FAQs

ZigBee FAQ

1. What is the ZigBee Alliance?
   
2. What is the ZigBee technology?
   
3. What is 802.15.4?
   
4. Why do we need the ZigBee technology?
   
5. What are ZigBee's technical attributes?
   
6. What kind of battery life can a user expect?
   
7. What methods does the ZigBee technology utilize to maintain low power consumption?
   
8. Will interference and coexistence be an issue for the ZigBee technology in the 2.4GHz band?
   
9. What are the international regulations?
   
10. How reliable is the ZigBee technology?
    
11. What are some examples of ZigBee applications?
    
12. What is the advantage of the ZigBee solution over proprietary solutions?
    
13. Is it possible to add ZigBee technology to existing appliances and other devices?
    
14. Are gateway products available?
    
15. How does the ZigBee technology compare to the LonWorks technology?
    
16. How does the ZigBee technology compare to X-10 technology?
    
17. How does the ZigBee solution compare with PowerLine Communications (PLC) solutions?
    
18. Why should I use the ZigBee technology over these other protocols?
    
19. When will the preliminary specification become available?
    
20. How many nodes can a ZigBee network support?
    
21. How does a device become associated with/disassociate from a ZigBee network?
    
22. What security issues are there and how will they be solved?
    
23. Who is supporting the ZigBee Alliance now?
    
24. What are the advantages of joining the ZigBee Alliance?
    
25. How is ZigBee related to IEEE 802.15.4?
    
26. When will products be available?
    
27. How big is the low data rate wireless market expected to be?
    
28. How does ZigBee protocol compare to the Bluetooth protocol?
    
29. Will ZigBee devices interfere with Bluetooth devices?
    
30. Why do we need both technologies?
    
31. How easy is it to develop ZigBee-compliant products?
    

1. What is the ZigBee Alliance?
   
   ZigBee Alliance members are defining global standards for reliable, cost-effective, low power wireless applications. The ZigBee Alliance is a rapidly growing, non-profit industry consortium of leading semiconductor manufacturers, technology providers, OEMs and end-users worldwide. Membership is open to all.
   
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2. What is the ZigBee technology?
   
   ZigBee is an open global standard providing wireless networking based on the IEEE 802.15.4 standard and taking full advantage of a powerful physical radio this standard specifies. ZigBee is the result of collaborative efforts by a global consortium of companies known as the ZigBee Alliance. ZigBee includes the following key features:
   

   • Reliability and self-healing

   • Support for a large number of nodes

   • Fast, easy deployment

   • Very long battery life

   • Security

   • Low cost

   • Ability to be used globally

   • Product interoperability

   • Vendor independence

   The term “ZigBee” originates from honeybees’ method of communicating newfound food sources. This silent-but-powerful communication system is known as the “ZigBee Principle.” By dancing in a zig-zag pattern, the bee is able to share critical information, such as the location, distance, and direction of a newly discovered food source to its fellow hive members.
   
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3. What is 802.15.4?
   
   IEEE 802.15.4 is a standard defined by the IEEE (Institute of Electrical and Electronics Engineers, Inc.) for low-rate, wireless personal area networks (WPANs). This standard defines the ”physical layer” and the “medium access layer.” The specification for the physical layer, or PHY, defines a low-power spread spectrum radio operating at 2.4 GHz with a basic bit rate of 250 kilobits per second. There are also PHY specifications for 915 MHz and 868 MHz that operate at lower data rates. For more information about IEEE 802.14.5 please refer to the official page.
   
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4. Why do we need the ZigBee technology?
   
   ZigBee is the only standards-based technology that addresses the unique needs of most remote monitoring and control and sensory network applications. The Alliance's members' low cost, low power solutions will enable the broad-based deployment of wireless networks that are able to run for years on standard batteries for a typical monitoring application.
   
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5. What are ZigBee's technical attributes?
   
   ZigBee-compliant products operate in the unlicensed bands worldwide, including 2.4GHz (global), 915Mhz (Americas) and 868Mhz (Europe). Raw data throughput rates of 250Kbs can be achieved at 2.4GHz (10 channels), 40Kbs at 915Mhz (6 channels) and 20Kbs at 868Mhz (1 channel). Transmission distance is expected to range from 10 to 75 meters, depending on power output and environmental characteristics.
   
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6. What kind of battery life can a user expect?
   
   While battery life is ultimately a function of battery capacity and application usage, the ZigBee protocol was designed from the ground up to support very long life battery applications. Users can expect a multi-year battery life when using standard batteries in a typical monitoring application.
   
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7. What methods does the ZigBee technology utilize to maintain low power consumption?
   
   Battery powered devices can be put to sleep for minutes or even hours. The duty cycle of communications in a ZigBee network is very low, resulting in very low average power consumption.
   
