With ultrawideband radio technology, you won’t have to be a superhero to do such amazing things as see and talk through walls and send huge blocks of data wirelessly at ultrafast speeds. But UWB technology isn’t quite ready to leap tall buildings in a single bound. Among other things, it must be tested to ensure it won’t interfere with other radio signals. Here’s an update on this potentially high-flying technology.
At first blush, ultrawideband radio sounds more like magic than technology–it uses no more power than the radio frequency noise generated by a laptop computer, yet can do things like see through walls or transmit an entire encyclopedia in half a second.
But fantastic as it may sound, the nascent technology has a lot of believers, including policymakers at the Federal Communications Commission who are gathering information so they can write rules to commercialize the technology.
Even though UWB is a radio-based technology, it runs counter to most concepts of traditional radio. UWB doesn’t send signals on waves, for example, nor does it transmit in a specific channel of radio spectrum.
Instead, UWB spreads across the entire spectrum, much like white noise. Signals are encoded in this noise as bursts that last only a trillionth of a second–a picosecond. The bursts are timed to provide information in the form of zeros and ones, the binary code common to all computer applications.
Only through the use of extensive computing power can such signals be sent and received, but as the cost of computing power has dropped, UWB has become feasible.
The first practical application for UWB has been developed for the military to provide a radar that penetrates tree leaves. But the potential for the civilian marketplace is what has entrepreneurs at several small companies eagerly awaiting FCC action. And federal regulators are encouraged by the prospect of opening new applications without using up precious spectrum to support them.
Some wonder whether these promises come with a hidden danger. Companies using global positioning system technology are especially worried that a proliferation of UWB devices could generate enough radio noise to overwhelm their equipment, causing it to fail or produce incorrect data.
Ralph Petroff, chairman and chief executive of Time Domain Corp., scoffs at such worries.
“Ultrawideband signals are no different in any physical way from the [radio frequency] given off by laptop computers,” said Petroff, whose company is the leading developer of UWB technology. “The only difference is that our signals are generated purposefully to carry information. Since when does the intent of a signal affect its interference characteristics?”
But Petroff acknowledges that some people will never believe that UWB is harmless to other radio spectrum users.
“We will be able to convince objective people,” he said. “But there are people who want zero interference, and that’s a standard no one can meet. We can meet a standard of no harmful interference, which ought to be enough.”
To help build support for the technology, Time Domain is focusing on UWB radar products that can see through walls and into the ground. Products using this technology could enable firefighters and police officers to look for people under rubble in collapsed buildings, see into rooms before they enter and do many other things not now possible.
“We want to offer some applications that are completely new instead of incremental improvements on existing products,” Petroff said.
Because the UWB radar works at the picosecond level, it gets a far more precise picture of things than conventional radar, he said.
“When Kerry Wood throws a fastball, a radar gun can clock its speed at 97 miles an hour,” Petroff said of the Cubs pitcher. “But that’s about all it can do. Our radar can take 20 million independent readings from that ball from the time it leaves Wood’s hand until it hits the catcher’s mitt. We can measure how fast the seams on the ball are spinning.”
While such claims smack of hyperbole, Time Domain, based in Huntsville, Ala., has working prototypes to demonstrate the technology’s capabilities.
But whether the technology is as benign as Petroff says is subject to debate, which is the reason the FCC has asked for testing.
“I think of this as background noise,” said Julius Knapp, chief of the FCC’s policy and rules division. “In the audio world it would be like an air conditioner humming in the background. You can have conversations over that with no trouble, but if the hum gets too loud, it becomes an annoyance and then a distraction.”
While it may be true that on average a UWB signal is equal to the noise given off by a laptop computer, the signals embedded in the signal do throw off those picosecond pulses, which peak at energies well above the average.
“That might be thought of as analogous to flashbulbs going off in a room,” Knapp said. “A lot of bulbs going off might not make a light that’s any brighter, but do they add up to raise the level of distraction?”
One center where tests of UWB signals are under way is on the campus of the University of Texas in Austin in a research lab established by the Department of Defense. Miguel Cardoza, who heads the division doing the testing, said the results almost certainly won’t satisfy everyone.
“We’re not trying to persuade anyone,” Cardoza said. “We’re just collecting as complete a set of data as possible. We’re trying to answer as many questions as possible, but we can’t answer them all, and we know our tests won’t please everybody.
“This will probably raise more questions than it answers, but there is no data out there now, so we are building an information base open to comment.”
UWB seeks to use radio spectrum in the same unlicensed way that covers toy walkie-talkies, garage door openers and countless other devices, said Mitchell Lazarus, an attorney specializing in communications law based in Arlington, Va.
“This is technology to handle the last 10 meters of a connection,” Lazarus said. “No matter what the tests being done now show, some people will argue against them. They’ll claim the tests were poorly designed.”
Lazarus, who represents some UWB backers, expects the FCC will probably write rules covering the new technology by next summer or autumn.
If that happens, Martin Rofheart, chief executive at XtremeSpectrum Inc. in Greenbelt, Md., said his firm will have products on the market by the end of next year.
XS, founded by Rofheart and John McCorkle, grew out of the development of ultrawideband radar for the military. The firm has a prototype that transmits data at 50 megabits a second, and it will soon demonstrate a model that operates at 100 megabits a second, Rofheart said.
“We can deliver products that deliver extraordinarily high rates of data using very low power,” he said.
Such products are precisely what wireless Web-enabled devices need, he said. They will fill a role the wireless industry has assigned to conventional radio technologies such as the so-called Bluetooth products that Motorola Corp. and others have begun to build.
“Think of ultrawideband as Bluetooth on steroids,” Rofheart said.
