[mother of all dsls]
hi shlomi,
maybe we'll be getting news soon after all... nice pop today... all the action seemed to start around 2:00 this afternoon... seems like maybe someone heard something (or called in from brazil)
and thanks for the info on clal... it took an extra day, but an article is up now on globe's confirming clal's 17.7% stake in orctf.. am guessing that maybe those of you in israel get a different version of (online) globes from those of us here in the usa?
will be interesting to see how this one plays out with clal/ecilf/orctf and so forth...
altho much of the focus recently (and rightly so) has been on adsl.. expect in the not too distant future, we'll be hearing more regarding both hdsl2 and vdsl as those orctf chipsets must be getting close..
and indeed from the following article, as siemens is using orctf vdsl, and siemens "is sampling the first VDSL chips"... seems fair to conclude the chips they are sampling are harris/orctf... interesting article too..
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November 02, 1998, Issue: 1033
Section: Semiconductors
VDSL offers new potential
Loring Wirbel
Among a raft of papers on symmetric and asymmetric digital subscriber lines at the recent DSLcon in Framingham, Mass., at least five focused on the mother of all DSLs: the very high-bit-rate, or VDSL, service. VDSL has been moribund for two years, since its 51-Mbit/second downstream speed requires short copper loops and the type of infrastructure with fiber in the neighborhood usually seen only in switched digital-video schemes.
Switched digital video never got very far as a market, but VDSL is finding new potential on the wings of alternative carriers who are laying fiber out to residential neighborhood nodes and want a simpler place to access local copper other than through a phone company central office.
Jim Szeliga, general manager of Orckit Communications Inc., made a strong case for Internet2 as a driver for home broadband access within five years. VDSL previously was seen as driven by one-way video delivery from a central server farm, Szeliga said, but the real driver will be the demand by residential customers for streaming multimedia traffic from Internet2 gigaPOPs. Depending on what speed of downstream VDSL is desired and the types of passive optical networks used, VDSL can be provisioned for significantly less than $400 per user. While still high, it's still less than true fiber-to-the-home architectures, which are unlikely to be cost-effective for residential use for several decades, Szeliga said.
Siemens Semiconductor Inc. already is sampling the first VDSL chips in an anticipated onslaught for higher speeds, which telecom marketing manager Uwe Hering said will be driven by ADSL customers desiring much higher (and in some cases, symmetrical) speeds, but with virtual parity in chip-set costs. Depending on installation details, POTS splitters can be much less complex with VDSL, and power dissipation can be 40 percent less than ADSL.
But those figures are based on quadrature-amplitude-modulation line codes. Jacky Chow, director of VDSL development at Texas Instruments Inc., provided details at DSLcon of yet another line-code war emerging in the DSL camps. Broadcom Corp. has lined up several companies behind QAM, including Analog Devices, Aware, Rockwell and Orckit. But Alcatel, TI, Nortel, Cadence Design Systems and an assortment of other companies have chosen to back a discrete-multitone derivative, SDMT/Zipper. The ANSI T1E1.4 committee will start work on a standard for VDSL this month, which will initially include both line codes. Soon, however, the camps represented by VDSL Coalition and VDSL Alliance will need to come to terms on line codes, if the vision of a near-term VDSL market is to become a reality.
techweb.com
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in the above article seems a few names were left off the qam side of the qam/dmt vdsl linecode faceoff.. probably most importantly lucent.. from lu's website:
"Microelectronics Group News Announcement
Industry leaders form VDSL coalition
FOR RELEASE: MONDAY, MARCH 10, 1997
A group of leading semiconductor, modem and communications-network equipment firms today committed to join a newly established coalition supporting Very-high-speed Digital Subscriber Line (VDSL) standards for the next generation of broadband telecommunication applications. VDSL-based broadband equipment architectures will satisfy the demand for high-bandwidth transport services, which can simultaneously deliver faster Internet access, interactive video and higher-speed data communications services.
The main goal of the VDSL Coalition, as the group will be known, is to collectively investigate, define and resolve technical issues related to the development of cost-effective and practical integrated VDSL solutions. Members of the VDSL Coalition include Analog Devices, BroadBand Technologies, Broadcom, Globespan Technologies, Harris Semiconductor, Lucent Technologies, Metalink, Orckit Communications, Rockwell International/Brooktree Division and Schmid Telecom.
The group is developing VDSL system specification proposals to be presented to the American National Standards Institute's (ANSI's) T1E1.4 working group. The T1E1.4 working group has the responsibility of developing the physical layer modulation schemes and transceiver protocols for VDSL standards.
The ANSI T1E1.4 standards body is an industry-wide working group that meets quarterly to discuss proposals, results of transceiver performance models and other issues leading to the development of a standard. The VDSL Coalition presented its initial systems specifications proposal at the February 4th T1E1.4 standards body meeting. The coalition's proposal to the ANSI working group incorporates several asymmetric and symmetric line-bit-rate profiles (52, 26, 13 Mb/s) for VDSL systems.
