Broadband Powerline (BPL) Interference into VDSL2 on Drop Lines: Measurements and Analyses Ken Kerpez, Telcordia Technologies pursuant to work supported by AT&T email@example.com 732 699-2234
Coupling Measurements Set-Up POWER PHONE
Twenty-five coupling measurementsBPL – VDSL2 Vary with BPL termination impedences, drop wire type, drop length
VDSL2 Profile 8a Bit Rates Interference from -60 dBm/Hz BPL,80 ft exposure length, From well-established VDSL2 simulations Upstream VDSL2 Downstream VDSL2 Upstream bit rates of VDSL2 lowered 40% on average Downstream bit rates of VDSL2 lowered 14% on average
Other measurements • BPL emissions • BPL assumed -60 dBm/Hz, flat, on power drop line • Exceeded FCC part 15 limit up to about 10 dB in some cases • Live BPL line coupling into live VDSL line • Up to 21 percent decrease in VDSL bit rate • Measured in a lab, 30 ft exposure • VDSL1
Ways of mitigating impact 1. Lower power VDSL2 Profile 8a or 12a downstream bit rates averaged over the 25 canonical measured couplings, Flat BPL transmit PSD varying from -50 dBm/Hz to -80 dBm/Hz
Ways of mitigating impact 2. Avoid low frequencies VDSL2 Profile 8a or 12a downstream bit rates averaged over the 25 canonical measured couplings. Lowest BPL band-edge varying from 1.7 MHz to 8 MHz.
Approaches to mitigate impact from BPL into VDSL2 • Define transmit PSD spectral mask • Use more advanced BPL transmit PSD shaping ? • Optional VDSL compatible transmit mode ? • when needed, when nearby VDSL2 detected, etc.