Origin of Word

ZigBee

Origin of word

Word ZigBee was originated from word ZigZag indicating cross-shaped network cables and Bee to indicate economical communication method.
Word ZigBee was proposed and decided by committee members in early phase of standard committee of ZigBee.

Introduction

ZigBeeis the set of specs built around theIEEE802.15.4 wireless protocol. The IEEE is theInstitute of Electrical and Electronics Engineers, anon-profitorganization dedicated to furthering technology involving electronics and electronic devices. The802 groupis the section of the IEEE involved in network operations and technologies, including mid-sized networks and local networks.Group 15deals specifically withwireless networkingtechnologies, and includes the now ubiquitous 802.15.1 working group, which is also known as Bluetooth®. The standard itself is regulated by a group known as theZigBee 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 2.4GHzISM 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 generationautomated manufacturing, with small transmitters in every device on the floor, allowing for communication between devices to a centralcomputer. 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 60 ZigBee devices may be found in an average American home, all communicating with one another freely and regulating common tasks seamlessly.

ZigBee® Overview

ZigBee is a low-power wireless communications technology and international standard protocol for the next-generation wireless network, reducing data size and allowing for lower-cost network construction with simplified protocol and limited functionality. ZigBee uses the PHY and MAC layers defined by IEEE® 802.15.4, which is the short-distance wireless communication standard for 2.4 GHz band. ZigBee comprises the ZigBee platform specifications and ZigBee profiles defined by the ZigBee Alliance.

ZigBee Key Features:

1. Low Power-The benefits of simple, cost-effective, low-power wireless connectivity that ZigBee technology provides address a variety of markets, including industrial and home monitoring, control and automation, as well as health care diagnostics. Freescale provides all the building blocks used in a complete ZigBee-compliant platform solution: the RF transceiver, MAC and ZigBee software, microcontrollers and sensors. The development hardware and reference designs provide developers with the tools they need to easily and quickly implement these building blocks. One solution, one provider—built, tested, compatible and ready for integration.

2. Robust-802.15.4 provides a robust foundation for ZigBee, ensuring a reliable solution in noisy environments. Features such as energy detection, clear channel assessment and channel selection help the device pick the best possible channel, avoiding other wireless networks such as Wi-Fi®. Message acknowledgement helps to ensure that the data was delivered to its destination. Finally, multiple levels of security ensure that the network and data remain intact and secure.

3. Mesh Networking-The ability to cover large areas with routers is one of the key features of ZigBee that helps differentiate itself from other technologies. Mesh networking can extend the range of the network through routing, while self healing increases the reliability of the network by re-routing a message in case of a node failure

4. Interoperability-The ZigBee Alliance helps ensure interoperability between vendors by creating testing and certification programs for ZigBee devices. Users can be assured the devices that go through certification testing and use the ZigBee logo will work with other devices based on the same applications. This provides end customers with the customers with peace of mind while creating brand awareness of products with the ZigBee logo.

Characteristics

/ 1. ZigBee consumes low electricity supply and can be configured to large scale sensor networks by integrating with sensor (Activity, light, temperature and humidity, etc) and transmitter/receiver devices. This type of structure is defined as foundation technology for sensing, monitoring and controlling.

/ 2. ZigBee has recognized as next generation short-distance wireless communication standard based on strong advantages including lowest costs, lowest energy consumption which can be last 2 years with 2 AA type batteries, scalability of up to 65,000 nodes, simple network configuration and reliability from immediate recovery function from data transmission errors. Especially, ZigBee supports multi-hop function to ensure highest transmission success rates.
3. 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 .
4. Low power consumption, with battery life ranging from months to years. Considering the number of devices with remotes in use at present, it is easy to see that more numbers of batteries need to be provisioned every so often, entailing regular (as well as timely), recurring expenditure. In the ZigBee standard, longer battery life is achievable by either of two means: continuous network connection and slow but sure battery drain, or intermittent connection and even slower battery drain.
5. Maximum data rates allowed for each of these frequency bands are fixed as 250 kbps @2.4 GHz, 40 kbps @ 915 MHz, and 20 kbps @868 MHz.
6. High throughput and low latency for low duty-cycle applications (<0.1%)
7. Channel access using Carrier Sense Multiple Access with Collision Avoidance (CSMA - CA)
8. Addressing space of up to 64 bit IEEE address devices, 65,535 networks
9. 50m typical range
10. Fully reliable “hand-shaked” data transfer protocol.
11. Different topologies as illustrated below: star, peer-to-peer, mesh
Applicable fields
ZigBee, unlike other wireless communication technology, consumes low electricity power and inexpensive to implement. These advantages allow to be applied diverse Ubiquitous environments including intelligent home networks, automated commercial devices, building automation industry, commercial automation, environment monitoring, toy and industries and telematics

Device types
ZigBee networks use three device types:

· Thenetwork coordinatormaintains overall network knowledge. It's the most sophisticated of the three types and requires the most memory and computing power.

· Thefull 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).

