From 4ebdbec8142d7daf144c5f8af1f299129eda581d Mon Sep 17 00:00:00 2001
From: Piotr Krysik <perper@o2.pl>
Date: Sat, 6 Jun 2009 14:35:29 +0200
Subject: added separate header for viterbi detector

---
 src/lib/viterbi_detector.h | 498 +--------------------------------------------
 1 file changed, 1 insertion(+), 497 deletions(-)

(limited to 'src/lib/viterbi_detector.h')

diff --git a/src/lib/viterbi_detector.h b/src/lib/viterbi_detector.h
index 2a2fede..9ecb2a0 100644
--- a/src/lib/viterbi_detector.h
+++ b/src/lib/viterbi_detector.h
@@ -53,500 +53,4 @@
 ** TEST(S):  Tested with real world normal burst.
 */
 
-#include <gnuradio/gr_complex.h>
-#include <gsm_constants.h>
-#define PATHS_NUM (1 << (CHAN_IMP_RESP_LENGTH-1))
-
-void viterbi_detector(const gr_complex * input, unsigned int samples_num, gr_complex * rhh, unsigned int start_state, const unsigned int * stop_states, unsigned int stops_num, float * output)
-{
-   float increment[8];
-   float path_metrics1[16];
-   float path_metrics2[16];
-   float * new_path_metrics;
-   float * old_path_metrics;
-   float * tmp;
-   float trans_table[BURST_SIZE][16];
-   float pm_candidate1, pm_candidate2;
-   bool real_imag;
-   float input_symbol_real, input_symbol_imag;
-   unsigned int i, sample_nr;
-
-/*
-* Setup first path metrics, so only state pointed by start_state is possible.
-* Start_state metric is equal to zero, the rest is written with some very low value,
-* which makes them practically impossible to occur.
-*/
-   for(i=0; i<PATHS_NUM; i++){
-      path_metrics1[i]=(-10e30);
-   }
-   path_metrics1[start_state]=0;
-
-/*
-* Compute Increment - a table of values which does not change for subsequent input samples.
-* Increment is table of reference levels for computation of branch metrics:
-*    branch metric = (+/-)received_sample (+/-) reference_level
-*/
-   increment[0] = -rhh[1].imag() -rhh[2].real() -rhh[3].imag() +rhh[4].real();
-   increment[1] = rhh[1].imag() -rhh[2].real() -rhh[3].imag() +rhh[4].real();
-   increment[2] = -rhh[1].imag() +rhh[2].real() -rhh[3].imag() +rhh[4].real();
-   increment[3] = rhh[1].imag() +rhh[2].real() -rhh[3].imag() +rhh[4].real();
-   increment[4] = -rhh[1].imag() -rhh[2].real() +rhh[3].imag() +rhh[4].real();
-   increment[5] = rhh[1].imag() -rhh[2].real() +rhh[3].imag() +rhh[4].real();
-   increment[6] = -rhh[1].imag() +rhh[2].real() +rhh[3].imag() +rhh[4].real();
-   increment[7] = rhh[1].imag() +rhh[2].real() +rhh[3].imag() +rhh[4].real();
-
-
-/*
-* Computation of path metrics and decisions (Add-Compare-Select).
-* It's composed of two parts: one for odd input samples (imaginary numbers)
-* and one for even samples (real numbers).
-* Each part is composed of independent (parallelisable) statements like  
-* this one:
-*      pm_candidate1 = old_path_metrics[0] - input_symbol_real - increment[7];
-*      pm_candidate2 = old_path_metrics[8] - input_symbol_real + increment[0];
-*      if(pm_candidate1 > pm_candidate2){
-*         new_path_metrics[0] = pm_candidate1;
-*         trans_table[sample_nr][0] = -1.0;
-*      }
-*      else{
-*         new_path_metrics[0] = pm_candidate2;
-*         trans_table[sample_nr][0] = 1.0;
-*      }
-* This is very good point for optimisations (SIMD or OpenMP) as it's most time 
-* consuming part of this function. 
