Added support for reduced sampling rates

srslte/examples/pdsch_ue.c

@@ -62,6 +62,7 @@ void init_plots();
 pthread_t plot_thread; 
 sem_t plot_sem; 
 uint32_t plot_sf_idx=0;
+bool plot_track = true; 
 #endif
 
 #define PLOT_CHEST_ARGUMENT
@@ -323,10 +324,12 @@ int main(int argc, char **argv) {
     /* set sampling frequency */
     int srate = srslte_sampling_freq_hz(cell.nof_prb);
     if (srate != -1) {  
-      /* Modify master clock rate for 15 Mhz */
+      if (srate < 10e6) {
-      if (cell.nof_prb == 75) {
+        cuhd_set_master_clock_rate(uhd, 4*srate);        
-        cuhd_set_master_clock_rate(uhd, 23.04e6);
+      } else {
+        cuhd_set_master_clock_rate(uhd, srate);        
       }
+      printf("Setting Sampling frequency %.2f MHz\n", (float) srate/1000000);
       cuhd_set_rx_srate(uhd, (double) srate);      
     } else {
       fprintf(stderr, "Invalid number of PRB %d\n", cell.nof_prb);
@@ -530,6 +533,7 @@ int main(int argc, char **argv) {
       if (!prog_args.disable_plots) {
         if ((sfn%4) == 0 && decode_pdsch) {
           plot_sf_idx = srslte_ue_sync_get_sfidx(&ue_sync);
+          plot_track = true;
           sem_post(&plot_sem);
         }
       }
@@ -538,6 +542,13 @@ int main(int argc, char **argv) {
       printf("Finding PSS... Peak: %8.1f, FrameCnt: %d, State: %d\r", 
         srslte_sync_get_peak_value(&ue_sync.sfind), 
         ue_sync.frame_total_cnt, ue_sync.state);      
+      #ifndef DISABLE_GRAPHICS
+      if (!prog_args.disable_plots) {
+        plot_sf_idx = srslte_ue_sync_get_sfidx(&ue_sync);
+        plot_track = false; 
+        sem_post(&plot_sem);                
+      }
+      #endif
     }
         
     sf_cnt++;                  
@@ -646,12 +657,21 @@ void *plot_thread_run(void *arg) {
       plot_real_setNewData(&pce, tmp_plot2, 4*12*ue_dl.cell.nof_prb);        
       
       if (!prog_args.input_file_name) {
+        if (plot_track) {
           int max = srslte_vec_max_fi(ue_sync.strack.pss.conv_output_avg, ue_sync.strack.pss.frame_size+ue_sync.strack.pss.fft_size-1);
           srslte_vec_sc_prod_fff(ue_sync.strack.pss.conv_output_avg, 
                           1/ue_sync.strack.pss.conv_output_avg[max], 
                           tmp_plot2, 
                           ue_sync.strack.pss.frame_size+ue_sync.strack.pss.fft_size-1);        
           plot_real_setNewData(&p_sync, tmp_plot2, ue_sync.strack.pss.frame_size);        
+        } else {
+          int max = srslte_vec_max_fi(ue_sync.sfind.pss.conv_output_avg, ue_sync.sfind.pss.frame_size+ue_sync.sfind.pss.fft_size-1);
+          srslte_vec_sc_prod_fff(ue_sync.sfind.pss.conv_output_avg, 
+                          1/ue_sync.sfind.pss.conv_output_avg[max], 
+                          tmp_plot2, 
+                          ue_sync.sfind.pss.frame_size+ue_sync.sfind.pss.fft_size-1);        
+          plot_real_setNewData(&p_sync, tmp_plot2, ue_sync.sfind.pss.frame_size);        
+        }
         
       }
 

srslte/include/srslte/common/phy_common.h

@@ -43,6 +43,8 @@
 
 #include "srslte/config.h"
 
+#define USE_REDUCED_SAMPLING_RATES
+
 #define SRSLTE_NSUBFRAMES_X_FRAME  10
 #define SRSLTE_NSLOTS_X_FRAME      (2*SRSLTE_NSUBFRAMES_X_FRAME)
 
@@ -95,8 +97,8 @@ typedef enum {SRSLTE_CP_NORM, SRSLTE_CP_EXT} srslte_cp_t;
 #define SRSLTE_CP_LEN_NORM(symbol, symbol_sz) ((symbol==0)?SRSLTE_CP_LEN((symbol_sz),SRSLTE_CP_NORM_0_LEN):SRSLTE_CP_LEN((symbol_sz),SRSLTE_CP_NORM_LEN))
 #define SRSLTE_CP_LEN_EXT(symbol_sz)          (SRSLTE_CP_LEN((symbol_sz),SRSLTE_CP_EXT_LEN))
 
