Page 894 - 5G Basics - Core Network Aspects

2 Transport aspects

Table 12-4 – FTU-O state definitions

State name Description

O-SELFTEST Temporary state entered after power-up in which the FTU performs a self test;
(mandatory) Transmitter is off (QUIET signal at U-O interface);
Receiver is off (no response to R-TONES-REQ signal – see [ITU-T G.994.1]);
If self-test passes, the FTU-O transitions to the O-IDLE state;
If self-test fails, the FTU-O transitions to the O-UNIT-FAIL state.
O-UNIT-FAIL Steady state entered after an unsuccessful FTU-O self-test;
(mandatory) Transmitter is off (QUIET signal at U-O interface);
Receiver is off (no response to R-TONES-REQ signal);
The ME retrieves the self-test results from the FME.
O-IDLE Steady state entered after successful self-test;
(mandatory) Transmitter is off (QUIET signal at U-O interface);
Receiver is off (no response to R-TONES-REQ signal);
The FME waits for an initialization request from the ME.
O-SILENT Steady state defined in the ITU-T G.994.1, entered upon initialization request from the
(mandatory) ME;
Transmitter is off (QUIET signal at U-O interface);
Receiver is on in case of FTU-R initiated HS (monitors for R-TONES-REQ signal, if
detected, transitions to the O-INIT/HS state);
FME waits for initialization request from ME to transition to the O-INIT/HS state in case
FTU-O initiated HS.
O-INIT/HS Temporary state entered to perform the ITU-T G.994.1 phase of initialization;
(mandatory) Transmitter is on (starts by transmitting C-TONES signal);
Receiver is on (starts by monitoring for R-SILENT0 signal);
If silent period or no mode selected, transitions back to the O-SILENT1 state;
If operating mode selected then transitions to the O-INIT/TRAIN state.
O-INIT/TRAIN Temporary state entered to perform other phases of initialization;
(mandatory) Transmitter is on (starts with O-P-QUIET1);
Receiver is on (starts by monitoring for R-P-QUIET1);
If initialization passes, transitions to the O-SHOWTIME state;
If initialization fails, transitions to the O-DEACTIVATING1 state.
O-SHOWTIME Steady state entered to transmit user data;
(mandatory) Online reconfigurations occurs within this state;
Upon conditions satisfying the fast-retrain policy (FRpolicy), transitions to the
O-DEACTIVATING2 state;
When link transition to L3 state is granted, the FTU-O transitions to the
O-DEACTIVATING1 state;
The FME reports the FTU-O performance parameters to the ME.
O-DEACTIVATING1 Temporary state entered upon line transition to L3 state;
(mandatory) Transmitter is on (transmits idle symbols at the required positions of all logical frames:
values Zi at the precoder input are set to zero but pre-compensation signals are
transmitted to support downstream FEXT cancellation);
Receiver is on (to support upstream FEXT cancellation and detect the status of the
FTU-R);
The VCE updates the downstream and upstream FEXT cancellation coefficients; after the
update is complete, the precoder output Zi' is set to zero and the FTU-O transitions to
the O-SILENT state.

884