Wednesday, September 21, 2011

Alcatel-Lucent Pushes Broadband Faster with VDSL2 Vectoring

Alcatel-Lucent is pushing broadband over copper further and faster with VDSL2 Vectoring technology. The company is first to market with a VDSL2 vectoring solution capable of delivering 100 Mbps over existing copper loop lengths of 400 meters.


Alcatel-Lucent is equally committed to FTTx and VDSL2, said Stefaan Vanhastel, Fixed Access Product Marketing manager at the company. While fiber access is seen as the end game for wireline access, the company sees copper as a big opportunity to meet national broadband goals quickly and at a lower cost than fiber, especially in markets with high labor costs. There are approximately 1.25 billion households worldwide currently connected by a copper telephone line.


VDSL2 vectoring uses digital signal processing to remove crosstalk between copper pairs in a bundle, similar to noise cancellation in headphones. From line cards at the central office or DSLAM, the system measures the crosstalk from all the lines in the bundle and then generates an anti-phase signal to cancel out the noise. For this solution, Alcatel-Lucent developed its own chipset and software. It began field trials in 2010 with a number of operators, including Belgacom, A1 Telekom Austria, Swisscom, Orange, P&T Luxemburg and Türk Telekom.


Alcatel-Lucent's VDSL2 Vectoring solution includes both Board-level Vectoring (ideal for small nodes) and System-Level Vectoring options for the company's existing ISAM DSLAM platforms, including the 7356 ISAM, the 7330 ISAM and the 7302 ISAM. The new products include a 48-port Board Level Vectoring card, a 48-port System Level Vectoring card, and a Vector Processing card supporting 192 ports initially and expanding to 384-ports of system level vectoring by next year.


Alcatel-Lucent is also working with carriers to improve broadband speeds over copper by pursuing VDSL2/FTTx architectures where the goal is to push fiber as deep as possible into the network and shorten the copper loops, as well as by applying VDSL2 bonding where two copper pair are aggregated into one connection. Work continues on Phantom Mode techniques. The company noted that it has supplied more than half of the VDSL2 lines in the field today, worldwide. http://

  • In April 2010, Alcatel-Lucent's Bell Labs unveiled a "DSL Phantom Mode" technique that achieves downstream transmission speeds of 300 Mbps over distances up to 400 meters and up to 100 Mbps at 1km. This new DSL performance boost is expected to reinvigorate copper access network, including in-building VDSL2 network, for 100+ Mbps services.


    The gains are achieved using a virtual or "phantom" channel that supplements the two physical wires that are the standard configuration for copper transmission lines. This analogue phantom mode technique is further enhanced using vectoring to eliminate interference or "crosstalk" between copper wires, and the bonding of two copper pairs into an aggregated pipe. The company has demonstrated these techniques in lab tests.


    The "phantom mode" technique of creating virtual channels has actually been understood for decades. Alcatel-Lucent said this breakthrough was enable by combining phantom mode with the power of fast processor to eliminate crosstalk between copper pairs in a binder. Practical implementation will require CPE capable of bonding the 3 channels over two copper pairs. Vectorized VDSL2 silicon will also be required.

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