Open Spectrum: Take It or Lose It

by Doc Searls

Over at ZDNet, Kevin Werbach suggests a cure for bandwidth blues that looks as subversive and fundamental as both the Internet and Linux. It's called Open Spectrum. Here's how he draws the big picture:

The concept is that wireless frequencies could be shared among many users rather than assigned in exclusive licenses to individual companies. Smart devices subject to rules ensuring that no one player could hog the airwaves would replace networks defined by governments and service providers. Spectrum would be used more efficiently. Bandwidth would be cheaper and more ubiquitous.

We have a taste of this already with WiFi, or 802.11b, which is how most of us connect wirelessly to the Net. But WiFi is just what we've squeezed out of the small wedge of spectrum. Already, Kevin reports, there are 10 million WiFi devices and 4,000 public wireless access points, and they're growing like weeds. You can walk down some streets in San Francisco with a wireless laptop and sense a dozen different base station signals. Some are wireless company intranets. Some are paid public access points (like MobileStar's, which are in many Starbucks cafes, and WayPort's, which are in many airports and hotels). Others are cooperatives serving the public or only their members. Those include NoCatNet (by some O'Reilly folks in Sonoma County, CA), in London, and SFLan in San Francisco. But let's face it, these are a few wireless drops in the wired Net's bucket. Geographically, the ratio ought to be the other way around.

To get what's possible here, you have to break loose from the idea that a wireless link has to be nailed down to a specific frequency, and that bandwidth will vary mostly with signal strength. Thanks to spread spectrum technology, many signals can share (or roam among) many frequencies using very low power signals in a given locality. They don't need to crowd each other out or step on each other. Here's how Kevin puts it:

... if the receivers are smart enough, many transmitters can send signals with low power over a wider range of bands and not interfere. The signals are split up into coded chunks that are reassembled on the other end, much as routers manage traffic on the Internet. Everyone in the room can talk at once, as long as they do so quietly. And if you listen carefully, you'll recognize the unique pitch of a friend's voice across the room despite the distance and the large number of simultaneous conversations.

And where would Linux come in? Lots of places, but especially where it gets embedded:

Using smart "software-defined" radios, nodes in unlicensed wireless networks could cooperate actively. Devices can act as repeaters for traffic between nodes. They could dynamically select power levels and coding schemes based on the behavior of other nodes. And they could cooperatively sample and adapt to background noise. Through these mechanisms, which could be encouraged through equipment certification rules, the spectrum would go from a fixed resource to one that expands with additional computing power and technical innovation. New users could actually increase the bandwidth available by contributing to the cooperative intelligence of the network.

So what's keeping us from making this happen? In a word, the Feds. We need enough spectrum to make it work. Toward that end, Kevin has written an Open Letter to the FCC on Spectrum Policy in which he makes a number of specific recommendations, including adoption of the "intelligent radio bill of rights" suggested by Bran Ferren, the former head of R&D for Disney Imagineering.

Kevin, by the way, is a former insider with the FCC, having served as Counsel for New Technology policy there. He also helped make the FCC hip to the Web in the first place, designing the agency's first web site. In law school at Harvard, Kevin was publishing editor of the Law Review (he says he actually enjoyed law school, which is maybe why he went into other work--like writing and pushing out the Net's envelope). These days he's busy driving the Open Spectrum cause as editor of Release 1.0, published by Esther Dyson's EDventure Holdings. Open Spectrum: The Paradise of the Commons is his lead piece in the current issue of the publication.

The big question for me isn't "Can we get behind this?" It's "What can we do?" and "What's being done already that we can support?"

I have a bad feeling about what will happen if we don't. One of Michael Powell's most-quoted lines since he became FCC chairman is "Openness is not always good." On the plus side, this issue isn't about open vs. closed. It's about public vs. private. All we're asking for is some open, public spectral space--just enough to do what we've already done with the Net.

Doc Searls is Senior Editor of Linux Journal.


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