Radios Get Smart

Here’s why: widespread use of cognitive radios could make more efficient use of radio spectrum. Estimates of how much additional traffic the airwaves could hold vary, but by some accounts, less than 14 percent of radio spectrum is truly busy at any given time. That includes big chunks of spectrum that are assigned but that aren’t fully used. Prime among them are the upper ranges of the TV bands: channels 14 to 83, better known as ultrahigh frequency or UHF. In 2004, a study by the International Telecommunication Union, in Geneva, found that “many TV channels are unused over significant geographical areas” and concluded that “cognitive radio techniques appear to be a promising approach” for using spectrum more efficiently while avoiding interference with current operations.