Adtran Offers G.Fast Crosstalk Cure
Adtran today is unveiling a patent-pending approach to enabling the newest form of advanced copper technology -- G.fast -- to more easily co-exist with the VDSL2 technology already being deployed, and thus be brought to market faster and at lower cost by telcos eager to get to near-gigabit speeds over their existing infrastructure. (See Adtran Speeds Up Copper Links With Frequency Division Vectoring.)
Frequency Division Vectoring essentially allows G.fast, which delivers higher speeds over shorter loop lengths, to be added as an over-the-top channel on VDSL, eliminating the crosstalk issues that make the two incompatible over a single copper pair. By enabling that compatibility, Adtran Inc. (Nasdaq: ADTN)'s FDV can allow a telco to get started deploying G.fast where it has loop lengths of 250 meters or less, to deliver close to 1 Gbit/s, without ripping out existing VDSL2 deployments or having to invest heavily in deploying G.fast over an entire service area.
"Vectored VDSL can provide 100 Mbit/s downstream and 40 Mbit/s upstream, so it provides as much capacity for sustained loads as GPON [gigabit passive optical networks]," says Adtran CTO Kevin Schneider. "Now a carrier can also use G.fast with dynamic crosstalk avoidance at speeds up to 500 Mbit/s over short lines."
G.fast, which is still an evolving standard at the ITU, increases speed over copper lines by using wider frequency profiles than those used by VDSL2, operating on 106MHz and at some point promising to operate at 212MHz. VDSL2 uses 17MHz or 30MHz bands.
Adtran's FDV technology will be presented to the ITU for inclusion in the standards process later this month, Schneider says. Adtran realizes that for the technology to take hold, it has to be offered by more than one vendor, he adds. But Adtran also hopes to leverage its invention in competing with its prime rivals in access, Alcatel-Lucent (NYSE: ALU) and Huawei Technologies Co. Ltd.
Telcos have to be able to compete with cable companies in the speed wars and have been disadvantaged by the DOCSIS 3.0 technology that let cable deliver speeds up to 100 Mbit/s, the Adtran CTO notes. What the industry is looking for is the ability to bump up speeds as close to one gig as possible, but do so cost-effectively.
What Adtran is proposing allows telcos to take advantage of their existing distribution plant, including aggregation points and deployments of fiber-to-the-building for office towers and multi-dwelling units, he notes. By eliminating the crosstalk issue, Adtran is making the full range of bandwidth available for use by G.fast deployment without disrupting the services already deployed.
— Carol Wilson, Editor-at-Large, Light Reading