Adtran has introduced a variation of DSL technology that the company says will enable VDSL2 and G.fast to coexist, which would enable DSL carriers to deploy G.fast on a node by node basis, rather than having to upgrade entire markets from VDSL2 to G.fast.
Adtran is looking to patent an approach it calls frequency division vectoring. FDV doubles data rates and increases the reach of intermediate-rate services – between 100 Mbps to 1 Gbps, the company said.
VDSL2 has a maximum of 30 MHz of bandwidth, and is capable of transmitting data at about 200 Mbps symmetrical, on copper loops of about a kilometer (or about 3,300 feet). G.fast, meanwhile, has a wider spectrum than VDSL2 at 106 MHz (a second profile doubles that to 212 MHz), to achieve up to 500 Mbps (theoretically up to 1 Gbps), but it is practical only with copper loops shorter than 250 meters.
Both techniques are subject to crosstalk, though G.fast is said to be especially susceptible. Vectoring was developed to minimize the problem. If "FDV" is an accurate descriptor, Adtran has apparently found an approach that makes vectoring an inherent element of the modulation process.
The two approaches can’t be mixed and matched – or couldn’t, before Adtran proposed FDV.
The company said FDV expands the addressable market for G.fast by broadening its applicability from fiber-to-the-building (FTTB) and fiber-to-the-distribution points (FTTdp) out to existing street cabinet sites.
This allows service providers to fortify recent cabinet investments while mitigating the operational challenges that currently exist regarding providing power to new FTTdp deployments.