Compute and apply symbol rotation for DL and UL

- now done according to the proper DL/UL frequency
- this makes it compatible with FDD mode

executables/nr-uesoftmodem.c

@@ -531,7 +531,8 @@ int main( int argc, char **argv ) {
     fapi_nr_config_request_t *nrUE_config = &UE[CC_id]->nrUE_config;
 
     nr_init_frame_parms_ue(&UE[CC_id]->frame_parms, nrUE_config, *mac->scc->downlinkConfigCommon->frequencyInfoDL->frequencyBandList.list.array[0]);
-    init_symbol_rotation(&UE[CC_id]->frame_parms, UE[CC_id]->frame_parms.dl_CarrierFreq);
+
+    init_symbol_rotation(&UE[CC_id]->frame_parms);
     init_nr_ue_vars(UE[CC_id], 0, abstraction_flag);
 
     #ifdef FR2_TEST

openair1/PHY/INIT/nr_init.c

@@ -494,7 +494,7 @@ void nr_phy_config_request(NR_PHY_Config_t *phy_config) {
 //  }
   RC.gNB[Mod_id]->configured     = 1;
 
-  init_symbol_rotation(fp,fp->dl_CarrierFreq);
+  init_symbol_rotation(fp);
 
   LOG_I(PHY,"gNB %d configured\n",Mod_id);
 }

openair1/PHY/MODULATION/nr_modulation.c

@@ -502,35 +502,62 @@ void nr_dft(int32_t *z, int32_t *d, uint32_t Msc_PUSCH)
 }
 
 
-void init_symbol_rotation(NR_DL_FRAME_PARMS *fp,uint64_t CarrierFreq) {
+void init_symbol_rotation(NR_DL_FRAME_PARMS *fp) {
+
+  uint64_t dl_CarrierFreq = fp->dl_CarrierFreq;
+  uint64_t ul_CarrierFreq = fp->ul_CarrierFreq;
+  double f[2] = {(double)dl_CarrierFreq, (double)ul_CarrierFreq};
 
   const int nsymb = fp->symbols_per_slot * fp->slots_per_frame/10;
   const double Tc=(1/480e3/4096);
   const double Nu=2048*64*(1/(float)(1<<fp->numerology_index));
-  const double f0= (double)CarrierFreq;
   const double Ncp0=16*64 + (144*64*(1/(float)(1<<fp->numerology_index)));
   const double Ncp1=(144*64*(1/(float)(1<<fp->numerology_index)));
   double tl=0,poff,exp_re,exp_im;
   double Ncp,Ncpm1=Ncp0;
 
-  poff = 2*M_PI*((Ncp0*Tc))*f0;
-  exp_re = cos(poff);
-  exp_im = sin(-poff);
-  fp->symbol_rotation[0]=(int16_t)floor(exp_re*32767);
-  fp->symbol_rotation[1]=(int16_t)floor(exp_im*32767);
-  LOG_I(PHY,"Doing symbol rotation calculation for gNB TX/RX, f0 %f Hz, Nsymb %d\n",f0,nsymb);
-  LOG_I(PHY,"Symbol rotation %d/%d => (%d,%d)\n",0,nsymb,fp->symbol_rotation[0],fp->symbol_rotation[1]);
-  for (int l=1;l<nsymb;l++) {
-    if (l==(7*(1<<fp->numerology_index))) Ncp=Ncp0;
-    else Ncp=Ncp1;
-    tl += (Nu+Ncpm1)*Tc;					     
-    poff = 2*M_PI*(tl + (Ncp*Tc))*f0;
+  for (uint8_t ll = 0; ll < 2; ll++){
+
+    double f0 = f[ll];
+    int16_t *symbol_rotation = fp->symbol_rotation[ll];
+
+    poff = 2 * M_PI * ((Ncp0 * Tc)) * f0;
     exp_re = cos(poff);
     exp_im = sin(-poff);
-    fp->symbol_rotation[l<<1]=(int16_t)floor(exp_re*32767);
-    fp->symbol_rotation[1+(l<<1)]=(int16_t)floor(exp_im*32767);
-    LOG_I(PHY,"Symbol rotation %d/%d => tl %f (%d,%d) (%f)\n",l,nsymb,tl,fp->symbol_rotation[l<<1],fp->symbol_rotation[1+(l<<1)],
-	  (poff/2/M_PI)-floor(poff/2/M_PI));
-    Ncpm1=Ncp;
+    symbol_rotation[0] = (int16_t)floor(exp_re * 32767);
+    symbol_rotation[1] = (int16_t)floor(exp_im * 32767);
+    LOG_I(PHY, "Doing symbol rotation calculation for gNB TX/RX, f0 %f Hz, Nsymb %d\n", f0, nsymb);
+    LOG_I(PHY, "Symbol rotation %d/%d => (%d,%d)\n",
+      0,
+      nsymb,
+      symbol_rotation[0],
+      symbol_rotation[1]);
+
+    for (int l = 1; l < nsymb; l++) {
+
+      if (l == (7 * (1 << fp->numerology_index))) {
+        Ncp = Ncp0;
+      } else {
+        Ncp = Ncp1;
+      }
+
+      tl += (Nu + Ncpm1) * Tc;
+      poff = 2 * M_PI * (tl + (Ncp * Tc)) * f0;
+      exp_re = cos(poff);
+      exp_im = sin(-poff);
+      symbol_rotation[l<<1] = (int16_t)floor(exp_re * 32767);
+      symbol_rotation[1 + (l<<1)] = (int16_t)floor(exp_im * 32767);
+
+      LOG_I(PHY, "Symbol rotation %d/%d => tl %f (%d,%d) (%f)\n",
+        l,
+        nsymb,
+        tl,
+        symbol_rotation[l<<1],
+        symbol_rotation[1 + (l<<1)],
+        (poff / 2 / M_PI) - floor(poff / 2 / M_PI));
+
+      Ncpm1 = Ncp;
+
+    }
   }
 }

