STOCKHOLM, Sweden ( ChipWire) -- STMicroelectronics and Telia Research AB this week announced the demonstration of very-high-bit-rate digital subscriber line (VDSL) technology over conventional copper wire using a prototype baseband chip built by STMicro. The two companies said systems providing an upgrade from asymmetric DSL could be deployed as early as 2001.
The partners started on the Zipper-VDSL technology in June 1998 and now claim to hold the top spot in the application of frequency-division discrete multitone (DMT) technology to next-generation broadband connections over copper.
Last week Texas Instruments Inc. unveiled a VDSL transceiver chip and, with Alcatel, announced their intention to pursue the DMT approach to VDSL and perform interoperability tests.
In another European VDSL partnership, Infineon Technologies AG in Munich plans at this week's DSLcon Europe in Amsterdam to show off its second-generation two-chip VDSL set and to reveal the key role played in both VSDL generations by Israeli startup Savan Communications Ltd. Savan, founded by executives from Orckit Communications Ltd. and Libit Signal Processing Ltd., has focused on system-on-chip designs for VDSL based on quadrature amplitude modulation and frequency-division duplexing.
The VDSL chips designed by Infineon and Savan will reduce all chip support to two devices, bringing a full residential modem down to matchbox size. The transceiver now integrates a host controller core, while the analog front end incorporates a line driver.
For its part, telecom service operator Telia has a heightened interest in broadband services because Sweden plans to provide such access to everyone.
VDSL technology has an aggregate capacity of up to 60 Mbits/second over short distances and represents a thousandfold increase in capacity over the 56-kbit/s modems in use today and a tenfold increase in capacity over ADSL, which is starting to be deployed by telephone companies.
The Zipper technology provides fine-grained programmability for up to 2,048 carrier channels. This provides a number of benefits, said Gerard Fargere, director of STMicro's Advanced System Technology Laboratory in Grenoble, France.
"The up and down frequency bands allocation can be done according to operators' or customers' needs as well as standardization and future market needs," Fargere said. "Operators can choose between offering fixed or selectable bandwidths and between symmetrical and asymmetrical services."
The use of frequency-division DMT is also important because it provides backward compatibility to ADSL technology and pure voice services on the same copper wire. In theory, voice service could coexist with ADSL and VDSL on the same wire, Fargere said.
"This is of great importance to operators who face demands to unbundle services and allow other operators to offer services over the same wire," said Claes Nycander, president of Telia.
The STM-Telia prototype is based on a 0.25-micron CMOS digital IC, designed in cooperation with France Tlcom's Centre National d'Etudes des Tlcommunications (CNET) laboratory in Grenoble.
The 8 x 8-mm die includes two 2,048-point FFT engines and a dedicated DSP data path to implement digital filters and programmable channel assignments. It also includes some 16-Mbit/s static RAM although that is more than will be required in a final implementation.
Fargere said the mapper and demapper were built in a separate FPGA. The analog front end is a discrete solution, and the whole system is controlled by a separate microcontroller.
"In the next implementation we will only need about 4 Mbits of memory on chip," he said. "We have filled the die with memory to give ourselves flexibility to adjust algorithms."
Fargere said STMicro would determine next year whether the DSP data path would be replaced with a programmable DSP core. He said that stripping out excess memory would certainly make room to bring a microcontroller core on chip.
"We hope to get a complete commercial solution ready for the end of 2000 with chips and software, so that operator trials could be done in 2001," said Andrea Cuomo, vice president of advanced system technology at STMicroelectronics. "We expect a lot of operators will want to test VDSL and will give us feedback."
--Additional reporting by Loring Wirbel in the U.S.