A PAPER PRESENTATION ON
Zigbee technology
G.PULLAIAH COLLEGE OF ENGINEERING AND TECHNOLOGY
(Affiliated to Jawaharlal Nehru Technological University, Anantapur, A.P)Nandikotkur Road, Kurnool
Department of Information Technology
Presented By
M.Susmitha S.Praveena
IVth B.Tech(IT) IVth B.Tech(IT)
GPCET GPCET
Mail id:[email protected] Mail id:[email protected] Phone number: 9493323533 phone number: 9030777645
ABSTRACT:
For the last few years, we've witnessed a great expansion of remote control devices in our day-to-day life. Five years ago, infrared (IR) remotes for the television were the only such devices in our homes. Now we quickly run out of fingers as we count the devices and appliances we can control remotely in house. This number will only increase as more devices are controlled or monitored from a distance, especially if through cell phones. And we can expect this number to increase even more if power consumed by these devices is very very less. To interact with all these remotely controlled devices, we'll need to put them under a single standardized control interface that can interconnect into a network, specifically a HAN or home-area network. One of the most promising HAN protocols is ZIGBEE, a software layer based on the IEEE 802.15.4 standard. This paper will introduce you to ZigBee -- how it works and how it is going to make life more comfortable in future.
INTRODUCTION
Technologists have never had trouble coming up with potential applications for wireless sensors. In a home security system, for example, wireless sensors would be much easier to install than sensors that need wiring. The same is true in industrial environments, where wiring typically accounts for 80% of the cost of sensor installations. And then there are applications for sensors where wiring isn't practical or even possible.
One alternative to avoid wiring is to have remote for each device. Why so many remotes? Right now, the more remotely controlled devices we install in our homes, the more remotes we accumulate. Devices such as TVs, garage door openers, and light and fan controls predominantly support one-way, point-to-point control. They are not interchangeable and they don't support more than one device. Because most remotely controlled devices are proprietary and not standardized among manufacturers, even those remotes used for the same function (like turning on and off lights) are not interchangeable with similar remotes from different manufacturers. In other words, we’ll have as many
separate remote control units as we have devices to control. Some modern IR remotes enable us to control multiple devices by "learning" transmitting codes. But because the range for IR control is limited by line of sight, they're used predominantly for home entertainment control. A HAN [Home Area Network] can solve both problems because it doesn't need line-of-sight communication and because a single remote (or other type of control unit) can command many devices.
But the problem is that most wireless sensors use too much power, which means that their batteries either have to be very large or get changed far too often. Add to that some skepticism about the reliability of sensor data that's sent through the air, and wireless sensors simply haven't looked very appealing. When Wi-Fi and Blue tooth came along, people naturally looked to them as a replacement for the clunky, outdated X-10 system. But neither of these technologies is ideal for home automation. We really don't need the bandwidth (and consequential power-consumption) of Wi-Fi, or even Blue tooth for that matter, to monitor the moisture level of our vegetable garden. What we need is a tiny, cheap, low-power wireless device that's only job is to send or receive a few bits of data now and then. A low-power wireless technology called ZigBee is rewriting the wireless sensor equation. ZigBee is a secure network technology that
rides on top of the recently ratified IEEE 802.15.4 radio standard. ZigBee promises to put wireless sensors in everything from factory automation systems to home security systems to consumer electronics. In conjunction with 802.15.4, ZigBee offers battery life of up to several years for common small batteries. ZigBee technology provides static and dynamic star, cluster tree, mesh networking structures that allow larger area coverage, scalable networks and single point failure of avoidance.
WHAT IS ZIGBEE? ZigBee is a home-area network (wireless software technology) designed specifically to replace the proliferation of individual remote controls. On the whole, Zigbee is a technology based or developed on IEEE 802.15.4 protocol, aimed at low to medium data rate applications typically with low power requirements operating in license free bands. While other wireless standards are concerned with exchanging large amounts of data, ZigBee is for devices that have smaller throughput needs. The other driving factors are low cost, high reliability, high security, low battery usage, simplicity and interoperability with other ZigBee devices.
