3.2.4.10.2. Turbo Decoder parameters¶
3.2.4.10.2.1. --dec-type, -D
¶
Type: text Allowed values: TURBO
CHASE
ML
Default: TURBO
Examples: --dec-type CHASE
Select the algorithm you want to decode the codeword.
Description of the allowed values:
Value | Description |
---|---|
TURBO |
Select the Turbo decoder, the two sub-decoders are from the RSC code family. |
CHASE |
See the common --dec-type, -D parameter. |
ML |
See the common --dec-type, -D parameter. |
3.2.4.10.2.2. --dec-implem
¶
Type: text Allowed values: STD
FAST
Default: FAST
Examples: --dec-implem FAST
Select the decoder implementation.
Description of the allowed values:
Value | Description |
---|---|
STD |
Select the STD implemenation. |
FAST |
Select the fast implemenation from [CTL+16]. |
3.2.4.10.2.3. --dec-sub-type, -D
¶
Please refer to the RSC --dec-type, -D parameter.
3.2.4.10.2.4. --dec-sub-implem
¶
Please refer to the RSC --dec-implem parameter.
3.2.4.10.2.5. --dec-sub-simd
¶
Please refer to the RSC --dec-simd parameter.
3.2.4.10.2.6. --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.
3.2.4.10.2.7. --dec-fnc
¶
Enable the FNC post processing technique from [TLLeGal+16].
Note
This parameter requires the Turbo code to be concatenated with a CRC to work, see the CRC parameters.
3.2.4.10.2.8. --dec-fnc-ite-m
¶
Type: integer Default: 3
Examples: --dec-fnc-ite-m 2
Set the first iteration at which the FNC is used (c.f the --dec-fnc parameter).
3.2.4.10.2.9. --dec-fnc-ite-M
¶
Type: integer Default: 10
Examples: --dec-fnc-ite-M 6
Set the last iteration at which the FNC is used (c.f the --dec-fnc parameter).
3.2.4.10.2.10. --dec-fnc-ite-s
¶
Type: integer Default: 1
Examples: --dec-fnc-ite-s 2
Set the iteration step for the FNC technique (c.f the --dec-fnc parameter).
3.2.4.10.2.11. --dec-fnc-q
¶
Type: integer Default: 10
Examples: --dec-fnc-q 6
Set the search space for the FNC technique (c.f the --dec-fnc parameter).
3.2.4.10.2.12. --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.
3.2.4.10.2.13. --dec-sc
¶
Enables the SC decoder from [Ton17] (in French).
Note
This parameter requires the Turbo code to be concatenated with a CRC to work, see the CRC parameters.
3.2.4.10.2.14. --dec-sf-type
¶
Type: text Allowed values: ADAPTIVE
ARRAY
CST
LTE
LTE_VEC
Examples: --dec-sf-type ADAPTIVE
--dec-sf-type CST 0.5
Select a SF to be applied to the extrinsic values after each half iteration [VF00]. 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).
Description of the allowed values:
Value | Description |
---|---|
ADAPTIVE |
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. |
ARRAY |
Select an hard-coded array of SFs (c.f. Table 3.3). |
CST |
Set the same SF to be applied for each iterations. |
LTE |
Select a 0.75 SF. |
LTE_VEC |
Select a 0.75 vectorized SF (faster than LTE ), used in
[CTL+16]. |
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 |
3.2.4.10.2.16. References¶
[CTL+16] | (1, 2) A. Cassagne, T. Tonnellier, C. Leroux, B. Le Gal, O. Aumage, and D. Barthou. Beyond Gbps turbo decoder on multi-core CPUs. In International Symposium on Turbo Codes and Iterative Information Processing (ISTC), 136–140. IEEE, September 2016. doi:10.1109/ISTC.2016.7593092. |
[Ton17] | T. Tonnellier. Contribution to the Improvement of the Decoding Performance of Turbo Codes : Algorithms and Architecture. PhD thesis, Université de Bordeaux, 2017. URL: https://tel.archives-ouvertes.fr/tel-01580476. |
[TLLeGal+16] | T. Tonnellier, C. Leroux, B. Le Gal, B. Gadat, C. Jégo, and N. Van Wambeke. Lowering the error floor of turbo codes with CRC verification. IEEE Wireless Communications Letters (WCL), 5(4):404–407, August 2016. doi:10.1109/LWC.2016.2571283. |
[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. |