[opendtv] Re: Spectrum is too valuable

  • From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
  • To: "opendtv@xxxxxxxxxxxxx" <opendtv@xxxxxxxxxxxxx>
  • Date: Sat, 7 Nov 2015 00:50:19 +0000

Craig Birkmaier wrote:

There is no question that a system could serve more homes
with broadband if they repurposed spectrum now used for
analog or digital TV streams.

Amazing how long it took to get that point across, though, right? A real
struggle.

The question is how much bandwidth is needed in any
neighborhood to replace the broadcast TV service with on
demand UDP TV streams?

Simple, Craig. You only need, say, two or three broadband streams per home for
this, depending on how many people are watching TV simultaneously. So, if a
single DOCSIS 6 MHz channel can support 38 Mb/s downstream (256-QAM), that
should be more than adequate for two homes, each steaming 3 HD shows
simultaneously (or many more streams in SD). So, rough estimate, how many homes
can be fed with the spectrum used up by the broadcast MPEG-2 TS streams?

The wide distribution of the TV programs is made possible by the servers
feeding the head-ends. And these servers, in turn, can be updated via satellite
out-of-band links. So you don't have to clutter up the ISP backbone networks
with *all* of the TV programs, especially not the popular ones.

Don't know why you changed subjects and started talking about
upstream bandwidth.

Because I know what I'm talking about?

There is no way the current FOTA broadcast TV service could
deliver unicast said to every home in a market without massive
spectral reuse - i.e. tons of cells serving a small number of
homes. Cable is no different.

Do some numbers, Craig. It's funny how you finally did some, below, and yet you
couldn't go and retract this statement before posting?

So the best we can do today with DOCSIS 3.0 is 6.33 X 900,000,000
= 5.697 Gbps

Yes, I just finished telling you that yesterday, Craig.

Today PONs serve between 25 and 2000 homes, with the average
being 500.

By reclaiming all of the broadcast bandwidth, how many homes can be fed from a
single PON? You have all the number you need, Craig. Hint: in many cases, *no
change* will be required in the PON cabling, going by your figure of 25 to 2000
being the current status, and 500 the current average. And no matter what, the
PON changes can be reduced. You can't fool mother nature, Craig.

Bert



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