[opendtv] Re: News: TV Braces for the Apple Tablet

  • From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
  • To: "opendtv@xxxxxxxxxxxxx" <opendtv@xxxxxxxxxxxxx>
  • Date: Mon, 1 Feb 2010 16:08:53 -0600

Craig Birkmaier wrote:

> Not true. You do NOT need to duplicate the content payload for
> every device tuned to a multicast stream, just the device
> handshaking.

Sorry Craig, no. The cell connection to each phone is the equivalent of the 
Ethernet link between a layer 2 Ethernet fan-out "switch" and the PC connected 
to it. That link capacity is not shared with anyone else but the 
direct-connected PC. One cat5 cable per PC.

In the cell phone case, it is those individual RF links that are the prime real 
estate we're trying to conserve. In a wired network, those individual 
connections are plentiful (although upstream from them, the capacity may not be 
so plentiful, which is why you may have a 1 GigE connection, but never capable 
of download speeds that fast in practice).

Kon's point about "peer to peer broadcast," which I assume is the same as 
ad-hoc networks, is a bit of a long shot. It is not currently used in cellular 
systems, and it has a major drawback. You will have a lot of POed customers 
with dead cell phone batteries, if their cell phones are constantly behaving as 
mini cell towers.

> It would be quite feasible for a wireless broadband provider to
> use some of their spectrum for broadcasts and other spectrum for
> two-way data, including the necessary data links to tune into
> these broadcasts.

What a colossal weaste! It's also possible to bypass the small cells, and use 
existing broadcast frequencies for broadcast, and instead use the small cell 
structure for the two-way unicasts it's optimnized for.

> Is this not how Flo TV works?

No. FLO = broadcast.

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