ITU finalises gigabit over copper lines standard

Standards authority the International Telecommunications Union (ITU) has finalised a new digital subscriber line standard which it says may enable broadband service speeds of up to one gigabit per second over copper phone lines.

Called G.fast, the new standard has been in the works for the past few years, with large vendors Alcatel-Lucent and Huawei claiming very high speeds over existing copper and coax lines using the new broadband transmission technology.

Now that the G.fast standard is finalised, equipment vendors have begun shipping electronics and other hardware tailored to the technology, on top of ongoing field trials, ITU said.

Certified G.fast equipment is expected to show up on the market by the end of 2015. No work is required at customer premises to deploy G.fast, and the new standard co-exists with VDSL2 broadband.

ITU said G.fast "combines the best aspects of fibre and DSL" within a fibre-to-the-distribution point architecture, such as fibre-to-the-node model promoted by the Australian Coalition ahead of fibre-optic connections directly to user premises.

According to ITU, G.fast provides fibre-like speeds within 400 metres of a distribution point.

This, ITU claims, means G.fast will increase the feasibility of bandwidth-intensive services such as 4K and 8K streaming video and IPTV, advanced cloud-based storage as well as being sufficient to meet the broadband needs of small to medium enterprises.

G.fast combines line pair bonding, vectoring for noise cancellation and phantom mode technologies to increase bandwidth. The performance targets set by the ITU are:

• 500-1000 Mbps for FTTB deployments at less than 100 metres and straight loops
• 500 Mbps at 100 metres
• 200 Mbps at 200 metres
• 150 Mbps at 250 metres

Using 106MHz of bandwidth compared to the 8.6, 17.7 or 30MHz maximum for today's VDSL2 broadband, G.fast will offer flexible down and upstream rate allocations.

Two mandatory rate allocations - 90/10 and 50/50 - have been made mandatory to meeting the G.fast standard, with 50/50 and 10/90 being optional.