Keynote Talk Transcript, 8th Annual Conference on Next Generation
Networks Washington, DC, November 9, 1994
Visions of the 21st Century Communications: Is the Shortage of Radio
Spectrum for Broadband Networks of the Future a Self Made Problem?
by: Paul Baran, baran@com21.com
Copyright 1994.
INTRODUCTION
John McQuillan:
I would like to introduce you to our next session which I consider to
be one of the real highlights of the Conference: our Keynote
Presentation:
Visions of the 21st Century Communications
Many of us are wondering what is the role for ATM in the next decade
and beyond. It's not far away now, and one of the questions we haven't
talked about at this Conference, that we want to focus on now, is
wireless and whether the spectrum for wireless is really the scarce
resource that many of us have been familiar with all our lives or
whether it's really an abundant one.
One of the great challenges for the 21st Century, I believe, is to get
all the power of broadband networking that we've been talking about,
and, at the same time have the convenience and flexibility of wireless
communications. This would indeed be the grand unification. ATM isn't
the grand unification - - it's wireless ATM that is the grand
unification. And what will it take to bring ATM into the home?
Well I'm really delighted to be able to introduce to you this
morning's Keynote presenter, Paul Baran, Chairman of Com21, a company
that was formed by Paul to work on 21st Century communications.
Paul is a really notable entrepreneur, inventor and visionary. Paul
has started many successful companies and made many important
inventions in this industry. Among the many companies he's started and
he currently is a director I'd like to mention is Metricom. Metricom
is a packet radio public company that offers wireless packet radio
communication for personal computers and has got fairly widespread
installation now in California.
But to make perhaps a more personal introduction for a moment, I did
my Ph.D. work in Adaptive Routing Algorithms at Harvard twenty years
ago. I did my Ph.D. in 1974. At the time I tried to read everything I
could about what had been done in packet networking up until that
point and I came across Paul Baran's work at RAND Corporation ten
years previous in 1964.
When Paul sat down, and I don't know how he did this, but he wrote a
series of ten reports describing, analyzing and predicting packet
switches, based on hardware, adaptive routing algorithms, wireless
links between them and really conceived of the whole way that we're
planning to build hardware ATM based systems today. So, Paul sees
things before other do.
You know, in fact, one tries to describe people by their time
constant. Some people think one day at a time. Some people are good at
planning month by month or year by year. You know you can't ask
someone to do a three year plan in a business if they're a one week
kind of a person. You can think of running the military: You've got to
have a day at a time foot soldier; you've got to have your logistics
people be people who can plan a little bit longer; and then the
generals who are planning the theaters of operation have got to be
able to see out a year or two.
Well, I've never met anybody with a longer time constant and a more
accurate record than Paul Baran... Paul!
PAUL BARAN:
Thank you John!
John entitled this talk Visions of the 21st Century. I am humbled
trying to do justice to such an over-reaching title. I am reminded of
that Wausau Insurance Company TV commercial. An efficiency expert is
introduced who is supposed to give a detailed presentation on
insurance recommendations. This guy gets up to the podium and says one
word, "Wausau". Then he walks off the stage to an awkward silence,
until the audience presumably gets the point.
I have to confess that I am tempted to say the three magical letters,
ATM (Asynchronous Transfer Mode) and then sit down. ATM pretty well
defines where the higher level protocol portion of the network
evolution is going in the future. At least in the mind of some of we
ATM techno-bigots.
Having covered so much ground so quickly, there is another part of the
network that deserves discussion in the remaining time. That is the
physical media itself.
PHYSICAL MEDIA
We have only a limited number of terrestrial transmission media to
consider. Really, only four. For the metropolitan network, the cable
TV network appears to be the winner, using a combination of fiber at
the top of the tree networks, while the tails are coaxial drop cables
to houses and businesses. This two-way path provides a lower cost
transmission pipe to the home than twisted copper pairs and can even
support telephony at a lower cost than in place twisted pairs. This is
the position announced by Pac Tel in California. Thus, we expect to
see both the telephone and TV cable companies competing using
essentially the same technology.
It is amusing to note that while Ethernet moves from coax to twisted
pair at 100Mb/s, just the opposite direction of evolution may be
occurring in the telco competition from twisted pair to coax.
When it comes to transmission over distances greater than about a
kilometer, fiber is the clear winner. And the capabilities of fiber
suggest continuing significant cost declines and capability increases
over time in terms of $/bit-kilometer.
ON WIRELESS
The last medium that I want to talk about is wireless. Wireless has a
major potential role to play in the last 100 meters of network systems
by allowing rapid easy interconnection without a jumble of wires.
