Page 985 - 5G Basics - Core Network Aspects

Transport aspects 2

NOTE: If RMC frames are received with no errors, the FRA-R is expected to arrive in less than 6ms (this takes into
account the response time and some margin for transmission time).

13.3.1.1.1 Parameters controlling the FRA procedure
The list of DPU-MIB parameters controlling the FRA procedure is presented in Table 13-9. These parameters
are used in the FRA triggering criteria defined in clause 13.3.1.1.1.5.
Each of the four FRA triggering parameters can have different values for the FTU-O (upstream) and the
FTU-R (downstream).
• FTU-O (upstream): Configured through the DPU-MIB.
• FTU-R (downstream): Configured through the DPU-MIB and communicated to the FTU-R during
initialization (in O-MSG 1 message).

Table 13-9 – Parameters controlling the FRA procedures

Parameter Definition
FRA-TIME FRA-TIME determines the duration of the FRA time window used in the standard FRA
triggering criteria.
FRA-NTONES FRA-NTONES determines the minimum percentage of subcarriers with bi>0 that are to be
detected as degraded ones over the time window equal to FRA–TIME in order to arm the first
FRA triggering criterion.
FRA-RTX-UC FRA-RTX-UC determines the minimum number of rtx–uc anomalies received throughout a time
window equal to FRA–TIMEds in order to arm the second FRA triggering criterion.
FRA-VENDISC Determines whether vendor-discretionary FRA triggering criteria may be used.
The control parameters fra-ntones (see clause 13.3.1.1.1.2), fra-rtx-uc (see clause 13.3.1.1.1.3), and
fra-time (see clause 13.3.1.1.1.1) are derived from the DPU-MIB parameters FRA-NTONES, FRA-RTX-UC, and
FRA-TIME. The value zero for FRA-TIME in the DPU-MIB indicates that vendor discretionary values for
fra-ntones, fra-rtx-uc, and fra-time may be used instead of the values configured in the DPU-MIB for
FRA-NTONES, FRA-RTX-UC, and FRA-TIME, respectively.

The control parameter fra-vendisc is equal to the DPU-MIB parameter FRA-VENDISC. The value ONE for
FRA-VENDISC indicates that vendor discretionary FRA triggering criteria may be used. The value ZERO for
FRA-VENDISC indicates that vendor discretionary FRA triggering criteria shall not be used.

13.3.1.1.1.1 FRA time window (fra-time)
The fra-time is the duration of the time window used in the standard FRA triggering criteria (see clause
13.3.1.1.1.5). This time window shall be applied to contiguous non-overlapping time steps. The start time of
this window is vendor discretionary. The valid range of non-zero values is from one logical frame length to
one superframe length in steps of one logical frame length. The special valid value zero shall be used to
indicate that both monitoring of the percentage of degraded subcarriers (see clause 13.3.1.1.1.2) and
monitoring of the number of rtx-uc anomalies (see clause 13.3.1.1.1.3) are disabled.

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

13.3.1.1.1.2 Minimum percentage of degraded tones (fra-ntones)

The fra-ntones is the minimum percentage of loaded subcarriers (i.e., subcarriers with bi>0) that are
detected as degraded throughout a time window equal to fra-time in order to arm the first FRA triggering
criteria (see clause 13.3.1.1.1.5).
A degraded subcarrier is a subcarrier that has been identified as needing a reduction in active bit loading
because, with its current active bit loading, it is expected to contribute substantially to the decrease of
SNRM. The valid range of non-zero values is from one to 100 in step of one. The valid value zero shall be

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