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Encyclopedia > ZigBee

ZigBee is the name of a specification for a suite of high level communication protocols using small, low-power digital radios based on the IEEE 802.15.4 standard for wireless personal area networks (WPANs). ZigBee is targeted at RF applications that require a low data rate, long battery life, and secure networking. This article needs to be cleaned up to conform to a higher standard of quality. ... ZigBee is a proprietary set of high level communication protocols designed to use small, low power digital radios based on the IEEE 802. ... Standardization, in the context related to technologies and industries, is the process of establishing a technical standard among competing entities in a market, where this will bring benefits without hurting competition. ... A wireless personal area network (WPAN) is a personal area network (PAN) that uses radio rather than wires. ...


The relationship between IEEE 802.15.4-2003 and ZigBee is similar to that between IEEE 802.11 and the Wi-Fi Alliance. The ZigBee 1.0 specification was ratified on December 14, 2004 and is available to members of the ZigBee Alliance. An entry level membership, called Adopter, in the ZigBee Alliance costs US$ 3500 annually and provides access to the specifications and permission to create products for market using the specifications. For non-commercial purposes, the ZigBee specification is available to the general public at the ZigBee Specification Download Request. Most recently, the ZigBee 2006 specification was posted in December 2006. IEEE 802. ... Official Wi-Fi logo The Wi-Fi Alliance is a trade group that owns the trademark to Wi-Fi. ... is the 348th day of the year (349th in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... ISO 4217 Code USD User(s) the United States, the British Indian Ocean Territory,[1] the British Virgin Islands, East Timor, Ecuador, El Salvador, the Marshall Islands, Micronesia, Palau, Panama, Caicos Islands, and the insular areas of the United States Inflation 2. ...


ZigBee operates in the industrial, scientific and medical (ISM) radio bands; 868 MHz in Europe, 915 MHz in the USA and 2.4 GHz in most jurisdictions worldwide. The technology is intended to be simpler and cheaper than other WPANs such as Bluetooth. The most capable ZigBee node type is said to require only about 10% of the software of a typical Bluetooth or Wireless Internet node, while the simplest nodes are about 2%[citation needed]. However, actual code sizes are much higher, closer to 50% of Bluetooth code size[citation needed]. ZigBee chip vendors have announced 128 kilobyte devices[citation needed]. The industrial, scientific and medical (ISM) radio bands were originally reserved internationally for non-commercial use of RF electromagnetic fields for industrial, scientific and medical purposes. ... By the mid 20th century humans had achieved a mastery of technology sufficient to leave the surface of the Earth for the first time and explore space. ... Simplicity is the property, condition, or quality of being simple or un-combined. ... In economics, business, and accounting, a cost is the value of inputs that have been used up to produce something, and hence are not available for use anymore. ... Bluetooth logo This article is about the electronic protocol named after Harald Bluetooth Gormson. ...


As of 2006, the retail price of a Zigbee-compliant transceiver is approaching $1, and the price for one radio, processor, memory package is about $3.[1] Comparatively, before Bluetooth was launched (1998) it had a projected price, in high volumes, of $4 - $6[citation needed]; the price of consumer-grade Bluetooth chips is now under $3.[2] Year 2006 (MMVI) was a common year starting on Sunday (link displays full 2006 calendar) of the Gregorian calendar. ...


First stack release is now called "Zigbee 2004". The 2nd stack release (today, 26 June 2007, the current public one) is called 2006, and mainly replaces the MSG/KVP structure used in 2004 with a "cluster library". The 2004 stack is now more or less obsolete. The ZigBee Alliance has started work on ZigBee 2007, looking to extend the ZigBee 2006 specification capabilities, the main enhancements are optimising certain network level functionality (such as data aggregation). There're also some new application profiles like Automatic Meter Reading, Commercial building automation and home automation based on the "cluster library principe".


Zigbee 2007 is sometimes called "Pro", but Pro is a stack profile, which defines certain stack settings and mandatory features.


ZigBee 2007 at the network level is not backwards compatible with ZigBee 2004/2006, although a ZigBee 2004/2006 RFD node can join a 2007 network and visa-versa. It's not possible to mix 2004/2006 routers with 2007 routers/coordinator.

Contents

Uses

ZigBee protocols are intended for use in embedded applications requiring low data rates and low power consumption. ZigBee's current focus is to define a general-purpose, inexpensive, self-organizing, mesh network that can be used for industrial control, embedded sensing, medical data collection, smoke and intruder warning, building automation, home automation, domotics, etc. The resulting network will use very small amounts of power so individual devices might run for a year or two using the originally installed battery. In telecommunication, data signaling rate (DSR) is the aggregate rate at which data pass a point in the transmission path of a data transmission system. ... In electrical engineering, power consumption refers to the electrical energy over time that must be supplied to an electrical device to maintain its operation. ... Mesh networking is a way to route data, voice and instructions between nodes. ... Light control computerized system Home automation (also called domotics) is a field within building automation, specializing in the specific automation requirements of private homes and in the application of automation techniques for the comfort and security of its residents. ... Domotics is the application of computer and/or robotic technology to household appliances and buildings. ...


