[opendtv] Re: 20050509 Mark's Monday Memo

  • From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
  • To: <opendtv@xxxxxxxxxxxxx>
  • Date: Thu, 26 May 2005 17:31:13 -0400

Tom Barry wrote:

> The government could probably create a spectrum
> market fairly quickly simply by leasing all
> spectrum to the highest bidders instead of selling
> or "loaning" it.  Lease cost could be adjusted
> periodically based upon market forces, with staggered
> lease expirations.  The government wouldn't have to
> actually run the any spectrum utility, simply ensure
> that no one could just squat on the spectrum by
> making that squat too expensive.

Which is essentially what they've done, as I see it.
Not to the highest bidder, but instead to companies
that provide a service the govt finds desirable.
Meaning, broadcast radio (initially) and then TV too,
freely available to all receivers out there.

I don't think Craig wants the govt to actually run the
utility. At least, I never saw that implied. Which
begs the question, if cable TV could evolve from a
mere rural TV distribution service to media giants in
their own right, why wouldn't any other similar
utility go through the same evolution?

As to the spectral efficiency or usage aspects, again,
I don't see the big advantages of the FCC handing the
TV spectrum to a single gatekeeper. Craig uses numbers
like 60-100 MHz available in a market, but even that
number is suspect. Interference issues won't go away
just because the spectrum is owned by one entity. If
the "utility" can offer 100 MHz in a given location,
then separate companies should be able to do the same,
in the aggregate. And entities like USDTV can use an
aggregated bandwidth, where they merge the bandwidth
from multiple frequency channels.

Let's just assume for a moment that IEEE 802.16 is
the standard that applies to this utility. This makes
some sense, since WiMax is meant to be a metropolitan
area standard. Well, there are plenty of interference
considerations to be made if you want to use WiMax,
and the standard spells them out. Some frequencies
can only be used indoors. There are channel spacing
requirements that differ in the different parts of
the allowable spectrum. Individual channels are
allowed to be sized anywhere from about 1.75 MHz to
20 MHz (and including specifically 6, 7, and 8 MHz),
using n-QAM or OFDM (or OFDMA, which would not
apply to our braodcast environment).

There are power limitations to consider, to prevent
interference. IEEE 802.16 Annex B discusses these for
the frequencies below 11 GHz, which presumably would
apply in our case. Most of the discussion is about
mesh nets or nets inside a building or across the
street. Obviously, these are usually 1 W or less ERP.

I guess what I'm trying to get across is that there
are no magic shorcuts here. The physics won't change
just because one entity might manage or operate the
"utility," as opposed to multiple entities. If you
want to obtain ubiquitous coverage of large areas,
whether this is done by a single "utility" over
multiple WiMax bands, or by individual mini
utilities over similarly sized ATSC or DVB-T RF
bands, the same problems have to be addressed and


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