VARIOUS
TECHNOLOGIES BEFORE ZIGBEE AND THE NEED FOR ZIGBEE:
FIRST THERE WAS X-10:
Of the few attempts to establish a standard for home networking that would control various home appliances, the X-10 protocol is one of the oldest. It was introduced in 1978 for the Sears Home Control System and the Radio Shack Plug'n Power System. It uses power line wiring to send and receive commands. The X-10 PRO code format is the de facto standard for power line carrier transmission. X-10 transmissions are synchronized to the zero-crossing point of the AC power line. A binary 1 is represented by a 1ms burst of 120KHz at the zero-cross point and binary 0 by the absence of 120KHz. The network consists of transmitter units, receiver units, and bi-directional units that can receive and transmit X-10 commands. Receiving units work as remote control power switches to control home appliances or as remote control dimmers for lamps. The transmitter unit is typically a normally open switch that sends a predefined X-10 command if the switch is closed. The X-10 commands enable us to change the status of the appliance unit (turn it on or off) or to control the status of a lamp unit (on, off, dim, bright). Bi-directional units may send their current status (on or off) upon request. A special code is used to accommodate the data transfer from analog sensors. Availability and simplicity have made X-10
the best-known home automation standard. It enables plug-and-play operation with any home appliance and doesn't require special knowledge to configure and operate a home network. The downside of its simplicity is slow speed, low reliability, and lack of security. The effective data transfer rate is 60bps, too slow for any meaningful data communication between nodes. High redundancy in transition is dictated by heavy signal degradation in the power line. For any power appliances, the X-10 transmission looks like noise and is subject to removal by the power line filters. Reliability and security issues rule out the use of the X-10 network for critical household applications like remote control of an entry door.
NEXT COMES
BLUETOOTH AND WIFI: In the last few years, new wireless local area networks (WLANs) such as Wi-Fi and Bluetooth became available. Wireless cameras for remote monitoring are an example of how to employ those technologies in home automation and control areas. But the problem is that those technologies don't satisfy the requirements for a HAN.Why because, if we take a look at the type of data that circulates within a network of sensors and actuators, we may find that most of it is small packets that control devices or obtain their status. For many applications, such as wireless smoke and CO2
detectors or wireless home security, the device mostly stays in deep-sleep mode and only sends a short burst of information if a trigger event occurs. The main requirements for devices in such types of networks are:
• Extremely low power consumption
• The ability to sleep for a long time
• Simplicity
• Low cost
A home network should also support different configurations, such as a star or mesh network, to effectively cover a household area of 30 to 70 meters. Then evolved our ZigBee.
EVOLUTION OF ZIGBEE
• ZigBee-style networks began to be conceived near 1998, when many engineers realized that both WiFi and Bluetooth were going to be unsuitable for many applications. In particular, many engineers wanted to design self-organizing ad-hoc networks of digital radios. The simple one-chip design of Bluetooth digital radios was also inspirational for many engineers. ZigBee can be interpreted as an attempt to use ad-hoc networking software with slightly redesigned BlueTooth radios.
• The IEEE protocol layers were completed in May 2003.
• The ZigBee protocols have failed to release several times, and the most recently advertised release date is November 2004.
GENERAL
CHARACTERESTICS OF ZIGBEE:
Zigbee has been designed to provide the following features:
Data rates of 250 kbps (@2.4 GHz), 40 kbps (@ 915 MHz), and 20 kbps (@868 MHz), Low power consumption, simply implemented
Optimized for low duty-cycle applications (<0.1%)
Low cost to the users means low device cost, low installation cost and low maintenance. ZigBee devices allow batteries to last up to years using primary cells (low cost) without any chargers (low cost and easy installation). ZigBee’s simplicity allows for inherent configuration and redundancy of network devices provides low maintenance.
High density of n CSMA-CA channel access
Yields high throughput and low latency for low duty cycle devices like sensors and controls
• Nodes per network : ZigBee’s use of the IEEE
802.15.4 PHY and MAC allows networks to handle any number of devices. This attribute is critical for massive sensor arrays and control networks.