· Thereduced function device (RFD)carries limited (as specified by the standard) functionality to lower cost and complexity. It's generally found in network-edge devices.

Traffic Types

ZigBee/IEEE 802.15.4 addresses three typical traffic types. IEEE 802.15.4 MAC can accommodate all the types.
1. Data isperiodic. The application dictates the rate, and the sensor activates, checks for data and deactivates.
2. Data isintermittent. The application, or other stimulus, determines the rate, as in the case of say smoke detectors. The device needs to connect to the network only when communication is necessitated. This type enables optimum saving on energy.
3. Data isrepetitive, and the rate is fixed a priori. Depending on allotted time slots, called GTS (guaranteed time slot), devices operate for fixed durations.

Released specifications

1. ZigBee Home Automation- ZigBee Home Automation offers a global standard for interoperable products enabling smart homes that can control appliances, lighting, environment, energy management and security, as well as the expandability to connect with other ZigBee networks.

2. ZigBee Smart Energy 1.0- ZigBee Smart Energy is the world's leading standard for interoperable products that monitor, control, inform and automate the delivery and use of energy and water. It helps create greener homes by giving consumers the information and automation needed to easily reduce their consumption and save money, too.

This standard supports the diverse needs of a global ecosystem of utilities, product manufacturers and government groups as they plan to meet future energy and water needs.

3. ZigBee Telecommunication Services- ZigBee Telecom Services offers a global standard for interoperable products enabling a wide variety of value-added services, including information delivery, mobile gaming, location-based services, secure mobile payments, mobile advertising, zone billing, mobile office access control, payments, and peer-to-peer data-sharing services.

This single standard offers an affordable and easy way to introduce innovative new services that touch almost everyone using mobile phones and other portable electronic devices. It offers a variety of value-added services for mobile phone network operators, retailers, businesses, and governments. Now these groups have new ways to reach prospective customers. Consumers can use their mobile phones to pay for products and services, create their own gaming and communication networks, receive discounts or coupons from retailers, and obtain directions or information on public spaces with GPS.

4. ZigBee Health Care- ZigBee Health Care offers a global standard for interoperable productsenabling secure and reliable monitoring and management of non-critical, low-acuity healthcare services targeted at chronic disease, aging independence and general health, wellness and fitness.

These smart and easy-to-use products promote aging independence along with greater overall health, wellness and fitness awareness. A variety of these products even offer an innovative connection with health care professionals like doctors and nurses, allowing them to monitor your health even while you're at home.

ZigBee Health Care supports the needs of a diverse global ecosystem of service providers, care providers, payers, product manufacturers and policymakers in providing a standard way to easily monitor, control and automate the delivery and use of health, wellness and fitness data for home and professional uses.

5. ZigBee Remote Control- ZigBee Remote Control provides a global standard for advanced, greener and easy-to-use RF remotes that removes line-of-sight restrictions while also delivering two-way communication, longer range of use and extended battery life. It was designed for a variety of consumer electronic devices including HDTV, home theater equipment, set-top boxes and other audio equipment.

Since ZigBee Remote Control replaces 30+ year old infrared technology, it frees consumers from pointing remotes at devices. It offers consumers more flexibility, allowing control of devices from nearby rooms and placement of those devices almost anywhere - including behind wood, interior walls or glass. A greener choice, ZigBee Remote Controls are more energy efficient and last longer than infrared. You can read more of the details on the energy efficiency of ZigBee Remote Controls in ourwhite paper.

Specifications under development

§ ZigBee Smart Energy 2.0

§ ZigBee Building Automation

§ ZigBee Retail Services

The relationship betweenIEEE 802.15.4and ZigBeeis similar to that betweenIEEE 802.11and theWi-Fi Alliance. The ZigBee 1.0 specification was ratified on 14 December 2004 and is available to members of the ZigBee Alliance. Most recently, the ZigBee 2007 specification was posted on 30 October 2007. The first ZigBee Application Profile, Home Automation, was announced 2 November 2007. As amended byNIST, the Smart Energy Profile 2.0 specification will remove the dependency on IEEE 802.15.4. Device manufacturers will be able to implement any MAC/PHY, such asIEEE 802.15.4(x) andIEEE P1901, under an IP layer based on6LoWPAN.

ZigBee operates in the industrial, scientific and medical (ISM) radio bands; 868MHz in Europe, 915MHz in the USA and Australia, and 2.4GHz in most jurisdictions worldwide. Thetechnologyis intended to be simpler and less expensive than otherWPANssuch asBluetooth. ZigBee chip vendors typically sell integrated radios and microcontrollers with between 60KB and 256KB flash memory.

Device types
ZigBee networks use three device types:

· Thenetwork coordinatormaintains overall network knowledge. It's the most sophisticated of the three types and requires the most memory and computing power.

· Thereduced function device (RFD)carries limited (as specified by the standard) functionality to lower cost and complexity. It's generally found in network-edge devices.

Power and beacons
Ultra-low power consumption is how ZigBee technology promotes a long lifetime for devices with nonrechargeable 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.