[opendtv] Re: News: TV Braces for the Apple Tablet
- From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
- To: "opendtv@xxxxxxxxxxxxx" <opendtv@xxxxxxxxxxxxx>
- Date: Fri, 29 Jan 2010 18:54:07 -0600
Craig Birkmaier wrote:
> Sorry Bert, but with IP Multicast, telco networks are far more
> spectrally efficient than ATSC MHP for video delivery.
By the way, even this is wrong, Craig, assuming you are talking about cellco
wireless nets here.
If you want to transmit IP multicast to individual cell phones, and NOT just
use IP multicast within the wired backhaul nets between cell towers, and then
broadcast the signal, you need to establish two-way links to each cell phone.
Because that's how IP multicast works, Craig. What makes IP multicast
"efficient" is that it reduces the traffic between IP routers. IP routers are
in the backhaul network.
Now, for IP multicast to the cell phone, each individual cell phone needs to
communicate using unicast transmissions with its local cell tower. Each
individual cell phone needs to tell the cell tower which multicast group it
wants to participate in, and it needs to keep doing this every time it gets a
query from the cell tower. These are frequent, like once a minute at the least.
Not only that, but the two-way link between each cell phone and the cell tower
is unique to that cell phone. Its power is adjusted according to the distance
from cell tower to cell phone, and it goes through a handover procedure as the
cell phone reaches the edge of a given tower's coverage area.
So as you can see, the spectrum required in the wireless parts of the cell
network is not used any more efficiently here than it would be unicasting that
video. The advantage of IP multicast is only in the backhaul network. On the
other hand, if the cell phone uses a broadcast-only chunk of spectrum, one
which does not eat into cell tower's two-way link capacity, that's when you'll
see the advantage.
Bert
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Other related posts:
- » [opendtv] News: TV Braces for the Apple Tablet- Craig Birkmaier
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Manfredi, Albert E
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Mike Tsinberg
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Manfredi, Albert E
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Cliff Benham
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Craig Birkmaier
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Craig Birkmaier
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Tom Barry
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Manfredi, Albert E
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Manfredi, Albert E
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Craig Birkmaier
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Bob Miller
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Tom Barry
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Manfredi, Albert E
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Tom Barry
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Craig Birkmaier
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Manfredi, Albert E
- » [opendtv] Re: News: TV Braces for the Apple Tablet - Manfredi, Albert E
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Allen Le Roy Limberg
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- » [opendtv] Re: News: TV Braces for the Apple Tablet- Kon Wilms
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Cliff Benham
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- » [opendtv] Re: News: TV Braces for the Apple Tablet- Manfredi, Albert E
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Craig Birkmaier
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- » [opendtv] Re: News: TV Braces for the Apple Tablet- Kon Wilms
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Manfredi, Albert E
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Manfredi, Albert E
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Kon Wilms
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Kon Wilms
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Manfredi, Albert E
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Kon Wilms
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Kon Wilms
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Craig Birkmaier
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Craig Birkmaier
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Manfredi, Albert E
- » [opendtv] Re: News: TV Braces for the Apple Tablet- Craig Birkmaier