FCC White Space Plan Isn't Exactly WiFi on Steroids

News Analysis: The FCC has to create a band plan, usage rules and protection policies for digital data channels to make broadcast spectrum "white space" usable for Internet traffic.

The announcement that the Federal Communications Commission was prepared to approve unlicensed digital operations in slices of frequency spectrum occupied by television guard bands is being greeted eagerly by many, including Google and Microsoft.

Ultimately it will probably be a good idea, but it's by no means clear that it will be the panacea to a national broadband solution that some hope it will be. In fact, there's every possibility that the whole "White Space" excitement is badly overhyped and in the long run will likely to lead to more disappointment than broadband growth.

First, it helps to know exactly what this "white space" that everyone's talking about really is. No doubt you have some idea that a television channel is a set of frequencies used by broadcasting stations for transmitting their signals. In the past, the FCC has always allocated a slice of spectrum between TV channels as a guard band. These were frequencies where nothing was allowed to operate so that television could be protected from interference from another broadcast station operating on an adjacent frequency.

The reason the stations needed this guard band was because television signals really consisted of two radio transmissions, one for the audio and one for the video. One signal was transmitted in analog using AM and the other using FM. The result was that these signals used a lot of bandwidth, and the amount of bandwidth could vary slightly depending on the nature of the signal. The guard bands kept things separate, and given the fairly primitive technology used by television receivers when these were set up, the television sets needed that space as much as the broadcasters did.

Since then, things have changed. Television in the United States is almost entirely digital, except for some low-power community stations. Television receivers have vastly improved technology with far greater precision, so guard bands are less necessary. The idea is to use those formerly empty bands for digital transmission that includes (but isn't restricted to) high-speed broadband. This all sounds good, right?

The problem is that television broadcasters don't want their signals interfered with any more than they ever did. While televisions stations produce an effective radiated power in the hundreds of thousands of watts in some cases, it's not the transmitted signal they're worried about. Because radio waves diminish greatly with distance, and because every white space data device includes its own little transmitter, the broadcasters are worried that somebody's broadband Internet will interfere with their programming at sites where their signals are relatively weak.

Wayne Rash

Wayne Rash

Wayne Rash is a freelance writer and editor with a 35 year history covering technology. He’s a frequent speaker on business, technology issues and enterprise computing. He covers Washington and...