• Simple protocol, global implementation ZigBee’s protocol code stack is estimated to be about 1/4th
of Bluetooth’s or 802.11’s. Simplicity is essential to cost, interoperability, and maintenance. The IEEE 802.15.4 PHY adopted by ZigBee has been designed for the 868 MHz band in Europe, the 915 MHz band in N America, Australia, etc; and the 2.4 GHz band is now recognized to be a global band accepted in almost all countries.
• Multiple topologies: star, peer-to-peer, mesh
• 255 devices per network Addressing space of up to:
18,450,000,000,000,000,00 0 devices (64 bit IEEE address) 65,535 networks Optional Guaranteed Time
Slot
Fully handshaked protocol for transfer reliability • Range: 10m nominal
(1-100m based on settings) • Location Aware: Yes, but
optional
HOW DOES ZIGBEE WORKS?
Bluetooth wireless technology has received a lot of attention for wireless
connectivity. Now its Zigbee’s turn. ZigBee allows small, low-cost devices to quickly transmit small amounts of data such as temperature readings for thermostats, on/off requests for light switches, or keystrokes for a wireless keyboard. Based on a recently approved international packet radio standard, ZigBee uses the same unlicensed 900MHz and 2.4GHz frequencies as many cordless telephones to send data over distances up to 20 meters. ZigBee devices, typically battery-powered, can actually transmit information much farther than 20 meters because each device within listening distance passes the message along to any other device within range. Only the intended device acts upon the message.
Here is a small example for Zigbee’s efficiency:
EXAMPLE OF ZIGBEE’S
ACCURACY IN
RESPONDING:
Given enough devices spread around a house, this multi-hop “mesh networking” approach can use redundant pathways to make sure the message gets through even if one of the devices is out of order. For example, if you were sitting in bed and flipped a portable switch to preheat the hot tub in the back yard, the message might normally pass through a node in the kitchen. However, if your kitchen ZigBee’s battery died, the message could still get
through in a wireless version of an end-around play. By simultaneously transmitting the message to the den, your tub switch could bypass the kitchen transmitter, still getting the “on” message to the tub. But because another major ZigBee innovation is power efficiency, the kitchen battery is not likely to go dead in the first place. By instructing nodes to wake up only for those split second intervals when they’re needed, ZigBee is so chintzy with electricity that batteries might last for years. ZIGBEE PROTOCOLS
The protocols are build on recent algorithmic research to automatically construct a low-speed ad-hoc network of nodes. In most large cases, the network is a cluster of clusters. It can also form a mesh or a single cluster. The ZigBee protocols minimize the time the radio is ‘on’ in order to reduce the power used by the radio. The network synchronizes nodes to talk and listen at particular times when they have anything to hear or say. At the longer sleep intervals (up to 33 seconds), nodes need more precise timing. The basic mode within a cluster is "Carrier Sense Multiple Access," (CSMA) that is, the nodes talk in the same way that people converse. The problem with CSMA is that the nodes have to listen all the time. To reduce power further, ZigBee permits an optional "beacon" mode, in which a selected node transmits a periodic beacon message. In beacon mode, each
node listens and responds near one of 16 times evenly distributed between beacons. This is operationally similar to people meeting on a regular schedule to talk.
STACK ARCHITECTURE OF ZIGBEE:
The following figure shows the stack architecture of ZigBee.
A very brief overview of this stack architecture:
Application layer
The ZigBee application layer consists of the APS sub-layer, the ZDO and the manufacturer-defined application
objects. The manufacturer-defined application objects implement the actual applications according to the ZigBee-defined application descriptions
ZigBee Device Object
Defines the role of the device within the network (e.g., ZigBee coordinator or end device)
Initiates and/or responds to binding requests
Establishes a secure relationship between network devices selecting one of ZigBee’s security methods such as public key, symmetric key, etc.
Application Support Layer
This layer provides the following services:
Discovery: The ability to determine which other devices are operating in the personal operating space of a device. Binding: The ability to match
two or more devices together based on their services and their needs and forwarding messages between bound devices
Network Layer
The responsibilities of the ZigBee NWK layer include: Starting a network: The ability to
successfully establish a new network.
