Sorry about that.
WORLD'S LEADING WIRELESS TELECOM
TECHNOLOGY DEVELOPED
( Xinhua News Agency )
World's Leading Wireless Telecom Technology Developed
BEIJING (Dec. 29) XINHUA - A new wireless telecommunications
technology two or three years ahead of international standard passed
state appraisal here today.
According to an official from China's Ministry of Posts and
Telecommunications, the SCDMA (synchronous code division multiplex
access) wireless local loop system is the first leading wireless access
technology developed by Chinese scientists and engineers. China owns
the sole intellectual property rights for the technology.
New technologies adopted by the system such as SCDMA, smart antenna and
software radio have received patents at home and abroad.
The system proved to have excellent and stable transmission quality
during operation in the seven trial networks in large Chinese cities.
Experts believe the SCDMA system is best for rural areas, small- and
medium-size cities, and suburbs that have difficulty in plugging in
telecommunications lines.
Overseas forecasts say that 100,000 subscribers will be connected to
wireless local loop systems by the end of the century, and more than 60
percent of them will be in developing countries.
China is projected to account for 20 percent of the world's wireless
local loop subscription.
The new system will be put into mass production next June.
WORLD'S LEADING WIRELESS TELECOM TECHNOLOGY DEVELOPED., Xinhua
News Agency, 12-29-1997.
CHINA TO ADOPT SCDMA TELECOM
TECHNOLOGY
( Xinhua News Agency )
China to Adopt SCDMA Telecom Technology
BEIJING (Dec. 30) XINHUA - China has made progress in the
telecommunications research of adopting new technology to connect
switchboards with telephone users without wire.
According to the experts of China's Ministry of Posts and
Telecommunications, the new technology called as SCDMA (synchronous
code division multiplex access) system will save some 100 billion yuan
annually in laying cables for telephone networks.
They said that the technology is two or three years ahead of the
current telecom development in the world's telecommunications sector.
The SCDMA system is one of the key scientific research program included
in China's Ninth Five-Year Plan (1996-2000) and it is convenient to
operate in rural areas and urban suburbs, as well as in small- and
medium-sized cities.
Since August this year, the system has been tried out in seven cities
including Chongqing and Chengdu in Southwest China.
Experts said that the system has recently passed the assessment and
will be put into production soon.
Copyright 1997 Xinhua News Agency (via Comtex). All rights reserved
CHINA TO ADOPT SCDMA TELECOM TECHNOLOGY., Xinhua News Agency,
12-30-1997.
Caged speed: the coming of S-CDMA.
(Synchronous Code Division Multiple
Access)(Cover Story)
( America's Network )
Ultrafast cable modems can pump data upstream over existing (and noisy) coax plant,
giving cable providers a tremendous boost in the interactive data wars. But will
providers put the 'old reliables' aside and rally around the technology upstarts?
The shoemakers don't make cable modems the way they used to. Moreover, the
cable television industry is no longer content with the telcos' characterization of
CATV's Internet access and Quality of Service (QoS) capabilities.
With at least two Silicon Valley start-ups (Terayon Corp. and Com21) coming out
with lightning-fast, cell-based cable modems, the interactive data race appears ready
for pitched battle. Along with Microsoft Corp.' s $1 billion investment in Comcast
Corp., plus the news that @Home Network will go public as CATV's most
aggressive cable-based Internet service provider (ISP), it's hard not to sense the
rumbling of a new broadband war. But will the cable industry compete effectively
against the telcos for high capacity, data-oriented Internet customers? Do they have
the right tools and the right networks? Can they bet on effective but
Johnny-come-lately technology when the already established cable vendors have put
lots of less than state-of-the-art cable modems out there? Stay tuned.
The broadband services race is changing, thanks to little startups inventing cheap,
noise-resistant solutions for existing cable plant. As telcos tussle over the best means
of broadband access - ADSL, ISDN, ATM to the desktop and others - cable
companies already may have their pick of better technology that requires little or no
network upgrade and makes sturdier economic sense to them and their customers
(see sidebar, page 20).
"In my view, [the cable modem choice] is a no-brainer," says Tim Savageaux, telecom
analyst and director of Robertson Stephens & Co., a San Francisco investment firm.
