Page 935 - 5G Basics - Core Network Aspects

Transport aspects 2

Field 3 "Upstream reference PSD (MREFPSDus)" indicates the MREFPSDus as defined in clause 7.3.2
(Table 7-1) on all MEDLEYus subcarriers indicated in field 4. The format shall be presented using the "PSD
descriptor" format defined in Table 12-22 and the number of breakpoints being described shall be from 2
to 32. The update of PSD values obtained by the FTU-O on other subcarriers than MEDLEYus set shall be
ignored. The indicated breakpoint values and the interpolated values of MREFPSDus shall not deviate from
the actual value of the transmit PSD, as measured in the termination impedance at the U interface, by more
than 1 dB.

Field 4 "Final MEDLEY set of active US subcarriers "includes a complete set of upstream MEDLEY subcarriers
using the band descriptor presented in Table 12-21, along with all subcarriers from the BLACKOUTus set
(O-PRM, field 5) that fall within the range of frequencies for the included complete set of upstream MEDLEY
subcarriers. The final MEDLEY set of active US subcarriers shall consist of all subcarriers included in this field
except the upstream BLACKOUTus subcarriers (O-PRM, field 5). This field shall contain only subcarriers that
belong to the proposed MEDLEY set of active US subcarriers as indicated in the field 2 of O-PRM message.

12.3.3.3 Signals transmitted during channel discovery phase

12.3.3.3.1 Signals during QUIET 1 stage
12.3.3.3.1.1 O-P-QUIET 1

The O-P-QUIET 1 signal shall consist of QUIET symbols only.
The duration of O-P-QUIET 1 signal is variable with a valid range from 2 to 128 superframes. Its duration is
determined by the FTU-O and is not necessarily an integer number of superframes.
The O-P-QUIET 1 signal shall be followed by the O-P-VECTOR 1 signal. The FTU-O terminates the QUIET 1
stage by starting transmission of the O-P-VECTOR 1 signal at a superframe boundary.

12.3.3.3.1.2 R-P-QUIET 1
The R-P-QUIET 1 signal shall consist of QUIET symbols only.
The R-P-QUIET 1 signal shall be continued until the FTU-R receives the O-SIGNATURE message.

12.3.3.3.2 Signals during O-VECTOR 1 stage

12.3.3.3.2.1 O-P-VECTOR 1
Upon completion of the O-VECTOR 1 stage, the VCE determines the downstream PSD to be used during
further stages of channel discovery phase (CDPSDds).
NOTE – During transmission of the O-P-VECTOR 1 signal, the VCE estimates the downstream FEXT channels from the
initializing lines into the vectored lines based on the reported VF samples from the FTU-Rs of the vectored lines. Upon
completion of the O-VECTOR 1 stage, downstream FEXT cancellation matrices are established by the VCE for all
vectored lines and FEXT from the initializing line into vectored lines is cancelled.
The O-P-VECTOR 1 signal shall consist of downstream sync symbols and quiet symbols only. Sync symbols
shall be transmitted at each downstream sync symbol position. Quiet symbols shall be transmitted at all
other downstream symbol positions (see Figure 10-26). The sync symbols shall be generated as described in
clause 10.2.2.1. The SOC shall be in its inactive state.
The O-P-VECTOR 1 signal shall use all subcarriers from the SUPPORTEDCARRIERSds set. The transmit PSD of
all subcarriers shall be equal to STARTPSDds.
The FTU-O shall use the probe sequence assigned to the initializing line by the vectoring control entity
(VCE).

The duration of the O-VECTOR 1 stage is vendor discretionary, but shall be an integer number of
superframes with the minimum of four superframes and maximum of 1 536 superframes (to be consistent
with the timeout specified in clause 12.3.1). The O-P-VECTOR 1 signal shall be followed by the
O-P-CHANNEL-DISCOVERY 1-1 signal; transition to O-P-CHANNEL-DISCOVERY 1-1 signal determines the
actual duration of the O-VECTOR 1 stage. The start time of the CHANNEL DISCOVERY 1-1 stage is

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