andrew.kantor@roanoke.com 981-3384

Virginia Tech's Center for Wireless Telecommunications is developing a high-capacity communications system that would be smart enough to configure itself to work through all sorts of interference.

That makes it a potential boon to military and emergency services personnel, who often have to deal with rubble-strewn streets or smoke-filled rooms. But just as important, it will allow communications systems to make much better use of the airwaves around them, potentially reducing or even eliminating the need for the government to divide the radio spectrum.

Called "cognitive radio" - a term coined in the late 1990s by Dr. Joseph Mitola - the Virginia Tech work originally was funded by the National Science Foundation to the tune of about $1.5 million as a way to establish communications networks at disaster sites when communications, electrical systems and even physical buildings were in disarray.

Emergency services personnel would need a way to set up voice and data networks, but wouldn't want to spend much time fiddling with the equipment.

Cognitive-radio networks might be the answer, according to Dr. Charles Bostian, engineering coordinator of the CWT, who describes it as "a merger of artificial intelligence with radio technology."

When powered up at a disaster site - natural or man-made - a cognitive radio would automatically establish the connections it needed by using what Bostian calls a "distributed cognitive engine." That's the built-in software that would be smart enough to configure the signal to overcome whatever obstacles are blocking it - adjusting power, frequency, modulation and even bouncing it off buildings and rubble. Today's radios are easily stymied by obstructions, as anyone who has tried to use a cellphone in an elevator knows.

"[We're] looking at a scenario where the internal communications have been destroyed through some disaster, and the emergency responders need some form of communication," said Tom Rondeau, a graduate student at the center.

Using this cognitive-radio concept within an emergency area can be really beneficial, he explained, because emergency personnel don't need to be concerned with adjusting dials to get a signal. "All they do is use what the radio gives them. They don't have to worry about making the radio work."

Bostian put it succinctly: In the event of a disaster, those responders "need a radio that's smart enough to do its thing and not bother anyone else."

During wartime, knowing the U.S. military's reliance on electronic systems and networks, an enemy might try to jam those communications electronically. A cognitive radio would, in theory, be able to sense the jamming and make changes until it was able to break through to its intended recipient.

Bostian explained: "We have done a proof of concept test where we had a radio transmitting TV images, we turned on a jammer, and without allowing the radios to change frequencies, they were able to adjust their modulation format, power and encoding to get rid of the jammer."

Don't let the term "radio" fool you - this isn't just about basic voice communications. This is radio in the broader sense of radio frequency transmissions, which include everything from walkie-talkies to video to high-speed data networks. Any of these potentially can be made cognitive.

"If the radio is capable of accepting commands from a computer," Bostian said, "we can make it intelligent." Further, he said, having several cognitive radios connected can create an entire high-speed network that can adjust itself based on its surroundings.

"We can have a network which itself is intelligent because the individual members of the network are intelligent," Bostian said.

A cognitive-radio system also could have uses well beyond disasters and battlefields; they could make much better use of the airwaves.

Right now, the Federal Communications Commission allocates different frequencies of the radio spectrum for different uses - TV and radio stations, amateur radio, cellphones and even baby monitors. This ensures that when you tune in 96.3 you get WROV and not some whining 2-year-old.

But the radio spectrum is only so big, and various technologies have stretched it to its limits. (Cellphones, for example, use different techniques for sharing the same chunk of frequencies.)

Cognitive radio could add a new dimension to sharing the spectrum: intelligence. A cognitive cellphone, for example, could see what frequencies were available and use those, then change its usage every fraction of a second if necessary.

"The advantage of a cognitive radio is that it could potentially negotiate with the other radios that are around and decide what part of the spectrum it was going to use," Bostian said.

By being smart enough to understand its environment, a cognitive radio could, in Bostian's words, "find out what providers were using its spectrum ... and negotiate a deal with them that would allow it to transmit."

Bostian's team currently has several funding proposals in the works, while it continues to perfect its intelligent radio systems. A real-world working system is likely only a few years away. "A lot of the details of what you can do with cognitive radio haven't been worked out yet," Bostian said.