Add configuration for phase compensation

For 7.2 FH, some RUs do phase compensation, whereas for others, the DU
does it. In fact, this can be "negotiated" using the M plane. Since we
don't have the M plane yet, add a configuration option to set where
phase compensation is performed.

openair1/PHY/defs_gNB.h

@@ -604,6 +604,10 @@ typedef struct PHY_VARS_gNB_s {
 
   // reference amplitude for TX
   int16_t TX_AMP;
+
+  // flag to activate 3GPP phase symbolwise rotation
+  bool phase_comp;
+
   // PUCCH0 Look-up table for cyclic-shifts
   NR_gNB_PUCCH0_LUT_t pucch0_lut;
 

openair1/SCHED_NR/phy_procedures_nr_gNB.c

@@ -221,18 +221,20 @@ void phy_procedures_gNB_TX(processingData_L1tx_t *msgTx,
 //  if ((frame&127) == 0) dump_pdsch_stats(gNB);
 
   //apply the OFDM symbol rotation here
-  for (aa=0; aa<cfg->carrier_config.num_tx_ant.value; aa++) {
-    apply_nr_rotation_TX(fp,
-                         &gNB->common_vars.txdataF[aa][txdataF_offset],
-                         fp->symbol_rotation[0],
-                         slot,
-                         fp->N_RB_DL,
-                         0,
-                         fp->Ncp == EXTENDED ? 12 : 14);
+  if (gNB->phase_comp) {
+    for (aa=0; aa<cfg->carrier_config.num_tx_ant.value; aa++) {
+      apply_nr_rotation_TX(fp,
+                           &gNB->common_vars.txdataF[aa][txdataF_offset],
+                           fp->symbol_rotation[0],
+                           slot,
+                           fp->N_RB_DL,
+                           0,
+                           fp->Ncp == EXTENDED ? 12 : 14);
 
-    T(T_GNB_PHY_DL_OUTPUT_SIGNAL, T_INT(0),
-      T_INT(frame), T_INT(slot),
-      T_INT(aa), T_BUFFER(&gNB->common_vars.txdataF[aa][txdataF_offset], fp->samples_per_slot_wCP*sizeof(int32_t)));
+      T(T_GNB_PHY_DL_OUTPUT_SIGNAL, T_INT(0),
+        T_INT(frame), T_INT(slot),
+        T_INT(aa), T_BUFFER(&gNB->common_vars.txdataF[aa][txdataF_offset], fp->samples_per_slot_wCP*sizeof(int32_t)));
+    }
   }
 
   VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME(VCD_SIGNAL_DUMPER_FUNCTIONS_PHY_PROCEDURES_gNB_TX + gNB->CC_id, 0);

openair1/SIMULATION/NR_PHY/dlsim.c

@@ -610,6 +610,7 @@ int main(int argc, char **argv)
   gNB = RC.gNB[0];
   gNB->ofdm_offset_divisor = UINT_MAX;
   gNB->ldpc_offload_flag = ldpc_offload_flag;
+  gNB->phase_comp = true; // we need to perform phase compensation, otherwise everything will fail
   frame_parms = &gNB->frame_parms; //to be initialized I suppose (maybe not necessary for PBCH)
   frame_parms->nb_antennas_tx = n_tx;
   frame_parms->nb_antennas_rx = n_rx;