Monday, May 17, 2010
With the advent of its DSL Phantom Mode technology, Alcatel-Lucent is proving once again that there's still some credence to the late 90s mantra that there's 'gold in that copper line.'
Alcatel-Lucent's Bell Labs conducted a trial of its DSL Phantom Mode technology that enables 300 Mbps DSL speeds over a short span (400 meters) on two copper wire pairs. When carried over a 1 km line it was able to demonstrate 100 Mbps speeds.
To obtain these speeds, Alcatel-Lucent combined this phantom circuit--a technique pioneered in the late 1800s to create virtual analog phone lines--with VDSL2, VDSL2 bonding and VDSL2 vectoring. Vectoring eliminates interference or "crosstalk" that arises between adjacent copper wire pairs, while pair bonding allows service providers to combine multiple pairs to obtain higher speeds.
When a service provider deploys VDSL2 on short copper loops to a home or business, they can typically get about 80 to 100 Mbps. However, when a second line is added the performance and speed is degraded.
The reason the performance in VDSL2 becomes degraded when you add a second line, argues Stefaan Vanhastel, Director Product Marketing, Alcatel-Lucent Wireline Networks is that "is when you add a second line you get cross talk between the two lines."
Vanhastel added that "by using vectoring, which is a noise cancelling technology, you can eliminate noise" and improve the performance of the copper lines.
Although the 300 Mbps VDSL2 demonstration was done in a controlled lab environment, with plans to conduct field trials with customers in 2011, the technology could resonate with Alcatel-Lucent's sizeable VDSL2 customer base that is keen on extending as much as they can out of their current copper investments. Currently, Alcatel-Lucent has 60 VDSL2 projects in tow--30 of which are deployments with large carriers including the likes of AT&T and Belgacom.