"With @Home Network going public - and that will give you the market sentiment of
how successful cable modems will be - we're talking about an order of magnitude
difference between downloading data at 28 kbps for ordinary analog telco modems
vs. multimegabits for cable modems." Because Internet users are already paying $20 a
month for less-than-sterling telco-based Internet service, plus paying the cost of a
second phone line and the modem itself, "cable is a much greater value proposition,"
Savageaux contends.
PERFORMANCE COUNTS
Although costing models are generally more complex, the cable industry is seeing a
revolution in low-cost data transport. One upstart is Terayon, an Israeli-founded,
California company with Japanese backing (from Sumitomo Corp.) that has trialed its
high-speed cable modems at Urawa Cable Television in Japan (operated by Jupiter
Telecom), and MSO sites in the United States and Asia. The trials use Terayon' s
patented physical layer technology for the upstream path - Synchronous Code
Division Multiple Access (SCDMA).
S-CDMA is a proprietary flavor of CDMA that's used over a 6 MHz band to pump
as much as 54 Mbps of data upstream over "dirty" coax plant. Invented by Shlomo
Rakib, president and chief technology officer of Terayon, and a former electronics
researcher in the Israeli military, S-CDMA employs "direct sequence spread
spectrum" technology to boost upstream transmission.
Some similarities with narrowband CDMA include the modulation technique for
S-CDMA, which relies on unique, nonoverlapping codes to perform the spreading.
function on each user's signal. Rakib further refined the idea to maintain a high degree
of "orthogonality," he says, a term meaning no mutual interference, even when cable
quality is extremely noisy.
"We synchronize all the signalS arriving at the headend and guarantee the
orthogonality of the code," Rakib says. "The synchronous part of the access allows all
users to together so that signals don't interfere with each other and can
reach the head end more orthogonal to each other. This increases capacity without the
noise levels going up."
Put a simpler way, in typical asynchronous CDMA systems, portions of the codes
from different sources can over-hp, raising the noise level within the receiver and
hence degrading capacity. By contrast, SCDMA synchronizes all of the cable modem
units to the head-end. This permits each unit to spread its signal more effectively
(orthogonally) with respect to other cable modems sharing the line. The result is more
efficient channel utilization.
THE PROOF IS IN THE NOISE
The proof of Terayon's effectiveness is its apparently robust performance in noisy
conditions. Unlike other traditional cable modems, which generally spec out at a 25
dB signal-to-noise ratio, Terayon's TeraPro S-CDMA modems have no signal to
noise spec and can, therefore, operate in the high-noise portion of the upstream path,
below 20 megahertz (the range of operation is between 5 MHz and 42 MHz).
"S-CDMA is less vulnerable to narrowband interference and, with error correction
technology, the system can confront the noise," says Zaki Rakib, Shlomo's brother,
collaborator and CEO of Terayon, who holds two Ph.D's in applied math and
engineering. "The system operates at 14 Mbps (per channel) in each direction, which
means around 60 megabits are available (including overhead) on five channels." He
cites advantages over wireless narrowband (IS-95) CDMA: "In wireless systems you
can' t synchronize or secure targets, because they aren't fixed. In addition, power
balancing isn't an issue for us at all, because we're talking about fixed targets."
Terayon is evangelizing its early field thai results. According to the company, tests of
untreated coax have shown that SCDMA modems can provide 98% or higher
error-free performance in a 30,000-home system, even when subjected to extreme
plant noise. The company claims (and early field trials seem to bear this out) that
network operators can use Tera-Pro for high-capacity broadband services over pure
two- way coax without upgrading to fiber. This in itself is exceptional, because 80%
of existing cable plant is still coax and much of it is deemed "unusable" for two-way
broadband data because of noisiness.
"What we offer is a way to get into the [Internet and interactive two-way data
business] at reasonable cost," says John Hamburger, a Terayon spokesman. "The
operators are already at a point where they' re upgrading as much as they can, but we
allow operators to use our equipment [whether they've got pure coax or not] for
high-capacity data as they upgrade to HFC. The bottom line is you don't need to put
in fiber or high-pass filters. You don't need to put in gold-plated plant."
