The magnificent five

Five chip companies have announced an initiative aimed at producing interoperable DMT-based semiconductors that meet international standards for broadband VDSL.

Alcatel Microelectronics, GlobespanVirata, Ikanos Communications, STMicroelectronics and Zarlink Semiconductor have announced an initiative aimed at producing interoperable DMT-based semiconductors that meet international standards for broadband VDSL.

The Discrete Multi-Tone Very-high-data rate Digital Subscriber Line (DMT-VDSL) initiative is committed to DMT as the line coding technology of choice for the delivery of more reliable, higher quality VDSL-based data, video and voice services to homes and businesses.

The five member companies are independently developing VDSL chipsets based on DMT modulation technology as adopted by European Telecommunications Standards Institute (ETSI) and the American National Standards Institute (ANSI). These member companies have agreed to achieve verifiable interoperability this year between their respective products, using the ITU-T’s (International Telecommunications Union) standard band plans, including Plan 998 and Plan 997, at speeds up to 52 Mb/s.

Achieving joint interoperability will boost the number of products that meet global specifications, and accelerate the market for VDSL solutions by increasing choice and lowering costs for equipment manufacturers.

VDSL itself is an emerging standard for symmetrical and asymmetrical transmission in support of full-service access network applications including data, video and voice channels, plus high-speed Internet – at up to 52 Mb/s using existing copper telephone lines.

In real-world conditions, noise and other line interference degrades signal integrity, impacting the speed and distance of VDSL transmission. DMT modulation overcomes this interference by configuring the transmitted signal in real-time to match the line conditions. The result is higher quality, error-reduced communications at higher data rates over longer distances. Tests show that VDSL modems and other products designed with DMT-based components will deliver significantly improved speed and distance performance.

Carriers have already standardised on DMT for their Asymmetric Digital Subscriber Line (ADSL) transmission. According to Dell’Oro Group, a market research firm that specialises in strategic competitive analysis in the networking industry, the number of DSL subscribers on a world-wide basis will reach 32 million by year-end 2002.