[opendtv] Re: The Guardian: TV should switch to internet, peers suggest

  • From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
  • To: "opendtv@xxxxxxxxxxxxx" <opendtv@xxxxxxxxxxxxx>
  • Date: Wed, 21 Oct 2015 01:45:33 +0000

Craig Birkmaier wrote:

i agree that maintaining a FOTA broadcast system is in the national
interest. Fortunately, I don't think there is any possibility of
the service going away any time soon.

I certainly agree that a free information service is a good thing. However, in
coming years, it will not need to be limited to just an OTA one-way broadcast
scheme.

The FCC is currently working up an expansion of its telephone lifeline service,
right? This will mean that broadband access will become, and soon, as universal
as telephone service is now. This makes FOTI TV a very good substitute for FOTA.

If you're not destitute, but you still use FOTA TV, you would simply replace
your telephone bill with a broadband bill. And that broadband pipe will give
you telephone service as well as FOTI TV and the rest of the Internet.

If you were using FOTA TV because you couldn't afford cable, then the
government will provide you with a broadband pipe anyway, lifeline service,
which will be more than adequate for FOTI TV streaming. The congloms and their
broadcasters will need to seize this opportunity. There's a role for both, IMO.

This raises an interesting question. It was necessary to give
broadcasters UHF spectrum because of the propagation
characteristics of the VHF band. The signals from the big sticks
simple carried too far, requiring the checkerboard spectrum
assignments that exist today.

I think your premise is wrong. Whether you use UHF or VHF, to achieve
continuous coverage (e.g. up and down the East and West coasts) you will need
that checkerboard. The reason for UHF is simply that in order to avoid
co-channel interference, where this continuous coverage is needed, any single
market could not provide more than a handful of channels at best. UHF was
supposed to allow more TV competition, and it did. (Even though initially,
receivers needed something like 6 channels of UHF guardband, to prevent
adjacent interference within a market. Wasteful!)

So the question is, how can the VHF spectrum be used with
modern modulation techniques and lower power to provide a TV
service that serves every market?

First, you need a scheme that minimizes co-channel interference. Which means, a
scheme with low PAPR.

And then, you can create a more dense, low power checkerboard. This obviously
costs more, but it's not much different from what they've been doing in Europe
for a very long time. So each market will see, say, NBC on a couple or more
different frequency channels, depending where you live. Just scale down the
current large-area checkerboard.

Very similar to cellular schemes. Plenty of frequency reuse, and more tightly
defined market boundaries. SFNs aren't the only way to do this. A cellular
broadcast scheme has advantages, in that tower spacing becomes ONLY a matter of
covering the needed area. The angst about exceeding the echo tolerance of
receivers, if you don't create a dense mesh of towers, goes away.

Bert



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