-#define SRSLTE_SLOT_LEN(symbol_sz)     (480*((symbol_sz)/64))
+#define SRSLTE_SLOT_LEN(symbol_sz)     (symbol_sz*15/2)
-#define SRSLTE_SF_LEN(symbol_sz)       (2*SRSLTE_SLOT_LEN(symbol_sz))
+#define SRSLTE_SF_LEN(symbol_sz)       (symbol_sz*15)
 #define SRSLTE_SF_LEN_MAX              (SRSLTE_SF_LEN(SRSLTE_SYMBOL_SZ_MAX))
 
 #define SRSLTE_SLOT_LEN_PRB(nof_prb)   (SRSLTE_SLOT_LEN(srslte_symbol_sz(nof_prb)))

srslte/lib/common/src/phy_common.c

@@ -197,6 +197,21 @@ int srslte_symbol_sz(uint32_t nof_prb) {
   if (nof_prb<=0) {
     return SRSLTE_ERROR;
   }
+#ifdef USE_REDUCED_SAMPLING_RATES
+  if (nof_prb<=6) {
+    return 128;
+  } else if (nof_prb<=15) {
+    return 256;
+  } else if (nof_prb<=25) {
+    return 384;
+  } else if (nof_prb<=50) {
+    return 768;
+  } else if (nof_prb<=75) {
+    return 1024;
+  } else if (nof_prb<=100) {
+    return 1536;
+  }
+#else
   if (nof_prb<=6) {
     return 128;
   } else if (nof_prb<=15) {
@@ -210,6 +225,7 @@ int srslte_symbol_sz(uint32_t nof_prb) {
   } else if (nof_prb<=100) {
     return 2048;
   }
+#endif
   return SRSLTE_ERROR;
 }
 

srslte/lib/sync/test/pss_file.c

@@ -140,7 +140,7 @@ int main(int argc, char **argv) {
     init_plots();
 #endif
   
-  flen = 4800*(fft_size/64);
+  flen = fft_size*15*5;
   
   buffer = malloc(sizeof(cf_t) * flen * 2);
   if (!buffer) {
@@ -200,7 +200,7 @@ int main(int argc, char **argv) {
       exit(-1);
     }
     if (n < flen - peak_offset) {
-      fprintf(stdout, "End of file\n");
+      fprintf(stdout, "End of file (n=%d, flen=%d, peak=%d)\n", n, flen, peak_offset);
       break;
     }
     
@@ -337,7 +337,7 @@ plot_real_t pssout;
 
 plot_real_t psss1;//, psss2;
 
-float tmp[100000];
+float tmp[1000000];
 cf_t tmpce[SRSLTE_PSS_LEN];
 
 

srslte/lib/sync/test/pss_usrp.c

@@ -149,7 +149,26 @@ int main(int argc, char **argv) {
     init_plots();
 #endif
 
-  flen = 4800*(fft_size/64);
+  float srate = 15000.0*fft_size; 
+  
+  flen = srate*5/1000;
+
+  printf("Opening UHD device...\n");
+  if (cuhd_open(uhd_args, &uhd)) {
+    fprintf(stderr, "Error opening uhd\n");
+    exit(-1);
+  }
+  
+  if (srate < 10e6) {
+    cuhd_set_master_clock_rate(uhd, 4*srate);        
+  } else {
+    cuhd_set_master_clock_rate(uhd, srate);        
+  }
+
+  printf("Set RX rate: %.2f MHz\n", cuhd_set_rx_srate(uhd, srate) / 1000000);
+  printf("Set RX gain: %.1f dB\n", cuhd_set_rx_gain(uhd, uhd_gain));
+  printf("Set RX freq: %.2f MHz\n", cuhd_set_rx_freq(uhd, uhd_freq) / 1000000);
+  cuhd_rx_wait_lo_locked(uhd);
   
   buffer = malloc(sizeof(cf_t) * flen * 2);
   if (!buffer) {
@@ -177,16 +196,8 @@ int main(int argc, char **argv) {
 
   srslte_sss_synch_set_N_id_2(&sss, N_id_2);
 
-  printf("Opening UHD device...\n");
-  if (cuhd_open(uhd_args, &uhd)) {
-    fprintf(stderr, "Error opening uhd\n");
-    exit(-1);
-  }
   printf("N_id_2: %d\n", N_id_2);  
-  printf("Set RX rate: %.2f MHz\n", cuhd_set_rx_srate(uhd, flen*2*100) / 1000000);
+
-  printf("Set RX gain: %.1f dB\n", cuhd_set_rx_gain(uhd, uhd_gain));
-  printf("Set RX freq: %.2f MHz\n", cuhd_set_rx_freq(uhd, uhd_freq) / 1000000);
-  cuhd_rx_wait_lo_locked(uhd);
   cuhd_start_rx_stream(uhd);
   
   printf("Frame length %d samples\n", flen);