Wasted Forever ... Like Water Over a Dam
These days Baran's vision, however, goes far beyond wireline communications. Baran takes the Internet model and extends it boldly to wireless communications. On June 23, 1995, on the occasion of the Marconi Centennial, marking the 100th anniversary of the invention of the radio, Baran gave a momentous keynote speech in Bologna, Italy. In it he demanded a radical reconception of wireless networks.
"The first 100 years of radio," he declared, were marked by a perpetual "scarcity of spectrum.... One of the very first questions asked of young Marconi about his nascent technology was whether it would ever be possible to operate more than one transmitter at a time. Marconi's key British patent #7,777 taught the use of resonant tuning to permit multiple transmitters.... [Yet] even today, with over 30,000 times more spectrum at our disposal than in Marconi's day, entrepreneurs wishing to implement new services encounter the same perpetual shortage of frequencies."
Focusing on the most desired bands between 300 and 3,000 megahertz (UHF), Baran asserted that when you "tune a spectrum analyzer across a band of UHF frequencies,:" you discover that "much of the radio band is empty much of the time. This unused spectrum might be available for transmission if we could take measurements and know exactly when and where to send the signal."
As an example, he cited "the many millions of cordless telephones, burglar alarms, wireless house controllers, and other appliances now operating within a minuscule portion of the spectrum and with limited interference to one another. These early units are very low power {dumb devices} compared to equipment being developed that can change its frequencies and minimize radiated power to better avoid interference to itself and to others.
"In part," he declared, "the frequency shortage is caused by thinking solely in terms of dumb transmitters and dumb receivers. With today's smart electronics, even occupied frequencies could potentially be used."
The chief reason for the apparent shortage of spectrum, he concluded, is regulation of it. Echoing his earlier critique of wireline communications, he declared that "the present regulatory mentality tends to think in terms of a centralized control structure, altogether too reminiscent of the old Soviet economy. As we know today, that particular form of centralized system... ultimately broke down. Emphasis with that structure was on limiting distribution rather than on maximizing the creation of goods and services. Some say that this old highly centralized model of economic control remains alive and well today-not in Moscow but within our own radio regulatory agencies."
The heart of the problem is the concept of spectrum as public property -- as scarce real estate or a precious natural resource. Spectrum is nothing of the kind. It has been created by a series of brilliant technical innovations, beginning with Marconi and continuing in a steady stream of high technology oscillators and digital signal processors: from magnetrons and kystrons to varactor multipliers and surface acoustical wave devices, from gallium arsenide and indium phosphide heterojunctions to voltage-controlled oscillators and Gunn or IMPATT diodes. Spectrum is chiefly a product of inventors and entrepreneurs. Americans will rue the day when foreign governments and international organizations begin auctioning and taxing, marshaling and mandating the use of these mostly American technologies.
The real estate model applies chiefly to broadcasters and others using analog modulation schemes in which all interference shows up in the signal. A television signal requires some 50 decibels of signal to noise power, or 100,000-to-1. By contrast, error-corrected digital signals can offer virtually perfect communications at a signal-to- noise ratio well below 10 decibels, or 10,000 times less. Moreover, new digital systems can divide and subdivide the spectrum space into cells and differentiate calls by spread- spectrum codes or even isolate particular connections in space by space-division-multiple-access-devices that function as "virtual wires" allocating all of the spectrum to each call.
Baran pointed out that "any transmission capacity not used is wasted forever, like water over the dam. And there has been water pouring here for many, many years, even during an endless spectrum drought.:" Although Baran urged as an ideal the transfer of the 480 megahertz of spectrum currently occupied by analog broadcasters to fiber optics and cable coax, he said, "We don't have to wait [for this ideal solution]....The existing spectrum can be more efficiently used by resorting to smart receivers and transmitters."