[opendtv] Next gen OTA TV proposal

From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
To: "opendtv@xxxxxxxxxxxxx" <opendtv@xxxxxxxxxxxxx>
Date: Fri, 24 Jun 2011 16:22:41 -0500
Mark Aitken wrote:

> The attached is the "Spectrum Utility" answer to part of the equation -
> of this I am firmly convinced. This represents the core concept that I
> am driving within the broadcast industry for the Next Generation
> Broadcast Television standard.

Mark, this is your hybrid broadcast and two-way cellular system, using LTE.

The advantage of going this route is that you can seamlessly vary the amount of 
spectrum a market uses for OTA TV broadcast vs. for two-way wireless.

The disadvantage is that what is used for one-way broadcast would not be as 
spectrally efficient as it otherwise could be, because you're still using LTE. 
We've seen the numbers, and to approach even our current 8T-VSB numbers, you 
need a very close spacing of towers.

Here's a thought. Given that you do expect to deploy relatively closely spaced 
towers anyway, why not assign the TV broadcast to its own frequency channels? 
Then go to something like 4 X 4 MIMO, which can increase spectral efficiency of 
the broadcast by a relatively safe 3X or so, in broadcast. Then the FCC can get 
their 100 MHz of spectrum back and the broadcasters end up with more usable 
capacity than they have now? Those same towers would be shared with the two-way 
wireless infrastructure.

I don't think there's a limitation on modulation schemes that would be okay 
with this. And another point is, in rural settings, where you probably couldn't 
begin to afford the mesh of towers, the system becomes SIMO. Not a problem, 
most likely, because you would also not have to support as many TV stations, 
and/or because in rural settings more of the TV band is available in a given 
market.

Where the MIMO is used, I don't think you can make this into a SFN very easily, 
though. As described here:

http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=01269950

Which means that you'd be using a true cellular structure, and space-time 
codes, for the high capacity TV frequency channels. Not a problem, especially 
in the US, where the SFN doesn't buy much at all for spectrum savings (single 
market limitation).

In short, separate out the TV from the two-way service, but in doing so, 
increase the TV band b/s/Hz to the point where giving up 1/3 of the available 
spectrum is no big deal.

At the same time, you could go to DVB-T2, with tuners upgraded for MIMO of 
course.

Bert

 
 
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[opendtv] Next gen OTA TV proposal

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