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https://github.com/gnss-sdr/gnss-sdr
synced 2024-12-14 12:10:34 +00:00
Modernize code for Viterbi decoder
This commit is contained in:
Carles Fernandez
parent
4fe8c078ea
commit
589788d2e3
@ -207,14 +207,14 @@ galileo_telemetry_decoder_gs::~galileo_telemetry_decoder_gs()
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}
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void galileo_telemetry_decoder_gs::viterbi_decoder(double *page_part_symbols, int32_t *page_part_bits)
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void galileo_telemetry_decoder_gs::viterbi_decoder(float *page_part_symbols, int32_t *page_part_bits)
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{
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Viterbi(page_part_bits, out0.data(), state0.data(), out1.data(), state1.data(),
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page_part_symbols, KK, nn, DataLength);
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}
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void galileo_telemetry_decoder_gs::deinterleaver(int32_t rows, int32_t cols, const double *in, double *out)
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void galileo_telemetry_decoder_gs::deinterleaver(int32_t rows, int32_t cols, const float *in, float *out)
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{
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for (int32_t r = 0; r < rows; r++)
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{
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@ -226,10 +226,10 @@ void galileo_telemetry_decoder_gs::deinterleaver(int32_t rows, int32_t cols, con
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}
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void galileo_telemetry_decoder_gs::decode_INAV_word(double *page_part_symbols, int32_t frame_length)
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void galileo_telemetry_decoder_gs::decode_INAV_word(float *page_part_symbols, int32_t frame_length)
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{
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// 1. De-interleave
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std::vector<double> page_part_symbols_deint(frame_length);
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std::vector<float> page_part_symbols_deint(frame_length);
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deinterleaver(GALILEO_INAV_INTERLEAVER_ROWS, GALILEO_INAV_INTERLEAVER_COLS, page_part_symbols, page_part_symbols_deint.data());
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// 2. Viterbi decoder
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@ -318,10 +318,10 @@ void galileo_telemetry_decoder_gs::decode_INAV_word(double *page_part_symbols, i
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}
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void galileo_telemetry_decoder_gs::decode_FNAV_word(double *page_symbols, int32_t frame_length)
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void galileo_telemetry_decoder_gs::decode_FNAV_word(float *page_symbols, int32_t frame_length)
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{
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// 1. De-interleave
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std::vector<double> page_symbols_deint(frame_length);
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std::vector<float> page_symbols_deint(frame_length);
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deinterleaver(GALILEO_FNAV_INTERLEAVER_ROWS, GALILEO_FNAV_INTERLEAVER_COLS, page_symbols, page_symbols_deint.data());
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// 2. Viterbi decoder
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@ -81,12 +81,12 @@ private:
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galileo_telemetry_decoder_gs(const Gnss_Satellite &satellite, int frame_type, bool dump);
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void viterbi_decoder(double *page_part_symbols, int32_t *page_part_bits);
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void viterbi_decoder(float *page_part_symbols, int32_t *page_part_bits);
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void deinterleaver(int32_t rows, int32_t cols, const double *in, double *out);
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void deinterleaver(int32_t rows, int32_t cols, const float *in, float *out);
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void decode_INAV_word(double *page_part_symbols, int32_t frame_length);
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void decode_FNAV_word(double *page_symbols, int32_t frame_length);
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void decode_INAV_word(float *page_part_symbols, int32_t frame_length);
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void decode_FNAV_word(float *page_symbols, int32_t frame_length);
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int d_frame_type;
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int32_t d_bits_per_preamble;
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@ -96,7 +96,7 @@ private:
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uint32_t d_PRN_code_period_ms;
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uint32_t d_required_symbols;
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uint32_t d_frame_length_symbols;
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std::vector<double> d_page_part_symbols;
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std::vector<float> d_page_part_symbols;
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boost::circular_buffer<float> d_symbol_history;
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@ -39,6 +39,8 @@ add_library(telemetry_decoder_libs
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)
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target_link_libraries(telemetry_decoder_libs
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PUBLIC
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Volkgnsssdr::volkgnsssdr
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PRIVATE
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Gflags::gflags
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Glog::glog
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@ -41,7 +41,9 @@
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#ifndef GNSS_SDR_CONVOLUTIONAL_H_
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#define GNSS_SDR_CONVOLUTIONAL_H_
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#include <cstdlib> // for calloc
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#include <volk_gnsssdr/volk_gnsssdr.h>
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#include <algorithm>
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#include <vector>
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/* define constants used throughout the library */
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const float MAXLOG = 1e7; /* Define infinity */
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@ -57,7 +59,7 @@ const float MAXLOG = 1e7; /* Define infinity */
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*
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* This function is used by nsc_enc_bit(), rsc_enc_bit(), and rsc_tail()
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*/
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inline static int parity_counter(int symbol, int length)
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inline int parity_counter(int symbol, int length)
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{
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int counter;
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int temp_parity = 0;
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@ -85,7 +87,7 @@ inline static int parity_counter(int symbol, int length)
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*
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* This function is used by nsc_transit()
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*/
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inline static int nsc_enc_bit(int state_out_p[],
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inline int nsc_enc_bit(int state_out_p[],
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int input,
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int state_in,
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const int g[],
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@ -115,7 +117,7 @@ inline static int nsc_enc_bit(int state_out_p[],
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/*!
