gr::fec::code::ldpc_bit_flip_decoder Class Reference

LDPC bit flip decoding class. More...

#include <gnuradio/fec/ldpc_bit_flip_decoder.h>

Public Member Functions
bool	set_frame_size (unsigned int frame_size) override=0
	Sets the uncoded frame size to frame_size. More...
double	rate () override=0
	Returns the coding rate of this decoder. More...
Public Member Functions inherited from gr::fec::generic_decoder
virtual void	generic_work (void *inbuffer, void *outbuffer)=0
int	unique_id ()
std::string	alias ()
	generic_decoder (void)
	generic_decoder (std::string name)
virtual	~generic_decoder ()
virtual double	rate ()=0
virtual int	get_input_size ()=0
virtual int	get_output_size ()=0
virtual int	get_history ()
virtual float	get_shift ()
virtual int	get_input_item_size ()
virtual int	get_output_item_size ()
virtual const char *	get_input_conversion ()
virtual const char *	get_output_conversion ()
virtual bool	set_frame_size (unsigned int frame_size)=0
virtual float	get_iterations ()

Static Public Member Functions
static generic_decoder::sptr	make (const fec_mtrx_sptr mtrx_obj, unsigned int max_iter=100)
	Build a bit flip decoding FEC API object. More...

Additional Inherited Members
Public Types inherited from gr::fec::generic_decoder
typedef std::shared_ptr< generic_decoder >	sptr
Public Attributes inherited from gr::fec::generic_decoder
int	my_id
std::string	d_name
Static Public Attributes inherited from gr::fec::generic_decoder
static int	base_unique_id
Protected Attributes inherited from gr::fec::generic_decoder
gr::logger_ptr	d_logger

Detailed Description

LDPC bit flip decoding class.

A hard decision bit flip decoder class for decoding low density parity check (LDPC) codes. The decoder requires knowledge of the matrix used to create (encode) the codewords. The simple algorithm is:

1. Compute parity checks on all of the bits.
2. Flip the bit(s) associated with the most failed parity checks.
3. Check to see if new word is valid. ( \(\overline{x}\) is a codeword if and only if \(\mathbf{H}\bar{x}^{T}=\overline{0}\).) If it is not valid, go back to step 1.
4. Repeat until valid codeword is found or the maximum number of iterations is reached.

Member Function Documentation

make()

static generic_decoder::sptr gr::fec::code::ldpc_bit_flip_decoder::make ( const fec_mtrx_sptr  mtrx_obj, unsigned int  max_iter = 100  )

static

Build a bit flip decoding FEC API object.

Parameters

mtrx_obj	The LDPC parity check matrix to use for decoding. This should be the same matrix used for encoding. Provide either a ldpc_H_matrix or a ldpc_G_matrix object.
max_iter	Maximum number of iterations to complete during the decoding algorithm. The default is 100 because this seemed to be sufficient during testing. May be increased for possibly better performance, but may slow things down.

rate()

double gr::fec::code::ldpc_bit_flip_decoder::rate ( )

overridepure virtual

Returns the coding rate of this decoder.

Implements gr::fec::generic_decoder.

set_frame_size()

bool gr::fec::code::ldpc_bit_flip_decoder::set_frame_size ( unsigned int  frame_size )

overridepure virtual

Sets the uncoded frame size to frame_size.

Sets the uncoded frame size to frame_size. If frame_size is greater than the value given to the constructor, the frame size will be capped by that initial value and this function will return false. Otherwise, it returns true.

Implements gr::fec::generic_decoder.

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The documentation for this class was generated from the following file:

• ldpc_bit_flip_decoder.h