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G.fast broadband standard approved and on the market

Compliant chips and equipment in the hands of service providers   

Geneva, 05 December 2014 – ITU members today achieved final approval of G.fast, the new ITU broadband standard designed to deliver access speeds of up to 1Gbit/s over existing telephone wires. The standard answers to service providers’ need for a complement to fibre to the home (FTTH) technologies in scenarios where G.fast proves the more cost-efficient strategy.

G.fast, within the fibre to the distribution point (FTTdp) architecture, combines the best aspects of fibre and DSL. Within 400 metres of a distribution point, G.fast provides fibre-like speeds matched with the customer self-installation of DSL, resulting in cost-savings for service providers and improved customer experience.

Dr Hamadoun I. Touré, Secretary-General, ITU: “The time from G.fast’s approval to its implementation looks set to be the fastest of any access technology in recent memory. A range of vendors has begun shipping G.fast silicon and equipment, and service providers’ lab and field trials are well underway.”

Today’s approval of the physical-layer protocol aspects of G.fast – defined by Recommendation ITU-T G.9701 “Fast Access to Subscriber Terminals (FAST) - Physical layer specification” – follows the approval in April this year of ITU-T G.9700, a companion text specifying methods to ensure that G.fast equipment will not interfere with broadcast services such as FM radio.

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 WiFi hotspots.

G.fast’s ‘zero touch’ operations, administration and management will increase the speed of new-service rollouts. This remote management of user connections will simplify migrations to G.fast, and the standard’s coexistence with VDSL2 offers service providers the agility required to switch customers between G.fast and VDSL2 as business operations demand.

The development of G.fast has been coordinated with the Broadband Forum’s FTTdp system architecture project. ITU and the Broadband Forum have been working in collaboration to ensure that G.fast solutions can be quickly placed into FTTdp deployments.

“The Broadband Forum is working closely with the ITU to ensure compliance with the G.fast standard and certify chipsets and equipment,” said Robin Mersh, CEO of the Broadband Forum.  “We have already set our first plugfest for January 2015.”

The Broadband Forum has begun developing a test suite and certification programme for G.fast systems. The test suite will provide for interoperability, functional and performance testing. A beta-trial of the certification programme is planned for mid-2015, and certified G.fast implementations are expected to appear on the market before the end of 2015.

ITU-T Study Group 15 has initiated work on an extended set of features for G.fast, targeting performance enhancements which will include additions to its range of low-power states. These features are likely to be available for incorporation into service providers’ G.fast deployments as early as 3 July 2015.

See a Note to Technical Editors in annex for a G.fast feature list and standards timeline.

For more information, please contact:

Paul Conneally
Head, ITU Corporate Communications
telephone +41 22 730 5601
mobile +41 79 592 5668
email paul.conneally@itu.int   


Note to Technical Editors: G.fast features and timeline

Answering to business strategy requirements

G.fast delivers high-speed broadband access over copper telephone wires, operating on lines up to 400-metres long

  • G.fast enables service providers to capitalize on existing infrastructure, achieving fibre-like speeds without rewiring urban areas already equipped with copper.

Customer self-installation

  • Despite G.fast’s leap forward in sophistication over DSL access technology, it maintains the installation simplicity of ADSL. G.fast customer equipment, in line with that of ADSL, will arrive in a box containing only a G.fast-compliant modem and dongles to protect telephones.

‘Zero touch’ operations, administration and management

  • Upgrading a customer to G.fast does not require the deployment of a technician to a customer premises or capable distribution point to effect the switchover.
  • This remote management of user connections will simplify migrations to G.fast, and the standard’s coexistence with VDSL2 offers service providers the ability to switch customers between the two standards as business operations demand.

Coexistence with xDSL

  • G.fast’s spectrum compatibility with VDSL2 enables service providers to play to the strengths of each standard in different environments.