All members of the coalition have investigated the technical aspects of different modulation technologies and have endorsed the use of single-carrier line-coding technologies, which include Carrierless Amplitude and Phase (CAP), and Quadrature Amplitude Modulation (QAM) for the downstream transmission of the VDSL link.
Coalition members have experience in both the single-carrier and multicarrier techniques. For example, four coalition members have designed Discrete Multi-Tone (DMT)-based modems for Asymmetrical Digital Subscriber Line (ADSL) applications and are aware of the merits of the single-carrier and multicarrier technologies. These coalition members have decided that the single-carrier solutions offer significant advantages for VDSL systems which involve shorter transmission distances and higher operating speeds than ADSL systems.
"Low-power, low-cost VDSL transceivers that allow for a high density of service ports per circuit board are key market enablers for rapid deployment of broadband services such as Switched Digital Video (SDV) and ultra-high-speed Internet access services in the local loop," said Tom O'Shea, technical engineer, BroadBand Technologies. "As an equipment supplier for broadband local access products, BroadBand Technologies believes that single-carrier VDSL technologies -- currently available -- provide a robust solution for the reuse of existing loop plant cable while meeting these deployment requirements most effectively."
The advantages of CAP/QAM-based solutions for the downstream portion of a VDSL system include low-complexity silicon implementation, lower silicon cost, reduced system power requirements, ability to integrate multiple channels into a single piece of silicon, and reduced overall complexity/cost for systems. The group is still evaluating technologies for the upstream direction of the VDSL transmission link for point-to-point and point-to-multipoint applications.
"The successful deployment of current and future Digital Subscriber Line (DSL) services relies on frequency spectrum compatibility with existing services operating in the same cable bundle," said Christof Heidelberger, vice president of engineering at Schmid Telecom. "As a supplier of High-bit-rate Digital Subscriber Line (HDSL) equipment, we prefer the frequency division multiplexing (FDM) techniques used in single-carrier systems because they allow for the allocation of downstream and upstream signal bands so that the coexistence of symmetrical and asymmetrical VDSL service profiles in a cable bundle is possible. FDM systems do not require synchronization of the downstream and upstream bands," he continued. "This reduces the complexity at the system level, thus simplifying the provisioning of single-carrier VDSL systems in the field."
The coalition's proposed system specification requests the feedback of service providers, system, and other vendors in the development of an appropriate standard for the VDSL application. Single-carrier technology similar to that which is being proposed for this VDSL standard has already been adopted as part of the Digital Audio/Visual Council's (DAVIC) specification for Fiber-to-the-curb (FTTC) systems. An acceptance of a VDSL standard based on the coalition's proposal means that system vendors will be poised to rapidly deploy VDSL systems since many coalition participants have silicon-based products and capabilities today that can be readily adapted to the VDSL application.
lucent.com
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and there is a very informative article on why qam is the way to go for vdsl on the orctf website:
"QAM: the Choice for VDSL Transmission Line Code
by ehud rokach vdsl product manager orckit
...The VDSL modem at the ONU (Optical Network Unit) must comply with a limited power budget due to special power dissipation problems inherent to ONU equipment. These power requirements come about due to the limited space, harsh environmental conditions, and difficulty (or unfeasibility) of implementing forced air cooling in the curbside cabinet where the ONU is typically located. Target values for ONU power dissipation are in the 1 Watt per line range. Comparing this requirement with the power consumption of today's ADSL modems makes it clear that one can not "scale&" an ADSL solution to VDSL data rates while keeping the power consumption at any reasonable level.
As a consumer oriented technology and product, cost is also a crucial issue. VDSL is expected to be used for video distribution and multimedia applications that target, to large extent, residential consumer markets. This translates to very challenging cost targets for VDSL modem chips. In VLSI implementation, cost is tightly related to complexity and die area. A VDSL modem, with line code being one of the major factors, must therefore be designed with strong emphasis on reducing the complexity.
The main options for a VDSL line code can be divided into single-carrier and multi-carrier modulation schemes. QAM is the most widely used representative of single carrier systems, while DMT is the natural representative of multi-carrier modulation as the standard line code for ADSL. Both QAM- and DMT-based systems can be designed for the VDSL application and can provide similar levels of basic reach / noise margin performance. However, there are significant differences between the two approaches when it comes to complexity. Following an extensive study done at Orckit analyzing the implementation of single and multi-carrier modems for VDSL, we concluded that a QAM VDSL modem presents significant complexity and power consumption advantages when compared with a DMT VDSL modem. The power dissipation advantage, mainly at the ONU side, is the result of lower computational complexity of the QAM modulator and demodulator functions. A QAM-based ONU VDSL modem is likely to consume 25% the power of a DMT-based solution having similar performance...."
orckit.com
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til later
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