gNB: small optimization in gNB_I0_measurements()

openair1/PHY/NR_ESTIMATION/nr_measurements_gNB.c

@@ -144,7 +144,8 @@ void gNB_I0_measurements(PHY_VARS_gNB *gNB,int slot, int first_symb,int num_symb
   NR_DL_FRAME_PARMS *frame_parms = &gNB->frame_parms;
   NR_gNB_COMMON *common_vars = &gNB->common_vars;
   PHY_MEASUREMENTS_gNB *measurements = &gNB->measurements;
-  int rb, nb_symb[275]={0};
+  int rb, nb_symb[frame_parms->N_RB_UL];
+  bzero(nb_symb, sizeof(nb_symb));
 
   allocCast2D(n0_subband_power,
               unsigned int,
@@ -162,27 +163,35 @@ void gNB_I0_measurements(PHY_VARS_gNB *gNB,int slot, int first_symb,int num_symb
 
   for (int s=first_symb;s<(first_symb+num_symb);s++) {
     int offset0 = ((slot&3)*frame_parms->symbols_per_slot + s) * frame_parms->ofdm_symbol_size;
-    for (rb=0; rb<frame_parms->N_RB_UL; rb++) {
-      if ((gNB->rb_mask_ul[s][rb >> 5] & (1U << (rb & 31))) == 0 && // check that rb was not used in this subframe
-          !(I0_SKIP_DC && rb == frame_parms->N_RB_UL>>1)) {         // skip middle PRB because of artificial noise possibly created by FFT
-        int offset = offset0 + (frame_parms->first_carrier_offset + (rb*12))%frame_parms->ofdm_symbol_size;
-        nb_symb[rb]++;
-        for (int aarx=0; aarx<frame_parms->nb_antennas_rx; aarx++) {
-          int32_t *ul_ch = (int32_t *)&common_vars->rxdataF[aarx][offset];
+    for (int aarx = 0; aarx < frame_parms->nb_antennas_rx; aarx++) {
+      int32_t *ul_ch = (int32_t *)&common_vars->rxdataF[aarx][offset0 + frame_parms->first_carrier_offset];
+      for (rb = 0; rb < frame_parms->N_RB_UL; rb++) {
+        if ((gNB->rb_mask_ul[s][rb >> 5] & (1U << (rb & 31))) == 0 && // check that rb was not used in this subframe
+            !(I0_SKIP_DC
+              && rb == frame_parms->N_RB_UL >> 1)) { // skip middle PRB because of artificial noise possibly created by FFT
+          if (aarx == 0)
+            nb_symb[rb]++;
           int32_t signal_energy;
-          if (((frame_parms->N_RB_UL&1) == 1) &&
-              (rb==(frame_parms->N_RB_UL>>1))) {
-            signal_energy = signal_energy_nodc(ul_ch, 6);
-            ul_ch = (int32_t *)&common_vars->rxdataF[aarx][offset0];
-            signal_energy += signal_energy_nodc(ul_ch, 6);
+          if (rb == (frame_parms->N_RB_UL >> 1)) {
+            if ((frame_parms->N_RB_UL & 1) == 1) {
+              signal_energy = signal_energy_nodc(ul_ch, 6);
+              ul_ch = (int32_t *)&common_vars->rxdataF[aarx][offset0];
+              signal_energy += signal_energy_nodc(ul_ch, 6);
+              ul_ch += 6;
+            } else {
+              ul_ch = (int32_t *)&common_vars->rxdataF[aarx][offset0];
+              signal_energy = signal_energy_nodc(ul_ch, 12);
+              ul_ch += 12;
+            }
           } else {
             signal_energy = signal_energy_nodc(ul_ch, 12);
+            ul_ch += 12;
           }
           n0_subband_power[aarx][rb] += signal_energy;
           LOG_D(PHY,"slot %d symbol %d RB %d aarx %d n0_subband_power %d\n", slot, s, rb, aarx, signal_energy);
-        } //antenna
-      }
-    } //rb
+        }
+      } // rb
+    } // antenna
   } // symb
   int nb_rb=0;
   int32_t n0_subband_tot=0;