Page 942 - 5G Basics - Core Network Aspects

2 Transport aspects

12.3.3.3.7 Signals during VECTOR 2 stage

12.3.3.3.7.1 O-P-VECTOR 2
The O-P-VECTOR 2 signal shall have the same structure as the O-P-CHANNEL-DISCOVERY 1 signal and shall
consist of downstream sync symbols and initialization symbols. The SOC shall be in its active state and use
robust bit mapping. The SOC symbol repetition rate, RS, and the IDS shall be applied. The SOC quadrant
scrambler shall be in the reset mode. The transmit PSD shall be V2PSDds, which is derived from CDPSDds by
applying constraints indicated in the R-UPDATE message. The O-P-VECTOR 2 signal shall use all subcarriers
from the SUPPORTEDCARRIERSds set. The probe sequence modulating sync symbols shall be continued
from the O-P-VECTOR 1-1 and O-P-SYNCHRO 3 signals with no interruption.

The FTU-O shall start transmission of the O-P-VECTOR 2 signal right upon completion of transmission of the
O-P-SYNCHRO 3 signal, starting from symbol 0 of the following logical frame. From the start of the
O-P-VECTOR 2 signal, the SOC shall transmit O-IDLE for at least three superframes followed by an
O-VECTOR-FEEDBACK message that communicates to the FTU-R a request to start reporting VF samples and
the parameters of the VF samples to be reported, as defined in Table 12-28. The O-VECTOR-FEEDBACK
message shall be sent using RQ mode (see clause 12.2.2.2).

After transmission of O-VECTOR-FEEDBACK message, the FTU-O shall transmit O-IDLE until the end of this
stage. Upon reception of the R-ACK message, the FTU-O shall transmit an O-P-SYNCHRO 3-1 signal from the
symbol with index zero of the first downstream logical frame of a superframe.

12.3.3.3.7.2 O-P-VECTOR 2-1
During transmission of the O-P-VECTOR 2-1 signal, the FTU-O obtains VF samples from the FTU-R and
computes precoding coefficient to cancel the downstream crosstalk from active lines into joining lines and
between joining lines.
The O-P-VECTOR 2-1 signal shall have the same structure as the O-P-CHANNEL-DISCOVERY 1 signal and shall
consist of downstream sync symbols and initialization symbols. The SOC shall be in its active state and use
robust bit mapping. The SOC symbol repetition rate, RS, and the IDS shall be applied. The SOC quadrant
scrambler shall be in reset mode. The transmit PSD shall be kept equal to V2PSDds until the end of this
stage and the precoder shall not be applied towards the joining lines. The O-P-VECTOR 2-1 signal shall use
all subcarriers from the SUPPORTEDCARRIERSds set. The probe sequence modulating sync symbols shall be
continued from O-P-VECTOR 2 and O-P-SYNCHRO 3-1 signals with no interruption.
The FTU-O shall start transmission of O-P-VECTOR 2-1 signal after the last symbol of O-P-SYNCHRO-3-1
signal (starting from the symbol with index 0 of the first logical frame following the last symbol of
O-P-SYNCHRO-3-1 signal). From the start of O-P-VECTOR 2-1 signal the FTU-O shall transmit O-IDLE.
Upon reception of R-VECTOR-FEEDBACK messages sufficient to perform channel estimation, the
FTU-O computes the precoder coefficients and PSD updates for all active and all joining lines.
The FTU-O shall not acknowledge R-VECTOR-FEEDBACK messages; the FTU-O terminates transmission of R-
VECTOR-FEEDBACK messages and completes this stage by sending the O-P-SYNCHRO 4 signal.
The actual duration of the O-P-VECTOR 2 signal is determined by the VCE. The start time of the
O-P-SYNCHRO 4 signal transmission shall be at the symbol with index 0 of the first downstream logical
frame of the superframe. Transmission of the O-P-SYNCHRO 4 signal may terminate transmission of O-IDLE
prior to the completion of the last SOC symbol repetition.
After transmission of the O-P-SYNCHRO 4 signal, the FTU-O shall transition to the PARAMETER UPDATE
stage.
12.3.3.3.7.3 R-P-VECTOR 2

The R-P-VECTOR 2 signal shall have the same structure as the R-P-CHANNEL-DISCOVERY 1 signal and shall
consist of upstream sync symbols and initialization symbols. The SOC shall be in its active state and use a
robust bit mapping. The SOC quadrant scrambler shall be in reset mode. The transmit PSD shall be equal to

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