3.2.4.10.2. RSC DB Decoder parameters¶
3.2.4.10.2.1. --dec-type, -D
¶
- Type
text
- Allowed values
BCJR
CHASE
ML
- Default
BCJR
- Examples
--dec-type BCJR
Select the decoder algorithm.
Description of the allowed values:
Value |
Description |
---|---|
|
Select the BCJR DB decoder [Rsdb-BCJR74]. |
|
See the common --dec-type, -D parameter. |
|
See the common --dec-type, -D parameter. |
3.2.4.10.2.2. --dec-implem
¶
- Type
text
- Allowed values
GENERIC
DVB-RCS1
DVB-RCS2
- Default
DVB-RCS1
- Examples
--dec-implem DVB-RCS1
Select the implementation of the decoder algorithm.
Description of the allowed values:
Value |
Description |
---|---|
|
Select a generic implementation that works on any trellis. |
|
Select an implementation dedicated to the DVB-RCS1 trellis
(faster than the |
|
Select an implementation dedicated to the DVB-RCS2 trellis
(faster than the |
3.2.4.10.2.3. --dec-max
¶
- Type
text
- Allowed values
MAXS
MAXL
MAX
- Examples
--dec-max MAX
Select the approximation of the \(\max^*\) operator used in the trellis decoding.
Description of the allowed values:
Value |
Description |
---|---|
|
\(\max^*(a,b) = \max(a,b) + \log(1 + \exp(-|a - b|))\). |
|
\(\max^*(a,b) \approx \max(a,b) + \max(0, 0.301 - (0.5 |a - b|))\). |
|
\(\max^*(a,b) \approx \max(a,b)\). |
MAXS
for Max Star is the exact \(\max^*\) operator. MAXL
for
Max Linear is a linear approximation of the \(\max^*\) function. MAX
for Max is the simplest \(\max^*\) approximation with only a
\(\max\) function.
Note
The BCJR with the \(\max\) approximation is also called the max-log-MAP algorithm.
3.2.4.10.2.4. References¶
- Rsdb-BCJR74
L. Bahl, J. Cocke, F. Jelinek, and J. Raviv. Optimal decoding of linear codes for minimizing symbol error rate (corresp.). IEEE Transactions on Information Theory (TIT), 20(2):284–287, March 1974. doi:10.1109/TIT.1974.1055186.