3.2.4.2.2. BCH Decoder parameters¶
3.2.4.2.2.1. --dec-type, -D
¶
- Type
text
- Allowed values
ALGEBRAIC
CHASE
ML
- Default
ALGEBRAIC
- Examples
--dec-type ALGEBRAIC
Select the decoder algorithm.
Description of the allowed values:
Value |
Description |
---|---|
|
Select the Berlekamp-Massey algorithm [Bch-Ber15, Bch-Mas69] followed by a Chien search [Bch-Chi64]. |
|
See the common --dec-type, -D parameter. |
|
See the common --dec-type, -D parameter. |
3.2.4.2.2.2. --dec-implem
¶
- Type
text
- Allowed values
FAST
GENIUS
STD
- Default
STD
- Examples
--dec-implem FAST
Select the implementation of the decoder algorithm.
Description of the allowed values:
Value |
Description |
---|---|
|
A standard implementation of the BCH. |
|
Select the fast implementation optimized for SIMD architectures. |
|
A really fast implementation that compare the input to the original codeword and correct it only when the number of errors is less or equal to the BCH correction power. |
Note
In the STD
implementation, the Chien search finds roots of the
error location polynomial. If the number of found roots does not match the
number of found errors by the BM algorithm, then the frame is not modified.
However, in the FAST
implementation the correction of the bits
is done at the same time as the execution of the Chien search. Then when the
latter fails, the frame can be modified.
Note
When a frame is very corrupted and when the above STD
and FAST
implementations can be wrong in the correction by converging to another
codeword, the GENIUS
implementation cannot fail. Results may then differ
from a real word implementation.
3.2.4.2.2.3. --dec-corr-pow, -T
¶
- Type
integer
- Default
5
- Examples
--dec-corr-pow 18
Set the correction power of the BCH decoder. This value corresponds to the number of errors that the decoder is able to correct.
3.2.4.2.2.4. References¶
- Bch-Ber15
E. R. Berlekamp. Algebraic Coding Theory (Revised Edition). World Scientific, May 2015. First edition from 1968. doi:10.1142/9407.
- Bch-Chi64
R. Chien. Cyclic decoding procedures for bose- chaudhuri-hocquenghem codes. IEEE Transactions on Information Theory (TIT), 10(1):357–363, October 1964. doi:10.1109/TIT.1964.1053699.
- Bch-Mas69
J. Massey. Shift-register synthesis and bch decoding. IEEE Transactions on Information Theory (TIT), 15(1):122–127, January 1969. doi:10.1109/TIT.1969.1054260.