Bell Labs, the research arm of Alcatel-Lucent, is claiming a broadband speed record of 10 gigabits per second (Gbps) on traditional copper telephone lines.
The same technology, called XG-FAST, can be used to deliver symmetrical 1 Gbps on copper access networks, Bell Labs said.
If the technology can be commercialized in the next few years, it could have significant ramifications for phone companies, some of whom insist they must rip out copper and replace it with fiber in order to remain competitive with cable competitors. The cable industry plans to get to 1 Gbps with DOCSIS 3.1 (aka Gigasphere) on extant coax wires, and is confident it can get to at least 10 Gbps riding that technology.
XG-FAST is an extension of G.fast, a new broadband standard currently being finalized by the ITU. On the upside, the technology achieves ultrafast transmission rates. On the downside, it can do so only on extremely short loop lengths.
When G.fast becomes commercially available in 2015, it will use a frequency range for data transmission of 106 MHz, giving broadband speeds up to 500 Mbps, over a distance of 100 meters.
XG-FAST, meanwhile, uses a frequency range up to 500 MHz to achieve higher speeds, though over shorter distances. Bell Labs achieved 1 Gbps symmetrical over 70 meters on a single copper pair. Signals at higher frequencies were completely attenuated after 70 meters, the company reported.
10 Gbps was achieved over a distance of 30 meters by bonding two lines, Bell Labs said. Both tests used standard copper cable provided by a European operator.
Marcus Weldon, President of Bell Labs, said, “by pushing broadband technology to its limits, operators can determine how they could deliver gigabit services over their existing networks, ensuring the availability of ultra-broadband access as widely and as economically as possible.”
In practical situations, other significant factors that can influence actual speeds (not taken into account during these tests but which have been studied extensively elsewhere) include the quality and thickness of the copper cable and cross-talk between adjacent cables (which can be removed by vectoring), Bell Labs said.
Commenting on the achievement, Federico Guillén, President of Alcatel-Lucent’s Fixed Networks business said: “The Bell Labs speed record is an amazing achievement, but crucially in addition they have identified a new benchmark for ‘real-world’ applications for ultra-broadband fixed access. XG-FAST can help operators accelerate FTTH deployments, taking fiber very close to customers without the major expense and delays associated with entering every home. By making 1 gigabit symmetrical services over copper a real possibility, Bell Labs is offering the telecommunications industry a new way to ensure no customer is left behind when it comes to ultra-broadband access.”
Maximum aggregate speed
G.fast phase 1*
G.fast phase 2*
Bell Labs XG-FAST**
2 Gbps (1 Gbps symmetrical)
Bell Labs XG-FAST with bonding***
10 Gbps (two pairs)
* Industry standard specifications. G.fast allows for upload and download speeds to be configured by the operator.
** In a laboratory, reproducing real-world conditions of distance and copper quality.
*** Laboratory conditions.