Device types

There are three different types of ZigBee device:

  • ZigBee coordinator(ZC): The most capable device, the coordinator forms the root of the network tree and might bridge to other networks. There is exactly one ZigBee coordinator in each network since it is the device that started the network originally. It is able to store information about the network, including acting as the Trust Centre & repository for security keys.
  • ZigBee Router (ZR): As well as running an application function a router can act as an intermediate router, passing data from other devices.
  • ZigBee End Device (ZED): Contains just enough functionality to talk to its parent node (either the coordinator or a router); it cannot relay data from other devices. This relationship allows the node to be asleep a significant amount of the time thereby giving you the much quoted long battery life. A ZED requires the least amount of memory, and therefore can be less expensive to manufacture than a ZR or ZC.

Protocols

The protocols build on recent algorithmic research (Ad-hoc On-demand Distance Vector, neuRFon) to automatically construct a low-speed ad-hoc network of nodes. In most large network instances, the network will be a cluster of clusters. It can also form a mesh or a single cluster. The current profiles derived from the ZigBee protocols support beacon and non-beacon enabled networks. The Ad-hoc On-demand Distance Vector (AODV) routing algorithm is an algorithm for routing data across Wireless Mesh Networks. ... The neuRFon project (named for a combination of neuron and RF) was a research program begun in 1999 at Motorola Labs to develop ad hoc wireless networking for wireless sensor network applications. ...


In non-beacon enabled networks (those whose beacon order is 15), an unslotted CSMA/CA channel access mechanism is used. In this type of network ZigBee Routers typically have their receivers continuously active, requiring a more robust power supply. However, this allows for heterogeneous networks in which some devices receive continuously, while others only transmit when an external stimulus is detected. The typical example of a heterogeneous network is a wireless light switch: the ZigBee node at the lamp may receive constantly, since it's connected to the mains supply, while a battery-powered light switch would remain asleep until the switch is thrown. The switch then wakes up, sends a command to the lamp, receives an acknowledgment, and returns to sleep. In such a network the lamp node will be at least a ZigBee Router, if not the ZigBee Coordinator; the switch node is typically a ZigBee End Device. In computer networking, Carrier Sense Multiple Access With Collision Avoidance (CSMA/CA) is a network control protocol in which (a) a carrier sensing scheme is used, (b) a data station that intends to transmit sends a jam signal, (c) after waiting a sufficient time for all stations to receive the... A wireless light switch is a light switch that uses radio transmissions to command a light to turn off or on, instead of interrupting the power line going to the light. ...


In beacon enabled networks, the special network nodes called ZigBee Routers transmit periodic beacons to confirm their presence to other network nodes. Nodes may sleep between beacons, thus lowering their duty cycle and extending their battery life. Beacon intervals may range from 15.36 milliseconds to 15.36 ms * 214 = 251.65824 seconds at 250 kbit/s, from 24 milliseconds to 24 ms * 214 = 393.216 seconds at 40 kbit/s and from 48 milliseconds to 48 ms * 214 = 786.432 seconds at 20 kbit/s. However, low duty cycle operation with long beacon intervals requires precise timing which can conflict with the need for low product cost. In telecommunication and electronics, the term duty cycle has the following meanings: The duty cycle D is defined as the ratio between the pulse duration () and the period (T) of a rectangular waveform In a periodic phenomenon, the ratio of the duration of the phenomenon in a given period to... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ...


In general, the ZigBee protocols minimize the time the radio is on so as to reduce power use. In beaconing networks, nodes only need to be active while a beacon is being transmitted. In non-beacon enabled networks, power consumption is decidedly asymmetrical: some devices are always active, while any others present spend most of their time sleeping.