openair1/PHY/MODULATION/nr_modulation.h

@@ -110,7 +110,7 @@ void apply_nr_rotation(NR_DL_FRAME_PARMS *fp,
 		       int nsymb,
 		       int length);
 
-void init_symbol_rotation(NR_DL_FRAME_PARMS *fp,uint64_t CarrierFreq);
+void init_symbol_rotation(NR_DL_FRAME_PARMS *fp);
 
 void apply_nr_rotation_ul(NR_DL_FRAME_PARMS *frame_parms,
 			  int32_t *rxdataF,

openair1/PHY/MODULATION/ofdm_mod.c

@@ -306,15 +306,23 @@ void apply_nr_rotation(NR_DL_FRAME_PARMS *fp,
 		       int length) {
   int symb_offset = (slot%fp->slots_per_subframe)*fp->symbols_per_slot;
 
+  int16_t *symbol_rotation = fp->symbol_rotation[0];
+
   for (int sidx=0;sidx<nsymb;sidx++) {
+
     LOG_D(PHY,"Rotating symbol %d, slot %d, symbol_subframe_index %d, length %d (%d,%d)\n",
-	  first_symbol+sidx,slot,sidx+first_symbol+symb_offset,length,
-	  fp->symbol_rotation[2*(sidx+first_symbol+symb_offset)],fp->symbol_rotation[1+2*(sidx+first_symbol+symb_offset)]);
-    rotate_cpx_vector(trxdata+(sidx*length*2),
-		      &fp->symbol_rotation[2*(sidx+first_symbol+symb_offset)],
-		      trxdata+(sidx*length*2),
-		      length,
-		      15);
+      first_symbol + sidx,
+      slot,
+      sidx + first_symbol + symb_offset,
+      length,
+      symbol_rotation[2 * (sidx + first_symbol + symb_offset)],
+      symbol_rotation[1 + 2 * (sidx + first_symbol + symb_offset)]);
+
+    rotate_cpx_vector(trxdata + (sidx * length * 2),
+                      &symbol_rotation[2 * (sidx + first_symbol + symb_offset)],
+                      trxdata + (sidx * length * 2),
+                      length,
+                      15);
   }
 }
 		       

openair1/PHY/MODULATION/slot_fep_nr.c

@@ -205,7 +205,7 @@ int nr_slot_fep(PHY_VARS_NR_UE *ue,
 #endif
     
     int symb_offset = (Ns%frame_parms->slots_per_subframe)*frame_parms->symbols_per_slot;
-    int32_t rot2 = ((uint32_t*)frame_parms->symbol_rotation)[symbol+symb_offset];
+    int32_t rot2 = ((uint32_t*)frame_parms->symbol_rotation[0])[symbol + symb_offset];
     ((int16_t*)&rot2)[1]=-((int16_t*)&rot2)[1];
     rotate_cpx_vector((int16_t *)&common_vars->common_vars_rx_data_per_thread[proc->thread_id].rxdataF[aa][frame_parms->ofdm_symbol_size*symbol],
 		      (int16_t*)&rot2,
@@ -386,7 +386,7 @@ int nr_slot_fep_init_sync(PHY_VARS_NR_UE *ue,
     }
 
     int symb_offset = (Ns%frame_parms->slots_per_subframe)*frame_parms->symbols_per_slot;
-    int32_t rot2 = ((uint32_t*)frame_parms->symbol_rotation)[symbol+symb_offset];
+    int32_t rot2 = ((uint32_t*)frame_parms->symbol_rotation[0])[symbol + symb_offset];
     ((int16_t*)&rot2)[1]=-((int16_t*)&rot2)[1];
 