Joining and leaving a network: The ability to gain membership (join) or relinquish membership (leave) a network.
Configuring a new device: The ability to sufficiently configure the stack for
operation as required.
Addressing: The ability of a ZigBee coordinator to assign addresses to devices joining the network.
Synchronization within a network: The ability for a
device to achieve
synchronization with another device either through tracking beacons or by polling.
Security: Applying security to outgoing frames and removing security to terminating frames Routing: Routing frames to their
intended destinations. MAC Layer
The Media Access Control (MAC) layer was designed to allow multiple topologies without complexity. The power management operation doesn’t require multiple modes of operation. The MAC allows a reduced functionality device (RFD) that needn’t have flash nor large amounts of ROM or RAM. The MAC was designed to handle large number of devices without requiring them to be ‘parked’.
PHY Layer
The Physical layer was designed to accommodate the need for the low cost yet allowing for high levels of integration. The use of direct sequence allows the analog circuitry to be very simple and very tolerant towards inexpensive implementations.
It would be better to think of IEEE 802.15.4 as the physical
radio and ZigBee as the logical network and application software.
FREQUENCY BANDS OF OPERATION OF ZIGBEE DEVICES:
ZigBee-compliant products operate in unlicensed bands worldwide, including 2.4GHz (global), 902 to 928MHz (Americas), and 868MHz (Europe). Raw data throughput rates of 250Kbps can be achieved at 2.4GHz (16 channels), 40Kbps at 915MHz (10 channels), and 20Kbps at 868MHz (1 channel). The transmission distance is expected to range from 10 to 75m, depending on power output
and environmental
characteristics. Like Wi-Fi, ZigBee uses direct-sequence spread spectrum in the 2.4GHz band, with offset-quadrature phase-shift keying modulation. Channel width is 2MHz with 5MHz channel spacing. The 868 and 900MHz bands also use direct-sequence spread spectrum but with binary-phase-shift keying modulation.
FRAME STRUCTURE
DEFINED IN IEEE 802.25.4: The frame structures have been designed to keep the complexity to a minimum while at the same time making them sufficiently robust for transmission on a noisy channel. Each successive protocol layer adds to the structure with layer-specific headers and footers.
The IEEE 802.15.4 MAC defines four frame structures:
• A data frame, used for all transfers of data.
• An acknowledgment frame, used for confirming successful frame reception.
• A MAC command frame, used for handling all MAC peer entity control transfers.
• A beacon frame, used by a coordinator to transmit beacons.
The following figure illustrates the four basic frame types defined in 802.15.4: data, ACK, MAC command, and beacon.
Data Frame format
• One of two most basic and important structures in 15.4
• Provides up to 104 byte data payload capacity • Data sequence numbering
to ensure that packets are tracked
• Robust structure improves reception in difficult conditions
• Frame Check Sequence (FCS) validates error-free data
• This frame structure improves reliability in difficult conditions. Acknowledgement Frame Format
• The other most important structure for 15.4
• Provides active feedback from receiver to sender that packet was received without error
• Short packet that takes advantage of standards-specified “quiet time” immediately after data packet transmission
MAC Command Frame format
• Mechanism for remote control/configuration of client nodes
• Allows a centralized network manager to configure individual clients no matter how large the network
• Beacons add a new level of functionality to a network
• Client devices can wake up only when a beacon is to be broadcast, listen for their address, and if not heard, return to sleep • Beacons are important for mesh and cluster tree networks to keep all of the nodes synchronized without requiring nodes to consume precious battery energy listening for long periods of time
NON BEACON NETWORK COMMUNICATION:
BEACON NETWORK
COMMUNICATION: Two channel-access mechanisms are implemented in 802.15.4. For a nonbeacon network, a standard ALOHA CSMA-CA (carrier-sense medium-access with collision avoidance) communicates with positive
acknowledgement for
successfully received packets. In a beacon-enabled network, a superframe structure is used to control channel access.
