In this era of fiber to the home, it is easy to dismiss copper-based DSL, the broadband connectivity technology commonly sold by phone companies world wide. Looks like it is too soon to completely write off this technology. Alcatel-Lucent, a company whose lineage is as old as the phone itself says its research arm, Bell Labs has been able to achieve downstream speeds of about 300 Mbps (over a distance of 400 meters) or 100 Mbps over a distance of one kilometer.
This is possible using a technology called DSL Phantom Mode.
At its core, DSL Phantom Mode involves the creation of a virtual or “phantom” channel that supplements the two physical wires that are the standard configuration for copper transmission lines. Bell Labs’ innovation and the source of DSL Phantom Mode’s dramatic increase in transmission capacity lies in its application of analogue phantom mode technology in combination with industry-standard techniques: vectoring that eliminates interference or “crosstalk” between copper wires, and bonding that makes it possible to take individual lines and aggregate them.
The idea behind DSL Phantom Mode is that the incumbent phone companies such as AT&T who are heavily invested into the aging copper infrastructure can keep using those pipes for a lot longer. However, phone companies such as Qwest will need to install new gear in the central office and in consumer homes.
Alcatel-Lucent’s efforts aren’t the only attempts to extend copper’s life and make DSL go faster and faster. Stanford University profession John Cioffi is working on a gigabit DSL solution and has started a company to give DSL a lift.