Nikos Theodosopoulous, vice president of UBS Securities, agrees in principle. "The
trials [Terayon has] had indicate good performance and the initial customer feedback
is positive," he says. "A lot of cable companies may not have the money or time to
upgrade their networks [for two-way interactive broadband]. Terayon allows them to
offer services over that portion of infrastructure they haven't upgraded and still provide
robust performance."
AN INDUSTRY TIDAL WAVE
Terayon isn't alone. There's a tremendous interest in all kinds of innovative cable plant
solutions, although consensus on the types of solutions remains in doubt, suggests
Steve Craddock, vice president of new media development, Comcast (Philadelphia),
one of the nation' s largest cable operators.
Craddock is also a member of MCNS, the Multimedia Cable Network System, a
consortium of five leading network operators (including Comcast, Cox, Time Warner,
TCI and Continental). Two years ago, MCNS created specs for a two-way cable
modem system that is now considered much less than state of the art; it uses a QPSK
(Quadrature Phase Shift Keying, essentially a TDMA technology) -compliant
technology (but not S-CDMA) for the upstream path. Craddock, among others,
acknowledges that MCNS specs could present problems for Terayon and other
non-compliant vendors.
"We're not looking for proprietary modems," Craddock says. "We're looking for
MCNS compliance; however, the process makes allowance for specifying advanced
physical layers, like SCDMA." He says there' s hope: MCNS is expected to request
updates for a second-generation advanced cable modem that may incorporate new
technology like Terayon' s and others.
"Basically, we segment the [two-way cable modem] market into consumer and
commercial," Craddock explains. "In the consumer market, we need modem
interoperability quickly to drive cable modems to the point of sale and retail. In this
case, you don't have to be sophisticated or complex, but just offer basic TCP/IP
operation for assymetric data operations (e.g., consumers browsing the Internet,
where data requests on the upstream path are much lower than the downstream path,
where major downloads of data occur). That's about the way 90% of people would
use cable-based data services, and that complies to the MCNS standard for variable
length packets for the upstream path."
Coaxial
A
C
E
Total
[TABULAR DATA OMITTED]
DUBBED ITALIAN MOVIES
For commercial data and voice applications, however, the situation is more complex.
Companies like Terayon and Com21 (Milpitas, Calif.) are offering very high capacity
cell-relay-based cable modems.
Cells should not be confused with S-CDMA; they are different technologies. Cells
(fixed-length packets) offer inherent advantages in terms of network management,
QoS guarantees, robustness and higher capacity. "in commercial installations, you're
less interested in driving [modems] through the point of sale," Craddock continues.
"Sponsoring companies that operate cable networks would have more tolerance for
buying a modem [that wouldn't be the same as everyone else's]," he believes.
Moreover, "a commercial requirement would be more bandwidth upstream - you
want symmetric flexibility. Also, you may need cell-based constant bit rate services
(such as voice over IP telephony) rather than variable rate. Remember, voice over an
ordinary [variable length frame] TCP/IP connection goes anywhere from a badly
dubbed Italian movie to something really horrible. You don't want to get delays." By
contrast, "ATM or cell relay modem solutions might be the real answer for
commercial services," he notes.
Craddock pronounces Terayon and Com21's cell relay technology "very interesting"
as an MSO prospect for two-way interactive cable services, especially for such
applications as high-volume file transfers, corporate work-at-home applications, video
conferencing and the like. He won' t, however, disclose an exact time frame for
making any purchase decisions. Comcast, among other top MSOs, including Rogers
Cable Systems (Toronto), are still evaluating new modem technologies and are
reluctant to disclose their involvement in field trials or their exact plans for deployment
over the next year.
Craddock, however, says this much: "Terayon uses S-CDMA for the physical layer
and a cell relay-type protocol. The other technology developed by Com21 produces
a cell relay-type modem which is MCNS compliant in the physical layer - QUAM
(Quadrature Amplitude Modulation) down, QPSK up. Terayon isn't compliant 'up';
they're using S-CDMA." However, because MCNS is already talking about a way to
define an advanced physical layer for two-way services, "Terayon has become very
interesting for us. Its cell relay-based architecture is good for commercial applications,
in our view; S-CDMA allows you to use a less-than-perfect upstream to transmit
data, and it's much more forgiving than any QPSK modem."