-*/
-   sample_nr=0;
-   old_path_metrics=path_metrics1;
-   new_path_metrics=path_metrics2;
-   while(sample_nr<samples_num){
-      //Processing imag states
-      real_imag=1;
-      input_symbol_imag = input[sample_nr].imag();
-
-      pm_candidate1 = old_path_metrics[0] + input_symbol_imag - increment[2];
-      pm_candidate2 = old_path_metrics[8] + input_symbol_imag + increment[5];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[0] = pm_candidate1;
-         trans_table[sample_nr][0] = -1.0;
-      }
-      else{
-         new_path_metrics[0] = pm_candidate2;
-         trans_table[sample_nr][0] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[0] - input_symbol_imag + increment[2];
-      pm_candidate2 = old_path_metrics[8] - input_symbol_imag - increment[5];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[1] = pm_candidate1;
-         trans_table[sample_nr][1] = -1.0;
-      }
-      else{
-         new_path_metrics[1] = pm_candidate2;
-         trans_table[sample_nr][1] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[1] + input_symbol_imag - increment[3];
-      pm_candidate2 = old_path_metrics[9] + input_symbol_imag + increment[4];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[2] = pm_candidate1;
-         trans_table[sample_nr][2] = -1.0;
-      }
-      else{
-         new_path_metrics[2] = pm_candidate2;
-         trans_table[sample_nr][2] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[1] - input_symbol_imag + increment[3];
-      pm_candidate2 = old_path_metrics[9] - input_symbol_imag - increment[4];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[3] = pm_candidate1;
-         trans_table[sample_nr][3] = -1.0;
-      }
-      else{
-         new_path_metrics[3] = pm_candidate2;
-         trans_table[sample_nr][3] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[2] + input_symbol_imag - increment[0];
-      pm_candidate2 = old_path_metrics[10] + input_symbol_imag + increment[7];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[4] = pm_candidate1;
-         trans_table[sample_nr][4] = -1.0;
-      }
-      else{
-         new_path_metrics[4] = pm_candidate2;
-         trans_table[sample_nr][4] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[2] - input_symbol_imag + increment[0];
-      pm_candidate2 = old_path_metrics[10] - input_symbol_imag - increment[7];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[5] = pm_candidate1;
-         trans_table[sample_nr][5] = -1.0;
-      }
-      else{
-         new_path_metrics[5] = pm_candidate2;
-         trans_table[sample_nr][5] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[3] + input_symbol_imag - increment[1];
-      pm_candidate2 = old_path_metrics[11] + input_symbol_imag + increment[6];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[6] = pm_candidate1;
-         trans_table[sample_nr][6] = -1.0;
-      }
-      else{
-         new_path_metrics[6] = pm_candidate2;
-         trans_table[sample_nr][6] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[3] - input_symbol_imag + increment[1];
-      pm_candidate2 = old_path_metrics[11] - input_symbol_imag - increment[6];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[7] = pm_candidate1;
-         trans_table[sample_nr][7] = -1.0;
-      }
-      else{
-         new_path_metrics[7] = pm_candidate2;
-         trans_table[sample_nr][7] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[4] + input_symbol_imag - increment[6];
-      pm_candidate2 = old_path_metrics[12] + input_symbol_imag + increment[1];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[8] = pm_candidate1;
-         trans_table[sample_nr][8] = -1.0;
-      }
-      else{
-         new_path_metrics[8] = pm_candidate2;
-         trans_table[sample_nr][8] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[4] - input_symbol_imag + increment[6];
-      pm_candidate2 = old_path_metrics[12] - input_symbol_imag - increment[1];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[9] = pm_candidate1;
-         trans_table[sample_nr][9] = -1.0;
-      }
-      else{
-         new_path_metrics[9] = pm_candidate2;
-         trans_table[sample_nr][9] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[5] + input_symbol_imag - increment[7];
-      pm_candidate2 = old_path_metrics[13] + input_symbol_imag + increment[0];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[10] = pm_candidate1;
-         trans_table[sample_nr][10] = -1.0;
-      }
-      else{
-         new_path_metrics[10] = pm_candidate2;
-         trans_table[sample_nr][10] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[5] - input_symbol_imag + increment[7];
-      pm_candidate2 = old_path_metrics[13] - input_symbol_imag - increment[0];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[11] = pm_candidate1;
-         trans_table[sample_nr][11] = -1.0;
-      }
-      else{
-         new_path_metrics[11] = pm_candidate2;
-         trans_table[sample_nr][11] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[6] + input_symbol_imag - increment[4];
-      pm_candidate2 = old_path_metrics[14] + input_symbol_imag + increment[3];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[12] = pm_candidate1;
-         trans_table[sample_nr][12] = -1.0;