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* \brief Function that creates the transit and output vectors
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*/
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inline static void nsc_transit(int output_p[],
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inline void nsc_transit(int output_p[],
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int trans_p[],
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int input,
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int g[],
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@ -144,7 +146,7 @@ inline static void nsc_transit(int output_p[],
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* \param[in] nn The length of the received vector
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*
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*/
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inline static float Gamma(const float rec_array[],
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inline float Gamma(const float rec_array[],
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int symbol,
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int nn)
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{
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@ -176,24 +178,20 @@ inline static float Gamma(const float rec_array[],
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* \param[out] output_u_int[] Hard decisions on the data bits
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*
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*/
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inline static void Viterbi(int output_u_int[],
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inline void Viterbi(int output_u_int[],
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const int out0[],
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const int state0[],
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const int out1[],
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const int state1[],
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const double input_c[],
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const float input_c[],
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int KK,
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int nn,
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int LL)
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{
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int i, t, state, mm, states;
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int number_symbols;
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uint32_t max_index;
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float metric;
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float *prev_section, *next_section;
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int *prev_bit;
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int *prev_state;
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float *metric_c; /* Set of all possible branch metrics */
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float *rec_array; /* Received values for one trellis section */
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float max_val;
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/* some derived constants */
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@ -201,34 +199,24 @@ inline static void Viterbi(int output_u_int[],
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states = 1 << mm; /* 2^mm */
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number_symbols = 1 << nn; /* 2^nn */
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/* dynamically allocate memory */
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prev_section = static_cast<float *>(calloc(states, sizeof(float)));
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next_section = static_cast<float *>(calloc(states, sizeof(float)));
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prev_bit = static_cast<int *>(calloc(states * (LL + mm), sizeof(int)));
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prev_state = static_cast<int *>(calloc(states * (LL + mm), sizeof(int)));
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rec_array = static_cast<float *>(calloc(nn, sizeof(float)));
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metric_c = static_cast<float *>(calloc(number_symbols, sizeof(float)));
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std::vector<float> prev_section(states, -MAXLOG);
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std::vector<float> next_section(states, -MAXLOG);
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std::vector<int> prev_bit(states * (LL + mm), 0);
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std::vector<int> prev_state(states * (LL + mm), 0);
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std::vector<float> rec_array(nn);
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std::vector<float> metric_c(number_symbols);
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/* initialize trellis */
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for (state = 0; state < states; state++)
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{
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prev_section[state] = -MAXLOG;
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next_section[state] = -MAXLOG;
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}
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prev_section[0] = 0; /* start in all-zeros state */
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prev_section[0] = 0.0; /* start in all-zeros state */
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/* go through trellis */
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for (t = 0; t < LL + mm; t++)
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{
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for (i = 0; i < nn; i++)
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{
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rec_array[i] = static_cast<float>(input_c[nn * t + i]);
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}
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rec_array.assign(input_c + nn * t, input_c + nn * t + (nn - 1));
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/* precompute all possible branch metrics */
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for (i = 0; i < number_symbols; i++)
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{
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metric_c[i] = Gamma(rec_array, i, nn);
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metric_c[i] = Gamma(rec_array.data(), i, nn);
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}
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/* step through all states */
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@ -258,19 +246,13 @@ inline static void Viterbi(int output_u_int[],
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}
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/* normalize */
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max_val = 0;
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for (state = 0; state < states; state++)
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{
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if (next_section[state] > max_val)
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{
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max_val = next_section[state];
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}
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}
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for (state = 0; state < states; state++)
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{
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prev_section[state] = next_section[state] - max_val;
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next_section[state] = -MAXLOG;
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}