 #ifdef DEBUG_FEP
@@ -513,7 +513,7 @@ void apply_nr_rotation_ul(NR_DL_FRAME_PARMS *frame_parms,
 
   for (int symbol=0;symbol<nsymb;symbol++) {
     
-    uint32_t rot2 = ((uint32_t*)frame_parms->symbol_rotation)[symbol+symb_offset];
+    uint32_t rot2 = ((uint32_t*)frame_parms->symbol_rotation[1])[symbol + symb_offset];
     ((int16_t*)&rot2)[1]=-((int16_t*)&rot2)[1];
     LOG_D(PHY,"slot %d, symb_offset %d rotating by %d.%d\n",slot,symb_offset,((int16_t*)&rot2)[0],((int16_t*)&rot2)[1]);
     rotate_cpx_vector((int16_t *)&rxdataF[frame_parms->ofdm_symbol_size*symbol],

openair1/PHY/NR_UE_TRANSPORT/nr_ulsch_ue.c

@@ -496,13 +496,19 @@ uint8_t nr_ue_pusch_common_procedures(PHY_VARS_NR_UE *UE,
   int symb_offset = (slot%frame_parms->slots_per_subframe)*frame_parms->symbols_per_slot;
   for(ap = 0; ap < Nl; ap++) {
     for (int s=0;s<NR_NUMBER_OF_SYMBOLS_PER_SLOT;s++){
-      LOG_D(PHY,"rotating txdataF symbol %d (%d) => (%d.%d)\n",
-	    s,s+symb_offset,frame_parms->symbol_rotation[2*(s+symb_offset)],frame_parms->symbol_rotation[1+(2*(s+symb_offset))]);
-      rotate_cpx_vector((int16_t *)&txdataF[ap][frame_parms->ofdm_symbol_size*s],
-			&frame_parms->symbol_rotation[2*(s+symb_offset)],
-			(int16_t *)&txdataF[ap][frame_parms->ofdm_symbol_size*s],
-			frame_parms->ofdm_symbol_size,
-			15);
+
+      LOG_D(PHY,"In %s: rotating txdataF symbol %d (%d) => (%d.%d)\n",
+        __FUNCTION__,
+        s,
+        s + symb_offset,
+        frame_parms->symbol_rotation[1][2 * (s + symb_offset)],
+        frame_parms->symbol_rotation[1][1 + (2 * (s + symb_offset))]);
+
+      rotate_cpx_vector((int16_t *)&txdataF[ap][frame_parms->ofdm_symbol_size * s],
+                        &frame_parms->symbol_rotation[1][2 * (s + symb_offset)],
+                        (int16_t *)&txdataF[ap][frame_parms->ofdm_symbol_size * s],
+                        frame_parms->ofdm_symbol_size,
+                        15);
     }
   }
 

openair1/PHY/defs_nr_common.h

@@ -327,7 +327,8 @@ struct NR_DL_FRAME_PARMS {
   /// Cyclic Prefix for DL (0=Normal CP, 1=Extended CP)
   lte_prefix_type_t Ncp;
   /// sequence which is computed based on carrier frequency and numerology to rotate/derotate each OFDM symbol according to Section 5.3 in 38.211
-  int16_t symbol_rotation[224*2];
+  /// First dimension is for the direction of the link (0 DL, 1 UL)
+  int16_t symbol_rotation[2][224*2];
   /// shift of pilot position in one RB
   uint8_t nushift;
   /// SRS configuration from TS 38.331 RRC

openair1/SIMULATION/NR_PHY/pbchsim.c

@@ -111,7 +111,7 @@ void nr_phy_config_request_sim_pbchsim(PHY_VARS_gNB *gNB,
 
   nr_init_frame_parms(gNB_config, fp);
 
-  init_symbol_rotation(fp,fp->dl_CarrierFreq);
+  init_symbol_rotation(fp);
 
   gNB->configured    = 1;
   LOG_I(PHY,"gNB configured\n");