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8. Will interference and coexistence be an issue for the ZigBee technology in the 2.4GHz band?
   
   The potential for interference exists in every band, including 2.4GHz. The IEEE 802.10 and 802.15.2 committees are addressing coexistence issues. Furthermore, the duty cycle of a ZigBee-compliant device is usually extremely low, meaning relatively very few packets of data are transmitted which minimizes the likelihood of an unsuccessful transmission.
   
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9. What are the international regulations?
   
   ZigBee-compliant products will adhere to all relevant international standards, including FCC, ETSI and ARIB.
   
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10. How reliable is the ZigBee technology?
    
    ZigBee was designed for the demanding RF environments found frequently found in commercial and industrial markets. With features such as collision avoidance, acknowledgement, support for guaranteed time slots and packet freshness, ZigBee-compliant networks will offer customers a highly reliable, standards-based solution.
    
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11. What are some examples of ZigBee applications?
    
    ZigBee technology is well suited to a wide range of applications in every industry. Essentially, any application that could benefit from interoperability, or that matches the fundamental RF characteristics of the IEEE 802.15.4 standard would benefit from a ZigBee solution. Examples include:
    • Wireless home security
    • Remote thermostats for air conditioner
    • Remote lighting, drape controller
    • Call button for elderly and disabled
    • Universal remote controller to TV and radio
    • Wireless keyboard, mouse and game pads
    • Wireless smoke, CO detectors
    • Industrial and building automation and control (lighting, etc.)
    
    
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12. What is the advantage of the ZigBee solution over proprietary solutions?
    
    The main advantages include product interoperability and vendor independence. In addition, customers can expect increased product innovation as a result of the industry standardization of the physical radio and logical networking layers. Instead of having to invest resources to create a new proprietary solution from scratch every time, companies will now be able to leverage these industry standards to instead focus their energies on finding and serving customers.
    
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13. Is it possible to add ZigBee technology to existing appliances and other devices?
    
    Possibly, depending on the application. This is not possible for white goods because intelligence is needed and software needs to be installed. White goods are not the main drivers for ZigBee technology, but newly developed white goods could be ZigBee-enabled. For lights, sensors, switches, remote controls etc. it would be possible to replace them.
    
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14. Are gateway products available?
    
    Some of the companies in the Alliance have gateway products under development that will enable ZigBee networks to connect into other home, building automation, and industrial networks.
    
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15. How does the ZigBee technology compare to the LonWorks technology?
    
    LonWorks uses a power line or twisted pair to carry the data signals whereas ZigBee sends data wirelessly.
    
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16. How does the ZigBee technology compare to X-10 technology?
    
    X-10 was originally designed as a low-speed, unidirectional PowerLine Carrier (PLC)-based solution. ZigBee makes significant improvements: reliable wireless, bi-directional, higher throughput, lower latency, more nodes per network, ease of installation and use. X-10 technology consists of a number of proprietary wireless communications protocols offered in products by a company of the same name.
    
    The ZigBee technology is an international standard for wireless data communications for telemetry and remote control applications. Fully interoperable ZigBee products, which can be "mixed and matched" by consumers, will be offered by a variety of manufacturers.
    
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17. How does the ZigBee solution compare with PowerLine Communications (PLC) solutions?
    
    As it is a wireless protocol, and many (though not necessarily all) of the nodes operate from local battery power, the installation costs for a ZigBee network are minimal. Though ZigBee data rates are lower than most PLC protocols, this simplifies signal processing, which lowers node cost as well. Finally, many ZigBee devices will be totally untethered and therefore significantly more mobile than PLC devices, which must be connected to a power socket for proper operation.
    
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18. Why should I use the ZigBee technology over these other protocols?
    
    Customers will choose ZigBee when they require a standards-based wireless network solution that is simple to develop and deploy, is optimized for low cost, low data rate applications, and demands long battery life, robust security, high data reliability, and product interoperability.
    
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19. When will the preliminary specification become available?
    
    The IEEE 802.15.4 specification for the Physical, Media Access and Data Link Layers is expected to be formally approved in 1Q03. Work is already underway to define ZigBee's network, security and application profile layers, and preliminary drafts are expected beginning in the summer of 2003.
    
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20. How many nodes can a ZigBee network support?
    
    The logical size of a ZigBee network ultimately depends on which frequency is selected, how often each device on the network needs to communicate, and how much data loss or retransmissions can be tolerated by the application. ZigBee's addressing scheme supports 255 active nodes per 'network coordinator', and multiple network coordinators can be linked together to support extremely large networks. With support for 16 channels in the 2.4GHz band, and 255 nodes per network coordinator, ZigBee networks can contain over 4,000 unique nodes in a single network with high system reliability.
    
