[opendtv] Re: IEEE Ericsson article on use of LTE for TV

  • From: Craig Birkmaier <craig@xxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Wed, 20 Jun 2012 00:27:04 -0400

At 7:26 PM -0500 6/19/12, Manfredi, Albert E wrote:
When you use your iPhone to watch anything at all, you are using the telco 2-way network ALWAYS. 

SO? I am buying bandwidth, sot content from the telco.


Even if it's material you stored ahead of time, it came from a 2-way network.


Really?

All of the audio CDs I digitized in iTunes came from a 2 -way network?
All of the "extra" mobile ready files that come on many new Blu-ray titles came from a 2-way network?
You are correct that almost all of the songs, apps, movies and TV shows I downloaded from the iTunes store traveled across a 2-way network. But not a telco wireless broadband network.
Remember that video I produced for the beer festival. It came from a DVD that I loaded into iTunes then copied to my phone. I DID use a two way network to UPLOAD the 480P and 720P files to YouTube.
The servers that stream that content may or may not reside inside the cellco's own network. Sometimes there are servers that mirror servers outside the ISP's infrastructure, to speed up response times and to support more unicast sessions within that ISP's network.
So now we are lumping together the entire Internet infrastructure, both wired and wireless... 

How convenient.
There is no such thing, in these consumer oriented networks, as a single "return path" that gets married to a potential broadcast path. At most, there is a 2-way link that can be used simultaneously with an otherwise independent broadcast link.
Excuse me. You are correct. I "may" use the telco two-way network to connect to the broadcaster to determine what content is being broadcast and to request unicast or multicast bit. OR I may simply pull in the program guide bits for the Broadcast LTE service and tune to what I want. 

Wither way, the broadcasters does not need to waste spectrum for a return path.
Most of the time, in these consumer networks, it makes very little sense to ACTUALLY marry a single uplink channel to a broadcast downlink. The scaling doesn't work out at all. Even in a town of a few thousand people, just how much of a 19.39 MB/s broadcaster's downlink can you dedicate to each person or household? Why bother with something that doesn't scale worth a damn?
I completely agree. There is no reason for a broadcaster to worry about the return path when it already exists.
I will concede that this makes it very difficult, if not impossible, to implement traditional 2-way unicast sessions. No big deal as it is relatively easy to deal with lost packets. The existing ATSC standards already do this, and if you want perfection, you can use the telco two-way network to request critical lost packets from the broadcaster.
Consumers accept the fact that digital broadcast are not perfect - momentary loss of signal, compression artifacts, and other poor quality due to cramming too much stuff into a multiplex are the current reality. There are many ways to deal with packet recovery when using a broadcast channel for critical file downloads. We worked out all of this stuff for data broadcasting more than a decade ago. 

Regards
Craig


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