Sharing The Airwaves Spread spectrum technology could bring a new dawn for broadcasting


Hal Plotkin, Special to SF Gate
Thursday, April 11, 2002

URL: sfgate.com/cgi-bin/article.cgi?file=/gate/archive/2002/04/11/sprdspctrm.DTL

Consumer watchdog groups cried foul last February after the U.S. Court of Appeals in Washington, D.C., struck down federal regulations that limited the number of television stations a single company can own. On the surface, the decision appears certain to accelerate the trend toward even more heavily concentrated ownership of broadcast properties. It’s possible, warn the critics, that within a few years just one or two big firms might control nearly all the existing TV and radio stations in the country.

In the end, however, that might not matter — not if the movement toward spread-spectrum broadcasting continues to gain momentum. Like many social and political movements, this more technically oriented uprising is being led primarily by scholars and activists at top universities, including MIT, Harvard, Columbia, Stanford and the University of Pittsburgh.

The battle cry: It’s time for the Federal Communications Commission to get out of the business of deciding who gets to be a broadcaster and who doesn’t.

The key is using the electromagnetic spectrum more efficiently.

The spectrum, more informally called “the airwaves,” is a range of frequencies over which signals (including radio, television and telephone) can be transmitted. Ever since the first days of commercial broadcasting, to prevent interference, individual station signals have traveled along dedicated frequencies, one station per frequency. Federal regulations reserved wide bands of frequencies for certain types of uses, and individual frequencies within those bands were set aside for the exclusive use of specific broadcasters, all of whom had to be licensed by the federal government. Whenever a TV or radio station is sold, what’s really being transferred, apart from studios, employees and water coolers, is the license to transmit over the station’s frequency.

Scarce broadcast licenses now fetch tens or even hundred of millions of dollars in more heavily populated areas.

Seventy-five years ago, dividing the spectrum made sense. The alternative at the time was chaos, which would have made commercial broadcasting impossible. At the dawn of the radio age, hardly anyone objected to the federal government coddling the infant broadcasting industry.

It is, however, a baby no longer. What’s more, advances in spread-spectrum technology have altered what is possible when it comes to broadcasting. Rather than preventing interference by allowing just one broadcaster per frequency, spread spectrum gets the job done by splitting transmissions into tiny segments that automatically hop from frequency to frequency on a space-available basis.

The technique makes much more efficient use of the overall spectrum by packing transmissions into the pauses that would otherwise occur between signals. The result is a vast increase in the number of programs that can be simultaneously transmitted over the airwaves, which eliminates the need to reserve any frequencies for the exclusive use of just one broadcaster. It also makes the constitutionality of the old spectrum-allocation rules highly suspect.

Where It Came From

Some say the idea leaked out of the German military via an indiscreet officer trying to impress the glamorous, Austrian-born, pre-World War II actress Hedy Lamarr (1940’s “most beautiful woman in the world”). What is known is that Lamarr patented the concept along with her business partner, popular symphony composer George Antheil, in 1942, and they promptly turned the idea over to the Pentagon. It was just one of many similar schemes the patriotic actress and her associates had cooked up to foil the Nazis. The U.S. military has used top-secret variations of the technology to safeguard its most sensitive transmissions ever since.

For their part, Lamarr and Antheil always maintained that they came up with the syncopation-like technique after noticing the way musicians use timing to anticipate melodic changes.

The original mechanical devices Lamarr and Antheil constructed to handle the frequency-hopping chore were crude and cumbersome, however, which limited its application solely to military broadcasting, rather than to more sophisticated commercial operations as well.

Back to the Future

Fast-forward 60 years to the age of the microprocessor.

Modern chip-based signal processors can now quite easily handle the rapid frequency changes that used to be controlled by Lamarr and Antheil’s clunky machines (which relied on something similar to piano rolls). Meanwhile, modern signal filters, dynamic real-time frequency tuners and advanced data-compression algorithms have also further extended the carrying capacity of spread-spectrum broadcasting.

