Microsoft Building One-Mile Wi-Fi

Despite protestations from the Bush administration, the FCC succeeded last year in making a certain chunk of the nation's TV and radio spectrum--dubbed "white space"--available to unlicensed broadcasters. That meant that companies could begin developing super Wi-Fi devices that create networks at a distance of miles, instead of the 50+ feet we're used to today. The dream, nationwide wireless Internet access, was within reach.

But as Microsoft is now learning, there are obstacles. Among other requirements, the FCC has mandated that white space devices must be able to sense local TV and audio usage near their frequencies, and be able to divert to avoid interference with them. Distance presents a problem too, because various towns and states use their spectrum differently, so a network might have to use different channels in different areas; as ArsTechnica points out, a channel that is free in one county to carry a Wi-Fi signal might be used in the next county for something else.