Spectrum of the World Unite!
By Kevin Werbach, Mon Dec 03 00:00:00 GMT 2001
In the midst of telecommunications turmoil, a spectrum revolution is brewing.
Earlier this year, I watched the plotting of a revolution. In the radical hotbed of Cambridge, Massachusetts, an eclectic band of academics, activists and veterans of earlier battles gathered. Their goal: to overthrow the status quo. As one would expect, they spoke of freedom from oppression and the injustice of current property rights. They wanted to give away freely the resources corporations had spent billions of dollars on. They realized the odds against them were great, but they were convinced history was on their side.
The topic of the meeting? Open spectrum.
The revolutionary idea that brought together the group that day is that wireless spectrum scarcity is a self-fulfilling illusion. We make spectrum scarce and expensive by splitting it up and restricting its uses. Instead, with today's technology, we could treat spectrum as a commons shared by all. By using smart receivers instead of expensive networks, broadband wireless services could coexist in the same frequency bands. As with the Internet, bandwidth would become cheaper and more ubiquitous with innovation in hardware and software.
In case you're wondering, I didn't notify the authorities because one of them, a Commissioner of the Federal Communications Commission, was already in attendance. The open spectrum revolution is a long way from success, but people are starting to pay attention. The success of wireless local area networks (WLANs) using the IEEE 802.11b protocol has piqued interest in unlicensed wireless services. As exciting as WLANs may be, though, they are nothing compared to what might occur if significant swaths of spectrum were opened up for use as a commons.
"We could have the greatest wave of innovation since the Internet (and probably bigger in impact, because more pervasive) if we could unlock the spectrum to explore the new possibilities," says David Reed, one of the early architects of the Internet and formerly the chief scientist at Lotus Development. The concept of shared spectrum has several other high-profile proponents, including Paul Baran, the inventor of packet switching; cyber-law expert Lawrence Lessig; and futurist George Gilder. The reason you haven't heard more about it is that the concept has even better-known opponents: virtually every existing wireless operator.
Spectrum regulation began early in the 20th century with the commercial development of radio. The US Radio Act of 1927 established the basic framework still in use today in virtually every country. The federal government declared spectrum as a public resource, which it had authority to license to private broadcasters. Those broadcasters got the right to transmit over defined frequency bands, subject to regulations such as power limits and public interest obligations. The government prohibits others from broadcasting on those same bands in a manner that would cause interference with the licensed operator.
The basic idea behind this regulatory system is that spectrum is scarce. There are only so many usable frequencies, and overlapping use creates interference that prevents anyone from communicating successfully. Therefore, government must carefully portion out the resource.
It reserves significant quantities of spectrum for military and public uses such as police radios, and assigns other bands for scientific applications such as radio astronomy. It licenses some spectrum to private entities, subject to rules governing power and usage. Small slivers of spectrum have been designated as "unlicensed," meaning that anyone can transmit but there are no guarantees against interference.
In the early 1990s, the FCC and many other governments began to auction spectrum. Spectrum auctions have generated hundreds of billions of dollars in revenue for the US and other governments. However, the high costs of auctioned spectrum have come under fire, especially with the recent third-generation (3G) auctions in Europe. With "good" spectrum seeming increasingly scarce, carriers have pledged huge sums of money to acquire whatever becomes available, only to face skepticism from capital markets that they will ever recoup their costs.
A spectrum commons?
The technology that overthrows the fundamental assumption that spectrum must be licensed to avoid interference is spread-spectrum. In a spread-spectrum system, signals are chopped up, distributed across many frequency bands and then reassembled on the other end, much as the Internet routes packets. Spread spectrum is based on ideas worked out in the 1940s. It's widely used today in mainstream wireless systems, such as Qualcomm's code division multiple access ( Kevin Werbach is the Editor of Release 1.0, an influential monthly report that covers the converging worlds of technology, communications and the Internet. He also co-organizes the annual PC Forum and High Tech Forum conferences for technology industry executives.
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