ZigBee devices are required to conform to the IEEE 802.15.4-2003 Low-Rate Wireless Personal Area Network (WPAN) standard. The standard specifies its lower protocol layers—the physical layer (PHY), and the medium access control (MAC) portion of the data link layer (DLL). This standard specifies operation in the unlicensed 2.4 GHz, 915 MHz and 868 MHz ISM bands. In the 2.4 GHz band there are 16 ZigBee channels, with each channel requiring 5 MHz of bandwidth. The center frequency for each channel can be calculated as, FC = (2405 + 5*(k-11)) MHz, where k = 11, 12, ..., 26. For other senses of this word, see protocol. ... Layer may refer to: Look up Layer in Wiktionary, the free dictionary. ... This article does not cite any references or sources. ... The Media Access Control (MAC) data communication protocol sub-layer, also known as the Medium Access Control, is a part of the data link layer specified in the seven-layer OSI model (layer 2). ... This article does not cite any references or sources. ... MHZ redirects here. ... MegaHertz (MHz) is the name given to one million (106) Hertz, a measure of frequency. ... The industrial, scientific and medical (ISM) radio bands were originally reserved internationally for non-commercial use of RF electromagnetic fields for industrial, scientific and medical purposes. ... MHZ redirects here. ... MegaHertz (MHz) is the name given to one million (106) Hertz, a measure of frequency. ... MegaHertz (MHz) is the name given to one million (106) Hertz, a measure of frequency. ...


The radios use direct-sequence spread spectrum coding, which is managed by the digital stream into the modulator. BPSK is used in the 868 and 915 MHz bands, and orthogonal QPSK that transmits two bits per symbol is used in the 2.4 GHz band. The raw, over-the-air data rate is 250 kbit/s per channel in the 2.4 GHz band, 40 kbit/s per channel in the 915 MHz band, and 20 kbit/s in the 868 MHz band. Transmission range is between 10 and 75 meters (33~246 feet), although it is heavily dependent on the particular environment. The maximum output power of the radios is generally 0 dBm (1 mW). In telecommunications, direct-sequence spread spectrum (DSSS) is a modulation technique. ... Binary Phase Shift Keying, or BiPhase Shift Keying, (BPSK) is a method of encoding and/or transmitting data on top of a carrier. ... Quadrature phase-shift keying (quadriphase, quaternary phase-shift keying) is a form of modulation in which a carrier is sent in four phases, 45, 135, 225, and 315 degrees, and the change in phase from one symbol to the next encodes two bits per symbol. ... A kilobit is a unit of information storage, abbreviated kbit or sometimes kb. ... Look up second in Wiktionary, the free dictionary. ... Channel, in communications (sometimes called communications channel), refers to the medium used to convey information from a sender (or transmitter) to a receiver. ... The metre, or meter (symbol: m) is the SI base unit of length. ... A foot (plural: feet or foot;[1] symbol or abbreviation: ft or, sometimes, ′ – a prime) is a unit of length, in a number of different systems, including English units, Imperial units, and United States customary units. ... The correct title of this article is . ...


The basic channel access mode specified by IEEE 802.15.4-2003 is "carrier sense, multiple access/collision avoidance" (CSMA/CA). That is, the nodes talk in the same way that people converse; they briefly check to see that no one is talking before they start. There are three notable exceptions to the use of CSMA. Beacons are sent on a fixed timing schedule, and do not use CSMA. Message acknowledgements also do not use CSMA. Finally, devices in Beacon Oriented networks that have low latency real-time requirements may also use Guaranteed Time Slots (GTS) which by definition do not use CSMA. Carrier Sense Multiple Access (CSMA) is a probabilistic Media Access Control (MAC) protocol in which a node verifies the absence of other traffic before transmitting on a shared physical medium, such as an electrical bus, or a band of electromagnetic spectrum. ...


Software and hardware

The software is designed to be easy to develop on small, cheap microprocessors. The radio design used by ZigBee has been carefully optimized for low cost in large scale production. It has few analog stages and uses digital circuits wherever possible. It has been suggested that this article or section be merged with Analog electronics. ... Digital circuits are electric circuits based on a number of discrete voltage levels. ...


Even though the radios themselves are cheap, the ZigBee Qualification Process involves a full validation of the requirements of the physical layer. This amount of concern about the Physical Layer has multiple benefits, since all radios derived from that semiconductor mask set would enjoy the same RF characteristics. On the other hand, an uncertified physical layer that malfunctions could cripple the battery lifespan of other devices on a ZigBee network. Where other protocols can mask poor sensitivity or other esoteric problems in a fade compensation response, ZigBee radios have very tight engineering constraints: they are both power and bandwidth constrained. Thus, radios are tested to the ISO 17025 standard with guidance given by Clause 6 of the 802.15.4-2003 Standard. Most vendors plan to integrate the radio and microcontroller onto a single chip. (Some interesting links: [1][2] look for the USB Dongle) It has been suggested that ISO/IEC 17025 be merged into this article or section. ...


