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Technology Stocks : COM21 (CMTO)
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To: Frank A. Coluccio who wrote (2160)6/5/2000 10:01:00 AM
From: Mark Laubach   of 2347
 
These are my own ideas.

The entire cable industry is built around the analog RF
model for signal distribution. I think it will be awhile
before it could convert to all digital. The first
convergence I see as a possibility is the conversion of
analog NTSC programming to MPEG2 programming and then
signal distribution within a headend converted to digital.
The over the cable will still be analog RF, but carrying
digital information.

One question I have it where the tuner or virtual tuner
will move to as part of the evolution. If it stays in
the home, then an all digital equivalent of the coaxial
network delivered over fiber will need to process just
under 6 Gbps in the "set top box". Call it 10Gbps to
round it off. I get that number by taking the current
best downstream cable bandwidth of 810 Mhz, slicing
into 135 channels of 6 MHz and multiplying by 42 Mbps
for 256 QAM.

If the tuner moves up in the network, then the bits
to the home rate drops significantly but the switching
infrastructure increases dramatically and we're back to
the VOD Level 1 and Level 2 gateway architecture - which
turned out to be too expensive.

Another approach would be to move the transport to an
IP infrastructure and do things in more or less following
the Internet protocol model for making connections to
servers or to join/leave multicast groups. I know that
folks who come from an Internet background can see this
as the path. The cable industry however, has its roots
in the analog RF and MPEG world and is slow to change.

Btw, I haven't looked at PON for awhile now or where
the FTTH world has gone too. I would have to study
up just a little bit to make accurate comment.

With regards to analog rf and cmts's. It would be somewhat
more straightforward on the downstream to remove the rf
front end and connect what's left to an MPEG2 switch,
since DOCSIS uses MPEG2 transport stream framing.
At some point, this would get converted to RF before
hitting the subscriber and would be transparent to
cable modems (in theory). Upstream is a different
beast and does not have a simple conversion from
analog burst modulation to an all digital link.

These are just thoughts.

Mark
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