Page 1032 - 5G Basics - Core Network Aspects

2 Transport aspects

Annex X

Operation without multi-line coordination intended for a crosstalk-free
environment

(This annex forms an integral part of this Recommendation.)

Editorial note: This annex was introduced by Cor.3 to ITU-T G.9701, but is not shown in revision marks for
readability purposes.

X.1 Scope

This annex specifies operation of G.fast transceivers in a crosstalk free environment. In a crosstalk free
environment, vectoring is not used and synchronization between lines is not needed. The annex is
applicable for either twisted-pair (TP) or coaxial cables.

Unless otherwise and specifically stated in this annex, all definitions and requirements specified in the main
body of this Recommendation are applicable for transceivers compliant with this annex.

X.2 Definitions

This annex defines the following terms:
X.2.1 Crosstalk-free environment: an operational environment with no or negligible crosstalk between
lines. Negligible crosstalk is such that, with no coordination between the lines, there is no impact on the
performance of any line due to operation of other lines.

X.3 Abbreviations and acronyms

This annex uses the following abbreviations and acronyms:
DTA Dynamic Time Assignment

X.4 Reference model(s)

The reference model of a DPU intended for operation in a crosstalk-free environment is given in Figure X.1.
The reference model in Figure X.1 is consistent with the one in Figure 5-2, except it has no ɛ-c-1 and ɛ-1-n
signal exchanges and has introduced DTA functionality. The VCE is still present to support test parameters
(see clause 11.4.1.2).

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