3.2.4.12.2. Turbo DB Decoder parameters¶
3.2.4.12.2.1. --dec-type, -D¶
- Type
text
- Allowed values
TURBO_DBCHASEML- Default
TURBO_DB- Examples
--dec-type CHASE
Select the decoder algorithm.
Description of the allowed values:
Value |
Description |
|---|---|
|
Select the standard Turbo decoder. |
|
See the common --dec-type, -D parameter. |
|
See the common --dec-type, -D parameter. |
3.2.4.12.2.2. --dec-implem¶
- Type
text
- Allowed values
STD- Default
STD- Examples
--dec-implem STD
Select the implementation of the decoder algorithm.
Description of the allowed values:
Value |
Description |
|---|---|
|
Select the STD implementation. |
3.2.4.12.2.3. --dec-sub-type, -D¶
Please refer to the RSC DB --dec-type, -D parameter.
3.2.4.12.2.4. --dec-sub-implem¶
Please refer to the RSC DB --dec-implem parameter.
3.2.4.12.2.5. --dec-crc-start¶
- Type
integer
- Default
2- Examples
--dec-fnc-crc-ite 1
Set the first iteration to start the CRC checking.
Note
This parameter requires the Turbo code to be concatenated with a CRC to work, see the CRC parameters.
3.2.4.12.2.6. --dec-fnc¶
Enable the FNC post processing technique.
Note
The FNC post processing technique is detailed in [Trdb-TLLeGal+16].
Note
This parameter requires the Turbo code to be concatenated with a CRC to work, see the CRC parameters.
3.2.4.12.2.7. --dec-fnc-ite-m¶
- Type
integer
- Default
3- Examples
--dec-fnc-ite-m 2
Set the first iteration at which the FNC is used.
See the --dec-fnc parameter.
3.2.4.12.2.8. --dec-fnc-ite-M¶
- Type
integer
- Default
10- Examples
--dec-fnc-ite-M 6
Set the last iteration at which the FNC is used.
See the --dec-fnc parameter.
3.2.4.12.2.9. --dec-fnc-ite-s¶
- Type
integer
- Default
1- Examples
--dec-fnc-ite-s 2
Set the iteration step for the FNC technique.
See the --dec-fnc parameter.
3.2.4.12.2.10. --dec-fnc-q¶
- Type
integer
- Default
10- Examples
--dec-fnc-q 6
Set the search space for the FNC technique.
See the --dec-fnc parameter.
3.2.4.12.2.11. --dec-ite, -i¶
- Type
integer
- Default
6- Examples
--dec-ite 8
Set the maximal number of iterations in the Turbo decoder.
If the Turbo code is concatenated with a CRC and if the CRC is checked, the decoder can stop before making all the iterations.
3.2.4.12.2.12. --dec-sf-type¶
- Type
text
- Allowed values
ADAPTIVEARRAYCSTLTELTE_VEC- Examples
--dec-sf-type ADAPTIVE--dec-sf-type CST 0.5
Select a scaling factor (SF) to be applied to the extrinsic values after each half iteration.
This is especially useful with the max-log-MAP sub-decoders (BCJR with the \(\max\) approximation): the SF helps to recover a part of the decoding performance loss compare to the MAP algorithm (BCJR with the \(\max^*\) operator).
Note
The SF technique is detailed in [Trdb-VF00].
Description of the allowed values:
Value |
Description |
|---|---|
|
Select the adaptive SF, for the first and second iterations a SF of 0.5 is applied, for the other iterations the SF is 0.85. |
|
Select an hard-coded array of SFs (c.f. Table 3.3). |
|
Set the same SF to be applied for each iterations. |
|
Select a 0.75 SF. |
|
Select a 0.75 vectorized SF (faster than |
Iteration |
Value |
|---|---|
1 |
0.15 |
2 |
0.25 |
3 |
0.30 |
4 |
0.40 |
5 |
0.70 |
6 |
0.80 |
7 |
0.90 |
8 |
0.95 |
3.2.4.12.2.13. --dec-sub-max¶
Please refer to the RSC --dec-max parameter.
3.2.4.12.2.14. References¶
- Trdb-TLLeGal+16
T. Tonnellier, C. Leroux, B. Le Gal, C. Jégo, B. Gadat, and N. Van Wambeke. Lowering the error floor of double-binary turbo codes: the flip and check algorithm. In International Symposium on Turbo Codes and Iterative Information Processing (ISTC), 156–160. IEEE, September 2016. doi:10.1109/ISTC.2016.7593096.
- Trdb-VF00
J. Vogt and A. Finger. Improving the max-log-MAP turbo decoder. IET Electronics Letters, 36(23):1937–1939, November 2000. doi:10.1049/el:20001357.