Page 938 - 5G Basics - Core Network Aspects

2 Transport aspects

described in clause 10.2.2.1. The SOC shall be in its active state. The probe sequence modulating sync
symbols shall be continued from the previous stage with no interruption.

The O-P-CHANNEL-DISCOVERY 1 signal shall use all subcarriers from the SUPPORTEDCARRIERSds set. SOC
symbols shall use robust SOC bit mapping (see clause 10.2.2.2.1). The transmit PSD shall be equal to
CDPSDds, as determined during the O-VECTOR 1 stage. The actual value of CDPSDds is communicated to
the FTU-R in the O-SIGNATURE message.

From the start of the first superframe of the O-CHANNEL DISCOVERY 1 stage (symbol with index 0 of the
first downstream logical frame), the SOC shall transmit O-IDLE for a period of eight superframes (IDS and
SOC symbol repetition are disabled in the first superframe) plus any additional symbols required to
complete SOC repetition, followed by the O-SIGNATURE message, as defined in clause 12.3.3.2.1. The
O-SIGNATURE message shall be sent in auto-repeat mode (see clause 12.2.2.1). After detection of
R-P-VECTOR 1 signal, the SOC shall stop transmission of O-SIGNATURE message and transmit O-IDLE
followed by transmission of O-TG-UPDATE message, as defined in clause 12.3.3.2.1. The O-TG-UPDATE
message shall be transmitted in auto-repeat mode. The SOC quadrant scrambler shall be in reset mode.
Starting from the beginning of the first downstream logical frame of the second superframe of this stage,
every transmitted SOC symbol shall be repeated as defined in clause 10.2.2.3. The number of SOC symbol
repetitions, R, shall be as selected during the ITU-T G.994.1 phase of initialization (see clause 12.3.2.1.2).

After repetition is applied, all SOC symbols shall be modulated by the IDS, as defined in clause 10.2.2.2. The
IDS shall be as selected during the ITU-T G.994.1 phase of initialization.
During the transmission of O-IDLE that follows detection of R-P-VECTOR 1 signal, the FTU-O estimates the
correction to the initial value of the time gap Tg1'. As the estimation is complete, the value is communicated
to the FTU-R in the O-TG-UPDATE message. The duration of the O-IDLE is determined by the FTU-O and
depends on the required estimation time.
The O-P-CHANNEL-DISCOVERY 1 signal shall be followed by the O-P-SYNCHRO 1 signal. Transition to O-P-
SYNCHRO 1 signal determines the actual duration of the O-CHANNEL DISCOVERY 1 stage. The start time of
O-P-SYNCHRO 1 signal transmission is determined by the VCE and shall be at the symbol with index zero of
the first downstream logical frame of the superframe. Transmission of O-P-SYNCHRO 1 signal may
terminate the last repetition of the O-TG-UPDATE message.

12.3.3.3.4.2 R-P-VECTOR 1
The transmission of the R-P-VECTOR 1 signal shall start from the following superframe after the FTU-R
successfully detects the O-SIGNATURE message and adopts the upstream transmission parameters
indicated in the O-SIGNATURE message. Prior to transmission of the R-P-VECTOR 1 signal, the FTU-R shall
continue transmission of the R-P-QUIET 1 signal.

During transmission of the R-P-VECTOR 1 signal, the FTU-R applies the time gap Tg1'.
NOTE – During transmission of the R-P-VECTOR 1 signal, the VCE may estimate the upstream FEXT channels between
all lines (both initializing lines and vectored lines). Upon completion of the R-VECTOR 1 stage, the time position of
upstream symbols of the joining lines is aligned with vectored lines and upstream FEXT cancellation matrices are
established by the VCE for all vectored lines and initializing lines, and upstream FEXT is cancelled.

The R-P-VECTOR 1 signal shall consist of upstream sync symbols and quiet symbols only. Sync symbols shall
be transmitted at each upstream sync symbol position. Quiet symbols shall be transmitted at all other
upstream symbol positions. The sync symbols shall be generated as described in clause 10.2.2.1. The SOC
shall be in its inactive state.
The R-P-VECTOR 1 signal shall use all subcarriers from the SUPPORTEDCARRIERSus set, as indicated in the
O-SIGNATURE message. The transmit PSD (STARTPSDus) shall be derived using the estimated electrical
length and UPBO parameters indicated in the O-SIGNATURE message.
The FTU-R shall use the probe sequence indicated in the O-SIGNATURE message, starting transmission from
the bit of the sequence computed using the upstream probe sequence start marker value indicated in the
O-SIGNATURE message.

928