Fiber-optic speeds achieved over copper lines

Apr 28, 2010 by Lin Edwards report

( -- Bell Labs, Alcatel-Lucent's research arm, has demonstrated industry record broadband download speeds of up to 300 Megabits per second using two traditional twisted pair copper telephone lines. The achievement could extend the use of copper-based broadband networks, which are in wide use around the world, and it could provide another means of providing faster broadband in areas where fiber-optic and other cable technologies are unavailable.

French telecommunications giant said the speeds achieved would enable service providers to use the existing copper-based infrastructure to satisfy demand for fast for home and business users for many years to come. Achieving faster speeds is important for Internet service providers who want to compete with the fundamentally different technology used by cable companies.

The demonstration used DSL (digital subscriber line) phantom mode, which was developed in 1986 as an analog telephony technique. This adds a “phantom” channel in addition to the two channels transmitted over a twisted pair copper telephone line. The positive half of the phantom is sent down one wire, and the negative half is sent down the other. Analog processors at the receiving end extract the two real signals and the phantom.

Phantom mode adds to the bandwidth but also introduces noise or “crosstalk” into the signal, and to cancel out this effect they used a “vectoring” technique. Bandwidth was also increased by a third technique called “bonding,” which treats the two lines in the twisted pair as if they were a single cable. Vectoring and bonding are standard means of increasing DSL broadband speed, but neither is widely used in the US.

The prototype technology achieved transmissions of 300 Megabits per second (Mbps) over 400 meters and up to 100 Mbps at up to one kilometer. Standard over ADSL using copper infrastructure are generally around 20 Mbps.

Head of Bell Labs research, Gee Rittenhouse, said in a company statement that DSL phantom mode is an important breakthrough because it “combines cutting-edge technology” with a business model that will enable service providers to offer the latest broadband services using the existing network infrastructure.

To use the new technique, the user must have two telephone lines already installed, and a modem designed to use the two lines.

Fast broadband speeds over copper lines were also demonstrated last year by Ericsson, who achieved transmission speeds of 500 Mbps, but their system used six bonded telephone lines, rather than the two in Alcatel-Lucent's prototype.

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More information: Company press release.

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User comments : 9

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not rated yet Apr 28, 2010
100 MB per second are not equal to 100 Mbps. And DSL was invented in 1886?
not rated yet Apr 28, 2010
The speeds sound great but they still are unable get rid of their legacy distance issues.
not rated yet Apr 28, 2010
they obviously meant 1986 - wikipedia reports first tested in 1988 --

well all signals degrade with distance based on the medium and copper is a horrible medium.
2 / 5 (2) Apr 28, 2010

well all signals degrade with distance based on the medium and copper is a horrible medium.

Compared to fiber. But compared to, say, spaghetti? Copper is pretty darn good.
5 / 5 (1) Apr 28, 2010
Yes, all signals degrade but as you mentioned copper is the worst specifically pots lines.
not rated yet Apr 28, 2010

Compared to fiber. But compared to, say, spaghetti? Copper is pretty darn good.

Yes, copper is better than spaghetti, string & cups, and semaphore. Fiber offers much better bandwidth, does not emit RFI, but 'connectivity' is a problem. I'm amazed at the back-flips people will attempt, just to squeeze a little more life out of the copper infrastructure. That's okay for now, but once bandwidth demand arrives, it's 'bye-bye baby.
not rated yet Apr 30, 2010
This is pushing copper to it's extreme limit. Fiber gets these sort of speeds without as much effort, and with the promise of even higher speeds in the future.
not rated yet Apr 30, 2010
Fiber optic speeds? That's kind of misleading considering there are networks running 100Gpbs over fiber.

But I do think for now this is good thing to squeeze as much out of copper as we can. There are MILLIONS of people in the USA in rural communities that will not get fiber to their homes for most likely a decade or two. Unless the government decides otherwise. Telecoms surely are not going to put in 20,50, or 100 miles of fiber costing millions to serve 100Mbps+ for 1-20 customers.

So until rural folks get fiber, maximizing copper is a good thing. Heck, most rural people can barely get 1.5Mbps where I live. Many still can only do dial-up. UGH!
not rated yet Jun 02, 2010
What is this???
Ericsson reached 500 Mbps over twisted pair a year ago!!!


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