ITU-T Recommendations

Vectoring is a transmission method that employs the coordination of line signals for reduction of crosstalk levels and improvement of performance. The degree of improvement depends on the channel characteristics. Vectoring may be for a single user or for multiple users' benefit.
Recommendation ITU-T G.993.5 is specifically limited to the self-far-end crosstalk (self-FEXT) cancellation in the downstream and upstream directions. It defines a single method of self-FEXT cancellation, in which FEXT generated by a group of near-end transceivers and interfering with the far-end transceivers of that same group is cancelled. This cancellation takes place between very high bit-rate digital subscriber line 2 (VDSL2) transceivers, not necessarily of the same profile. This Recommendation is intended to be implemented in conjunction with Recommendation ITU T G.993.2.
This version of this Recommendation integrates all of the previous amendments and corrigenda with the 2015 version 2.0 of Recommendation ITU-T G.993.5.
This version of Recommendation ITU-T G.993.5 corrects or adds the following functionality:
– Typographical correction in clause 8.2 (Corrigendum 1)
– Generalization of the segmentation of SOC messages in clause 10.4.2.2 for vectoring of profile 35b (Corrigendum 1)
– Transceiver O-DEACTIVATING state (Amendment 1)
– Annex A: Mitigating strong FEXT (Amendment 2)
– Annex B: Vectored Long Reach VDSL2 (Amendment 2)
– Encoding of R-P-VECTOR-2 in LR mode with long loop operation (Annex B) (Corrigendum 2)
– Long reach VDSL2 corrigendum related to MAXNOMATP (new).
Corrigendum 1 aligns the handshake codepoint names in clause B.3 with their names as used in Recommendation ITU-T G.994.1.