Page 1074 - 5G Basics - Core Network Aspects

2 Transport aspects

Nevertheless, the FTU-R's FEQ values may not be correct anymore (on some or all tones), and therefore
SNRM loss and possibly constellation decision errors may occur. The FTU-R may be able to continue
showtime by lowering the bit loading via an FRA procedure (which may be further followed by autonomous
SRA to optimize the bit loading).

Another possibility is that the TIGA command was received by the FTU-R but the TIGA-ACK got lost (e.g.,
due to impulse noise). In principle, in this case the FTU-R knows the settings indicated in TIGA command,
however the VCE/FTU-O cannot be sure of it. Therefore, using SCCC=1101 is a prudent approach, avoiding
de-synchronization in the bit loading tables between the FTU-O and FTU-R.

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