Wireless can allow the user to separate the terminal for maximum
convenience and effectiveness. The thick umbilical cords providing
today's lifeline connection between the computer and the network could
be eliminated
This morning I would like to discuss an issue that limits this
possibility of our next generation networks. In brief, I am going to
talk about a communications policy issue that will determine what we
can, and won't be able to do with our emerging networks of the future.
Our particular concern is that well meaning government administrators,
responsible for control of the radio spectrum space, are making
seemingly innocent decisions that could have disastrous unforeseen
consequences. It could even cause our networks of the future to be
unnecessarily expensive and less capable than if a wider appreciation
of what's really happening was better understood. Of course, any
negative consequences of such a result are totally at variance with
the objectives sought by those responsible for telecommunication
policy. What appears to be missing from the deliberations is an
understanding of some basic technological issues.
THE SHORTAGE
The key point at issue that we will question is the widespread belief
that we don't have enough radio spectrum to go around. This is a
common, fundamental belief. Since we live in a world of scarcity or
natural resources it is almost automatic that we believe that there is
a shortage of frequencies. This particular resource is somewhat
different.
This morning, let's start by reviewing this presumption of a permanent
shortage. Let's consider how, with an application of already known
technology, we could create even a surplus of frequencies. What may be
going on is an inadvertent shortage created by a regulatory structure
which has yet to appreciate the potential capabilities of the new
digital signal processing technology as applied to communications.
A LINK IS NOT A SYSTEM
When we talk about radio or wireless in the following, we should
appreciate that no single communications medium is ideal in every
situations, so we build communication networks by choosing the
combination of various media links, optimized as a network. If our
link requirement is for long distance transmission, then fiber optics
tends to be ideal. If it is for distribution of signals to many users
located only hundreds of meters apart from one another, then coax
cable or twisted pair is the preferred medium, depending on the data
rates. And, in the future when we deal with increasing numbers of
users, wireless could in turn become the preferred medium,
particularly for the network tails in an increasing number of
instances. Conceptually this remove the constraints of being like the
dog whose freedom of action is limited by the length of his leash.
A PARADOX
Of course any suggestion that there is no real shortage of UHF
spectrum is at variance with the common wisdom. But, tune a spectrum
analyzer across the band of UHF frequencies, and you will encounter a
few strong signals, while most of the band at any instant is primarily
silence, or very weak signals. (My words this morning are focused on
the UHF range, that's the frequencies from 300 to 3,000 megahertz --
the most valuable part of the radio spectrum for communications with
high data rate local data devices.)
The spectrum analyzer connected to an antenna shows that much of the
radio band is empty almost all the time! This spectrum is
theoretically available for sending a signal if we were to take
measurements and know exactly when and where to send the signal. The
frequency shortage is caused in part by thinking in terms of dumb
transmitters and dumb receivers. With smart electronics, even occupied
frequencies can be used. To the modern communications engineer lack of
strong signals anywhere, no matter how distributed, represents
theoretically unused capacity. This is capacity that could be utilized
with the proper signal processing. With advanced signal processing
techniques, any signal below the peak received signal represents
potential usable transmission capacity. But, there is a catch. the
assumption is that we are dealing with digital signals able to operate
with very low signal to noise ratios. That means if a signal is
slightly stronger than another that it can theoretically be received
without error. (This game doesn't work with old fashioned analog
modulation signals, such as high quality analog TV signals where
interference even 40 dB below the picture is visible.) [40dB is a
power ratio of 10,000. one part of interference to 10,000 parts of
signal is visible. Communications systems can be built with 10dB
ratio, or 1000 times less vulnerable to visible interference.] You can
think in terms of a curve of energy versus frequency. A potentially
available bandwidth curve can be visualized by inverting this received
energy versus frequency curve and then adding a separation energy band
level equal to the requisite signal to noise ratio. This suggests
potential spectrum that can be reused by choosing the right form of
modulation. This is why you need pristine pure channels for analog
transmission like TV, but can get away with a dirtier digital channel
. Digital transmission when properly done allows a small signal to
noise ratio to be used successfully to retrieve an error free signal.
And, never forget, any transmission capacity not used is wasted
forever, like water over the dam. Not using such techniques represent
lost opportunity.
TABOO FREQUENCIES
Another thing that you will see with your spectrum analyzer is that
there is a lot of unused TV spectrum, even in the big cities. As you
tune across the UHF TV band and there are big holes and these are
called "taboo channels" intentionally left unoccupied because of the
limitations of the early era television receivers. You may have
wondered about these big black holes, particularly since we now know
how to build far better cheap TV receivers than when this early rule
was adopted. So leaving all this wonderful spectrum space unused seems
to be wasteful, particularly when we know how to use better technology
so that more of it is usable. Again, any spectrum space not being used
is water over the dam - - and forever wasted.
