Making Room for UWB
A decision this month by the Federal Communications Commission to give a conditional go-ahead to companies seeking to market products employing UWB technology has gotten some industry watchers concerned.
While the emerging technology could enable a range of new mobile applications, critics claim that if ultrawideband is improperly implemented, it could interfere with other wireless technologies, including those used for public safety.
UWB operates by releasing many small bursts of radio signals over a wide swath of radio spectrum, in contrast to more established wireless technologies, which issue a protracted signal over a limited frequency range.
Proponents claim a variety of potential consumer, business and safety uses for UWB, from interference-free, energy-efficient, super-high-speed voice and data transmission to highly accurate imaging and location devices for public safety. For example, UWB devices could locate people trapped under debris or held hostage behind walls, find imperceptible structural defects in edifices, and enhance auto-collision-avoidance systems.
UWB opponents, however, charge that new devices could disrupt GPSes (Global Positioning Systems) and other airborne safety equipment, as well as cell phone systems.
The FCC, in a statement preceding its "First Report and Order," seemed to reject claims that UWB could create dangerous interference. "With appropriate technical standards, UWB devices can operate using spectrum occupied by existing radio services without causing interference, thereby permitting scarce spectrum resources to be used more efficiently," the commission said.
Since there is little operational experience with the technology, the FCC imposed initial tight limits on the spectrum ranges, erring "on the side of conservatism," it said, where there are "unresolved interference issues." The FCC also restricted some UWB use to military, quasi-military, scientific, commercial mining and construction personnel. It will review its standards in six to 12 months in the interest of making them more flexible.
"Were very pleased ... we went from being illegal to legal," said Jeff Ross, vice president for corporate development and strategy at Time Domain Corp., a Huntsville, Ala., company that has been pitching UWB to the FCC since 1987.
Ross said he will have to await final specifications from the FCC before he is able to discern the implications for potential products, but he expects to see a Time Domain chip set in a couple of months and products from partners by the end of the year.
"The biggest thing this technology will be used for is indoor, short-range, high-data-rate communications," such as personal area networks and device area networks operating at 100M bps over short distances, probably within a single room, Ross said. "I think youll see it first within the consumer market."
That products will be coming out so soon concerns some in civil aviation and national defense. In particular, the Air Transport Association of America Inc., representing the commercial aviation industry, has expressed concerns about UWB products use of the frequency range under 6GHz, what it calls the "safety-of-life spectrum," affecting aircraft technologies. The ATA also criticizes the FCC for what it says is a departure from previous practice, which placed the burden of proof on those introducing devices to prove the absence of harm.
The ATA was somewhat pleased with initial FCC limits that UWB radios must operate above 3.1GHz; this will protect GPS, which operates between 2GHz and 3.1GHz, said Bill Sears, ATAs director of communications for navigation and surveillance.
"But above 3.1GHz, there are some other systems that were concerned about," said Sears, in Washington. He cited the radio altimeter, which operates around 4.3GHz. It is used on large airplanes and corporate jets to measure the height above the ground for the aircrafts wheels during low-visibility approaches. Other areas of concern include instrument landing systems operating below 960MHz, microwave landing systems (5.03GHz to 5.15GHz) and terminal Doppler weather radar (5.6GHz to 5.650GHz).
"I think in six to 12 months, well still be in this same position we are right now," Sears said. "The problem is that this is going to open the door to future attacks on aviation-related services."
Ross rejected some critics arguments, stating that wireless applications on laptop and handheld computers operate at powers 2,000 times greater than UWB. He charged that many alarms about UWB are being raised for competitive reasons. But at the same time, Ross downplayed UWBs potential to undercut existing technologies, saying that, for example, GPS and UWB are actually "complementary" location technologies.
But Sears said the comparison between UWB and laptops, Palm Inc. PalmPilots and even hair dryers is not apt because UWB devices operate using an antenna and are "intentional" radiation devices operating across a much wider range of frequencies.
"We just dont know a lot about that," Sears said.