10Gbps over crumbling COPPER: Boffins cram bits down telco wire
XG-FAST tech could finesse fiber connections
Bell Labs has pumped data faster than ever before down antiquated copper wiring. The boffins used a frequency modulation system that they claim will be perfect for hooking up aging telco cables to future broadband fiber networks.
The technique is based on the G.fast standard being considered by the International Telecommunications Union; it's a DSL standard designed to sustain 500Mbps connections over legacy copper cable networks using a 106MHz frequency range.
The new Bell system, dubbed XG-FAST, increases the frequency range to 500MHz. We're told it can manage 10Gbps over a pair of copper cables 30 metres long, although speeds drops to 1Gbps of synchronous data over 70 meters.
"Our 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," said Marcus Weldon, president of Bell Labs.
"Our demonstration of 10Gbps over copper is a prime example: 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."
What's not clear is if Bell Labs can get even faster speeds over telco copper, but the team says that due to the limits of Shannon's Law (also known as the Shannon–Hartley theorem) this may not be possible.
Mathematical savant Claude Shannon devised formulas for calculating how much data can be transmitted without significant loss of information; it's possible that XG-FAST is getting close to the limits of what is possible with copper, particularly considering the parlous quality of some municipal wiring systems.
Nevertheless, Bell Labs hopes that the XG-FAST system can be a valuable way of connecting homes and businesses to fiber networks without having to install optical cable right up to the front door. If the existing copper wiring can be used, this reduces the rollout cost of high-speed broadband networks considerably.
"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," gushed Federico Guillén, president of Alcatel-Lucent's fixed networks business.
"XG-FAST can help operators accelerate [fiber to the home] 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." ®