[opendtv] Re: Doug Lung series on OFDM

  • From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
  • To: "opendtv@xxxxxxxxxxxxx" <opendtv@xxxxxxxxxxxxx>
  • Date: Tue, 13 Nov 2012 20:59:00 -0600

Craig Birkmaier wrote:

> Over the years, Bert has often cited articles by Doug Lung when we
> discuss RF standards - the infamous 8VSB vs COFDM debate.
>
> So I expect Bert will find this three part series by Lung, on a what
> would be required for broadcasters to transition to a new COFDM
> broadcast standard, to be of interest.
>
> Lot's of interesting stuff here for further discussion, but the fact
> that Lung is tackling this issue says volumes...

BTW, certainly Doug has a point that use of COFDM would be better for mobile 
reception of TV than even ATSC-MH, but there is no reason at all to expect that 
the wireless ISPs would allow their blessed handsets to have the needed tuner 
anyway. And, users of handhelds, while they are on the run, don't really seem 
to want "by appointment" TV anyway.

Another point: did you notice how mobile reception suffers when the COFDM mode 
goes to fewer subcarriers? Which means, a scheme optimized for mobility will 
not be optimized for static indoor reception. You actually lose some resistance 
to multipath if you want to support reception at freeway speeds. Not good for 
indoor reception with handheld devices, in other words. We already discussed 
this some time ago. Not that conducive to a single RF infrastructure for all 
wireless TV.

Also, I just got the current issue of IEEE Communications Magazine, which 
features articles on LTE-Advanced Release 11. This is the one that includes a 
bunch of new features, included in which is the multicast-broadcast mode and 
the FDD and TDD modes. Which makes piggybacking on wireless ISP nets, by 
broadcasters, that much more feasible. (I would expect only very few streams 
"need" to be broadcast on the infrastructure at any given time. E.g. only two 
or three per market, for late-breaking news that really matters, or for that 
Superbowl event).

Perhaps OTA station groups can seriously think about morphing into wireless 
ISPs, and also become TV OTT Internet sites.

Bert

 
 
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