SPREAD SPECTRUM
Today, spread spectrum modulation approaches can allow many more users
to share a common band of channels. This means spreading the
transmitted energy over a large number of frequencies and living with
more interference. But, there is a regulatory lag in allowing such
technology, such as spread spectrum, because it seems to require more
spectrum space, albeit commonly shared among many users. The idea of
preferring to use signals that take up more bandwidth is at variance
with the mind set of most regulators, whose objective has always in
the past been to minimize the occupied bandwidth.
NEGROPONTE'S SUGGESTION
We can save a vast amount of bandwidth by at least starting to off
load applications that hog bandwidth and that could be better served
by using alternative media. For example, TV cable now passes about 96%
of the US households and could allow many more TV channels to be
delivered to the home than can be supported over the air and could
release a vast amount of spectrum space. The use of TV cable started
primarily in the US and is also now rapidly growing internationally.
Professor Negroponte of MIT oft quoted half facetious words to the
effect that the way to solve this problem is Ôthat everything now sent
by radio should be sent over wires and everything now sent by wire
should be sent by radioÕ does have some merit. And the transfer need
not be 100%. Shorter range rf transceivers connected to fiber could
produce a significant improvement - - tremendous improvement, really.
Let's talk about the ...
EVOLUTION TO DIGITAL
Digital modulation is the key. It is far more bandwidth efficient than
todayÕs analog modulation. Digital modulation in lieu of the present
analog modulation allows ten times as many TV signals to be sent over
an existing TV cable and of better quality. If a TV cable carries 50
analog channels, then the same cable would now carry 500 channels. The
500 channel digital TV cable systems are in early manufacturing stage
today. The demand for this capability is not to present 500 different
channels of TV, but rather to allow the transmission of pay-per-view
movies with multiple start-times to make them more attractive to
potential viewers. So, the same program would start on the hour,
thirty minutes after the hour, on the next hour... so when you come
in, you would be able to see a movie right from the beginning.
RANGE REDUCTION
Another direction that promises great improvement in bandwidth
efficiency is in the reduction of the transmitted power. In the UHF
band the number of geographically dispersed users that can be
simultaneously accommodated in a fixed spectrum space varies as the
inverse square of distance. Cut the range in half, and the number of
users that can be supported is doubled. Cut the range by a factor of
ten, and 100 times as many users can be served. Reduce the power
further, and essentially any number of users can be fit into the exact
same spectrum space presently tied up supporting a few longer distance
users. Thus, a mixture of terrestrial links plus shorter range radio
links has the effect of increasing by orders and orders of magnitude
the amount of frequency spectrum that can be made available. We speak
of inverse square ranges. While true for free space signals, when it
comes to the real world, the payoff is even more dramatic. For
example, radio signal attenuation within concrete office buildings,
such as a building like this one we are in now is closer to the
inverse 4Õth power of the transmitted power. Given the attenuation
encountered in these type of buildings means that increasing radiated
power doesnÕt buy much in the way of range, anyway. By authorizing
high power to support a few users to reach slightly longer distances
we deprive ourselves of the opportunity to serve the many.
Now, how realistic is it to reduce the range of transmission for the
relatively few to allow a greater number to benefit? Consider todayÕs
millions of short range cordless telephones, all sharing a minuscule
slice of the radio spectrum, while a small number of licensed users
hog most of the spectrum. Most of these long range devices could be
served by using shorter range radios plus fiber to provide the longer
distances sought. Of course, the resulting path is not all wireless,
but neither is todayÕs cellular systems. The advantage of tetherless
operation is retained for the userÕs convenience, so that there is
very little Ògive up" here. There is no shortage of TV coaxial cable
nor of telephone line capacity to provide the wired medium portion of
the pair. Assuming that we did move in this direction, we could then
create a vast new radio communications capability to allow the support
of a far greater number of users and with greater bandwidths than
possible with today's present day regulatory constraints.
SMART TRANSMITTERS
A key technology in our new tool bag that should be mentioned is the
microcontroller that allows creating cost effective smart transmitters
and smart receivers. For example, a smart transmitter can first listen
and then automatically choose those frequencies that avoid the other
signals in the band. Think of it as just being a matter of being a
good neighbor. The smart transmitter reduces its power level to just
that needed to produce an error free signal and no greater. You donÕt
require that pristine pure slice of spectrum to have error-free
performance. Digital logic in the chip supports error correcting codes
to convert a small amount of redundancy in transmission, allowing
corrupted signals to be cleaned up to emerge error free.
