I posted this to a list where the nth iteration of "the FCC's rules are holding back SDRs" was going on. It got me thinking about here in the U.S., and in other countries where we appear to be on the cusp of introducing rules that could move us to the next generation of SDRs.<br>
<br>There is a problem we never talk about. How do we make the transition from the current wireless structure, which depends heavily on exclusive licensing, to a system that relies heavily on SDRs and unlicensed access? Most folks in our movement argue, in essence, for a "hot cut." Lets just authorize SDRs and that technology will naturally win. There is an associated argument that the failure of regulatory authorities (the one I'm most familiar with is the U.S. Federal Communications Commission) resist expanding the rules for SDRs not from genuine engineering concern, but because of the political influence of incumbents licensees, the mobile bullies, the dinosaurs, who will fight to the death to protect their business models and their irrational and baseless fear of interference.<br>
<br>Granted the later is true. But even leaving aside the economic problems, the mobile bullies,
etc., there is a very real engineering problem of compatibility with
embedded technologies. Bluntly put, I have come to doubt the idea that
we could suddenly make a "hot cut" from the existing world of
predominantly licensed to a new world of predominantly unlicensed
spectrum use. Indeed, I have come to view the problem here as remarkably
similar to the problem of IPv6 adoption. Those favoring an upgrade are
completely ignoring how human beings actually act and what is important
to those who view wireless merely as an input for doing cool stuff.<br>
<br>Before folks get the wrong idea, I continue to believe that the
technology will, ultimately, work just fine and in the predicted way.
That we can develop smart devices that remove the need for exclusive
licensing and that would therefore allow us to radically alter the way
in which we construct wireless networks and what we can expect them to
do, and at what price. But I do not believe it is enough simply to get
the FCC to change its rules. Worse, I have come to believe that the FCC
should phase in these technologies gradually. Not because I fear the
licensed lobby, but because there are 300 million people dependent on
devices operating under assumptions developed in the existing regime and
the vast majority of these devices are crappy pieces of hardware that
could not survive a sudden, radical shift in rule changes as they are
likely to be implemented in the real world.<br>
<br>What shook my faith was the current relatively minor incidences of
interference in FAA Doppler radar from unlicensed operation in the
neighboring 5.3 GHz band. Operation of unlicensed in 5.3, shared with
the U.S. military radar, is a triumph of engineering technology and
proof of the sensing concept. The military would not reveal any
information about the nature of its radar systems -- the wave form, the
energy, or positions of transmitters. It was necessary to build devices
that could nevertheless avoid interference with military radar yet still
prove useful and economical to build. After several years, this was
achieved, and we have seen the recent opening of the 5.3 GHz band for
commercial use.<br>
<br>The problem is that, as the equipment manufacture got ramped up and
economies of scale kicked in, production got just a smidge cheaper and
shoddier. Chips complied with sensing and avoidance in band, but became
just a bit noisier out of band. Shielding was reduced to make devices
just that half cent cheaper which can mean a difference between a
profitable run and an unprofitable run. All of which resulted in a
device just a little bit noisier than actually allowed.<br>
<br>This might not have been a problem had the neighboring service not
been FAA Doppler radar with _extremely_ sensitive double-array
receivers. As it was, however, the increase in the number of devices,
combined with their increased noisiness, began to cause interference
problems. Happily, the situation appears to be resolved.<br>
<br>But the process is entirely too reminiscent to me of how the 800 MHz
band got screwed up by Nextel. Any individual conversion of a system to
a digital two-way system was not problematic. But when you ramped up to
several million users, operating at about a zillion times greater
frequency of use that the previous set of users, it started to cause
problems.<br>
<br>Lesson 1: Reality always plays out funny. Not because the underlying
science or engineering is wrong. Often it is from extraneous factors.
It is _predictable_ that manufacturers will develop cheap devices. It is
known that the current universe of devices are built as cheaply and
inefficiently as possible given the current set of rules assumptions.
Change the underlying rules and unanticipated things happen as the
interplay of these facts on the ground start manifesting themselves at
hyper speed from dramatic ramp up. Because if we are right about how
much better these technologies are in terms of cost savings, ramp up
will be incredibly dramatic.<br>
<br>Lesson 2: Any serious plan to alter the current wireless paradigm
must take into account the embedded technology and figure out how to
change it, gradually. _This_ requires considerable subtlety and a
willingness to consider taking the scenic route to the ultimate goal.
This route must detour through lots of apparently unrelated places such
as overall improvements to receiver standards to enhance robustness on
the receiver/embedded tech end, creating incentives for licensed
services to want better spectrum sharing and spectrum reuse technologies
that do not directly undermine their business models. It includes a
couple of stops designed to introduce new considerations in business
model and encourage people to want to own/deploy their own networks
without worrying whether they also "own"/hold the license to the
spectrum. <br>
<br>In short, it is no longer merely a complicated technical problem.
Like conversion to IPv6, it is a complicated technical problem made
worse by the irrational and unrelated (and often contradictory) needs
and desires of the human beings actually using the legacy technology who
do not respond well to the argument of "look, just trust us and switch,
you stupid non-technical monkey boy." Unlike conversion to IPv6,
however, there is no near term looming crisis to drive people to the
preferred engineering solution.<br>
<br>For those serious about engendering a social revolution based on
technological change, this requires a radical rethinking of tactics and
strategy. It also requires gaining a new perspective on FCC regulations.
Absolutely they are manipulated by incumbents. But after nearly 10
years working with the Office of Engineering and Technology (OET) on
spectrum issues, I have developed a respect for their inherent
conservatism, even as I chafe under it and try to move them along a more
aggressive path. They _must_ consider what happens if we are wrong and
the ramp up unexpectedly screws up vital services in the embedded
technology. It is not enough to know that a solution is possible. It is
not enough to blame others for making cheap receivers for licensed
services. Because if this stuff screws up, real people are impacted.
That's enough to give anyone charged with the responsibility of making
the decision a serious case of cautious conservatism _without_ insulting
them by claiming they are simply tools of the existing licensed
incumbents. At them same time, however, anyone who thinks that the
economic incentives of incumbents and the political power they wield is
not a significant factor weighting against change would be a naive waif
doomed to failure.<br>
<br>So how do we move forward? Excellent question! I am only now
starting to struggle with this. But the first stage is to recognize the
enormous complexity of the problem and the pressing weight not merely of
economically invested incumbents, but of the embedded technology base
predicated on more than 75 years of technological assumptions. My gut feeling tells me that countries outside the U.S. willing to free themselves of the "Washington consensus" that got everybody to auction spectrum should have an advantage here, simply because the weight of embedded tech should bear less heavily on them. But this may not prove correct, at least in the short term.<br>
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<br>Harold</font>