In fact, you may already own a spread-spectrum device and not know it. Digital cell phones, for example, and other devices running on wireless data networks use a form of spread-spectrum technology. They do so over very small segments of the radio spectrum that the FCC opened up for that purpose beginning in 1982, after many years of prodding by telecom entrepreneurs and broadcast engineers.

After some initial fits and starts, the result extends past cell phones to include several popular and fast-growing wireless data networks, most notably the esoterically named IEEE 802.11B, also known as Wi-Fi (the wireless technology used by Apple, Dell, Compaq and others).

The outcome of these experiments is increasingly clear. Cell phones have exploded in popularity, and wireless data networks aren’t far behind. Both would work even better if they had more spectrum over which to spread. Many experts add that it’s now readily apparent that advanced spread-spectrum technologies would also work as well or even better for other types of transmissions, including both television and radio.

Unfortunately, the media conglomerates that own most of the nation’s TV and radio stations have a vested interest in the status quo and won’t easily give up their hammerlock on what, in the end, are public airwaves.

They have good reason to be worried: Once spread spectrum takes hold, the value of individual broadcast properties will be based on what that property produces, not the airwave frequencies it controls.

That sure sounds like a better world to me.

Some observers have recently suggested that one way to overcome predictable media-industry opposition to these changes is to compensate the networks for the financial losses they’ll suffer if and when they lose their monopoly grip on the airwaves. Others, however, say big media deserves what it gets, that the networks should have seen this technological evolution coming or should have hired better scientists or advisers, who would have cautioned them against buying up chunks of an obsolescence-bound broadcasting system. After all, no one protected the guy who bought up all those high-priced horse buggies at the dawn of the auto age, or, for that matter, people who made bad bets on Internet stocks.

Media-industry opposition notwithstanding, the key issue at play here is free speech. The U.S. Constitution speaks unambiguously about the right to it — and that means that if the technology permits free speech, which it now does, anyone should be able to broadcast whatever he or she wants without having to ask anyone else for permission, let alone without being forced to purchase that right from the federal government.

The pertinent legal issue revolves around a long-established legal precedent sometimes known as the “narrowly tailored” doctrine. Supreme Court precedent allows government restrictions on free speech, but only if those restrictions are “narrowly tailored to further a substantial government interest.”

That means that when it’s necessary, the government can impose certain restrictions on how and when free-speech rights can be exercised, even though the content itself can’t be restricted. (You can’t shout into someone’s window at night, for example, or, by extension, broadcast on another station’s frequency).

The “narrowly tailored” doctrine is what originally enabled the FCC to enact its now outdated spectrum-division allocations.

Leaving those old regulations behind could jump-start an exciting new era of free and open competition in the multibillion-dollar radio and TV broadcasting industry. At the same time, the growth of this new broadcasting method promises to help reinvigorate the overall tech sector by spurring consumer demand for a new generation of powerful televisions, audio receivers, software and related devices needed to tune in the frequency-hopping broadcasts.

Anyone able to purchase some relatively inexpensive equipment — entrepreneurs, schools, entertainment groups, businesses — would also be able to set up an over-the-air broadcast operation capable of reaching the entire country.

Given this technology-driven change in circumstances, the federal government’s only proper — and constitutional — role now is to set the ground rules for spread-spectrum use and then get out of the way.

Regrettably, the often technically inept U.S. Congress has complicated the situation in recent years by shortsightedly instructing the FCC to sell or lease additional bands of spectrum that had been reserved for other uses. The move is basically a sneaky way for politicians to raise revenue without a more direct and obvious tax hike.

But several carefully documented studies have revealed why, in the end, auctioning off portions of spectrum actually costs the government more than it gains. In a nutshell, that’s because doing so kills off the additional jobs (and taxes) that free competitive uses of spectrum would otherwise have provided.

Given the influence of big media, however, Congress is unlikely to be the moving force behind a switchover to a more modern and fair broadcasting system. The better hope would appear to rest in the courts, where the jumble of complicated technical issues will eventually be boiled down to what really matters. After all, we’re talking about free speech here.

In the end, the First Amendment won’t be worth squat if the federal government is allowed to continue restricting speech over the airwaves in an era when technology has eliminated any need for such restrictions.

Once again, the tiny microprocessor roars.

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