G.fast broadband standard Q&A
ITU-T G.9701, FTTdp (fibre to the distribution point), hybrid fiber-copper/xDSL, fiber to the home, MDU (Multi-Dwelling Unit)
“G.fast Brief Introduction“, as a complete new topic, is posted in FOT Blog one year ago.
And in today, December 2014, G.fast broadband standard approved and on the market, to service providers’ need.
Q: What is G.fast?
A: G.fast is the new ITU broadband standard. G.fast is defined to support up to 1Gbps over short (i.e., run over the last 250
meters) copper loops, and is designed to address gigabit broadband connectivity on hybrid fiber-copper carrier networks. Service
deployments are targeted from fiber-fed equipment located at a distribution point, such as a telephone pole, a pedestal, or
inside an MDU (Multi-Dwelling Unit), from the distribution point to the home.
Why require G.fast? (business strategy)
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.
Consumer expection: 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 (start frequency: 2.2, 8.5, 17.664 or 30 MHz), enables service providers to play to the strengths of each standard in different environments.
Fiber to the home (FTTH) Complements 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.
Deployment advantages of the FTTdp architecture?
A key benefit of FTTdp (fibre to the distribution point) 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.
G.fast Performance vs “service demand”
- 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)
Timeline: G.fast Systems Standards Development
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”.
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.
Recommendation ITU-T G.9701 “Fast Access to Subscriber Terminals (FAST) – Physical layer specification”