The International Telecommunication Union (ITU-T) Study Group 15 has given its formal “consent” to the start of the final approval process for the next generation G.fast (aka – FTTC2 / ITU G.9700) broadband standard, which could one day deliver speeds of up to 1000Mbps (1Gbps) over some BT hybrid fibre (mixed copper and fibre optic) lines.
At present BT uses Fibre-to-the-Cabinet (FTTC) technology to deliver speeds of up to 80Mbps, which works by replacing the existing copper cable between street cabinets and your local telephone exchange with a fibre optic line. The final copper line run from cabinets and into homes is then managed by VDSL2 technology (similar to ADSL but faster over short distances).
G.fast adopts a similar approach but it’s designed to take even better advantage of the latest advancements (e.g. Vectoring “2.0″ technology to reduce crosstalk interference), which would allow it to operate at speeds of up to 1Gbps (albeit over even shorter runs of copper cable – up to 250 metres). The most likely setup would be to combine G.fast with Fibre-to-the-Distribution-Point (FTTdp) technology, which takes the fibre optic cable even closer to homes (read our full overview).
Dr Hamadoun I. Touré, Secretary-General of the ITU, said:
“From ADSL in 1999 to G.fast in 2014, ITU-standardized DSL solutions have multiplied access speeds by a factor of 125 over the past 15 years. It is to the credit of ITU’s membership and the dedication of engineers working in our study groups that ITU standards continue to maximize returns on investment in legacy ICT infrastructure.”
Les Brown, Associate Rapporteur of the G.fast Experts Group, added:
“G.fast provides the speed of fibre with the ease of installation of ADSL2. The solution is as compelling to consumers as it is to service providers, coexisting with VDSL2 and complementing FTTH.”
BT recently confirmed a plan to trial G.fast technology and has openly spoken about top download speeds of up to 800Mbps (200Mbps upload) being possible for some super short lines (e.g. around 50 metres), although in reality the mass market headline figure is probably more likely to start at around 250Mbps but it’s still far too early to say for sure.
The latest “consent” stage is thus an important milestone because it marks the formal start of the ITU-T’s approval process, which is now expected to complete by Q3 2014 (a little later than originally expected but not far off the mark). Most importantly it means that hardware manufacturers can now begin development of the first draft of G.fast kit and the first proper gear should then surface in 2015.
In other words you probably won’t be seeing G.fast in the mass UK consumer market until around 2016/17 and that’s assuming BT can overcome a variety of potential technical and cost problems with its integration. The idea of G.fast is to deliver faster speeds without going to the massive £20-30bn expense of having to deploy a full national fibre optic (FTTH/P) network, although you do still bring the fibre optic side closer to homes via FTTdp.
In other words G.fast might be a fair bit cheaper than FTTH but it would still be a very slow, complex and expensive upgrade to deploy. In the meantime existing FTTC technology will continue to be upgraded with improvements like Vectoring (currently in trial) and possibly a greater allocation of radio spectrum (30MHz / Profile 30a [currently 17Mhz]), which could push top speeds beyond 100Mbps but at this stage nothing is confirmed.
As a side note it’s worth mentioning that G.fast uses a “parasitical power” setup, which means that it’s designed to work without mains power by drawing current from your own modem or router device.
UPDATE 12th December 2013
Added a comment from the ITU above. It’s also noted that the ITU-T G.9701 standard is on track to achieving final approval in conjunction with ITU-T G.9700, which specifies methods to ensure that G.fast equipment will not interfere with broadcast services such as FM radio.