History

  • ZigBee-style networks began to be conceived about 1998, when many installers realized that both WiFi and Bluetooth were going to be unsuitable for many applications. In particular, many engineers saw a need for self-organizing ad-hoc digital radio networks.
  • The IEEE 802.15.4 standard was completed in May 2003.
  • In the summer of 2003, Philips Semiconductors, a major mesh network supporter, ceased its investment. Philips Lighting has, however, continued Philips' participation, and Philips remains a promoter member on the ZigBee Alliance Board of Directors.
  • The ZigBee Alliance announced in October 2004 that its membership had more than doubled in the preceding year and had grown to more than 100 member companies, in 22 countries. By April 2005 membership had grown to more than 150 companies, and by December 2005 membership had passed 200 companies.
  • The ZigBee specifications were ratified on 14 December 2004.
  • The ZigBee Alliance announces public availability of Specification 1.0 on 13 June 2005, known as ZigBee 2004 Specification.
  • The ZigBee Alliance announces the completion and immediate member availability of its enhanced version of the ZigBee Standard in September 2006, known as ZigBee 2006 Specification..

Year 1998 (MCMXCVIII) was a common year starting on Thursday (link will display full 1998 Gregorian calendar). ... Wi-Fi (or Wi-fi, WiFi, Wifi, wifi), short for Wireless Fidelity, is a set of standards for wireless local area networks (WLAN) currently based on the IEEE 802. ... Bluetooth logo This article is about the electronic protocol named after Harald Bluetooth Gormson. ... Year 2003 (MMIII) was a common year starting on Wednesday (link displays 2003 calendar) of the Gregorian calendar. ... Year 2003 (MMIII) was a common year starting on Wednesday (link displays 2003 calendar) of the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 348th day of the year (349th in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ...

See also

Wibree is a digital radio technology (intended to become an open standard of wireless communications) designed for ultra low power consumption (button cell batteries) within a short range (10 meters / 30 feet) based around low-cost transceiver microchips in each device. ... EnOcean GmbH is a spin-off company of Siemens AG founded in 2001. ... The following is a comparison of various wireless data access standards and their performance by several different measures. ...

External links

  • ZigBee Alliance
  • IEEE 802.15.4 web site
  • open-ZB : an open-source toolset for the IEEE 802.15.4 and ZigBee protocols
  • ZigBeeLinks : Information and links about hardware, solutions and development of zigbee and 802.15.4 applications.
  • Design Considerations when Using ZigBee
  • Listing of major ZigBee semiconductor suppliers
  • ZigBee Wireless Networks for Industrial Systems (white paper)
  • ZigBee introduction course An introduction on ZigBee in the English and Dutch language.
  • Comparing WLAN and ZigBee for embedded applications
  • Who Needs ZigBee? - Explains the difference between wireless standards, and provides insight into how ZigBee differs from the others.
  • Palowireless ZigBee Resource Center Articles, news and resources.
  • OpenBee A ZigBee Development Kit with a ZigBee Stack developed in UML
  • A ZigBeeTM-subset/IEEE 802.15.4TM Multi-platform Protocol Stack A ZigBee-subset/IEEE 802.15.4 multi-platform stack for educational, research, personal use; compatible with Microchip PICDEMZ and TI/Chipcon CC2430 SOC platforms.
  • Using ZigBee Wireless Networking to Develop Commercial Products
  • ZigBeeLinks : Information and links about hardware, solutions and development of zigbee and 802.15.4 applications.
  • ZigBee Resources Including whitepapers, glossary and specification updates

In the field of software engineering, the Unified Modeling Language (UML) is a standardized specification language for object modeling. ...

References

  1. ^ Adams, Jon; Bob Heile (2005-10). Busy as a ZigBee. [IEEE]. Retrieved on 2007-01-16.
  2. ^ Compare with Other Technologies. Bluetooth SIG. Retrieved on 2007-01-16.

  Results from FactBites:
 
What Is ZigBee? (255 words)
The mission of the ZigBee Working Group is to bring about the existence of a broad range of interoperable consumer devices by establishing open industry specifications for unlicensed, untethered peripheral, control and entertainment devices requiring the lowest cost and lowest power consumption communications between compliant devices anywhere in and around the home.
ZigBee was formerly known as PURLnet, RF-Lite, Firefly, and HomeRF Lite.
ZigBee's technology is slower than 802.11b (11 Mbps) and Bluetooth (1 Mbps) but it consumes significantly less power.
ZigBee - Wikipedia, the free encyclopedia (2664 words)
ZigBee is the name of a specification for a suite of high level communication protocols using small, low-power digital radios based on the IEEE 802.15.4 standard for wireless personal area networks (WPANs).
The relationship between IEEE 802.15.4-2003 and ZigBee is similar to that between IEEE 802.11 and the Wi-Fi Alliance.
Zigbee introduction course An introduction on Zigbee in the English and Dutch language.
  More results at FactBites »

 
 

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