SOME KINDERGARTEN RULES
To take the fullest advantage of our new technology with its sharing
of a common resource requires that our smart transmitters and
receivers cooperate. This may sound complicated, but the rules to make
maximum effective use of the shared band are simple -- primarily a
matter of common decency in sharing resources. The rules are somewhat
similar to those you learned in kindergarten, assuming you lived in a
tough neighborhood.
Rule #1. Keep away from the big bullies in the playground. (Avoid the
strongest signals.)
Rule #2. Share your toys. (Minimize your transmitted power. Use the
shortest hop distances feasible. Minimize average power density per
Hertz.)
Rule #3. If you have nothing to say, keep quiet.
Rule #4. DonÕt pick on the big kids. (DonÕt step on strong signals.
You're going to get clobbered.)
Rule #5. If you feel you absolutely must beat up somebody, be sure to
pick someone smaller than yourself. (Now this is a less obvious one,
as weak signals represent far away transmissions; so your signals will
likely be attenuated the same amount in the reverse direction and
probably not cause significant interference.)
Rule #6. DonÕt get too close to your neighbor. Even the weakest
signals are very strong when they are shouted in your ear.
Rule #7. Lastly, donÕt be a cry baby. (If you insist on using obsolete
technology that is highly sensitive to interfering signals, donÕt
expect much sympathy when you complain about interfering signals in a
shared band.)
That about summarizes that subject other than to note that this isn't
the way we presently handle frequency assignments.
REGULATORY HISTORY
The hang-up here today is that our highly institutionalized regulatory
structures contain implicit assumptions about technology that once
were true; less so today, and probably not at all tomorrow. The
regulatory game is run by lawyers, while the issues are primarily
technical. Lawyers tend to view the frequency similar to a piece of
real estate. If I owned a frequency, then you canÕt use my frequency.
ItÕs mine, all mine. Frequencies today are treated as a property
right. Yet, communications engineers know that statistical averaging
of larger blocks of frequencies allow far better usage. That's
something we all know about. This is the heart of the concept of
sharing an ATM network. We all win as each shared user encounters far
better economics than if we had to dedicate a separate network to each
group of users. We did that in the old days. This concept of sharing
is what cellular radio is all about. Of course we finally did get
cellular, but over a decade was wasted because of the regulatory lag
between the time that technology was feasible until the time that it
was implemented. In fairness, newer thinking is increasingly being
incorporated in our regulatory decisions. But, from the point of view
of a technologist, the process is agonizingly slow. I think we can do
better.
WHERE WE ARE
Today the pioneer who proposes to use the radio spectrum in any truly
innovative way faces a bureaucratic hoop jumping game, interrupted
with interminable delays. Underneath it all is the implicit assumption
that there is a God given shortage of frequencies. That being so, the
government must dole out the slivers with great care. It does so using
a set of rules based on concepts inherited from an earlier era, but
now cast in administrative laws. The lawyerÕs real estate model of
frequencies is but a zero sum game; while the communications engineer
views it as a game where many more can win.
ORIGIN OF THE FREQUENCY SHORTAGE
Lack of frequencies is not a new problem. Next year, radio is going to
be 100 years old counting back from the time Marconi, as a teen
teenager, ran his first experiments in his back yard. Yes, we got
radio as a byproduct of an experimental hobby activity; not as the
result of any major corporation's research department. The first
experiments in radio were funded by Marconi's mother as his father
refused to come across with the pocket change for such foolishness --
at least until the time radio worked. Then, his father became a great
supporter -- with an excess of advice.
The issue of spectrum efficiency has been with us right from the
outset, starting with the early question, "Would it ever be possible
to allow more than one radio transmitter to operate at one time?"
Sharing the channel was one of the first challenge to early radio
technology development. Ever since the turn of this Century much of
the history of radio technology has focused on living within an
over-crowded radio spectrum. Given the limitations of past technology,
the shortage of preferred frequencies was real. Very real. And, with
an excess of potential users, it was mandatory for governments to
create the necessary rationing mechanism. National and international
regulatory structures evolved, concerned in major measure with the
ever present issue of scarcity of bandwidth. And, so it was
institutionalized into regulatory policy. And once institutionalized,
the basic assumptions that got us there are very rarely ever
re-examined. And, when they were, changes tended to occur at glacial
speeds. .
CREATING MONOPOLIES
To put things into perspective, let's take a moment to understand how
the game was played in the past, leading up to today and consider a
likely scenario or two. Early spectrum was acquired by the pioneer
user, but with the government use assuming priority. As additional
spectrum was awarded, it tended to be granted in response to economic
and political power of the applicants. Whatever organization held most
power obviously was serving most users. Economists regard regulation
as a substitute for competition and preferred its use whenever a
natural monopoly exists. Whenever a government issues frequency, it
creates a monopoly. Become a regulated monopoly, and the government
will keep out your competitors.