Super Frame Structure
The LR-WPAN standard allows the optional use of a superframe structure. The format of the superframe is defined by the coordinator. The superframe is bounded by network beacons, is sent by the coordinator and is divided into 16 equally sized slots. The beacon frame is transmitted in the first slot of each superframe. If a coordinator does not wish to use a superframe structure it may turn
off the beacon transmissions. The beacons are used to synchronize the attached devices, to identify the PAN, and to describe the structure of the super frames. Any device wishing to communicate during the
contention access period (CAP) between two beacons shall compete with other devices using a slotted CSMA-CA mechanism. All transactions shall be completed by the time of the next network beacon.
For low latency
applications or applications requiring specific data bandwidth, the PAN coordinator may dedicate portions of the active superframe to that application. These portions are called guaranteed time slots (GTSs). The guaranteed time slots comprise the contention free period (CFP), which always appears at the end of the active superframe starting at a slot boundary immediately following the CAP, as shown in Figure 5. The PAN coordinator may allocate up to seven of these GTSs and a GTS may occupy more than one slot period. However, a sufficient portion of the CAP shall remain for contention based access of other networked devices or new devices wishing to join the
network. All contention based transactions shall be complete before the CFP begins. Also each device transmitting in a GTS shall ensure that its transaction is complete before the time of the next GTS or the end of the CFP. HOW DOES ZIGBEE PROVIDE LOW COST?
There are three device types defined by the IEEE standard for the lowest system cost: Network coordinator, Full function devices and Reduced function devices.
The Network coordinator maintains
overall network
knowledge.It is the sophisticated of the three types and requires the most memory and computing power.
Full function device (FFD)
Can function in any topology
Capable of being the Network coordinator
Capable of being a node. Can talk to any other device Reduced function device (RFD)
Limited to star topology
Cannot become a network coordinator Talks only to a network coordinator Very simple implementation
An IEEE 802.15.4/ZigBee network requires at least one full function device as a network coordinator, but endpoint devices may be reduced functionality devices and thus the system cost can be reduced.
TOPOLOGIES OF DEVICES CONNECTED IN A ZIGBEE NETWORK:
The three device types as mentioned by IEEE standard can be connected in different topologies or addressing modes.
a) Network + device identifier (star)
b) Source/destination identifier (peer to peer). c) Cluster topology. These can be visualised as shown in the following figure
In a star topology, one of the FFD-type devices assumes
the role of network coordinator and is responsible for initiating and maintaining the devices on the network. All other devices, known as end devices, directly communicate with the coordinator.
In a mesh topology, the ZigBee coordinator is responsible for starting the network and for choosing key network parameters, but the network may be extended through the use of ZigBee routers. The routing algorithm uses a request-response protocol to eliminate sub-optimal routing. Ultimate network size can reach 264 nodes (more than we'll probably need). Using local addressing, you can configure simple networks of more than 65,000 (216) nodes, thereby
reducing address overhead. FUNCTIONS OF DEVICES
CONNECTED IN A
NETWORK:
The ZigBee Network Coordinator
Sets up a network
Transmits network beacons Manages network nodes
Stores network node information Routes messages between paired
nodes
Typically operates in the receive state
The ZigBee Network Node Designed for battery powered or
high energy savings
Searches for available networks Transfers data from its
Determines whether data is pending
Requests data from the network coordinator
Can sleep for extended periods POWER AND BEACONS OF ZIGBEE TECHNOLOGY:
Ultra-low power
consumption is how ZigBee technology promotes a long lifetime for devices with no rechargeable batteries. ZigBee networks are designed to conserve the power of the slave nodes. For most of the time, a slave device is in deep-sleep mode and wakes up only for a fraction of a second to confirm its presence in the network. ZigBee networks can use beacon or non-beacon environments. Beacons are used to synchronize the network devices, identify the HAN, and describe the structure of the superframe. The beacon intervals are set by the network coordinator and vary from 15ms to over 4 minutes. Sixteen equal time slots are allocated between beacons for message delivery. The channel access in each time slot is contention-based. However, the network coordinator can dedicate up to seven guaranteed time slots for noncontention based or low-latency delivery.
The non-beacon mode is a simple, traditional multiple-access system used in simple peer and near-peer networks. It operates like a two-way radio network, where each client is
autonomous and can initiate a conversation at will, but could interfere with others unintentionally. The recipient may not hear the call or the channel might already be in use.
