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id: variable_ldpc_encoder_H_def
label: LDPC Encoder Definition (via Parity Check)
parameters:
- id: value
label: Ignore Me
dtype: raw
default: '"ok"'
hide: all
- id: ndim
label: Parallelism
dtype: enum
options: ['0', '1', '2']
- id: dim1
label: Dimension 1
dtype: int
default: '1'
hide: ${ ('none' if (int(ndim) >= 1) else 'all') }
- id: dim2
label: Dimension 2
dtype: int
default: '1'
hide: ${ ('none' if (int(ndim) >= 2) else 'all') }
- id: H
label: Parity Check Matrix
dtype: raw
value: ${ value }
templates:
imports: from gnuradio import fec
var_make: "\n% if int(ndim)==0 #:\nself.${id} = ${id} = fec.ldpc_par_mtrx_encoder_make_H(${H})\n\
% elif int(ndim)==1 #:\nself.${id} = ${id} = map((lambda a: fec.ldpc_par_mtrx_encoder_make_H(${H})),\
\ range(0,${dim1})) \n% else:\nself.${id} = ${id} = map((lambda b: map((lambda\
\ a: fec.ldpc_par_mtrx_encoder_make_H(${H})), range(0,${dim2}))), range(0,${dim1}))\
\ \n% endif"
documentation: |-
This block creates a LDPC Encoder Definition variable.
This encoder performs a reduced complexity algorithm described by Richardson and Urbanke in Appendix A of their book: Modern Coding Theory. Compared to the block "LDPC Encoder Definition (via Generator)," this encoder requires orders of magnitude fewer operations to create each codeword. This is accomplished by completing a significant amount of the complex matrix manipulation (including inverse, multiplication, and Gaussian elimination operations) during preprocessing. The disadvantage of this encoder is that it requires a specially formatted matrix. However, GNU Radio includes python scripts to format a standard parity check matrix appropriately for this encoder, as well as a small library of encoding-ready matrices for use.
file_format: 1
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