3.2.4.3.1. LDPC Encoder parameters¶
3.2.4.3.1.1. --enc-cw-size, -N
¶
- Type
integer
- Examples
--enc-cw-size 1024
Set the codeword size \(N\).
Note
This parameter value is automatically deduced if the \(H\) parity matrix is given with the --dec-h-path parameter or if the \(G\) generator matrix is given with the --enc-g-path parameter.
3.2.4.3.1.2. --enc-info-bits, -K
¶
- Type
integer
- Examples
--enc-info-bits 512
Set the number of information bits \(K\).
Note
This parameter value is automatically deduced if the \(G\) generator matrix is given with the --enc-g-path parameter.
Note
In some cases, this parameter value can be automatically deduced if the \(H\) parity matrix is given with the --dec-h-path parameter. For regular matrices, \(K = N - M\) where \(N\) and \(M\) are the \(H\) parity matrix dimensions. For non-regular matrices, \(K\) has to be given.
3.2.4.3.1.3. --enc-type
¶
- Type
text
- Allowed values
LDPC
LDPC_H
LDPC_DVBS2
LDPC_IRA
LDPC_QC
AZCW
COSET
USER
- Default
AZCW
- Examples
--enc-type AZCW
Select the encoder type.
Description of the allowed values:
Value |
Description |
---|---|
|
Select the generic encoder that encode from a given \(G\) generator matrix (to use with the --enc-g-path parameter). |
|
Build the \(G\) generator matrix from
the given \(H\) parity matrix and then encode with the |
|
Select the optimized encoding process for the DVB-S2 \(H\) matrices (to use with the --enc-cw-size, -N and --enc-info-bits, -K parameters). |
|
Select the optimized encoding process for the IRA \(H\) parity matrices (to use with the --dec-h-path parameter). |
|
Select the optimized encoding process for the QC \(H\) parity matrices (to use with the --dec-h-path parameter). |
|
See the common --enc-type parameter. |
|
See the common --enc-type parameter. |
|
See the common --enc-type parameter. |
Note
The LDPC_DVBS2
encoder type allow the simulation of the
DVB-S2 standard but without the BCH code. All matrices described by
the standard (Tables 5a/5b page 22-23)
are available. You just need to give to the arguments
--enc-info-bits, -K and --enc-cw-size, -N the real
\(K\) and \(N\) LDPC dimensions, respectively.
3.2.4.3.1.4. --enc-g-path
¶
- Type
file
- Rights
read only
- Examples
--enc-g-path example/path/to/the/G_matrix.alist
Give the path to the \(G\) generator matrix in an AList or QC formated file.
3.2.4.3.1.5. --enc-g-method
¶
- Type
text
- Allowed values
IDENTITY
LU_DEC
- Default
IDENTITY
- Examples
--enc-g-method IDENTITY
Specify the method used to build the \(G\) generator matrix from the
\(H\) parity matrix when using the LDPC_H
encoder.
Description of the allowed values:
Value |
Description |
---|---|
|
Generate an identity on \(H\) to get the parity part. |
|
Generate a hollow \(G\) thanks to the LU decomposition with a guarantee to have the systematic identity. Do not work with irregular matrices. |
LU_DEC
method is faster than IDENTITY
.
3.2.4.3.1.6. --enc-g-save-path
¶
- Type
file
- Rights
write only
- Examples
--enc-g-save-path example/path/to/the/generated/G_matrix.alist
Set the file path where the \(G\) generator matrix will be saved (AList
file format). To use with the LDPC_H
encoder.
Hint
When running the LDPC_H
encoder, the generation of the \(G\)
matrix can take a non-negligible part of the simulation time. With this
option the \(G\) matrix can be saved once for all and used in the
standard LDPC
decoder after.