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volk_gnsssdr_32f_index_max_32u(&max_index, next_section.data(), states);
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max_val = next_section[max_index];
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prev_section = next_section;
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std::transform(prev_section.begin(), prev_section.end(), prev_section.begin(),
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[&max_val](const auto& prev_ele) { return (prev_ele - max_val); });
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std::fill(next_section.begin(), next_section.end(), -MAXLOG);
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}
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/* trace-back operation */
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@ -287,14 +269,6 @@ inline static void Viterbi(int output_u_int[],
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output_u_int[t] = prev_bit[t * states + state];
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state = prev_state[t * states + state];
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}
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/* free the dynamically allocated memory */
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free(prev_section);
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free(next_section);
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free(prev_bit);
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free(prev_state);
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free(rec_array);
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free(metric_c);
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}
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@ -54,14 +54,14 @@ public:
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const int32_t KK = 7; // Constraint Length
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int32_t mm = KK - 1;
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int32_t flag_even_word_arrived;
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void viterbi_decoder(double *page_part_symbols, int32_t *page_part_bits, int32_t _datalength)
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void viterbi_decoder(float *page_part_symbols, int32_t *page_part_bits, int32_t _datalength)
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{
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Viterbi(page_part_bits, out0, state0, out1, state1,
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page_part_symbols, KK, nn, _datalength);
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}
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void deinterleaver(int32_t rows, int32_t cols, const double *in, double *out)
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void deinterleaver(int32_t rows, int32_t cols, const float *in, float *out)
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{
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for (int32_t r = 0; r < rows; r++)
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{
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@ -73,10 +73,10 @@ public:
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}
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bool decode_INAV_word(double *page_part_symbols, int32_t frame_length)
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bool decode_INAV_word(float *page_part_symbols, int32_t frame_length)
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{
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// 1. De-interleave
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auto *page_part_symbols_deint = static_cast<double *>(volk_gnsssdr_malloc(frame_length * sizeof(double), volk_gnsssdr_get_alignment()));
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auto *page_part_symbols_deint = static_cast<float *>(volk_gnsssdr_malloc(frame_length * sizeof(float), volk_gnsssdr_get_alignment()));
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deinterleaver(GALILEO_INAV_INTERLEAVER_ROWS, GALILEO_INAV_INTERLEAVER_COLS, page_part_symbols, page_part_symbols_deint);
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// 2. Viterbi decoder
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@ -134,10 +134,10 @@ public:
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return crc_ok;
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}
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bool decode_FNAV_word(double *page_symbols, int32_t frame_length)
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bool decode_FNAV_word(float *page_symbols, int32_t frame_length)
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{
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// 1. De-interleave
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auto *page_symbols_deint = static_cast<double *>(volk_gnsssdr_malloc(frame_length * sizeof(double), volk_gnsssdr_get_alignment()));
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auto *page_symbols_deint = static_cast<float *>(volk_gnsssdr_malloc(frame_length * sizeof(float), volk_gnsssdr_get_alignment()));
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deinterleaver(GALILEO_FNAV_INTERLEAVER_ROWS, GALILEO_FNAV_INTERLEAVER_COLS, page_symbols, page_symbols_deint);
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// 2. Viterbi decoder
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@ -215,7 +215,7 @@ TEST_F(Galileo_FNAV_INAV_test, ValidationOfResults)
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start = std::chrono::system_clock::now();
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int repetitions = 10;
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// FNAV FULLY ENCODED FRAME
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double FNAV_frame[488] = {-1, 1, -1, -1, 1, -1, 1, 1, 1, -1, -1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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float FNAV_frame[488] = {-1, 1, -1, -1, 1, -1, 1, 1, 1, -1, -1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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1, -1, -1, 1, -1, -1, 1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, -1, -1, -1, 1, -1, -1, 1, -1, -1, -1, -1, 1, 1, 1, 1, 1, 1,
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-1, 1, -1, 1, -1, 1, 1, -1, -1, 1, -1, 1, -1, 1, -1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -1, 1, 1, -1, 1, -1, 1, -1,
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-1, 1, 1, -1, 1, 1, 1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, 1, 1, -1, -1, 1, 1, -1, -1, -1, -1,
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@ -240,7 +240,7 @@ TEST_F(Galileo_FNAV_INAV_test, ValidationOfResults)
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// INAV FULLY ENCODED FRAME
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double INAV_frame_even[240] = {-1, -1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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float INAV_frame_even[240] = {-1, -1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 1, -1, -1, -1, 1, 1,
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-1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1, -1, -1, 1, -1, -1, -1, 1, -1,
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@ -256,7 +256,7 @@ TEST_F(Galileo_FNAV_INAV_test, ValidationOfResults)
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-1, -1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 1, -1, 1, 1, 1};
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double INAV_frame_odd[240] = {1, -1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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float INAV_frame_odd[240] = {1, -1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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1, 1, 1, 1, -1, 1, -1, -1, 1, -1, 1, -1, -1, 1, -1, 1,
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1, 1, -1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1,
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-1, -1, 1, 1, -1, 1, 1, 1, -1, 1, 1, 1, 1, -1, -1, 1,
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