Alcatel-Lucent claims broadband record

Johannesburg, 10 Jul 2014

Bell Labs' speed record has identified a new benchmark for real-world applications for ultra-broadband fixed access.

Alcatel-Lucent's research arm, Bell Labs, claims to have set a world record in broadband speed, using traditional telephone copper wires.

According to the telecoms service provider, Bell Labs achieved a speed of 10Gbps (10 000Mbps) via copper, and developed prototype technology that demonstrates how existing copper access networks can be used to deliver 1Gbps symmetrical ultra-broadband access services.

"Achieving 1Gbps 'symmetrical' services - where bandwidth can be split to provide simultaneous upload and download speeds of 1Gbps - is a major breakthrough for copper broadband," says the company.

This development will enable operators to provide Internet connection speeds that are indistinguishable from fibre-to-the-home services, a major business benefit in locations where it is not physically, economically or aesthetically viable to lay new fibre cables all the way into residences. Instead, fibre can be brought to the curb-side, wall or basement of a building and the existing copper network used for the final few metres.

The Bell Labs tests used a prototype technology called XG-fast, an extension of G.fast technology, a new broadband standard currently being finalised by the International Telecommunication Union.

When G.fast technology becomes commercially available in 2015, it will use a frequency range for data transmission of 106MHz, giving broadband speeds up to 500Mbps over a distance of 100m. XG-fast, in contrast, uses an increased frequency range up to 500MHz to achieve higher speeds - but over shorter distances.

Bell Labs achieved 1Gbps symmetrical over 70m on a single copper pair, while 10Gbps was achieved over a distance of 30m by using two pairs of lines (a technique known as bonding). Both tests used standard copper cable provided by a European operator.

Pushing boundaries

Bell Labs president Marcus Weldon says the unit's constant aim is to push the limits of what is possible to "invent the future with breakthroughs that are 10 times better than are possible today".

Primary factors influencing broadband speeds over copper

* Distance: the longer the copper connection between the access node and the customer's telephone socket, the slower the broadband speed. This is dictated by attenuation.
* Frequency: the wider the frequency range, the faster the broadband speed that can be achieved. The Shannon Limit dictates the maximum possible speed for a given medium and frequency spectrum.
* Higher frequencies attenuate more quickly than lower frequencies, meaning there are diminishing returns in speed as the frequency range increases.
In practical situations, other significant factors that can influence actual speeds include the quality and thickness of the copper cable and cross-talk between adjacent cables.

The demonstration of 10Gbps over copper is a prime example, he says. "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.

Federico Guill'en, president of Alcatel-Lucent's fixed networks business, says the Bell Labs speed record is not only a notable achievement, it also identified a new benchmark for real-world applications for ultra-broadband fixed access.

"XG-fast can help operators accelerate fibre-to-the-home deployments, taking fibre very close to customers without the major expense and delays associated with entering every home."

According to Guinness World Records, Cisco rates South Korea as having the best broadband service in the world currently. The country's network yields an average download throughput of 33.5Mbps and has 100% broadband penetration.