The demand for high bandwidth, low latency data and voice connections that enable rich multi-media content consumption are stretching service providers’ legacy outside plant capabilities. The growing need for speeds of 100 Mb/s or more at distances of up to 400 m to optimize voice performance and provide multiple media services means either replacing existing plant with fiber, especially in the last mile, or finding a cost-effective and high-performance means for extending the life and functionality of existing copper infrastructure until it can be replaced.
Alcatel-Lucent (News - Alert) is solving this problem with vectoring technology that delivers sophisticated noise cancellation that enables VDSL2 (very-high-speed Digital Subscriber Line 2) lines to perform at their best and extend the useful life of existing copper infrastructure.
A recent Alcatel-Lucent article, Boosting VDSL2 Bit Rates with Vectoring, highlights how this cost-effective technology enables these higher speeds from a remote DSLAM. It thus satisfies subscriber demands for higher bandwidth and allows service providers to extend the life of their copper plant while meeting government mandated goals for enabling universal broadband access through fast build-outs.
The proof is in the performance
VDSL2 vectoring ensures field conditions are as close to ideal as possible, allowing each VDSL2 line to operate at its full potential, while also delivering higher bit rates. Downstream speeds of 100 MB/s at distances of up to 400 m, and 40 Mb/s are supported through loops as long as 1000 m. As the article points out, vectoring improved downstream bit rates for Orange (News - Alert), Swisscom, P&T Luxemburg and others in field trials. What is vectoring?
Vectoring is a noise-cancellation solution that addresses the gap between the maximum rate a network should be able to handle and the speeds service providers actually deliver when all field conditions are optimal. When lines carry VDSL2 signals, they are part of cables that tend to contain 10 to even a few hundred lines, which can generate crosstalk. This crosstalk lowers the theoretical maximum speed, while vectoring enables each line to perform independently, eliminating crosstalk.
However, as Alcatel-Lucent points out, all this is about to change. As Alcatel-Lucent recently announced, through a Bell Labs (News - Alert) innovation, it has achieved an industry milestone of 300 Mb/s over two 400 m lines through a combination of VDSL2 vectoring, bonding and phantom mode.
Easing the transition to fiber
Making the migration to VDSL2 vectoring can be a challenge, especially in fixed access environments. This is because most of the intelligence and processing necessary for vectoring remains in the Digital Subscriber Line Access Multiplexer (DSLAM), although minimal support is needed at the Customer Premises Equipment (CPE) to effectively estimate the key metric of crosstalk. The reason this is critical is that all VDSL2 lines must be included in the crosstalk estimation to drive full vectoring gain to ensure noise-cancellation and optimal bit rates. The good news is that most existing VDSL2 CPE can be easily software upgraded to support vectoring, or achieve a status of “vectoring-friendly” at the very least which is why vectoring is so effective as a transitional stage for providing high speeds prior to making end-of-life decisions about copper plant retirement.
Reality is that over time, service providers will continue the gradual transition to fiber. The trick in a highly competitive world is to do so in an orderly fashion that sustains profitability without sacrificing the need to literally as Alcatel-Lucent like to say enable customers to “take broadband everywhere” by extending high-speed network accessibility.
Next-generation x Digital Subscriber Line (xDSL) technologies, including bonding and vectoring give service providers the tools they need to meet market and regulatory demands for speed and performance, along with the flexibility to ensure a graceful migration to the future that does not destroy their economic vitality. As the article points out, “With more than 1.2 billion of the world’s households currently connected to a copper line, these technologies can also help governments meet their goals for universal broadband, which is critical for e-health, e-learning and socio-economic development.”
In fact the cost-effective economic extension of copper life increases its ROI enabling returns than can be invested in network modernization and rapid development and deployment of new services. This is a win/win/win — for service providers and their customers, and governments alike.
Susan J. Campbell is a contributing editor for TMCnet and has also written for eastbiz.com. To read more of Susan’s articles, please visit her columnist page.
Edited by Peter Bernstein