|
The ZigBee Alliance’s mission is to enable reliable, cost-effective, low-power, wirelessly networked monitoring and control products based upon an open global standard. The alliance – an industry association comprising original equipment manufacturers, semiconductor manufacturers, end users, and others – uses the robustness of the year-old IEEE 802.15.4 wireless packet radio communication standard and adds flexible mesh networking, enhanced security, and interoperability and compliance testing. ZigBee alleviates the wireless product developer’s concerns about radio technology, protocol, and network creation. The alliance fosters reliable data delivery, long battery life, adjustable data latency, and system simplicity at a lower system cost than that of current standards-based or proprietary solutions.
The ZigBee Alliance takes strong advantage of the nearly year-old IEEE 802.15.4 low-rate wireless standard, the first IEEE standard to focus on battery life, robustness, and reliability over data rate. The 15.4 standard employs simple and energy-efficient direct-sequence BPSK or O-QPSK modulation. A total of 27 RF carrier channels, including one in the European 868 MHz, 10 in the 902 to 928 MHz Americas, and 16 in the worldwide 2400 to 2483 MHz license-free bands employ 15.4. The standard’s basic node-to-node RF range of 30-75m makes it very similar to other low-power wireless technologies. At that point, mesh networking comes in. No longer does a single hop range constrain an application. If there are multiple valid routes from source to destination, ZigBee determines them and weighs each in a simple packet routing quality estimate that uses a variety of factors including signal strength, power source type, and external RF channel interference.
Compliant, second-generation, single-chip transceivers from major vendors like Motorola and others eliminate the need for the product designer to be an RF or RF circuits expert. By providing all-in-one package functionality from antenna connection to packet data along with complete developer kits and reference applications, the alliance’s member companies are strongly committed to making it easy to develop a wirelessly connected product. For example, Motorola’s transceiver requires less than 10 external passive components including a 40ppm, 16-MHz crystal, with no inductors. Board layout guidelines are minimal, allowing two-layer boards, printed antennas, and no external voltage regulators. The transceiver’s design extracts nearly 100 percent of battery life from a pair of alkaline cells with a minimum operating voltage of 2VDC. An SPI four-wire bus provides the data/command interface to the transceiver for a quick and easy interface to your application’s already existing microcontroller.
ZigBee has scheduled the standard’s public release for September 2004, and member companies now working within the alliance will release compliant products essentially concurrent with the standard’s publication. Complete interoperability and compliance testing functions are available through companies that are alliance members. As with all standards, market needs continue to expand or change, and a standard must work to keep up with new requirements. The ZigBee Alliance is no exception. Member companies have already generated a detailed roadmap for continued cost reduction and feature enhancement that will promote increasingly broader adoption of the technology.
Membership in the alliance is open to all interested companies. Membership provides access to the latest standards releases and allows member companies with specific needs to contribute toward enhancements to the standard, along with developing new classes of devices that may take advantage of ZigBee.
. . . . .
Jon Adams is chair of the ZigBee Alliance’s Qualification Group and is the director of Radio Technology and Strategy for the Motorola SPS Wireless and Mobile Systems Group. Jon has written and spoken on these technologies and has provided regular interviews about the topics with industry analysts. Contact Jon at jta@motorola.com.
Contact the alliance directly for membership and event details.
ZigBee Alliance
Tel.: 925-275-6607
Fax: 925-275-6691
Web site: www.zigbee.org
|