TERMINATING MONOPOLIES
When a better technology comes along that allows the feasibility of
multiple suppliers, it invalidates the natural monopoly argument. The
end of a monopoly is rarely a swift process and it is never painless
-- particularly if it were well run and highly profitable. After long
running anti-trust battles the US telephone monopoly, AT&T, was in
part fractured into seven local area monopolies and competition was
permitted in the long distance telephone and data communications
field. This was an extremely controversial move at the time, and was
met by all sorts of Chicken Little sky falling predictions. The sky
didn't fall. Instead we saw a major increase in effectiveness in long
distance services, fostered by the new competition. And this was
perceived as being so successful by other countries, that similar long
distance services are being deregulated throughout the world, even by
those nations with a long history of sole governmental control.
DEREGULATION OF THE REST OF THE SYSTEM
The first wave of deregulation was limited to long distance
communications, as the technology at the time could only support the
deregulation of the long distance carriers. Missing was the technology
to make local area competition feasible and permit deregulation of the
local carriers. This is now in the process of change. With cable TV
now passing almost every house in the US and spreading throughout the
world, an alternative and more cost effective channel will soon be in
place to support alternative local communications suppliers. The
combination of fiber/coaxial cable and perhaps radio appears to be the
lowest cost way of providing local communications and even telephony,
so the new competition is particularly threatening.
THE MOVE TO DEREGULATION
Pressure to deregulate the local carriers is underway. The local
telephone companies and the cable companies are in an unstable truce
before the all out war, with cross-merger discussions underway. The
fear of loosing one's monopoly is never a pleasant prospect to a
company. It means competition and the necessity to increase
efficiency; leading to big layoffs of long-term employees, giving up
perks and that sort of thing. Every month the newspaper carries
articles about another telephone company laying off another 10,000
people to become more efficient. The press has been surprisingly
polite in not asking what these tens of thousands of employees were
doing prior to the threat of competition.
CREATION OF A NEW MONOPOLY
If you spent all your life working in a monopoly and it is going away,
it is understandable that you may want to create another one. But,
where? If the technology is going to be a combination of TV cable
technology plus radio tails, a monopoly protection defense line might
be the regulated spectrum ownership of the tails of the network.
Maintenance of the monopoly then hinges on maintenance of a spectrum
shortage. Those that "own" today's frequencies face a diminished value
of their asset unless the shortage can be maintained.
THE AUCTIONING GAME
An idea evolved, first tried in New Zealand and now in the US, to
auction off small portions of the spectrum in response to the
unsatisfactory alternative involved in issuing frequencies in the
past. The era of granting frequencies as political favors ended with
the increased diligence of the press. A substitute mechanism, random
drawing, was then tried. This process was also grossly misused, as
thousands of applications were filed and the winners sold their
licenses to the legitimate users -- who in turn built their
monopolies. The overall history of the regulation of the radio
spectrum is the sort of thing that tends to give government a bad name
when it comes to running a business.
The frequencies being auctioned off today (and there's going to be a
big sale of these next month) came partially from a give-up of the
frequencies reserved by the military and partially from point to point
users who are to be assigned alternative frequencies, and who will
receive payment for new equipment in the process. While auctioning
might seem to be an answer to an unsolved problem, I believe that it
will exacerbate the problem and is more likely to lead to the creation
of new monopolies. He with the most up-front money gets to lock up
frequencies to create an oligopolistic position with a legal barrier
to competitive entry. It can be argued, on the other hand, that enough
blocks of frequencies are being auctioned simultaneously to insure
competition. But, history has shown that in a capital intensive game,
he who comes in second, but with most dollars wins by buying out the
early players. Everyone walks away happy. The early license holders
get a windfall and the last guy gets to milk the public cow with
minimum interference.
Next month an odd combination of formally competitive bedfellows will
gather together to jointly buy up big slices of the radio spectrum.
The November 7th issue of Time quotes Stahlman, an industry observer,
as saying "the behemoths who can afford to bid are the least likely to
be innovative." The same article also quotes TCI CEO John Malone as
saying in effect, "We are starting a new national telephone company."
And, so the seeds of a re-monopolization are being sowed -- all based
on the assumption of a shortage of spectrum space.
AN ALTERNATIVE APPROACH
A counter hypothesis that I would like to raise for your consideration
this morning is that there is really no real shortage and what we are
seeing is a manifestation of a self made problem that would go away if
we made better use of our present known technology.
In the words of Pogo, "We have met the enemy, and it is us."
