ADTRAN has developed a technology called Frequency Division Vectoring (FDV), which will enable telcos to migrate to the upcoming G.fast from their existing VDSL2 vectored copper wire networks.
G.fast can deliver speeds of up to 200 Mbps over copper wires, and the standard is currently being developed under the supervision of the telco’s ITU standards organization. ADTRAN already has some G.fast products in development and it plans to announce those products next year. Telco broadband providers that have invested in VDSL2 vectoring on their networks will eventually want to transition those networks to G.fast.
ADTRAN’s FDV technology enables G.fast and vectored VDSL2 to co-exist on the same copper line, and deliver G.fast speeds. “Carriers that have deployed vectored VDSL2 have a pretty substantial investment in that network,” ADTRAN’s CTO Kevin Schneider said during an analyst event this week, which The Online Reporter attended. “As they contemplate moving to a fiber-to-the-building (FTTB) architecture, they need to understand a migration path from their VDSL2 technology to the G.fast.”
Telcos are interested in deploying fiber to the building and leveraging the copper wires that are already in place inside the buildings, because taking out the copper wires and installing fiber in the building is very, very expensive, disruptive and time consuming.
In an FTTB architecture, the cabinet launch point for vectored VDSL2 typically is around 200 meters from the building. The G.fast cabinet must be located right next to the building, because G.fast can only deliver those higher speeds over spans of 250 meters or less. Telcos won’t want to rip out all of the vectored VDSL2 they’ve put in to replace with G.fast, and they’re not particularly interested in maintaining two cabinet as launch points – the vectored VDSL2 cabinet and then another G.fast cabinet closer to the building.
Problems also arise when the two technologies co-exist on the same line. “Typically, G.fast is defined to operate from 2 to 106 MHz; however, when it has to co-exist with the VDSL2, we end up with crosstalk,” Schneider said, because VDSL operates in the lower frequencies, up to 17 Mhz. There is crosstalk between the two technologies in those lower frequencies, which degrades the speeds and performances of the two technologies.
“The way to remedy that is to vacate that spectrum in G.fast, in a VDSL2 compatible mode,” Schneider said. “So, G.fast performance won’t be as fast as it would be if we didn’t have to deal with the compatibility of VDSL.”
The solution ADTRAN has developed is to add…
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