Alcatel-Lucent is trying, but it still doesn’t quite have the next generation of DSL up its sleeve. But it is gambling that it may manage it by perhaps next year. Last Summer it talked about Alcatel DSL delivering 50Mbps to all users – with peaks up to 100Mbps – anywhere in the network, not just right next to the exchange, because its new VDSL supported bonding right across the line card. Now it is talking about a specialized version of this which has the power to offer 300 Mbps up to 400 meters away and 100 Mbps at up to 1 kilometer away from the exchange.
These two steps seem to be complimentary technologies and the new claims come with a bit more explanation, although it’s pretty confusing stuff. Alcatel says that it uses something called DSL Phantom Mode, which appears to be a kind of third analog signal, apart form the two bonded signals, broken up and running across any one of the four lines in two separate twisted pairs. The Phantom signal might be a form of error correction we suppose, but it really is not explained any better than to say the following, ‘ Phantom Mode involves the creation of a virtual or ‘phantom’ analog channel that supplements the two physical wires that are the standard configuration for copper transmission lines.’ Like we said, obscure be an explanation will follow eventually.
The system also uses other industry-standard techniques which include vectoring to eliminate ‘crosstalk’ between copper wires when they are close together (for instance as a bonded pair departs from the exchange), and bonding, which makes it possible to take individual lines and aggregate them, which as we said before, is expected out this year from Alcatel.
What is perhaps more interesting right now is the way Alcatel says that it is already conducting work to refine deployment models and determine a specific set of CPE-models compatible with DSL Phantom Mode. What Alcatel has to do is get these techniques honed to the point where general purpose, robust chips can be made and then push for the technology to be a standard. That could eat as much as two years, but then there are few remaining obstacles in the way of introducing new ISAMs (Internet Subscriber Access Modules) and CPE (routers) which would drive DSL head to head against the broadband offerings based on coaxial cable such as the 160 Mbps DOCSIS 3.0.
‘We often think of the role innovation plays in generating technologies of the future, but DSL Phantom Mode is a prime example of the role innovation can play in creating a future for existing solutions and injecting them with a new source of value,’ said Gee Rittenhouse, head of Research for Bell Labs. ‘What makes DSL Phantom Mode such an important breakthrough is that it combines cutting edge technology with an attractive business model that will open up entirely new commercial opportunities for service providers, enabling them in particular, to offer the latest broadband IP-based services using existing network infrastructure.’
By that all he means is that line card access modules can be slid into place with the new chips, and modems and routers simply mailed to the client. The trouble this would represent for most broadband networks would be providing sufficient backhaul to allow such an upgrade to the access network, but at least that’s just a matter of laying more fiber or upgrading with established DWDM technology at the core.
Alcatel-Lucent has shipped 200 million DSL lines globally, but is in a race against the incumbent Chinese equipment manufacturers such as Huawei, to make the next DSL breakthrough, before its customers are severely disadvantaged by their cable counterparts installing DOCSIS 3.0.
In the long term these same customers are planning to slowly upgrade their networks with fiber to the home, but it will take 10 to 20 years to reach every subscriber with that technology, while the copper wires are already in the ground.