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Inventing the Internet Again
Smart
Radio is a Brain Behind the Antenna
To conceive of Baran’s model of wireless, begin by thinking of the
human eye and comparing it to a radio. Like a radio, the eye is essentially
a device for converting photons into electrons, pulses of electromagnetic
energy into electrical currents. Geared for visible light rather than
radio frequency signals, the eye is a receiving antenna. As radio technology
moves up through the microwaves toward the infrared realm-with infrared
wireless links from Canon now reaching 155 megabits per second-many of
the differences are dissolving.
Yet, in the crucial index of performance, the radio is drastically inferior
to the eye. While most radios can receive signals across a span of frequencies
ranging from the kilohertz to the megahertz, from thousands to a few million
cycles a second, the eye can grasp signals with a total bandwidth of more
than 350 trillion hertz (terahertz). That is the span of visible light,
from 400 terahertz to 750 terahertz, red to purple.
How is it that your eyes command 350 terahertz of bandwidth and your FM
radio around 20 megahertz, 17 million times less? It is not chiefly the
special powers of the retina and other optical faculties. Radio antennas
can collect an even larger span of frequencies. The difference is mostly
behind the receiver. Backing up the eyes is the processing power of some
10 billion neurons and trillions of synapses. Backing up the radio antenna
is a lot of fixed- analog hardware. Eyes are smart and aerobatic while
the radio is dumb and blind.
In Baran’s vision, the future of wireless is the replacement of current
dumb radios by smart digital radios that resemble eyes. Coupling radio
technology with computer technology, the antenna can acquire a brain.
Smart radios can eventually process gigahertz of spectrum (billions of
cycles a second). They can sort out the frequency channels much as eyes
sort out arrays of color, and pin down codes and sources of radiation
much as the eyes descry different sources, shapes, and patterns of light.
For example, a smart radio could process phone calls, videos, teleconferences,
geopositioning codes, speed-trap lasers, and emergency SOS’s.
The result will be a transformation of the nature of the spectrum. The
current real estate model will give way to a new view. Rights to spectrum
will roughly resemble drivers’ licenses for use on the highways.
Today you use your 350-terahertz eyes to survey the highway in front of
you and avoid other traffic. As long as you do not collide with other
users, pollute the air, or go too fast (use excessive power), you can
drive anywhere you want. As radios are computerized, they will be able
to “see” the radio frequency spectrum as your eyes see the roads.
Smart radios will be licensed to drive in open spaces in the air as long
as they don’t collide with other radios, overpower them, or pollute
the airwaves.
As Baran argues, the fulfillment of this dream is at hand. It is the broadband
digital radio or software radio. Essentially, the radios used in cellular
or PCS (personal communications services) phones will be able to differentiate
among frequencies; they will be able to tell which direction a signal
is coming from and isolate it in space; they will be able to identify
the language of codes and protocols and waveforms that it is using and
download software translators. No longer caught in a dedicated set of
channels, time slots, protocols, data types, and access standards, radios
will be smart and agile rather than dumb and fixed frequency.
Moore's Law Will Leapfrog Today's Limits
This will not happen tomorrow. But like any technological vista, it illuminates
the future. It opens the way to a new wireless paradigm, fully in place
shortly after the turn of the century, that will mandate an entirely new
model of wireless regulation and a new method for judging the evolution
of companies and their prospects. In general, the companies on the path
to broadband digital radios-the smart radio-will prevail over companies
that hook their futures to hardwired machines linked to narrow spans of
frequencies. Moore’s law, the doubling of computer power every 18
months or so, is enabling the creation of broadband cellular radios in
which most of the processing occurs in digital form.
Some of the first smart radios were built for the military. In Operation
Desert Storm, the cacophony of allied combat radios-some 15 of them using
a variety of frequencies, modulation techniques, encryption codes, and
waveform standards, such as AM or FM or PCM (pulse code modulation)-created
a virtual Babel in the sand. Units needed a separate radio system for
every radio (or radar) standard. As a result, the Pentagon launched the
Speakeasy project-one smart radio that could process all the different
standards in software. Made by Hazeltine and TRW, the first prototypes
were demonstrated successfully in 1994. Because standards change over
time and hardware improves at the pace of Moore’s law, a software
programmable radio also saves money. Rather than upgrading the system
in hardware every time the technology changes, software radios can be
upgraded merely by downloading a new software module.
Speakeasy engineers have spread the word through the cellular industry.
Stephen Blust, now at BellSouth Wireless, is leading an international
effort to create smart radio standards-the MMITS project. Today, with
the advance of an array of new digital technologies, including CDMA, TDMA,
GSM, DECT 1900, SMR, PHS, and a spate of others, every urban area is becoming
a Desert Storm of incompatible radios. Not only are these systems unable
to communicate with one another, but they also require separate spectrum
and base station equipment. All this redundant processing has raised the
costs and reduced the universality of wireless and prevented cell phones
from displacing wireline telephony.
The solution to complexity, however, is Moore’s law: Put it on a
chip. Reducing this Babel of complexity to silicon microchips, with hundreds
of millions of transistors on centimeter slivers of sand that ultimately
cost less than $2 to manufacture, smart radios can radically simplify
the cellular landscape. Freed of most wires, poles, backhoes, trucks,
workers, engineers, and rights of way, cellular should be far cheaper
than wireline.
For example, the conventional analog base station that receives your cellular
calls and connects them to the telephone network requires a million-dollar
facility of 1,000 square feet. This structure may contain a central- office-style
switch to link calls to the public switched telephone network, huge backup
power supplies and batteries to handle utility breakdowns, and racks of
radios covering every communications channel and modulation scheme used
in the cell. This can add up to 416 radios, together with all the maintenance
and expertise that multiple standards entail.
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