-      }
-      else{
-         new_path_metrics[12] = pm_candidate2;
-         trans_table[sample_nr][12] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[6] - input_symbol_imag + increment[4];
-      pm_candidate2 = old_path_metrics[14] - input_symbol_imag - increment[3];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[13] = pm_candidate1;
-         trans_table[sample_nr][13] = -1.0;
-      }
-      else{
-         new_path_metrics[13] = pm_candidate2;
-         trans_table[sample_nr][13] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[7] + input_symbol_imag - increment[5];
-      pm_candidate2 = old_path_metrics[15] + input_symbol_imag + increment[2];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[14] = pm_candidate1;
-         trans_table[sample_nr][14] = -1.0;
-      }
-      else{
-         new_path_metrics[14] = pm_candidate2;
-         trans_table[sample_nr][14] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[7] - input_symbol_imag + increment[5];
-      pm_candidate2 = old_path_metrics[15] - input_symbol_imag - increment[2];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[15] = pm_candidate1;
-         trans_table[sample_nr][15] = -1.0;
-      }
-      else{
-         new_path_metrics[15] = pm_candidate2;
-         trans_table[sample_nr][15] = 1.0;
-      }
-      tmp=old_path_metrics;
-      old_path_metrics=new_path_metrics;
-      new_path_metrics=tmp;
-
-      sample_nr++;
-      if(sample_nr==samples_num)
-         break;
-
-      //Processing real states
-      real_imag=0;
-      input_symbol_real = input[sample_nr].real();
-
-      pm_candidate1 = old_path_metrics[0] - input_symbol_real - increment[7];
-      pm_candidate2 = old_path_metrics[8] - input_symbol_real + increment[0];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[0] = pm_candidate1;
-         trans_table[sample_nr][0] = -1.0;
-      }
-      else{
-         new_path_metrics[0] = pm_candidate2;
-         trans_table[sample_nr][0] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[0] + input_symbol_real + increment[7];
-      pm_candidate2 = old_path_metrics[8] + input_symbol_real - increment[0];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[1] = pm_candidate1;
-         trans_table[sample_nr][1] = -1.0;
-      }
-      else{
-         new_path_metrics[1] = pm_candidate2;
-         trans_table[sample_nr][1] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[1] - input_symbol_real - increment[6];
-      pm_candidate2 = old_path_metrics[9] - input_symbol_real + increment[1];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[2] = pm_candidate1;
-         trans_table[sample_nr][2] = -1.0;
-      }
-      else{
-         new_path_metrics[2] = pm_candidate2;
-         trans_table[sample_nr][2] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[1] + input_symbol_real + increment[6];
-      pm_candidate2 = old_path_metrics[9] + input_symbol_real - increment[1];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[3] = pm_candidate1;
-         trans_table[sample_nr][3] = -1.0;
-      }
-      else{
-         new_path_metrics[3] = pm_candidate2;
-         trans_table[sample_nr][3] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[2] - input_symbol_real - increment[5];
-      pm_candidate2 = old_path_metrics[10] - input_symbol_real + increment[2];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[4] = pm_candidate1;
-         trans_table[sample_nr][4] = -1.0;
-      }
-      else{
-         new_path_metrics[4] = pm_candidate2;
-         trans_table[sample_nr][4] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[2] + input_symbol_real + increment[5];
-      pm_candidate2 = old_path_metrics[10] + input_symbol_real - increment[2];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[5] = pm_candidate1;
-         trans_table[sample_nr][5] = -1.0;
-      }
-      else{
-         new_path_metrics[5] = pm_candidate2;
-         trans_table[sample_nr][5] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[3] - input_symbol_real - increment[4];
-      pm_candidate2 = old_path_metrics[11] - input_symbol_real + increment[3];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[6] = pm_candidate1;
-         trans_table[sample_nr][6] = -1.0;
-      }
-      else{
-         new_path_metrics[6] = pm_candidate2;
-         trans_table[sample_nr][6] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[3] + input_symbol_real + increment[4];
-      pm_candidate2 = old_path_metrics[11] + input_symbol_real - increment[3];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[7] = pm_candidate1;
-         trans_table[sample_nr][7] = -1.0;
-      }
-      else{
-         new_path_metrics[7] = pm_candidate2;
-         trans_table[sample_nr][7] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[4] - input_symbol_real - increment[3];
-      pm_candidate2 = old_path_metrics[12] - input_symbol_real + increment[4];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[8] = pm_candidate1;
-         trans_table[sample_nr][8] = -1.0;
-      }
-      else{
-         new_path_metrics[8] = pm_candidate2;
-         trans_table[sample_nr][8] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[4] + input_symbol_real + increment[3];
