1 /* -*- c++ -*- */ 2 /* 3 * Copyright 2015 Free Software Foundation, Inc. 4 * 5 * This file is part of GNU Radio 6 * 7 * GNU Radio is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 3, or (at your option) 10 * any later version. 11 * 12 * GNU Radio is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with GNU Radio; see the file COPYING. If not, write to 19 * the Free Software Foundation, Inc., 51 Franklin Street, 20 * Boston, MA 02110-1301, USA. 21 */ 22 23 24 #ifndef INCLUDED_FEC_POLAR_DECODER_COMMON_H 25 #define INCLUDED_FEC_POLAR_DECODER_COMMON_H 26 27 #include <gnuradio/fec/api.h> 28 #include <gnuradio/fec/generic_decoder.h> 29 #include <gnuradio/fec/polar_common.h> 30 31 namespace gr { 32 namespace fec { 33 namespace code { 34 35 /*! 36 * \brief Class holds common methods and attributes for different 37 * decoder implementations 38 */ 39 class FEC_API polar_decoder_common : public generic_decoder, public polar_common 40 { 41 public: 42 /*! 43 * 44 * \param block_size codeword size. MUST be a power of 2. 45 * \param num_info_bits represents the number of information bits 46 * in a block. Also called frame_size. <= block_size 47 * \param frozen_bit_positions is an integer vector which defines 48 * the position of all frozen bits in a block. Its size 49 * MUST be equal to block_size - num_info_bits. Also it 50 * must be sorted and every position must only occur once. 51 * \param frozen_bit_values holds an unpacked byte for every 52 * frozen bit position. It defines if a frozen bit is 53 * fixed to '0' or '1'. Defaults to all ZERO. 54 */ 55 polar_decoder_common(int block_size, 56 int num_info_bits, 57 std::vector<int> frozen_bit_positions, 58 std::vector<char> frozen_bit_values); 59 ~polar_decoder_common(); 60 61 // FECAPI rate()62 double rate() { return (1.0 * get_output_size() / get_input_size()); }; get_input_size()63 int get_input_size() { return block_size(); }; get_output_size()64 int get_output_size() { return num_info_bits(); }; set_frame_size(unsigned int frame_size)65 bool set_frame_size(unsigned int frame_size) { return false; }; 66 67 private: 68 static const float D_LLR_FACTOR; 69 unsigned int d_frozen_bit_counter; 70 71 protected: 72 // calculate LLRs for stage 73 float llr_odd(const float la, const float lb) const; 74 float llr_even(const float la, const float lb, const unsigned char f) const; llr_bit_decision(const float llr)75 unsigned char llr_bit_decision(const float llr) const 76 { 77 return (llr < 0.0f) ? 1 : 0; 78 }; 79 80 // control retrieval of frozen bits. 81 const bool is_frozen_bit(const int u_num) const; 82 const unsigned char next_frozen_bit(); 83 84 // preparation for decoding 85 void initialize_decoder(unsigned char* u, float* llrs, const float* input); 86 87 // basic algorithm methods 88 void butterfly( 89 float* llrs, unsigned char* u, const int stage, const int u_num, const int row); 90 void butterfly_volk( 91 float* llrs, unsigned char* u, const int stage, const int u_num, const int row); 92 void butterfly_generic( 93 float* llrs, unsigned char* u, const int stage, const int u_num, const int row); 94 void even_u_values(unsigned char* u_even, const unsigned char* u, const int u_num); 95 void 96 odd_xor_even_values(unsigned char* u_xor, const unsigned char* u, const int u_num); 97 void extract_info_bits(unsigned char* output, const unsigned char* input) const; 98 99 // helper functions. 100 void print_pretty_llr_vector(const float* llr_vec) const; 101 }; 102 103 } // namespace code 104 } // namespace fec 105 } // namespace gr 106 107 #endif /* INCLUDED_FEC_POLAR_DECODER_COMMON_H */ 108