If the present approach is lacking, what might we do differently? If
our hypothesis is correct, then there is a potential for a limited
amount of spectrum to carry all the traffic imaginable (provided the
power and the range of the transmitters is limited), then public
policy is better served by moving to an environment of near zero
regulation. In such an environment anyone would be allowed to use the
spectrum, without the high front-end costs that keep out the true
innovators. Of course, the allowable power and power densities would
have to be realistically restricted.
CHAOS?
Would this lead to chaos? In my opinion, the answer is, probably not.
Consider the many millions of cordless telephones, burglar alarms,
wireless house controllers and other appliances that operate within a
minuscule portion of the spectrum and with limited interference to one
another. These early devices are "dumb devices" compared to equipment
being developed able to change the frequencies and minimize radiated
power to better avoid interference to themselves and to others. Of
course this means that there will have to be enough frequency spectrum
set aside to do so. But, once having done so we would have created a
communications environment able to handle orders of magnitude more
communications today.
ARENÕT WE DOING THAT ALREADY?
In the US the FCC has allowed unlicensed operation in the Industrial
Scientific and Medical bands These are "garbage bands" -- the home of
radar ovens and diathermy machines. Some say "too little and too
late." Nevertheless access to the ISM bands has proved to be of
tremendous value in the creation of truly innovative major new
services -- such as noise free high quality cordless telephones and
wireless burglar alarm services. However, a shadow is growing as some
in the FCC are proposing chopping up this band even into smaller
pieces, and then artificially limiting the use of this band to force
users over to the auctioned frequencies to increase the monopoly value
of the frequencies being auctioned.
POSTSCRIPT
Now, do we need all the regulation where each slice of frequency in
each geographical area is tightly controlled by Washington? Or might
we be better off if we used the Internet as our model? No central
node. Local decision control with a minimum of restrictions. The
Internet is growing rapidly. It is inexpensive and it allows the
broadest access to the world's information to a greater number of
people than ever initially imagined. Yet, it is theoretically chaotic,
as would be sharing a common band of frequencies by all comers. We
know that both examples of distributed networks can be made to work.
Nevertheless, today we see our regulators considering slicing up the
ISM band. In comparison to successful example of the freewheeling
Internet type model that works so remarkably well for huge numbers of
users, slicing up this common bank is like a move back to a
centralized control reminiscent of the old Soviet economy. And we know
so well today, that particular centralized system didn't work all that
well.
SUMMARY
So, in conclusion, I'd like to say that the role that wireless can
play in the ATM world of the 21st Century is bounded by just two
things:
1) the imagination of the system designer, and 2) our ability to
explain the implication of the emerging technologies to those
responsible for passing out the radio frequencies.
Unless the long range implications are better understood, we could
significantly delay the availability of technology of major economic
importance.
Thank you!
_________________________________________________________________
QUESTIONS (Submitted on cards and selected and read by John
McQuillan:)
John McQuillan: Thank you very much Paul, that's real food for
thought. It's a little depressing in a way to think that we've wasted
so much opportunity already. But, perhaps we can look forward to doing
a better job going forward.
We have a couple of questions here from the audience:
One promise of broadcast spectrum that you didn't touch on but that
certainly appeals to all of us is that we've tended to think of it as
"free" when we turn on our broadcast TV. It doesn't cost us anything
and when we do our garage opener, it's free. Isn't that going to
present a problem in moving some people out of radio spectrum and onto
cable because you have to pay for cable television unlike broadcast
television?
Baran: In short, the answer is "yes". But, it's more likely a matter
of providing a low tier free coverage for the broadcast channels. It
may well be in the cable company's interest to provide free access to
solely "over the air" signals. Once the cable is in-house, then the
cable operator could sell incremental other services.1 While the
answer is "yes", that nobody likes paying for services they can get
off the air free. But, the movement in growth of cable is very real
and I think its advantage increases with time, so, it is not out of
question. This is not something that's going to happen right away, and
we don't need 100% penetration everywhere, as the shortage bind is
only in the big cities.
McQuillan: Considering where we are in the U.S. with an embedded base
of dumb TVs, broadcasting monopolies and the general inertia of our
regulatory system, do you think it's possible that your ideas are
going to be adopted in other countries before they are in the U.S.?
Possibly in some emerging countries in the third world?
Baran: Could be! You know, when you said 21st Century, that covers an
awfully long period of time. What can happens over such a long period
is hard to imagine. All I can talk about is the trend line. It is hard
to pick an exact date and who's going to do what -- particularly when
you deal with political type decisions. We can predict technology
quite well, but historically it has been found nearly impossible to
predict political decisions as they tend to be a function of a single
person's whim, rather than the composite result of a large number of
separate actions that all combine together in the case of a technology
evolution direction.
McQuillan: Well here's a good question that picks up on one of your
very last thoughts. Paul, how can we improve our ability to explain
the implication of these emerging technologies to those responsible to
handing out spectrum?