Beacon mode is a
mechanism for controlling power consumption in extended networks such as cluster tree or mesh. It enables all the clients to know when to communicate with each other. Here, the two-way radio network has a central dispatcher that manages the channel and arranges the calls. The primary value of beacon mode is that it reduces the system's power consumption.
Non-beacon mode is typically used for security systems where client units, such as intrusion sensors, motion detectors, and glass-break detectors, sleep 99.999% of the time. Remote units wake up on a regular, yet random, basis to announce their continued presence in the network. When an event occurs, the sensor wakes up instantly and transmits the alert. The network coordinator, powered from the main source, has its receiver on all the time and can therefore wait to hear from each of these stations. Since the network coordinator has an "infinite" source of power it can allow clients to sleep for unlimited periods of time, enabling them to save power.
Beacon mode is more suitable when the network coordinator is battery-operated.
Client units listen for the network coordinator's beacon (broadcast at intervals between 0.015 and 252s). A client registers with the coordinator and looks for any messages directed to it. If no messages are pending, the client returns to sleep, awaking on a schedule specified by the coordinator. Once the client communications are completed, the coordinator itself returns to sleep.
Another key to longer battery life in a wireless connection is very fast connection time. Because of ZigBee applications low bandwidth requirements, a ZigBee node can sleep most of the time, thus saving battery power, and then wake up, send data quickly, and go back to sleep. And, because ZigBee can transition from sleep mode to active mode in 15 msec or less, even a sleeping node can achieve suitably low latency. Someone flipping a ZigBee-enabled wireless light switch, for example, would not be aware of a wake-up delay before the light turns on. In contrast, wake-up delays for Bluetooth are typically around three seconds.
SECURITY:
Security and data integrity are key benefits of the ZigBee technology. ZigBee leverages the security model of the IEEE 802.15.4 MAC sub layer, which specifies four security services:
• Access control — the device maintains a list of trusted devices within the network
• Data encryption, which uses symmetric key 128-bit advanced encryption standard
• Frame integrity to protect data from being modified by parties without cryptographic keys
• Sequential freshness to reject data frames that have been replayed—the network controller compares the freshness value with the last known value from the device and rejects it if the freshness value has not been updated to a new value
The actual security
implementation is specified by the implementer using a standardized toolbox of ZigBee security software.
When security of MAC layer frames is desired, ZigBee uses MAC layer security to secure MAC command, beacon, and acknowledgement frames. ZigBee may secure messages transmitted over a single hop using secured MAC data frames, but for multi-hop messaging ZigBee relies upon upper layers (such as the NWK layer) for security. The MAC layer uses the Advanced Encryption Standard (AES) as its core cryptographic algorithm and describes a variety of security suites that use the AES algorithm. These suites can protect the confidentiality,
integrity, and authenticity of MAC frames. The MAC layer does the security processing, but the upper layers, which set up the keys and determine the security levels to use, control this processing. When the MAC layer transmits (receives) a frame with security enabled, it looks at the destination (source) of the frame, retrieves the key associated with that destination (source), and then uses this key to process the frame according to the security suite designated for the key being used. Each key is associated with a single security suite and the MAC frame header has a bit that specifies whether security for a frame is enabled or disabled. PER FORMANCE
CHARACTERESTICS:
COMPARISION BETWEEN EXISTING WIRE LESS
TECHNOLOGIES AND
ZIGBEE:
The following table shows the comparison of the Zigbee,
Bluetooth, and Wi-Fi technologies.
SMALL COMPARISION BETWEEN BLUETOOTH AND ZIGBEE:
The main competition to zigbee comes from blue tooth. But the basic difference between zigbee and bluetooth is that Bluetooth has many different modes and states depending upon your latency and power requirements such as sniff, park, hold, active, etc.; ZigBee/IEEE
802.15.4 has active
(transmit/receive) or sleep. Application software needs to focus on the application, not on which power mode is optimum for each aspect of operation.
