Fixed issue with PSS correlation

lte/examples/cell_measurement.c

@@ -47,7 +47,8 @@
 float gain_offset = B210_DEFAULT_GAIN_CORREC;
 
 cell_search_cfg_t cell_detect_config = {
-  50, // nof_frames_total 
+  500, // maximum number of frames to receive for MIB decoding
+  50, // maximum number of frames to receive for PSS correlation 
   9.0 // early-stops cell detection if mean PSR is above this value 
 };
 

lte/examples/cell_scanner/cell_scanner.c

@@ -106,7 +106,8 @@ int cell_scanner_cell(cell_scanner_t *q, float frequency, int N_id_2, cell_scann
   printf("Tunning receiver to %.3f MHz\n", (double ) frequency/1000000);
 
   cell_search_cfg_t cfg; 
-  cfg.nof_frames_total = q->config.cell_detect_max_frames;
+  cfg.max_frames_pss = q->config.pss_max_frames;
+  cfg.max_frames_pbch = q->config.pbch_max_frames;
   cfg.threshold = q->config.cell_detect_early_stop_threshold;
   
   ret = cuhd_search_and_decode_mib(q->uhd, &cfg, N_id_2, &cell);

lte/examples/cell_scanner/cell_scanner.h

@@ -28,7 +28,8 @@
 #include "liblte/phy/phy.h"
 
 typedef struct {
-  int cell_detect_max_frames;
+  int pss_max_frames;
+  int pbch_max_frames;
   float cell_detect_early_stop_threshold;
   int measure_avg_nof_frames; 
   char *uhd_args; 

lte/examples/cell_scanner/cell_scanner_test.c

@@ -111,7 +111,11 @@ int main(int argc, char **argv) {
   cfg.cell_detect_early_stop_threshold = 20.0; // This is a normal value. 
   // maximum 5 ms frames that will be scanned maximum in the case the threshold is not exceed
   // ie for bad cells 
-  cfg.cell_detect_max_frames = 50; // this is 250 ms
+  cfg.pss_max_frames = 50; // this is 250 ms
+
+  // maximum 5 ms frames that will be received to decode the PBCH 
+  // ie for bad cells 
+  cfg.pbch_max_frames = 500; // this is 2500 ms
   
   // Number of 1 ms subframes that will be used to compute rsrp, rsrq, snr, etc average
   cfg.measure_avg_nof_frames = 1000; // 1 sec 

lte/examples/cell_search.c

@@ -55,7 +55,7 @@
 int band = -1;
 int earfcn_start=-1, earfcn_end = -1;
 
-cell_search_cfg_t config = {50, 1.1}; 
+cell_search_cfg_t config = {500, 50, 1.1}; 
 
 
 float uhd_gain = 60.0;
@@ -89,7 +89,7 @@ void parse_args(int argc, char **argv) {
       earfcn_end = atoi(argv[optind]);
       break;
     case 'n':
-      config.nof_frames_total = atoi(argv[optind]);
+      config.max_frames_pss = atoi(argv[optind]);
       break;
     case 't':
       config.threshold = atof(argv[optind]);
@@ -162,8 +162,8 @@ int main(int argc, char **argv) {
       exit(-1);
     }
     
-    if (config.nof_frames_total) {
+    if (config.max_frames_pss) {
-      ue_cell_search_set_nof_frames_to_scan(&cs, config.nof_frames_total);
+      ue_cell_search_set_nof_frames_to_scan(&cs, config.max_frames_pss);
     }
     if (config.threshold) {
       ue_cell_search_set_threshold(&cs, config.threshold);

lte/examples/cuhd_utils.c

@@ -103,8 +103,8 @@ int cuhd_cell_search(void *uhd, cell_search_cfg_t *config,
     return LIBLTE_ERROR; 
   }
   
-  if (config->nof_frames_total) {
+  if (config->max_frames_pss) {
-    ue_cell_search_set_nof_frames_to_scan(&cs, config->nof_frames_total);
+    ue_cell_search_set_nof_frames_to_scan(&cs, config->max_frames_pss);
   }
   if (config->threshold) {
     ue_cell_search_set_threshold(&cs, config->threshold);
@@ -158,7 +158,7 @@ int cuhd_search_and_decode_mib(void *uhd, cell_search_cfg_t *config, int force_N
   ret = cuhd_cell_search(uhd, config, force_N_id_2, cell);
   if (ret > 0) {
     printf("Decoding PBCH for cell %d (N_id_2=%d)\n", cell->id, cell->id%3);        
-    ret = cuhd_mib_decoder(uhd, config->nof_frames_total, cell);
+    ret = cuhd_mib_decoder(uhd, config->max_frames_pbch, cell);
     if (ret < 0) {
       fprintf(stderr, "Could not decode PBCH from CELL ID %d\n", cell->id);
       return LIBLTE_ERROR;

lte/examples/cuhd_utils.h

@@ -29,7 +29,8 @@
 #include "liblte/phy/phy.h"
 
