Page 895 - 5G Basics - Core Network Aspects

Transport aspects 2

Table 12-4 – FTU-O state definitions

State name Description

O-DEACTIVATING2 Temporary state entered upon fast retrain request;
(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
update is complete, the precoder output Zi' is set to zero, and FTU-O transitions to the
O-INIT/TRAIN state (start with O-P-QUIET1).

Table 12-5 – FTU-R state definitions
State name Description

R-SELFTEST Temporary state entered after power-up in which the FTU performs a self-test;
(mandatory) Transmitter is off (QUIET signal at U-R interface);
Receiver is off (no response to C-TONES signal);
If self-test passes, the FTU-R transitions to the R-IDLE state if it is under ME control or
transitions to the R-SILENT state if it is in automatic training mode;
If self-test fails, the FTU-R transitions to the R-UNIT-FAIL state.
R-UNIT-FAIL Steady state entered after an unsuccessful FTU-R self-test;
(mandatory) Transmitter is off (QUIET signal at U-R interface);
Receiver is off (no response to C-TONES signal);
The ME retrieves the self-test results.
R-IDLE Steady state entered after successful self-test if FTU-R is under ME control;
(mandatory) Transmitter is off (QUIET signal at U-R interface);
Receiver is off (no response to C-TONES signal);
The FME waits for initialization request from the ME.
R-SILENT Temporary state defined in ITU-T G.994.1 entered after self-test passes if the FTU-R is in
(mandatory) automatic training mode or from the R-IDLE state with ME command;
Transmitter is off (transmits R-SILENT0 signal);
Receiver is on in case of FTU-O initiated HS (monitors for C-TONES signal, if detected,
transitions to the R-INIT/HS state).
R-INIT/HS Temporary state entered to perform the ITU-T G.994.1 phase of initialization;
(mandatory) Transmitter is on (starts by transmitting R-TONES-REQ signal);
Receiver is on (starts by monitoring for C-TONES signal);
If silent period or no mode selected, transitions back to the R-SILENT state;
If operating mode selected, transitions to the R-INIT/TRAIN state.
R-INIT/TRAIN Temporary state entered to perform other phases of initialization;
(mandatory) Transmitter is on (starts with R-P-QUIET1);
Receiver is on (starts by monitoring for O-P-QUIET1);
If initialization passes, transitions to the R-SHOWTIME state;
If initialization fails, transitions to the R-SILENT state.

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