Triple-Play Service Deployment

Chapter 9: Troubleshooting High Speed Data Service
VDSL may be deployed in the same binder groups as ADSL. Two
examples are outlined in Figure 9.7. Cross talk problems from
VSDL service affecting ADSL service can be a significant issue in
such mixed environments. In the figure, the case where VDSL and
ADSL are serviced from the CO or Exchange, the VDSL signal can
affect the ADSL signal (see Point A in Figure 9.7.) In the case
where VDSL is served from a remote node, cross talk can be even
more of a problem. This occurs where the ADSL signal has been
attenuated and is weaker and the VDSL signal is stronger since it
is launched at the remote node (see Point B in the Figure 9.7).
Management of the PSD for VDSL, specifically reducing power on
a pair by pair basis to minimize the interference, is both possible
and needed. In these cases the use of different profiles to reduce
spectrum overlap is also beneficial.
CO/Exchange
DSLAM
OLT
Figure 9.7 VDSL crosstalk analysis
Crosstalk from VDSL
affecting ADSL:
Point A and Point B
Optical Node
VDSL
Profile 8b
VDSL
Profile 30a
ADSL2+1
231