking. Created by the ZigBee Alliance
HISTORY
ZigBee-style networks began to be conceived around 1998, when many installers realized that both Wi-Fi and Bluetooth were getting to be unsuitable for several applications. During the half-moon of 2007, ZigBee PRO, the improved ZigBee specification was finalized.
WHAT DOES ZIGBEE DO?
It is used for embedded application for low data rates and Low power consumption, Inexpensive. it’s Designed for wireless controls and sensors. Operates in Personal Area Networks (PAN’s) and device-to-device networks. It provides connectivity between small packet devices. It control of lights, switches, thermostats, appliances, etc.
ZIGBEE GENERAL CHARACTERISTICS
• Its Data rates of 20 kbps and up to 250 kbps. Support for Low Latency Devices.
• CSMA-CA Channel Access
• Low Power Usage consumption
• 3 Frequencies bands with 27 channels
• Extremely low duty-cycle (
• Supports sizable amount of nodes
• Very long battery life
• ZigBee transmission range is approx. 1-100 meters.
WHY ZIGBEE is required
• For Long Battery Lives
• It require low cost and really low current drain.
• It doesn’t need much power
• It uses low data rates
HOW ZIGBEE WORKS
Topology
• Star
• Cluster Tree
• Mesh
ARCHITECTURE
ZIGBEE PROTOCOL STACK ARCHITECTURE
PHYSICAL LAYER
Activation and deactivation of the radio transceiver. It provide Energy Detection (ED) within the present channel and Link Quality Indication (LQI) for received packets. it’s clear Channel Assessment for CSMA-CA . It provide Channel frequency selection and data transmission and reception.
MAC LAYER
This layer provides interface between physical layer and network layer and Interface between the SSCS and therefore the PHY layer. almost like the PHY layer, the MAC layer supports two services. The MAC data service is liable for the transmission and reception of the MPDUs through the PHY data service. The MAC management service, if the device may be a coordinator, manages the network beacons. it’s also liable for PAN
association and disassociation, frame validation, and acknowledgment providing “a reliable link between two peer MAC entities.” Uses the CSMA/CA for channel access and handles and maintains the GTS mechanism. Supports device security.
TRAFFIC MODES
ZigBee employs either of two modes, beacon or non-beacon to enable the to-and-fro data traffic.
Beacon mode is employed when the coordinator runs on batteries and thus offers maximum power savings, whereas the Non- Beacon mode finds favor when the coordinator is mains-powered.
IEEE 802.15.4 MAC LAYER
• Device Classes
• Full function device (FFD)
• Can function in any topology
• Capable of being Network coordinator
• Can ask the other device (FFD/RFD)
• Reduced function device (RFD)
• Limited to star
• Cannot become network coordinator
• Talks only to FFDs
• Address
• All devices must have 64 bit IEEE addresses
• Short (16 bit) addresses are often allocated to reduce packet size
• Frame Types
• Data Frame
• used for all transfers of knowledge
• Beacon Frame
• employed by a coordinator to transmit beacons
• Acknowledgment Frame
• used for confirming successful frame reception
• MAC Command Frame
• used for handling all MAC peer entity control transfers
DATA TRANSFER TYPES
• Three differing types of knowledge transfer exist.
• Data transfer from a tool to the PAN coordinator.
• Data transfer from the PAN.
• Peer-to-peer Data Transfer
• the kinds differ if the coordinator uses or doesn’t beacons
ZIGBEE FEATURES:-
Low duty cycle provides a long battery life. Support for multiple topology star and Mesh. This support up to 65000 nodes on a network. 128-bit encryption provide a secure connection. This provides collision avoidance technology.
APPLICATION SECTORS
Industrial and Commercial
Consumer Electronics
Personal Health care
PC & Peripherals
Home automation
There are some important advantages of zigbee which are given below,
• The zigbee has flexible network structure.
• It features a very long battery life.
• It is low power consumption.
• It is straightforward to put in .
• It are often easily implemented.
• It supports sizable amount of nodes i.e. 6500 nodes approximately.
• It features a very low cost.
• It is more reliable and self healing.
• Setting up the network is extremely simple and straightforward .
There are some disadvantages of zigbee which are given below,
• It is so highly risky to be used for official private information.
• The zigbee has low transmission rate.
• Replacement with zigbee compliant appliances are often costly.
• It doesn’t have many end devices available yet.
• It can’t be used as outdoor wireless communication system thanks to it’s short coverage limited.
• It isn’t secure like wi fi based secured system.
CONCLUSION
• ZigBee will play an important role within the mass adoption of cost effective, low power, mesh networking technology for monitoring and control applications, supported an open global standard. Near Future more flexibility and price savings for consumers and greater control over household appliances. • Used for campus-wide electrical and security systems from one computer
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