The ITU has formally approved the G.fast standard that will deliver broadband with speeds of up to 1Gbps over the existing copper wires between premises and fibre-equipped street cabinets. The new standard is a step up in speed and frequency from the VDSL2 systems currently used to deliver faster speeds - typically 40 or 80Mbps - than ADSL2.
G.fast's main advantage is that it's much cheaper to install than fibre to the premises (FTTP), and the ITU reckons customers will be able to install it themselves. The main disadvantages are that it's not as fast as FTTP, and that - as with ADSL and VDSL - speed falls off with distance.
The ITU's technical note says that G.fast should deliver speeds of 500 to 1000Mbps at distances of up to 100m. This falls to 200Mbps at 200m and 150Mbps at 250m. In the UK, BT reckons around 80 percent of connections will be less than 66m from distribution points. However, because of interference, practical speeds are likely to be around 500 to 600Mbps at 100m, not 1Gbps.
Current high-speed systems are based on taking fibre to the cabinet (FTTC). G.fast takes the fibre to a distribution point (FTTdp) somewhere between the cabinet and the premises. This might be, for example, a telephone pole or another junction box.
In a statement, the ITU said: "G.fast will increase the feasibility of implementing bandwidth-intensive services such as Ultra-HD '4K' or '8K' streaming and next-generation IPTV, advanced cloud-based storage, and communication via HD video. The standard will comfortably serve the broadband access needs of small-to-medium enterprises, with other envisioned applications including backhaul for small wireless cell sites and Wi-Fi hotspots."
Companies have already started shipping G.fast chips and routers in small quantities, and BT has been testing them at its Adastral Park research centre in Ipswich in the UK. (See: BT researchers claim gigabit broadband speeds using G.fast over copper wires.)
Robin Mersh, CEO of the Broadband Forum, says the Forum is developing a test suite and certification programme for G.fast systems, and will soon start testing interoperability. "We have already set our first plugfest for January 2015," he said.
The University of New Hampshire InterOperability Laboratory (UNH-IOL) says it "will serve as the world's first and only testing laboratory for the Broadband Forum's G.fast certification program".
Certified G.fast implementations are expected to appear on the market before the end of 2015.