A new technology known as super WiFi may soon be available in the U.S.—but it may not yet be able to be used in populated areas. Unveiled Monday by Federal Communications Commission chairman Julius Genachowski, super WiFi has been designed to increase capacity in places where regular WiFi networks have become overcrowded. Genachowski said the U.S. is in a “spectrum crisis,” as mobile devices have clogged up the bandwidth. Most airwaves are by local TV stations, with some vacant airwaves known as white spaces—and super WiFi will make use of these vacant airwaves. But there’s a catch: the most-populated places—the ones most in need of the spectrum—already have the least available white space.