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/* -*- c++ -*- */
/*
* Copyright 2015 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#ifndef INCLUDED_FEC_POLAR_DECODER_COMMON_H
#define INCLUDED_FEC_POLAR_DECODER_COMMON_H
#include <gnuradio/fec/api.h>
#include <gnuradio/fec/generic_decoder.h>
#include <gnuradio/fec/polar_common.h>
namespace gr {
namespace fec {
namespace code {
/*!
* \brief Class holds common methods and attributes for different
* decoder implementations
*/
class FEC_API polar_decoder_common : public generic_decoder, public polar_common
{
public:
/*!
*
* \param block_size codeword size. MUST be a power of 2.
* \param num_info_bits represents the number of information bits
* in a block. Also called frame_size. <= block_size
* \param frozen_bit_positions is an integer vector which defines
* the position of all frozen bits in a block. Its size
* MUST be equal to block_size - num_info_bits. Also it
* must be sorted and every position must only occur once.
* \param frozen_bit_values holds an unpacked byte for every
* frozen bit position. It defines if a frozen bit is
* fixed to '0' or '1'. Defaults to all ZERO.
*/
polar_decoder_common(int block_size,
int num_info_bits,
std::vector<int> frozen_bit_positions,
std::vector<uint8_t> frozen_bit_values);
~polar_decoder_common();
// FECAPI
double rate() { return (1.0 * get_output_size() / get_input_size()); };
int get_input_size() { return block_size(); };
int get_output_size() { return num_info_bits(); };
bool set_frame_size(unsigned int frame_size) { return false; };
private:
static const float D_LLR_FACTOR;
unsigned int d_frozen_bit_counter;
protected:
// calculate LLRs for stage
float llr_odd(const float la, const float lb) const;
float llr_even(const float la, const float lb, const unsigned char f) const;
unsigned char llr_bit_decision(const float llr) const
{
return (llr < 0.0f) ? 1 : 0;
};
// control retrieval of frozen bits.
const bool is_frozen_bit(const int u_num) const;
const unsigned char next_frozen_bit();
// preparation for decoding
void initialize_decoder(unsigned char* u, float* llrs, const float* input);
// basic algorithm methods
void butterfly(
float* llrs, unsigned char* u, const int stage, const int u_num, const int row);
void butterfly_volk(
float* llrs, unsigned char* u, const int stage, const int u_num, const int row);
void butterfly_generic(
float* llrs, unsigned char* u, const int stage, const int u_num, const int row);
void even_u_values(unsigned char* u_even, const unsigned char* u, const int u_num);
void
odd_xor_even_values(unsigned char* u_xor, const unsigned char* u, const int u_num);
void extract_info_bits(unsigned char* output, const unsigned char* input) const;
// helper functions.
void print_pretty_llr_vector(const float* llr_vec) const;
};
} // namespace code
} // namespace fec
} // namespace gr
#endif /* INCLUDED_FEC_POLAR_DECODER_COMMON_H */
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