Page 986 - 5G Basics - Core Network Aspects

2 Transport aspects

used to indicate that monitoring of the percentage of degraded subcarriers is disabled. If the value of fra-
time is 0, then the value of fra-ntones shall be set to 0.

The fra-ntones defined for the downstream and upstream are denoted as fra-ntones-ds and fra-ntones-us,
respectively.

13.3.1.1.1.3 Minimum number of rtx-uc anomalies (fra-rtx-uc)
The fra-rtx-uc is the minimum number of rtx-uc anomalies received throughout a time window equal to fra-
time in order to arm the second FRA triggering criteria (see clause 13.3.1.1.1.5).
The valid range of non-zero values is from 1 to 1 023 in steps of 1. The valid value 0 shall be used to indicate
that monitoring of the number of rtx-uc anomalies is disabled. If the value of fra-time is 0, then the value of
fra-rtx-uc shall be set to 0.
The fra-rtx-uc defined for the downstream and upstream are denoted as fra-rtx-uc-ds and fra-rtx-uc-us,
respectively.
13.3.1.1.1.4 Vendor discretionary criteria (fra-vendisc)

The fra-vendisc is set to ONE in order to allow vendor discretionary FRA triggering criteria to arm the third
FRA triggering criteria (see clause 13.3.1.1.1.5).
If set to ONE, vendor discretionary FRA triggering criteria may be used. If set to ZERO, vendor discretionary
FRA triggering criteria shall not be used.
The fra-vendisc defined for the downstream and upstream are denoted as fra-vendisc-ds and fra-vendisc-
us, respectively.

13.3.1.1.1.5 FRA triggering criteria
The default setting of BLT status (see Table 9-12) for FRA is aa=002, i.e., no adjustment.

If and only if at least one of the following conditions hold:
• The fra-time>0 and the fra-ntones>0 and the percentage of subcarriers in the MEDLEY SET with
bi>0 that are degraded throughout a time window equal to fra-time is at least fra-ntones;
• The fra-time>0 and the fra-rtx-uc>0 and the number of rtx-uc anomalies throughout a time
window equal to fra-time is at least fra-rtx-uc;
• The fra-vendisc is set to ONE and the vendor discretionary FRA triggering criteria are met;
then the FTU shall initiate an FRA request with BLT status being aa=012 or 102, see Table 9-12.

13.3.1.1.2 Parameters controlled by the FRA procedure
The FRA function allows updates to the active bit loading table of both the normal operation interval and
the discontinuous operation interval. These updates are accomplished by a coordinated change to the bits
values in the different sub-bands. The parameters controlled by FRA specify a configuration. These
parameters are summarized in Table 13-10.

Table 13-10 – Reconfigurable parameters of the FRA function
Parameter Definition

b i The number of bits per subcarrier with valid values all integers in the [0:Maximum bit loading] range,
subject to the limitations in clause 13.3.1.1. "Maximum bit loading" is a capability indicated during
initialization in the O-MSG 1 and R-MSG 2 messages for the FTU-O and FTU-R, respectively (and denoted
"FTU-O maximum bit loading" and "FTU-R maximum bit loading" accordingly).
B D The number of DTU bytes in a normal (non-RMC) data frame. According to the FRA command, B D of NOI or
DOI is updated.
B DR The number of DTU bytes in an RMC data frame. According to the FRA command, B DR of NOI or DOI is
updated.

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