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.

executables/nr-gnb.c

@@ -235,7 +235,7 @@ void rx_func(void *param)
     L1_nr_prach_procedures(gNB,frame_rx,slot_rx);
 
     //WA: comment rotation in tx/rx
-    if((gNB->num_RU == 1) && (gNB->RU_list[0]->if_south != REMOTE_IF4p5)) {
+    if (gNB->phase_comp) {
       //apply the rx signal rotation here
       int soffset = (slot_rx & 3) * gNB->frame_parms.symbols_per_slot * gNB->frame_parms.ofdm_symbol_size;
       for (int aa = 0; aa < gNB->frame_parms.nb_antennas_rx; aa++) {

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;

openair2/GNB_APP/L1_nr_paramdef.h

@@ -58,6 +58,8 @@
 #define HLP_TP_SIZ "thread_pool_size paramter removed, please use --thread-pool"
 #define CONFIG_STRING_L1_TX_AMP_BACKOFF_dB                 "tx_amp_backoff_dB"
 #define HLP_L1TX_BO "Backoff from full-scale output at the L1 entity(frequency domain), ex. 12 would corresponding to 14-bit input level (6 dB/bit). Default 36 dBFS for OAI RU entity"
+#define CONFIG_STRING_L1_PHASE_COMP                        "phase_compensation"
+#define HLP_L1_PHASE_COMP "Apply NR symbolwise phase rotation"
 /*----------------------------------------------------------------------------------------------------------------------------------------------------*/
 /*                                            L1 configuration parameters                                                                             */
 /*   optname                                         helpstr   paramflags    XXXptr              defXXXval                  type           numelt     */
@@ -83,6 +85,7 @@
   {CONFIG_STRING_L1_RX_THREAD_CORE,                    NULL,       0,         .uptr=NULL,           .defintval=-1,              TYPE_UINT,     0},          \
   {CONFIG_STRING_L1_TX_THREAD_CORE,                    NULL,       0,         .uptr=NULL,           .defintval=-1,              TYPE_UINT,     0},          \
   {CONFIG_STRING_L1_TX_AMP_BACKOFF_dB,                 HLP_L1TX_BO,0,         .uptr=NULL,           .defintval=36,              TYPE_UINT,     0},         \
+  {CONFIG_STRING_L1_PHASE_COMP,                        HLP_L1_PHASE_COMP,PARAMFLAG_BOOL, .uptr=NULL,.defintval=1,               TYPE_UINT,     0},         \
 }
 // clang-format on
 #define L1_CC_IDX                                          0
@@ -104,6 +107,7 @@
 #define L1_RX_THREAD_CORE                                  16
 #define L1_TX_THREAD_CORE                                  17
 #define L1_TX_AMP_BACKOFF_dB                               18
+#define L1_PHASE_COMP                                      19
 
 /*----------------------------------------------------------------------------------------------------------------------------------------------------*/
 #endif

openair2/GNB_APP/gnb_config.c

@@ -885,6 +885,7 @@ void RCconfig_NR_L1(void)
       RC.gNB[j]->L1_tx_thread_core = *(L1_ParamList.paramarray[j][L1_TX_THREAD_CORE].iptr);
       LOG_I(PHY,"L1_RX_THREAD_CORE %d (%d)\n",*(L1_ParamList.paramarray[j][L1_RX_THREAD_CORE].iptr),L1_RX_THREAD_CORE);
       RC.gNB[j]->TX_AMP = (int16_t)(32767.0 / pow(10.0, .05 * (double)(*L1_ParamList.paramarray[j][L1_TX_AMP_BACKOFF_dB].uptr)));
+      RC.gNB[j]->phase_comp = *L1_ParamList.paramarray[j][L1_PHASE_COMP].uptr;
       LOG_I(PHY, "TX_AMP = %d (-%d dBFS)\n", RC.gNB[j]->TX_AMP, *L1_ParamList.paramarray[j][L1_TX_AMP_BACKOFF_dB].uptr);
       AssertFatal(RC.gNB[j]->TX_AMP > 300, "TX_AMP is too small, must be larger than 300 (is %d)\n", RC.gNB[j]->TX_AMP);
       if (strcmp(*(L1_ParamList.paramarray[j][L1_TRANSPORT_N_PREFERENCE_IDX].strptr), "local_mac") == 0) {