ZigBee: The next-gen wireless hope

It doesn’t have much power and it’s relatively slow. That’s why the 802.15.4 wireless standard will soon be king of machine-to-machine communication.

The promise of wireless technology has always been hobbled by one flaw: wireless devices tend to be awful energy hogs. That’s where ZigBee steps in.

ZigBee is tech speak for the Institute of Electrical and Electronics Engineers’ (IEEE) 802.15.4 standard that promises wireless machine-to-machine communication with low power consumption, and low costs. It is already backed by some of the biggest names in tech, including Honeywell, Motorola, Philips, Samsung, Mitsubishi Electric, and Invensys.

Although many standards address mid- to high-data rates for voice, PC local-area networks, and video, there has not been a wireless network standard for the unique needs of sensors and control devices. Sensors and controls do not need the high bandwidth built into such standards as wi-fi and wi-max. They require a low-energy, low-latency network that allows messages to ping-pong across short distances.

Unlike Ericsson-developed Bluetooth, wi-fi, or even a traditional ethernet LAN, ZigBee does not need a centralized hub to coordinate message flow. If a building has multiple ZigBee devices, a message will connect the hot spots until it reaches its intended target. For example, a smoke alarm could pass its message through a thermostat, light switch, or motion detector to get its warning message to the central computer system. This not only boosts efficiency by requiring fewer wireless hubs, it helps keep a system up even if one, or a few, links in a chain are down or damaged.

In a large building, ZigBee technology could connect heating, ventilation, and air conditioning (HVAC), lighting, and security features. The result: a building that knows when a room is occupied and, potentially, by whom. Likewise, it knows when a room is empty – and can automatically turn off the lights or the air conditioning in unused areas.

“We estimate the average large corporation can save about 60 percent on HVAC and 40 percent on their lighting expenses,” says Venkat Bahl, vice chairman of the ZigBee Alliance and business development manager at Philips Semiconductor. He says energy cost savings have proved sizable with ZigBee test demonstrations at companies like automotive systems manufacturer Johnson Controls, which has 8 billion square feet of office space.

Mr. Bahl says ZigBee also has promise in the home. Because the standard is not proprietary, any home appliances manufacturer can install it into its products. It takes the universal remote control to a new level: one device to handle the TV, DVD player, lamps, and home thermostat.

Unlike wi-fi, which strives for always-on, large-pipe bandwidth, ZigBee was designed to be on only when needed, thus using less power. Bandwidth was secondary. The typical 802.11b wi-fi can transfer data at 10Mbps, good enough for streaming video. ZigBee, on the other hand, has a significantly slower maximum data rate of 128 Kbps – more similar to the rate of an average DSL connection.

The ZigBee Alliance stresses that their technology is not competing with wi-fi as much as it is answering the problems wi-fi was not designed to handle. Utility meters are one obvious example. ZigBee can be run off two AA batteries that would last a year, or even nickel-cadmium batteries that could be recharged by solar power. With its 70-meter range, a ZigBee gas meter would allow the local utility to check a home’s meter from the street with no need for a utility employee to enter the homeowner’s yard, or even to leave the safety of the company car.

In some cases, ZigBee’s hype is falling on skeptical ears. Ever since the 1939 World’s Fair teased millions of visitors with its vision of “Building the World of Tomorrow,” electronics manufacturers have been promising gadgets to bring such futuristic concepts as the automated home into reality. So far, technology has fallen short of that dream.

The first ZigBee products are set to be released by year’s end, but the IEEE has not yet approved all ZigBee protocols, meaning some manufacturers are betting on a non-standardized standard.

“Even though the specs aren’t complete, ZigBee has got a good chance to get us there,” says Patrick Gonia, a senior staff scientist with Honeywell Laboratories. His company is looking into using ZigBee in its home thermostats and commercial environmental control systems.

Honeywell has pursued wireless strategies since 1998, and is hot on ZigBee because its low power consumption and mesh network drive down costs while increasing flexibility.

Geoff Mulligan, chief scientist for Honeywell competitor Invensys agrees on the future of ZigBee. He believes today’s economics – not wishful thinking – and cost savings will drive a move to ZigBee-type wireless technology for building management. “In a building setup, 60 percent of the cost of system management is the installation of wires. There is a huge opportunity with ZigBee simply because of initial cost savings,” he says.

ZigBee also can be compatible with wi-fi, which means a smoke detector would be able to talk to your computer. He imagines a world where people can get a cell phone text message or instant message transmitted from a home PC alerting them that their smoke detector alarm has been triggered.

Although Mr. Mulligan says Invensys backs ZigBee, the company is taking a wait-and-see approach before including the technology in its 2004 product line, which includes the almost 15 million smoke detectors it makes each year.

Joyce Putscher, director of converging markets and technologies at research firm In-Stat/MDR says the market will take years to fully develop. “Heightened interest in ZigBee wireless connectivity could slowly make The Jetsons’ home of the future a reality. However, I doubt we’ll see that automated meal maker any time soon.”

For: Red Herring