The gains in LR-VDSL2* come from 3 sources, making it hard to quantify the outcome:
- Vectoring can give a big gain, but only if the line already suffered from crosstalk. No disturber => no gain.
- Removal of CAL could give a gain of up to 8Mbps for cabs that are ~2km from the exchange, but little gain for those outside the exchange or 5km away. But almost every line on the cab ought to be able to gain the same amount from this.
- The increase in total aggregate power probably helps lines with access to more tones. i.e shorter lines
I think there's another source for gains. For the LR-VDSL2 lines, they haven't only set CAL=0, they have removed the PSD mask from the ANFP entirely. For CAL=0, the ANFP PSD sets a maximum downstream limit of -49.5 dBm/Hz, but without the ANFP limits, it's -36.5 dBm/Hz.
Essentially, for the LR-VDSL2 lines, they've also increased the maximum power that can be transmitted on an individual downstream tone. In particular, this applies to the below 1.1 MHz tones (the ADSL downstream range).
