What is G.fast, G.hn and G.now technology?

G.x series technology and solutions

  Today, let’s introduce and talk about this new and hot series of G.x (G.fast / G.hn / G.now, the letter G stands for the ITU-T G series of recommendations) technology and solutions, with two questions: “what is G.fast, G.hn and G.now?” and “what is their advantages?”

Parts of the definitions were collected from wikipedia, assia-inc and so on. Those description and knowledge content we collected is only used for learn and study purpose here.

What is G.fast?

  G.fast aims at providing ultra-high speeds over copper twisted pairs, up to and sometimes even exceeding speeds of 1 Gbps. The planned loop lengths for G.fast are from 50 to 250 meters (150 to 750 feet). G.fast is being standardized as ITU-T Recommendation G.9701. Similar to vectored VDSL, G.fast supports vectoring, which reduces crosstalk that is found in multi-pair cables and at higher frequencies.

G.fast is a digital subscriber line (DSL) standard for local loops shorter than 500 m, with performance targets between 150 Mbit/s and 1 Gbit/s

  The first version of G.fast operates over frequencies of up to 106 MHz, and uses linear vector pre-coding to eliminate crosstalk in the downstream direction. A future version of G.fast may operate over frequencies of up to 212 MHz, and may support higher-performance non-linear pre-coding to allow for even higher speeds.

Frequency spectrum of the G.fast standard compared to VDSL2

Frequency spectrum of the G.fast standard compared to VDSL2

  G.fast is expected to be deployed in a Fiber-To-The-distribution point (FTTdp) architecture as shown in the Figure above. The “dp” may also be called the “terminal” or “drop-wire terminal,” and is where the Distribution-Point-Unit (DPU) is located. Fiber is fed to the terminal, and from there, very short copper cables and drops, up to about 250 meters (750 feet) long, serve subscribers.

  G.fast can coexist with ADSL and VDSL on adjacent pairs of copper wires by using frequencies above these technologies.

Both G.now and G.fast are candidates for Fiber-To-The-Building/Basement (FTTB) deployments, and perhaps for feeding small cells as they proliferate. For other types of deployments, G.now and G.fast entail a very high number of active electronic boxes in the Outside Plant, which raises concerns with regard to operational costs. G.now is available today, while G.fast is currently progressing through the standards. The first version of the ITU-T G.fast standard should be completed in December 2014, with some interoperability testing occurring in 2015 under the auspices of the Broadband Forum.

What is G.hn?

  G.hn is a family of ITU-T Recommendations (G.996x) defining home networking over phone lines, power lines and coaxial cables.

G.hn protocol stack

G.hn protocol stack

  G.hn is the common name for a home network technology family of standards developed under the International Telecommunication Union’s Telecommunication Standardization sector (the ITU-T) and promoted by the HomeGrid Forum and several other organizations. The G.hn specifications define networking over power lines, phone lines and coaxial cables with data rates up to 1 Gbit/s.

ITU-T Recommendation (the ITU’s term for standard) G.9960, which received approval on October 9, 2009, specified the physical layers and the architecture of G.hn. The Data Link Layer (Recommendation G.9961) was approved on June 11, 2010. The work was done in the ITU Telecommunication Standardization Sector, Study Group 15, About 20 companies participated in the work, including telephone, communication equipment, and home networking technology companies.

What is G.now?

  Based on the G.hn technology, G.now systems use standard G.hn chips and apply system-level software enhancements to deliver an access solution over phone lines of length of 200 meters (700 feet) or less. G.now can also operate over coaxial cabling, as a broadband access platform.

G.now technology in applications (FOT Blog)

G.now technology in applications (FOT Blog)

  There are several possible deployment scenarios for G.now; these include a single-port G.now system suitable for a single-family home or apartment; and multi-port G.now systems for small or large multiple-dwelling units. G.now systems are fed by GPON, EPON or active Ethernet; G.now can use either phone lines (up to 200 meters or 700 feet) or coaxial cabling.

What is their advantages?

  Features of the G.x (G.fast / G.hn / G.now) series technology and solutions:

  • Supplement of FTTx broadband solutions
  • Reuse of operator’s existing buildings and home network cabling
  • Support integration of phone twisted pair, coaxial cable and power cable (power line)
  • Bandwidth: data transmission rates up to 1 Gbit/s
  • Save money: Significantly reducing installation and operating costs

Ask for G.fast/G.hn/G.now Detail!

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