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| Alcatel Takes Vectoring to Luxembourg |
| Tuesday, 19 April 2011 15:59 |
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The green bands in the picture are the results in the first
 reported field trial of vectoring for noise cancellation. The results - on loops less than 1,000 meters - are excellent and as predicted by theory. Line speed as much as doubled in the instances noise was the problem. Other lines, which ran faster in the first place, saw gains as little as 20%. The first chart is from Alcatel, working with P&T Luxembourg. This is not production equipment and the chips may still be FPGA's. It's an important proof of concept, while manufacturers compete to be the first with well-tested, production ready gear (?2013.) Vectored noise cancellation is the grail of DSL, promising to add 50-100% to the performance on most loops under 1,000 meters. There's little doubt the results will be excellent in new builds, such as the VDSL/FTTN being installed from cabinets at British Telecom. All the lines can be connected to a single line card or otherwise organized to efficiently vector.
The harder problem is using vectoring to increase speeds in mixed deployments, which includes most of those already in existence. Ikanos is working on "node-scale" vectoring, which works across line cards and is promising. Further Alcatel data, this time working with Swisscom, showed excellent lab results (below) even in mixed binders more typical of existing builds. Results were good, even with 5 ADSL2 lines in the same binder.
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| Last Updated on Wednesday, 20 April 2011 04:16 |