Posted 2/01/2002
TV OVER ADSL BECOMES MORE
PRACTICAL
By Fred Dawson
 Telephone
companies may have to reassess assumptions about the limitations of ADSL
for video applications in the wake of new efforts aimed at lowering the
bit rates for delivering TV-quality pictures.
Most dramatically, Alcatel and
Thomson Multimedia demonstrated in mid-December delivery of MPEG2 video
over ADSL at line rates as low as 700kbps. The demonstration used new
encoders offered by Nextream, a joint venture between the two companies.
Until now, the lower limits for TV-quality MPEG2 over any medium have been
a minimum 1.5 mbps.
The companies bill the technology as
a standards-compatible breakthrough that will allow ILECs and CLECs to
implement broadcast and interactive TV services over existing DSL
platforms using any vendor's MPEG2-equipped DSL set-tops. Officials say
the lower bit rates were achieved using multi-pass encoding and
quality-restoring algorithms that operate in real time, thereby avoiding
any breach of the standardized decoding methods used with MPEG2.
"Having a widely used
standards-based solution is essential to moving this market forward," says
Herman Haas, director for video over DSL at Thomson Consumer Electronics,
which is introducing its first line of DSL-based set-top terminals this
year. "There's been little interest among the telephone guys in doing
video over ADSL if it requires using MPEG4 or some other encoding
technique that isn't in wide use."
Alcatel views the lowering of cost
barriers to telcos entering the consumer entertainment sphere as a vital
requirement as competition increases and capital spending declines, says
Mitch Strobin, vice president of marketing at the company's broadband
network division.
"What you're seeing is the result of
Alcatel working with ILECs to help them realize their strategic ambitions
of being able to compete with cable within the budgetary constraints
imposed by the current economic climate," he says. "This technology makes
it possible to deliver multiple channels of digital TV over already
deployed ADSL systems, and that's what the ILECs need in order to compete
cost effectively."
While Thomson and Alcatel hope this
initiative will make significant inroads into the U.S. ILEC market,
officials acknowledge early success is more likely in overseas and
Canadian markets, where telcos are eager to launch video entertainment
services and, in some cases, already have done so.
"Our initial commitment with this
technology has been focused in Europe, where we're actively working with
customers who will be undergoing trials this year," says Jim White, vice
president of marketing for Alcatel's broadband network division in North
America. "But we expect to be having a lot of communications with the
ILECs in the U.S. There's a recognition of the cable threat now that MSOs
(multiple system operators) are making serious inroads into the telephone
business, so the timing is very good."
So far, rural ILECS are the U.S.
telcos showing the most interest in delivering video entertainment over
ADSL links. In some cases, the rural ILECs are using video over copper
rather than cable to expand their traditional TV operations into new
territories.
In other cases, the rural ILECs are
exploiting the fact they have newer networks with shorter loop lengths
than the big incumbents have. These telcos have been able to operate MPEG2
over ADSL at bit rates in the range of 6-8 mbps, but they, too, would like
to have access to technology that makes more efficient use of bandwidth
for MPEG2, notes Reed Majors, vice president for marketing and business
development at Minerva Networks Inc.
Minerva, a supplier of video
headends for the DSL and other new markets, is addressing this need by
offering a new encoder that allows these ILECs to squeeze two MPEG2
channels over their ADSL lines at bit rates of about 3.2mbps per channel,
even when ATM is used as the transport medium, Majors says.
"Many cable vendors supply encoders
that deliver MPEG2 at lower speeds, such as 2.5mbps, but these devices
cost three times as much as what we're offering to the DSL sector," he
adds. "And the two channels of video delivered over ADSL using our
technology are much higher quality than the digital TV you see at these
lower rates from satellite and cable operators."
The Nextream and Minerva solutions
are addressing different market needs with different price points, and
they aren't necessarily directly competitive with each other, Majors
notes.
What matters is solutions are
entering the marketplace that will allow telephone companies to compete in
the consumer broadband market with a full range of services without having
to invest far more money in plant or proprietary multimedia platforms, he
adds.
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