COM21'S ROCKET SCIENCE
The contrast between Terayon's and other advanced technologies is startling, because
several different ones may lead to the same high- capacity path. Com21, for example,
started in 1994 (3Com owns an equity stake in the company), produces a high-end
cable modem system that president Richard Fenner (a former president of AT&T
Network Systems) describes as "cell-based technology that allows us to do constant
bit rate voice, data and video."
From that standpoint, Com21 is bluechip in offering voice, and differs from Terayon's
modem, which is for high-capacity data only. Fenner claims the Com21 system offers
full network and element management, a controller headend and aggregated capacity
upstream and downstream of 30 Mbps each way.
"We operate between 5 MHz and 42 MHz in slices of 1.82 megahertz, and we're
using QPSK," Fenner says. "We have more capacity upstream or downstream than
Terayon," a claim Terayon would dispute, given its aggregate claims of 54 Mbps and
higher over five channels upstream.
Fenner, however, insists his company's modems are as resilient against noise as any
on the market; Com21 has been tested. "We have a frequency agile system," he
explains. "If a modem turns out to be in a noisy environment. the gets
moved into a different frequency [between the 5 MHz and 42 MHz band]. Unlike
modems like [Bay Networks' ] LANCity, we do forward error correction, so we can
operate in a noisy environment without difficulty."
The most important aspect of the cable modem, however, is its ability to make money
for customers by helping them deliver differentiated classes of service, Fenner adds.
With shipments beginning this past April, and with expected revenues of $10 million
by fourth quarter - 60% of it overseas (its biggest customer is Flanders, Belgium, a
consortium that serves 2.1 million cable customers) - Fenner says that Com21 enables
MSOs "to divide up their bandwidth. In our case, they can have 16 different levels of
service and charge a different rate for each of those levels; they'll be able to offer
service to the low-priced customer for around $25 (for constant on-line service)
Dial-up ISPs are our competition in the low end - right up to commercial high-end
customers."
For Terayon, the future also looks bright, but large-scale deployments are up for
grabs. The company needs to make a business case for interactive data over existing
(and cheaper) cable plant to large and small operators alike. It needs to prove itself in
the field of big players - Motorola, for example, which already has significant market
share; LANCity, with over 50,000 modems shipped; General Instrument, which
offers internal telephone return-path modems and will offer standard two- way by
early 1998; and Scientific-Atlanta, which also offers low-end telco return, to name a
few.
Shipping commercially this month, Terayon claims it already has firm orders for
100,000 modems worldwide. But it has yet to find a foothold in the big-stakes world
of U.S. MSOs - the politics and players of MCNS, in other words. "We are in active
discussions with MCNS," says Denies Picker, Terayon's vice president of
engineering, and a former cable products group director at Motorola. "There is mutual
interest in finding a way for our technology to be adopted as a future advancement
within MCNS. But it's hard to predict when and how that will happen."
Shlomo Rakib acknowledges that entry as a latecomer into the MCNS operator
world is "a political process, and long process." While some experts wonder whether
Terayon can make it ("This is a case in which the best may not finish first," says a
Scientific-Atlanta observer), Rakib believes there is room for the best.
"Clearly, the MCNS specs are for well-maintained HFC plants," he says. "They're
addressing a small segment of the overall market. "We've done a lot of work in terms
of demonstrating the advantages of our modem, doing a lot of field trials, presenting
them with the results of field trials, satisfying the question they raised; there are good
chances that we will set a standard for an advanced PHI together with an MCNS
message."
That's the hope, anyway. Notes Robertson Stephens analyst Tim Savageaux: "The
cable modem world is much more up for grabs than the wireless world; operators
want something that works, they don't have some religious bent for time division
multiplexing or FDMA. Over time, if technology is compelling enough and allows the
operator to do what they need, it stands a good chance of adoption."
COPYRIGHT 1997 Advanstar Communications Inc.
Caged speed: the coming of S-CDMA. (Synchronous Code Division Multiple
Access)(Cover Story)., Vol. 101, America's Network, 07-15-1997, pp 16(6).
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