 typedef struct LIBLTE_API {
-  uint32_t nof_frames_total; // maximum number of 5ms frames to capture 
+  uint32_t max_frames_pbch; // maximum number of 5ms frames to capture for MIB decoding
+  uint32_t max_frames_pss; // maximum number of 5ms frames to capture for PSS correlation
   float threshold;   // early-stops cell detection if mean PSR is above this value 
 }cell_search_cfg_t;
 

lte/phy/lib/sync/src/pss.c

@@ -302,10 +302,10 @@ int pss_synch_find_pss(pss_synch_t *q, cf_t *input, float *corr_peak_value)
       conv_output_len = conv_cc(input, q->pss_signal_freq[q->N_id_2], q->conv_output, q->frame_size, q->fft_size);
     #endif
     } else {
-      for (int i=q->fft_size;i<q->fft_size+q->frame_size-1;i++) {
+      for (int i=0;i<q->frame_size-1;i++) {
-        q->conv_output[i] = vec_dot_prod_ccc(q->pss_signal_freq[q->N_id_2], &input[i-q->fft_size], q->fft_size);
+        q->conv_output[i] = vec_dot_prod_ccc(q->pss_signal_freq[q->N_id_2], &input[i], q->fft_size);
       }
-      conv_output_len = q->fft_size+q->frame_size-1; 
+      conv_output_len = q->frame_size-1; 
     }
 
    
@@ -364,6 +364,13 @@ int pss_synch_find_pss(pss_synch_t *q, cf_t *input, float *corr_peak_value)
           1000000*q->conv_output_avg[corr_peak_pos], 1000000*side_lobe_value,*corr_peak_value
         );
       }
+      
+      if (isnan(*corr_peak_value) || isinf(*corr_peak_value)) {
+        int i=0;
+        vec_save_file("corrout", q->conv_output_avg, conv_output_len*sizeof(float));
+        exit(-1);
+      }
+      
     }
 #else
     if (corr_peak_value) {
@@ -371,7 +378,11 @@ int pss_synch_find_pss(pss_synch_t *q, cf_t *input, float *corr_peak_value)
     }
 #endif
 
+    if (q->frame_size >= q->fft_size) {
       ret = (int) corr_peak_pos;                
+    } else {
+      ret = (int) corr_peak_pos + q->fft_size;
+    }
   } 
   return ret;
 }

lte/phy/lib/sync/src/sync.c

@@ -316,7 +316,6 @@ int sync_find(sync_t *q, cf_t *input, uint32_t find_offset, uint32_t *peak_posit
 
         /* compute cumulative moving average CFO */
         q->mean_cfo = VEC_EMA(cfo, q->mean_cfo, CFO_EMA_ALPHA);
-
       } else {
         INFO("No space for CFO computation. Frame starts at \n",peak_pos);
       }

lte/phy/lib/ue/src/ue_mib.c

@@ -127,7 +127,7 @@ int ue_mib_decode(ue_mib_t * q, cf_t *input,
     return LIBLTE_ERROR;
   }
   /* Reset decoder if we missed a frame */
-  if (q->frame_cnt > 16) {
+  if (q->frame_cnt > 8) {
     INFO("Resetting PBCH decoder after %d frames\n", q->frame_cnt);
     ue_mib_reset(q);
   }

lte/phy/lib/ue/src/ue_sync.c

@@ -218,6 +218,9 @@ static int find_peak_ok(ue_sync_t *q) {
     q->frame_total_cnt = 0;       
     q->frame_find_cnt = 0; 
     
+    /* Set tracking CFO average to find CFO */
+    q->strack.mean_cfo = q->sfind.mean_cfo;
+
     /* Goto Tracking state */
     q->state = SF_TRACK;            
   }
@@ -269,7 +272,7 @@ int track_peak_no(ue_sync_t *q) {
   /* if we missed too many PSS go back to FIND */
   q->frame_no_cnt++; 
   if (q->frame_no_cnt >= TRACK_MAX_LOST) {
-    INFO("\n%d frames lost. Going back to FIND\n", (int) q->frame_no_cnt);
+    printf("\n%d frames lost. Going back to FIND\n", (int) q->frame_no_cnt);
     q->state = SF_FIND;
   } else {
     INFO("Tracking peak not found. Peak %.3f, %d lost\n", 
@@ -375,7 +378,10 @@ int ue_sync_get_buffer(ue_sync_t *q, cf_t **sf_symbols) {
         
         /* Do CFO Correction if not done in track and deliver the frame */
         if (!q->strack.correct_cfo) {
-          cfo_correct(&q->sfind.cfocorr, q->input_buffer, q->input_buffer, -sync_get_cfo(&q->strack) / q->fft_size);               
+          cfo_correct(&q->sfind.cfocorr, 
+                      q->input_buffer, 
+                      q->input_buffer, 
+                      -sync_get_cfo(&q->strack) / q->fft_size);               
         }
         *sf_symbols = q->input_buffer;