-      pm_candidate2 = old_path_metrics[12] + input_symbol_real - increment[4];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[9] = pm_candidate1;
-         trans_table[sample_nr][9] = -1.0;
-      }
-      else{
-         new_path_metrics[9] = pm_candidate2;
-         trans_table[sample_nr][9] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[5] - input_symbol_real - increment[2];
-      pm_candidate2 = old_path_metrics[13] - input_symbol_real + increment[5];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[10] = pm_candidate1;
-         trans_table[sample_nr][10] = -1.0;
-      }
-      else{
-         new_path_metrics[10] = pm_candidate2;
-         trans_table[sample_nr][10] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[5] + input_symbol_real + increment[2];
-      pm_candidate2 = old_path_metrics[13] + input_symbol_real - increment[5];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[11] = pm_candidate1;
-         trans_table[sample_nr][11] = -1.0;
-      }
-      else{
-         new_path_metrics[11] = pm_candidate2;
-         trans_table[sample_nr][11] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[6] - input_symbol_real - increment[1];
-      pm_candidate2 = old_path_metrics[14] - input_symbol_real + increment[6];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[12] = pm_candidate1;
-         trans_table[sample_nr][12] = -1.0;
-      }
-      else{
-         new_path_metrics[12] = pm_candidate2;
-         trans_table[sample_nr][12] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[6] + input_symbol_real + increment[1];
-      pm_candidate2 = old_path_metrics[14] + input_symbol_real - increment[6];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[13] = pm_candidate1;
-         trans_table[sample_nr][13] = -1.0;
-      }
-      else{
-         new_path_metrics[13] = pm_candidate2;
-         trans_table[sample_nr][13] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[7] - input_symbol_real - increment[0];
-      pm_candidate2 = old_path_metrics[15] - input_symbol_real + increment[7];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[14] = pm_candidate1;
-         trans_table[sample_nr][14] = -1.0;
-      }
-      else{
-         new_path_metrics[14] = pm_candidate2;
-         trans_table[sample_nr][14] = 1.0;
-      }
-
-      pm_candidate1 = old_path_metrics[7] + input_symbol_real + increment[0];
-      pm_candidate2 = old_path_metrics[15] + input_symbol_real - increment[7];
-      if(pm_candidate1 > pm_candidate2){
-         new_path_metrics[15] = pm_candidate1;
-         trans_table[sample_nr][15] = -1.0;
-      }
-      else{
-         new_path_metrics[15] = pm_candidate2;
-         trans_table[sample_nr][15] = 1.0;
-      }
-      tmp=old_path_metrics;
-      old_path_metrics=new_path_metrics;
-      new_path_metrics=tmp;
-
-      sample_nr++;
-   }
-
-/*
-* Find the best from the stop states by comparing their path metrics.
-* Not every stop state is always possible, so we are searching in
-* a subset of them.
-*/
-   unsigned int best_stop_state;
-   float stop_state_metric, max_stop_state_metric;
-   best_stop_state = stop_states[0];
-   max_stop_state_metric = old_path_metrics[best_stop_state];
-   for(i=1; i< stops_num; i++){
-      stop_state_metric = old_path_metrics[stop_states[i]];
-      if(stop_state_metric > max_stop_state_metric){
-         max_stop_state_metric = stop_state_metric;
-         best_stop_state = stop_states[i];
-      }
-   }
-
-/*
-* This table was generated with hope that it gives a litle speedup during
-* traceback stage. 
-* Received bit is related to the number of state in the trellis.
-* I've numbered states so their parity (number of ones) is related
-* to a received bit. 
-*/
-   static const unsigned int parity_table[PATHS_NUM] = { 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0,  };
-
-/*
-* Table of previous states in the trellis diagram.
-* For GMSK modulation every state has two previous states.
-* Example:
-*   previous_state_nr1 = prev_table[current_state_nr][0]
-*   previous_state_nr2 = prev_table[current_state_nr][1]
-*/
-   static const unsigned int prev_table[PATHS_NUM][2] = { {0,8}, {0,8}, {1,9}, {1,9}, {2,10}, {2,10}, {3,11}, {3,11}, {4,12}, {4,12}, {5,13}, {5,13}, {6,14}, {6,14}, {7,15}, {7,15},  };
-
-/*
-* Traceback and differential decoding of received sequence.
-* Decisions stored in trans_table are used to restore best path in the trellis.
-*/
-   sample_nr=samples_num;
-   unsigned int state_nr=best_stop_state;
-   unsigned int decision;
-   bool out_bit=0;
-
-   while(sample_nr>0){
-      sample_nr--;
-      decision = (trans_table[sample_nr][state_nr]>0);
-
-      if(decision != out_bit)
-         output[sample_nr]=-trans_table[sample_nr][state_nr];
-      else
-         output[sample_nr]=trans_table[sample_nr][state_nr];
-
-      out_bit = out_bit ^ real_imag ^ parity_table[state_nr];
-      state_nr = prev_table[state_nr][decision];
-      real_imag = !real_imag;
-   }
-}
+void viterbi_detector(const gr_complex * input, unsigned int samples_num, gr_complex * rhh, unsigned int start_state, const unsigned int * stop_states, unsigned int stops_num, float * output);
-- 
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