G.fast is a more promising technology than originally expected, said BT Wholesale executive Colin Bannon at the Big Telecom Event in Chicago yesterday.
Manufacturers have targeted G.fast to support speeds of about 500 Mbps over copper phone wiring over a distance of about 100 meters. But Bannon said BT has been testing the technology in the laboratory and has been able to support speeds up to 1 Gbps over distances of 350 meters (approximately 1,100 feet). The company also has done small field trials of the technology. Bannon also noted that BT expects to see enhanced performance from G.fast after manufacturers implement modifications to their products that the carrier has recommended.
“I think we’re onto a winner here,” said Bannon in a presentation to BTE attendees.
The 350-meter distance is important because BT recently modernized its infrastructure to include cabinets at that distance from individual homes as part of a big push to boost broadband speeds and availability across the United Kingdom. The company has been pushing fiber deeper into its network to support higher broadband speeds for end users, but was only looking at G.fast for customers who were closer to the fiber endpoint than 350 meters.
“A technology we were planning to look at for four million sites [is] potentially workable over longer distances,” said Bannon. G.fast, he said, is “supremely promising not only for short range but for those cabinets we just spent three billion on.”
Within the next 10 years, Bannon anticipates that BT might use G.fast to support plans to make broadband speeds up to 500 Mbps available for most of the U.K. and to also support a premium offering of 1 Gbps.
G.fast Technology Tweaks
The product modifications that BT has requested from G.fast manufacturers include:
- Enable higher bits per tone (i.e. 15 vs. 12)
- Increase the transmit power (i.e. 8dBm)
- Increase the vectoring group sizes (>= 96 ports)
- Optimize the frequency usage with VDSL
- Lower noise floors (i.e. <-150dBM/Hz vs. 135 or 140)
BT is planning several field trials of G.fast for this summer including bringing service to 4,000 users in two locations. The company also has deployed the technology to 100 multi-dwelling units.
Bannon noted that in BT’s field trials, customers have experienced broadband speeds of up to 700 Mbps over distances of 50 meters and speeds of 500 Mbps over distances of 150 meters.
And after manufacturers make the modifications BT has requested “it’s going to get a lot better,” Bannon said.
