Gigabit speeds over telephone wires get closer thanks to new G.fast standard

The technology that gives copper broadband a new lease on life is called G.fast. It offers speeds at up to 1Gbps at distances of up to 100 meters. As the distance increases, the speeds decreases to about 150Mbps over 250 meters, according to the International Telecommunication Union, which has developed the underlying standard and announced G.fast's approval on Friday.

What performance users end up with depends on a number of factors, including the distance and the quality of the copper wires. The speeds quoted by ITU are just targets, which is far from the same thing as guaranteed performance.

However, tests conducted in the last two years have shown G.fast is capable of impressive speeds. For example, earlier this year British network operator BT said download speeds of around 700Mbps and upload speeds at 200Mbps over a distance of 66 meters were achieved during a field trial. G.fast gives operators some flexibility to decide the split between upload and download bandwidths.

The speed increase is needed for applications such as streaming 4K video (and in the future 8K video), IPTV, cloud-based storage, and communication via HD video, ITU said.

One of G.fast's biggest proponents is telecom operator Telekom Austria, which in October said it had connected the world's first subscriber to such a service to its domestic network. The speed the technology offers will meet the needs of even the most demanding households over the next 10 to 20 years, it said.

Telekom Austria has apartment buildings in cities in mind for large-scale commercial installations in 2016. In this case fiber is deployed all the way to the basement of a building, and existing copper lines are used for the final connection to the apartments. The speed combined with the distance limitations means G.fast depends on operators to roll out fiber almost all the way to homes or offices.

ITU expects the first rollouts to come before the end of next year. The technology will also be used to connect mobile base stations, Wi-Fi hotspots and small and medium sized companies, it said.

G.fast increases the bandwidth by using more spectrum. That places extra demands on equipment to be very good at handling interference, a far from trivial requirement.

Getting it to work has been a challenge for chipset manufacturers and equipment vendors. The standardization of G.fast started in 2011, and was meant to be finished by April. In the end, another seven months were needed, showing once again that standardization is a tricky business.

Send news tips and comments to mikael_ricknas@idg.com