Factories Get Wireless Help

Factories could wring a lot of efficiency gains out of wireless technology--tactics such as controlling robots and monitoring via radio frequency identification tags. The problem is, factories are a terrible place for wireless transmission, thanks to all that reflective metal.

Well, the government's on the job.

The U.S. National Institute of Standards and Technology is partnering with the U.S. Council for Automotive Research to develop a statistical representation of how radio waves move around a production floor and will use that to develop standards to prequalify wireless devices for use in factories. Auto factories are a prime candidate for greater wireless use.

Researchers began testing wireless signals at an auto assembly plant in August 2006 and completed additional tests this month at an engine plant and a metal stamping plant.

Metal structures such as fabrication and testing machines, platforms, fences, beams, conveyors, mobile forklifts, maintenance vehicles, and automobiles in progress all can influence signals. NIST's spectrum survey showed that machine noise--interference caused by heavy equipment--can impair signals for low-frequency applications such as those used in some controllers on production floors.

Signal-scattering tests revealed the potential for high levels of "multipath" interference, meaning that radio signals travel in multiple complicated paths from transmitter to receiver, arriving at slightly different times.

Meantime, manufacturers can take steps to minimize radio interference, NIST researchers say.

Those include using licensed frequency bands where possible and restricting use of personal electronics in high-traffic frequency bands such as 2.4 GHz. Absorbing material can help if it's installed in key locations. Also, wireless systems with high immunity to electromagnetic interference, equipment that emits little machine noise, and use of directional antennas can help cut multipath interference when transmitters and receivers are close together.