Complements fibre to the home (FTTH) strategies

  • In ‘greenfield’ scenarios, service providers will opt for FTTH.
  • In ‘brownfield’ scenarios – for example, an urban environment with an abundance of copper telephone wiring – G.fast will be more cost-efficient than FTTH.

The deployment advantages of the FTTdp architecture

  • A key benefit of FTTdp is that the distribution point unit (DPU) typically serves 1-20 lines, making it compact enough to place on a pole, in a small underground enclosure or in a small pedestal.

Answering to service provider requirements

Low power, cost and complexity

‘Zero touch’ operations, administration and management

Support for both TR-156 and TR-167 Broadband Forum architectures

Service rate performance targets

  • 500-1000 Mb/s for FTTB deployments at less than 100m, straight loops
  • 500 Mb/s at 100m
  • 200 Mb/s at 200m
  • 150 Mb/s at 250m
  • Aggregate service rates of equal to or more than 500 Mb/s with start frequency of 23 MHz and VHF and DAB bands notches

Capitalizes on the advantages of FTTH and DSL

  • FTTH bit-rates, with the customer self-installation of DSL
  • Complements FTTH, and enhances fibre to the cabinet (FTTC)

Coexistence with xDSL

  • Spectrum compatibility: G.fast operates at higher frequencies than VDSL2 (start frequency: 2.2, 8.5, 17.664 or 30 MHz)

Reverse power feeding (RPF) for the DPU from the customer premises

  • Persistent Management Agent (PMA) acts as management proxy in the event of the DPU losing power

Control of upstream/downstream asymmetry ratio

  • Flexible up/down data rate allocation
  • Mandatory: 90/10 and 50/50
  • Optional: from 50/50 to 10/90

Operates up to 106 MHz

  • Maximum power spectral density (PSD) much lower than in VDSL2
  • Configure PSD mask (e.g. start above VDSL2)
  • Configure RFI/IAB notches (e.g. notch FM band)

Improved robustness

    Uses Time Division Duplexing (TDD)

  • Can easily vary upstream/downstream asymmetry ratio
  • Easily supports low-power states
  • Discontinuous mode allows trade-off between power consumption and user data throughput
  • Point-to-point distribution

     Mandatory support for vectoring

  • Far-end crosstalk (FEXT) cancellation

PHY layer retransmission

  • Mitigating the effects of impulsive noise while maintaining low latency

Supports Fast Rate Adaptation (FRA)

  • Quickly adapts to changing channel or noise conditions

Timeline: Standardization, testing and certification of G.fast systems

Standards Development

January 2011:

At request of the Broadband Forum, ITU’s Standardization Sector (ITU-T) issued a call for papers on the transceiver aspects of FTTdp, resulting in the initiation of the G.fast project.

4 April 2014:

Approval of Recommendation ITU-T G.9700 “Fast access to subscriber terminals (FAST) - Power spectral density specification”, a specification to ensure that G.fast systems will not interfere with broadcast services such as FM radio.

5 December 2014:

Approval of Recommendation ITU-T G.9701 “Fast access to subscriber terminals (FAST) - Physical layer specification”.

First-half 2015:

Expected approval of G.9701 Amendment 1, providing an extended set of features for G.fast, which will include performance enhancements such as additions to its range of low-power states.

Testing and Certification

The Broadband Forum’s operator survey found strong support for a G.fast certification programme available to the industry before deployments take off, with interoperability as a top priority.

The Broadband Forum has initiated the development of a G.fast certification test plan (ID-337) and programme, and has chosen the University of New Hampshire InterOperability Laboratory as its Certification Test Lab.

Beta-trial of the G.fast certification programme planned for mid-2015

  • first plugfest planned for the end of January 2015

The G.fast certification test plan tests one DPU/CPE combination for interoperability

  • Functional, performance, stability, throughput

The University of New Hampshire InterOperability Laboratory will certify G.fast DPUs and CPEs independently

  • Based on criteria defined by the Broadband Forum, e.g., how many counterparts to interoperate with, etc.

Certified G.fast implementations expected before the end of 2015

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