Page 972 - 5G Basics - Core Network Aspects

2 Transport aspects

Table 13-4 – Parameters controlling the SRA procedures

Parameter Definition
The valid values for RA-DSNRMus and RA-DSNRMds are values from 0 to 31.0 dB in steps of
0.1 dB.
The valid values for RA-DTIMEus and RA-DTIMEds are values from 0 to 16 383 s in steps of 1
second.
NOTE – The parameters RA-USNRM and RA-DSNRM shall relate to the baseline bit-loading table. They have the same values as
the DPU-MIB SRA-USNRM and SRA-DSNRM configuration parameters, respectively.

13.2.1.1.3 SRA downshift procedure
If the SNR margin is below the downshift SNR margin (RA-DSNRM) and stays below that for more than the
time specified by the minimum downshift rate adaptation interval (RA-DTIME), the FTU shall attempt to
decrease the net data rate, such that the SNR margin is increased to a level higher than or equal to
RA-DSNRM + 1 dB (see Figure 13-1).

The SNR margin and downshift SNR margin here both relate to the baseline bit-loading table, i.e., the SNR
margin shall be calculated under the assumption that the active bit-loading table is identical to the baseline
bit-loading table.

Steady state operation

RA-DSNRM +1 dB
Continue SNR margin decrease Continue net data rate decrease
RA-DSNRM

Start net data rate decrease

Figure 13-1 – SRA downshift procedure

13.2.1.1.4 SRA upshift procedure
If the SNR margin is above the upshift SNR margin (RA-USNRM) and stays above that for more than the
time specified by the minimum upshift rate adaptation interval (RA-UTIME), the FTU shall attempt to
increase the net data rate, such that the SNR margin is decreased to a level lower than or equal to
RA-USNRM – 1 dB (see Figure 13-2).

The SNR margin and upshift SNR margin here both relate to the baseline bit-loading table, i.e., the SNR
margin shall be calculated under the assumption that the active bit-loading table is identical to the baseline
bit-loading table.

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