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21. How does a device become associated with/disassociate from a ZigBee network?
    
    The master device is put into enumeration or learn mode, which then allows new nodes onto the network for a defined amount of time (typical may be a few seconds). If during this time there is a request to join the network, a new node will be able to do so.
    
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22. What security issues are there and how will they be solved?
    
    Security and data integrity are key benefits of the ZigBee technology. ZigBee leverages the security model of the IEEE 802.15.4 RF standard, and extends this capability with robust encryption options that can be tailored to the specific needs of the networked device.
    
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23. Who is supporting the ZigBee Alliance now?
    
    A rapidly growing list of industry leaders worldwide has committed to providing ZigBee-compliant products and solutions. Over 35 companies are actively working to define the ZigBee standard, including five promoter companies (Honeywell, Invensys, Mitsubishi, Motorola and Philips) and over 30 participant companies including semiconductor manufacturers, wireless IP providers and OEMs. ZigBee's membership continues to grow as additional companies realize the market need for and benefits of standards-based interoperable wireless products.
    
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24. What are the advantages of joining the ZigBee Alliance?
    
    ZigBee members are collectively defining and creating new markets for interoperable wireless networks. By actively participating in the ZigBee Alliance, members have access to, and are able to influence, these emerging standards. In addition, members gain early access to the standard specifications and to other companies with complementary skills and capabilities. In addition to helping define the standards, members enjoy networking with other leading edge companies committed to providing interoperable wireless products and networks.
    
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25. How is ZigBee related to IEEE 802.15.4?
    
    It may be helpful to think of IEEE 802.15.4 as the physical radio and ZigBee as the logical network and application software. ZigBee is based on the IEEE 802.15.4 RF standard, and the Alliance is working closely with the IEEE to ensure an integrated and complete solution for the market.
    
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26. When will products be available?
    
    The IEEE 802.15.4 specification is expected to be ratified in 1Q03, so standards-based silicon (868/915Mhz and 2.4GHz) will be available shortly thereafter. ZigBee members are building interoperable network, security and application profiles on top of the IEEE 802.15.4 standard and this important work is already underway. The first ZigBee-compliant products are expected in the mid-2003, with large scale product deployment beginning in 2004.
    
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27. How big is the low data rate wireless market expected to be?
    
    The low data rate market is currently estimated at 150M units per year, according to ABI. This market is completely proprietary, as no industry standard has existed before now that addressed the unique needs of this market. The impact of industry standardization on the hardware and software layers is expected to at least triple the size of the current market within a few years. Key market accelerators include an inherently reliable, low-power, cost-effective design. When coupled with the peace of mind and flexibility that industry standards provide, customers in every industry will broadly embrace ZigBee technology to establish competitive advantage, redefine customer value chains and streamline business processes.
    
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28. How does ZigBee protocol compare to the Bluetooth protocol?
    
    
    1. The ZigBee stack is small (28Kbytes) compared to the Bluetooth stack (250K). This relates to lower cost and lower power consumption.
    2. Ultra-low power consumption is a key system design aspect of the ZigBee technology to allow long lifetime non-rechargeable battery powered devices versus rechargeable devices for Bluetooth. As an example the transition from sleep mode to data transition is much faster in ZigBee than for Bluetooth.
    3. ZigBee networking capabilities include 255 devices per network, compared to 8 for Bluetooth networks.
    4. The data rate for ZigBee technology is 250kbps compared to 1 Mbps for Bluetooth wireless technology.
    5. Range for ZigBee products is expected to be ~30 meters in a typical home, compared to ~10 meters for Bluetooth products (without power amplifier).
    
    
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29. Will ZigBee devices interfere with Bluetooth devices?
    
    Because the duty cycles are low in ZigBee networks the probability of interference and packet loss in Bluetooth networks is very low. If the Bluetooth network causes the loss of a ZigBee packet, the ZigBee sender is able to resend if it does not see the acknowledgement packet come back from the destination.
    
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30. Why do we need both technologies?
    
    Bluetooth wireless technology is well focused towards voice applications and higher data rate applications (cell phones, headsets, etc.). The ZigBee technology is better suited for control applications, which do not require high data rates, but must have low power, low costs and ease of use (remote controls, home automation, etc.).
    
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31. How easy is it to develop ZigBee-compliant products?
    
    Companies will be able to easily and cost-effectively embed ZigBee-compliant wireless networking capabilities into their products through the introduction of small, low power, wireless modules. The availability of standards-based hardware and software solutions dramatically reduces the cost and complexity of integrating embedded RF into the typical product design. Furthermore, ZigBee only requires a small amount of system resources (typically between 4KB - 30KB of RAM and ROM, versus over 250KB for Bluetooth), substantially simplifying the process of embedding wireless communications into products.
    
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