Page 946 - 5G Basics - Core Network Aspects

2 Transport aspects

At the beginning of the first upstream logical frame following the O-P-SYNCHRO 4 signal, the FTU-R shall
start transmission of the R-P-PRM-UPDATE 1 signal. From the start of the first upstream logical frame of the
R-P-PRM-UPDATE signal, the SOC shall send R-IDLE until the FTU-R receives the O-SNR message. The FTU-R
shall acknowledge by sending the R-SNR message and wait to receive the O-P-SYNCHRO 4-1 signal.

12.3.3.3.8.4 R-P-PRM-UPDATE 2

During transmission of the R-P-PRM-UPDATE 2 signal, the FTU-R communicates to FTU-O relevant
parameters obtained during the VECTOR 2 and PARAMETER UPDATE stages.

At the beginning of the first upstream logical frame following the O-P-SYNCHRO 4-1 signal, the FTU-R starts
transmission of R-P-PRM-UPDATE 2 signal which is the same as R-P-PRM-UPDATE 1 signal except SOC
quadrant scrambler shall be in reset mode. The SOC continues transmission of R-IDLE and waits for the
O-PRM message. The FTU-R shall acknowledge by sending the R-PRM message and shall continue
transmission of R-IDLE.

The actual duration of the R-P-PRM-UPDATE 2 signal is determined by the VCE. Upon reception of the O-P-
SYNCHRO 5 signal, the FTU-R shall complete transmission of the R-P-PRM-UPDATE 2 signal and transition to
the channel analysis and exchange phase starting from the symbol with index 0 of the first upstream logical
frame of the superframe following transmission of the O-P-SYNCHRO 5 signal.
12.3.3.3.8.5 O-P-SYNCHRO 4-1

The O-P-SYNCHRO 4-1 signal provides an exact time marker for transition from transmission of the
O-P-PRM-UPDATE 1 signal to transmission of the O-P-PRM-UPDATE 2. The O-P-SYNCHRO 4-1 signal shall
have the same format, start time and duration as the O-P-SYNCHRO 1 signal, except that the SOC quadrant
scrambler shall be in free running mode continued from the previous signal and the IDS shall not be
applied. During transmission of the O-P-SYNCHRO 4-1 signal, the SOC is inactive.
The element of the probe sequence carried by the sync symbol of the O-P-SYNCHRO 4-1 signal shall
continue the probe sequence transmitted during the O-P-PRM-UPDATE 1 stage with no interruption.
The symbols of the O-P-SYNCHRO 4-1 signal shall use all subcarriers from the SUPPORTEDCARRIERSds set
modulated as defined in clause 10.2.2.2.
The transmit PSD of the O-P-SYNCHRO 4-1 signal shall be PRMPSDds.

12.3.3.3.8.6 O-P-SYNCHRO 5
The O-P-SYNCHRO 5 signal provides an exact time marker for transition from the PARAMETER UPDATE
stage to the channel analysis and exchange phase. The O-P-SYNCHRO 5 signal shall have the same format,
start time and duration as the O-P-SYNCHRO 1 signal, except that the inverted symbols containing SOC IDLE
(see clause 12.2.3 for the equivalent definition when the SOC is in the active state) shall use normal bit
mapping and the IDS shall not be applied. During transmission of the O-P-SYNCHRO 5 signal, the SOC is
inactive.
The element of the probe sequence carried by the sync symbol of the O-P-SYNCHRO 5 signal shall continue
the probe sequence transmitted during the PARAMETER UPDATE stage with no interruption.
The symbols of the O-P-SYNCHRO 5 signal shall use all subcarriers from the MEDLEYds set modulated as
defined in clause 10.2.2.2.
The transmit PSD of the O-P-SYNCHRO 5 signal shall be PRMPSDds.

12.3.4 Channel analysis and exchange phase

12.3.4.1 Overview
The channel analysis and exchange phase is the final phase of initialization. During this phase:
– the FTU-O and FTU-R are transmitting sync symbols modulated by probe sequences;
– the SOC is active in both upstream and downstream;

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