Baran: That is my key objective of this discussion this morning. The
more people that are aware of the problem, the faster we're going to
work our way towards a solution. I think it behooves all of us who are
aware of the problem to pass the word around; to study it, to see
whether it makes sense to you. And, if it does, then it increases our
base of those that appreciate the nature of the game being played. I
think when this understanding becomes more widespread, we increase our
chances to see some movement over time.
McQuillan: One way of understanding your remarks is to say that there
are two themes. One is that there's a revolution in digital
technologies, especially digital signal processing, which is going to
allow us to completely rethink how we move information through the
radio frequencies and the other is that at the same time and for
rather different reasons, we're considering the deregulation or
re-regulation of these frequencies. Which do you really think is
really going to happen first: the large scale use of digital signal
processing technology giving us better frequency utilization, or an
effective deregulation of the spectrum we are currently using?
Baran: Either of these two directions can allow us to win the game.
If we can make much better use of our existing channel using digital
signal processing, then the pressure for saying there's a shortage of
frequency goes away. Or, it can be done by smarter regulation. Either
way we end up at the same point. So, are many paths - any one of which
can get us there. But, all can be blocked by intentionally unwise
regulation.
McQuillan: You know, for years I've had the mental model that
broadband and wireless were two orthogonal axes and you could get more
and more high performance in your network with a better and better
wire and better and better switching. Or, you could have more and more
convenience and portability in wirelessness if you were willing to
accept lighter weight, less power and more primitive devices. So in
the one limit, you have the Silicon Graphics work station on fiber
getting ATM at the other limit you've got the little pocket pager that
just basically delivers one bit saying "you've been paged" and you
carry that everywhere. Isn't it really utopian to suggest that we can
just throw away that model and we'll be able to have any communication
anywhere?
Baran: The answer is yes, but you can go high data rates very short
distances; or lower data rates further distances. Remember that we
don't need to build a system using only a single medium. We can use
combinations of media. So in this case, it will be radio for just that
portion where it's a pain to carry signals by physical wires and then
as quickly as possible, move over to a wired medium or fiber or coax
and then go the rest of the way by electrons or photons. It is a
matter of mixing, combining the two to get the advantage of both and
minimize the disadvantage of each.
McQuillan: So the vision of the 21st Century communications might be a
hybrid fiber coax or a fiber to the curb arrangement to the business
and the home. And then, broadband wireless within the last few hundred
meters within the building.
Baran: It could be only a few feet for very high data rate radio
devices or a mile or two for low data rate devices such as a PCN
telephone.
McQuillan: Paul's too much of a gentleman to go into this, but his
company, Com21 is pursuing this vision commercially. Paul has acquired
a number of patents in this area and so he's actually putting his
money where his ideas are on this point.
Timely subject, we've cleverly planned this conference so that this
session and the subsequent one on "Discussion of Washington" seem to
happen the day after the elections.....what do you think?
We've got a whole new ball game in Washington now - - all new House
and Senate - - Republican controlled. (I'm not going to pause for
applause or for any other kinds of comments - this is a non-partisan
event.) [LAUGHTER] I'm just asking Paul - - well, what do you think?
Does that change your views of how we might be proceeding here?
Baran: No, no. The concept of selling off of the frequencies seems to
have political acceptance by both parties, but for different reasons.
I think that the Democrats it looks like the new way of raising
taxes...
McQuillan: Yes, I noticed that...without using that word!
Baran: ... and to the Republicans, it appears to be a way of
privatizing government assets. So this move is politically acceptable
by both those that like raising taxes by stealth, and by those that
believe that government has no role here as this is something best
left to the marketplace.
McQuillan: So why wait for regulatory change? If signals can sneak in
and coexist on the bands, then no one else will really notice when you
occupy an unused tiny slice of spectrum in the neighborhood.
[LAUGHTER]
But wait, there's more, so start now - - develop a base of important
users - - don't worry about the dinosaurs, the mice are fleet afoot
and hard to spot in the grass.
Baran: Very good! Great idea!
McQuillan: It's pretty radical!
Baran: We're getting to see some bootleg stations in the FM band. Once
upon a time the FCC was very tough about it. But so much of this sort
of stuff is going on that they're sort of looking the other way. It
could be like marijuana - - where you have tight rules but they don't
get enforced. And, after a while the rules become unenforceable. I'd
hate to see us move in that direction. I'd prefer to have us face up
to the fact that there's a change needed here, and we would much
prefer to work within the laws.
But the point you raise is a very good one. There's a heck of a lot of
stuff you can do (using the spectrum) without getting caught.
[LAUGHTER]
McQuillan: In a way that might be the American way or the free market
way: that we the users have to demonstrate with action to the
government the right way to go and then they'll regulate almost in
hindsight or in afterthought.
