Page 939 - 5G Basics - Core Network Aspects

Transport aspects 2

During transmission of R-P-VECTOR 1 signal, the FTU-R shall monitor the SOC channel to detect the
O-TG-UPDATE message. Upon reception of O-TG-UPDATE message, the FTU-R shall adjust the gap Tg1' to the
value indicated in O-TG-UPDATE message and continue transmission of R-P-VECTOR 1 signal. The probe
sequence shall continue with no interruption.

The duration of the R-VECTOR 1 stage is determined by the FTU-O: the FTU-R shall terminate transmission
of the R-P-VECTOR 1 signal right upon reception of the O-P-SYNCHRO 1 signal and shall transition to the
CHANNEL DISCOVERY 2 stage starting from the symbol with index 0 of the upstream logical frame following
the last symbol of the O-P-SYNCHRO 1 signal.
12.3.3.3.4.3 O-P-SYNCHRO 1

The O-P-SYNCHRO 1 signal provides an exact time marker for transition from the CHANNEL DISCOVERY 1
stage to the CHANNEL DISCOVERY 2 stage. The duration of the O-P-SYNCHRO 1 signal shall be one
superframe.

The O-P-SYNCHRO 1 signal shall consist of a downstream sync symbol and initialization symbols. Sync
symbol shall be transmitted at the downstream sync symbol position. SOC symbols shall be transmitted at
the first sds symbol positions of each downstream logical frame (i.e., O-P-SYNCHRO 1 transmission of SOC
symbols shall start at the symbol with index 0 of the first downstream logical frame in the superframe); all
other initialization symbols shall be quiet. During transmission of the O-P-SYNCHRO 1 signal, the SOC is
inactive.

The sync symbol shall be generated and modulated by the probe sequence as described in clause 10.2.2.1.
The element of the probe sequence carried by the sync symbol of the O-P-SYNCHRO 1 signal shall continue
the probe sequence transmitted during the CHANNEL DISCOVERY 1 stage with no interruption.
The symbols of the O-P-SYNCHRO 1 signal shall use all subcarriers from the SUPPORTEDCARRIERSds set
modulated as defined in clause 10.2.2.2. The quadrant scrambler shall be in reset mode. The IDS shall be
applied as defined in clause 10.2.2.2.
The first sds symbol positions of all the downstream logical frames of the O-P-SYNCHRO 1 signal shall carry
inverted symbols containing SOC IDLE (see clause 12.2.3 for the equivalent definition when the SOC is in the
active state) with robust bit mapping.

The transmit PSD of the O-P-SYNCHRO 1 signal shall be equal to CDPSDds.

12.3.3.3.5 Signals during CHANNEL DISCOVERY 2 stage
12.3.3.3.5.1 O-P-CHANNEL-DISCOVERY 2

During transmission of the O-P-CHANNEL-DISCOVERY 2 signal, the FTU-O communicates to the FTU-R the
necessary information to update the upstream PSD and timing advance.

The O-P-CHANNEL-DISCOVERY 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. During this stage every transmitted SOC symbol shall be repeated
according to the number of repetitions, RS, which is 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 the same as defined for O-P-CHANNEL-DISCOVERY 1 signal. The SOC
quadrant scrambler shall be in reset mode.
The transmit PSD shall be equal to CDPSDds. The O-P-CHANNEL-DISCOVERY 2 signal shall use all subcarriers
from the SUPPORTEDCARRIERSds set. The probe sequence modulating sync symbols shall be the one
communicated in O-SIGNATURE message.
If the O-P-CHANNEL-DISCOVERY 1 signal uses the probe sequence communicated in O-SIGNATURE
message, this probe sequence shall be continued from O-P-CHANNEL-DISCOVERY 1 signal into O-P-
CHANNEL-DISCOVERY 2 signal with no interruption.

If the O-P-CHANNEL-DISCOVERY 1 signal uses the special probe sequence communicated during the
handshake, the probe sequence communicated in O-SIGNATURE message shall be used in O-P-CHANNEL-

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