add few modif in extract RB dlsch

openair1/PHY/LTE_TRANSPORT/dlsch_demodulation_NB_IoT.c

@@ -4071,7 +4071,7 @@ unsigned short dlsch_extract_rbs_single_NB_IoT(int **rxdataF,
   int             *dl_ch0,*dl_ch0_ext,*rxF,*rxF_ext;
   unsigned short  UL_RB_ID_NB_IoT; // index of the NB-IoT RB
   uint8_t         id_offset; // offset of pilot position in symbols: 0,1,2 
-
+  unsigned short  NB_IoT_start,bandwidth_even_odd;      // Index of the first RE in the RB dedicated for NB-IoT, bandwidth_even_odd = 0 even 1 odd
   unsigned char symbol_mod,crs_pilots=0,j=0,poffset=0; 
   unsigned char nrs_pilots=0,nrs_offset=0; // nrs_pilots: flag of presence of pilot, nrs_offset: offset from first subcarrier
 
@@ -4110,8 +4110,14 @@ unsigned short dlsch_extract_rbs_single_NB_IoT(int **rxdataF,
 
     rxF_ext   = &rxdataF_ext[aarx][symbol*(frame_parms->N_RB_DL*12)];
     
+    bandwidth_even_odd = frame_parms->N_RB_DL % 2;     // 0 for even, 1 for odd
 
-    // if ((frame_parms->N_RB_DL&1) == 0)  // even number of RBs
+    if(UL_RB_ID_NB_IoT <= (frame_parms->N_RB_DL>>1))
+    { // RB in first half (below DC)
+      NB_IoT_start = UL_RB_ID_NB_IoT*12 + frame_parms->first_carrier_offset;
+    } else { // RB in the second half (above DC): DC is taken into account
+      NB_IoT_start = 1 + bandwidth_even_odd*6 + 6*(2*UL_RB_ID_NB_IoT - (frame_parms->N_RB_DL+bandwidth_even_odd));  
+    }
 
     for (rb=0;rb<1;rb++) {
 
@@ -4129,14 +4135,8 @@ unsigned short dlsch_extract_rbs_single_NB_IoT(int **rxdataF,
       if (rb_alloc_ind == 1)
         nb_rb++;
       
-        // if (rb==(frame_parms->N_RB_DL>>1)) {
-        if (UL_RB_ID_NB_IoT <= (frame_parms->N_RB_DL>>1)) { // NB-IoT RB is in the first half 
-          rxF       = &rxdataF[aarx][(UL_RB_ID_NB_IoT*12 + frame_parms->first_carrier_offset + (symbol*(frame_parms->ofdm_symbol_size)))];
-        }// For second half of RBs skip DC carrier
-        else{ // NB-IoT RB is in the second half 
-          rxF       = &rxdataF[aarx][(1 + 6*(2*UL_RB_ID_NB_IoT - frame_parms->N_RB_DL) + (symbol*(frame_parms->ofdm_symbol_size)))];
-          //dl_ch0++;
-        }
+        rxF       = &rxdataF[aarx][NB_IoT_start + (symbol*(frame_parms->ofdm_symbol_size))];
+
 
       // // PBCH
       // if (subframe==0) {

openair1/PHY/LTE_TRANSPORT/nsss_NB_IoT.c

@@ -212,10 +212,10 @@ int rx_nsss_NB_IoT(PHY_VARS_UE_NB_IoT *ue,int32_t *tot_metric)
 			return(-1);
 		}
 
-		for (k=0;k<126;k++){ 
+		for (k=0;k<126;k++){ // corresponds to u in standard
 			metric = 0;  
 
-			for (m=0;m<132;m++){
+			for (m=0;m<132;m++){ // 132 resource elements in NSSS subframe
 
 				metric += (int32_t)d[(k*126+m)<<1] * (int32_t)nsss_sf[(k*126+m)<<1] + 
 						(int32_t)d[((k*126+m)<<1)+1] * (int32_t)nsss_sf[((k*126+m)<<1)+1]; // real part of correlation