Baran: That's right! That's the history of the Internet.
McQuillan: Indeed, yes!
Baran: Chaos up!
McQuillan: Right, and now President Clinton says "I want everybody in
the administration to have a mailbox in the Internet". Whereas a few
years before that would have been unheard of. Partly because no one
knew what it was and partly because everybody thought it was a joke.
It's funny how things can transition from being a joke or being wrong
to being the middle of the road accepted idea.
Well in your vision of the future, there are these potentially large
number of end stations which contending for spectrum by using spread
spectrum technology and by using a lot of very clever electronics,
doesn't this end up meaning that the end stations need to be quite
expensive to be so smart?
Baran: No! With silicon the complexity is no longer a factor. As long
as the numbers are big, and they will be in this case, you can pile an
awful lot of capability into a very inexpensive chip or a few chips.
And the cost of the chips is pretty much a matter of dividing a fixed
cost by a number. If the number is big then the cost per chip can be
fairly low.
McQuillan: Do you think that can get so cheap that it can go into
telephones?
Baran: Oh, yes!
McQuillan: Putting you on the spot here, do you think we'll see ATM
telephones?
Baran Yes!
McQuillan: That's really the end game here isn't it?
Baran Yeah, I could see cells going right down to the telephone
instrument itself. We've looked at that one and it seems to make
sense.
McQuillan That's the logical conclusion of this line of thinking is
that you build fiber to the curb or hybrid fiber coax. You deliver
video and data but you're also delivering telephony and then all the
devices in the home or the business that televisions and the computer,
but also the telephones have to be peers, have to be wireless, so that
means they have to have wireless ATM. Thought for the day.
Baran: The ATM cell is the key.
McQuillan: For those of you in the chip business, this is a good
thought for the day.
Is the FCC examining this question of the last mile becoming wireless
for broadband services for the home?
Baran: I don't know. I don't think that's very high on their agenda.
The FCC has a few very good technical people, but they're totally
outnumbered by the lawyers. [LAUGHTER]
McQuillan: I'm sorry to hear that, but I'm not at all surprised. I
mean, that's what we get in Washington and I don't know, what do we do
to change it? You seem to be advocating a kind of a public awareness
and education campaign. Is there any reason to believe that would work
or do we have any example of that working before?
Baran: Well, it worked yesterday! [LAUGHTER & APPLAUSE]
McQuillan: If only we had direct election of FCC Commissioners that
would really be something.
So, I know this is a difficult question, but being an optimist for a
moment, when do you think that we might get a significant adoption of
your ideas?
Baran: I think that this is one of these multiple S shaped curves....
these things always take a hell of a lot longer than you think they
should. Someone pointed out that no truly new communications system
ever got from laboratory to full field implementation in less than
fifteen years. So we're talking pretty long time constants. But that
doesn't mean we can't see some thinks occurring very early. There's
the bottom of the pyramid and then we start moving up.
McQuillan: It also doesn't mean that we can't use that insight to be
quite clear about what's strategic and what's counter strategic in
moving over the next few years. There's a lot of efforts I see as
pretty counter strategic to this line of thinking in this whole
revolution of cable companies doing telephony and telephone companies
doing cable. Clearly, I think one's view of what are the important
assets to protect needs to get revised from this prospective that
spectrum is abundant rather than scarce and that digital signal
processing is one of the key technologies, rather than a, let's say,
HDTV being one of the key technologies, you know, in this view, which
I share, compression isn't really the issue. While fiber's very
important, that's not really the issue either because we've been
living with fiber for a long time, but we can't afford to put fiber
everywhere. The real issue is, what do you do to get to the user and I
think Paul's contribution here is to suggest that we've solved a lot
of the other problems but we don't really have a good solution yet for
getting all the way to the user and that wireless represents the
solution that people aren't thinking of for that.
So, Paul, thank you very much for being with us this morning!
_________________________________________________________________
Footnote added after the talk:
Assuming fewer 100 million TV households of which 65% already take
cable then fewer than 35 million households would require access to
the cable. Cable systems generally are wired for taps for 100%
penetration (because they don't know who will and won't take cable.)
The missing items is running coax drop cables to the houses without
cable. Assuming a cost of about $30 per house in a mass contracted out
installation, the total cost would be about $1 Billion to free up over
400 MHz of high quality bandwidth for the entire country. This is
about 1/10 the cost of the amount that is expected for the PCS
licenses being auctioned off. And, it is only 5% of the $20 Billion
annual cable TV revenues. If this approach was limited solely to those
few large cities where any semblance of scarcity can be said to exist,
the cost would then be correspondingly lower.
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