Bell Labs pushes 10Gbps over copper telephone lines

Alcatel-Lucent's Bell Labs claims to have "set a new broadband speed record of 10Gbps using traditional copper telephone lines" in a research project that could ultimately bring gigabit speed to broadband networks that combine fiber with copper.

Those 10Gbps speeds can only be achieved over 30 meters; at 70 meters, top speeds drop to 1Gbps, according to today's announcement. Alcatel-Lucent says that 1Gbps upload and download speeds may be possible in the real world over networks that bring fiber to the curbside and rely on copper for the final few meters. Such a setup would be similar to AT&T's U-verse fiber-to-the-node service, although U-verse places the fiber about 600 to 900 meters away from homes and currently tops out at 45Mbps.

To reach the higher speeds, Bell Labs (which became famous when it was still part of AT&T) is relying on a new DSL standard known as G.fast, which promises up to 1Gbps over copper phone lines. Alcatel-Lucent says that Bell Labs has developed an extension of G.fast called XG-FAST.

"When it becomes commercially available in 2015, G.fast will use a frequency range for data transmission of 106MHz, giving broadband speeds up to 500Mbps over a distance of 100 meters," Alcatel-Lucent said. "In contrast, XG-FAST uses an increased frequency range up to 500MHz to achieve higher speeds but over shorter distances. Bell Labs achieved 1Gbps symmetrical over 70 meters on a single copper pair. 10Gbps was achieved over a distance of 30 meters by using two pairs of lines (a technique known as 'bonding'). Both tests used standard copper cable provided by a European operator."

Broadband deployments happen slowly, a fact many US customers are painfully aware of, but Alcatel-Lucent hopes this new method will accelerate deployment of high-speed Internet by "taking fiber very close to customers without the major expense and delays associated with entering every home."

Source: ArsTechnica