Bluetooth seems best suited for:
Synchronization of cell phone to PDA
Hands-free audio
Timing considerations: Zigbee:
• New slave enumeration = 30 msec
• Sleeping slave changing to active=15 msec.
• Active slave channel access time=15msec
Bluetooth:
• New slave enumeration time =>3 sec, typically 20 sec.
• Sleeping slave changing to active= 3 sec.
• Active slave channel access time=2 msec
Power considerations: Zigbee:
•2+years from normal batteries.
•Designed to optimize slave power requirements.
Bluetooth:
• Power model as a mobile phone (regular daily charging.)
• Designed to maximize adhoc functionality
APPLICATIONS:
Because ZigBee technology is based on industry standard it provides inter operability allowing inter communications between different devices from different manufacturers and offers system integrators and consumers flexible purchase options. ZigBee also offers simplicity and a cost effective approach through building construction and remodeling with wireless technology. Furthermore the low power consumptions features of ZigBee technology sustain these battery-powered networks.
One model application in development, for instance, is a wireless alarm system to prevent damage to buildings through fire, water etc. Using ZigBee means that battery powered smoke detectors and other sensors can be connected up in no-cable network and report back to a remote central unit.
In addition to retrofitting, ZigBee may reduce costs for
Original Equipment
Manufacturers (OEMs) because typical target applications already use an MCU; thus , there is only a minimal incremental cost needed for additional memory added to the MCU to house the
MAC and Zigbee software. Finally, free scale’s 2.4GhzBand Mc13192 RF transceiver modem can be used worldwide, eliminating the need for various markets or regions.
At home:
Consumer products in the home using ZigBee technology include home automation systems with lightning and HVAC control devices, security systems, blind and curtain controls, as well as remote controls for set-top boxes and other entertainment devices. Consumer products with accessosory interfaces can add Zigbee technology functionality after purchase. Compact Flash or PCMCIA slots in PDAS or notebook PCs are examples. The health care and fitness markets can also benefit from Zigbee technology. Health tracking devices, such as pedometers and heart rate monitors, are typical target applications. Equipment used in sports medicine and physical therapy can become more mobile by introducing a wireless component.
Building Applications: CONCLUSION:
IEEE 802.15.4 is a new standard that still needs to pass through the circles of rigorous technology critics and establish its own place in the industry. To address this need, the ZigBee Alliance, an industry working group, is developing standardized application software on top of the IEEE 802.15.4 wireless standard. The alliance is working closely with the IEEE to ensure an integrated, complete, and interoperable network for the market. For example, the working group will provide interoperability certification
testing of 802.15.4 systems that include the ZigBee software layer. The ZigBee Alliance will also serve as the official test and certification group for ZigBee devices. ZigBee is the only standards-based technology that addresses the needs of most remote monitoring and control
and sensory network
applications. The ZigBee Alliance is not pushing a technology; rather it is providing a standardized base set of solutions for sensor and control systems. As a pioneer in wireless mobile technology, the Fraunhofer Institute for Open Communication Systems FOKUS has opted for “ZigBee”
–the commercial buzzword for the new IEEE 802.15.4 transmission standard for wireless applications.
Predictions for the future of ZigBee-enabled devices are a popular topic for numerous market-research firms. ZigBee will come to the forefront in developing standard solutions, particularly for areas where saving time and energy is of the essence. But as with any crystal ball reading, the results of those analyses are subject to interpretation. Backed by IEEE, ZigBee has the potential to unify methods of data communication for sensors, actuators, appliances, and asset-tracking devices. It offers a means to build a reliable but affordable network backbone that takes advantage of battery-operated devices with a low data rate and a low duty cycle. ZigBee can be used in many applications, from industrial automation, utility metering, and building control to even toys. Home automation, however, is the biggest market for ZigBee-enabled devices. This follows from the number of remote controlled devices (or devices that may be connected wirelessly) in the average household. This cost-effective and easy-to-use home network potentially creates a whole new ecosystem of interconnected home appliances, light and climate control systems, and security and sensor sub networks.
REFERENCES: www.zigbee.org www.embedded.com www.designnews.com www.raycommelectronics.co.uk www.techonline.com/community www.technologyreview.com/articles
