Page 872 - 5G Basics - Core Network Aspects

2 Transport aspects

NOTE 1 – The reporting of the ACTPSDREFds allows a VCE to calculate an actual PSD at the U-O reference point that
includes power from the precoder signals, reported in the DPU-MIB as ACTPSDpsds.
NOTE 2 – V2PSD is not communicated in an initialization message.
In the upstream direction, the actual transmit PSD reference ACTPSDREF for a particular subcarrier shall
report interpolated values (in dBm/Hz) obtained from MREFPSDus as reported by the FTU-R in R-PRM
message. The MREFPSDus values shall not deviate from the actual PSD during channel analysis and
exchange phase, as calculated into the termination impedance (see clause 7.3 of [ITU-T G.9700]) at the U-R
interface, by more than 1 dB.
NOTE 3 – The reporting of the ACTPSDREFus allows a VCE to calculate an actual PSD at the U-R reference point that
includes the upstream gain adjustments gi, reported in the DPU-MIB as ACTPSDpsus.
Spectrum shaping caused by time-domain filters and analogue filters included in the transmission path
between the output of the modulator and U interface, shall be taken into consideration.
The ACTPSDREF per subcarrier shall be calculated during the initialization.
The valid range of values is from –65 to –100 dBm/Hz in steps of 0.1 dBm/Hz.

A special value shall indicate that the subcarrier is not transmitted.
NOTE 4 – Examples of subcarriers that are not transmitted are subcarriers in RFI bands or IAR bands, subcarriers
outside of LPM and subcarriers outside the MEDLEY set.

11.4.1.2.6 Actual aggregate transmit power (ACTATP)

The actual aggregate transmit power (ACTATP) is the maximum over NOI and DOI of the total amount of
output power delivered by the transmit PMD function to the U reference point at tip-and-ring (in dBm into
a 100 Ohm termination impedance, see [ITU-T G.9700]), at the instant of measurement, assuming a
continuous transmission (either completely in the NOI or completely in the DOI) of data symbols over the
whole TDD frame duration (100% duty cycle) by all active lines of the vectored group.
NOTE – ACTATP includes the direct signal as well as the precoder compensation signals.

At the DPU side, the near-end ACTATP shall be calculated during the initialization. It may be updated
autonomously and shall be updated on request during the showtime L0, L2.1N, L2.1B and L2.2 link states
(see clause 11.2.2.6.2). The near-end ACTATP value may be computed by the VCE.
At the NT side, the near-end ACTATP shall be calculated by the FTU-R during initialization using the assigned
values of gi. It may be updated autonomously and shall be updated on request during showtime L0, L2.1N,
L2.1B and L2.2 link states (see clause 11.2.2.6.2). The near-end ACTATP shall be sent on request to the ME
at the DPU side during showtime.
The actual aggregate transmit power shall be represented as a 10-bit two's complement signed integer
actatp, with the value of ACTATP defined as
ACTATP = actatp/10 dBm.
This data format supports an ACTATP granularity of 0.1 dB, with an ACTATP range from
−31.0 to + 31.0 dBm, corresponding to the set of valid values of actatp = –310 to 310.
A special value actatp = –311 indicates a value of SNRM = –31.1 dBm or lower.

A special value actatp = 311 indicates a value of SNRM = 31.1 dBm or higher.
A special value actatp = –512 indicates that the parameter is undetermined.

All other values for actatp are reserved by ITU-T.
11.4.1.2.7 Signal attenuation (SATN)

11.4.1.2.7.1 Downstream signal attenuation (SATN_DS)

The downstream signal attenuation is denoted as SATN_DS. SATN is defined as the difference in dB
between the total power of the direct signal transmitted by the FTU-O, and the total power of the signal

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