Revert to timing adjustment based on cyclic prefix and improves it

executables/nr-ue.c

@@ -456,26 +456,10 @@ void syncInFrame(PHY_VARS_NR_UE *UE, openair0_timestamp *timestamp) {
 }
 
 int computeSamplesShift(PHY_VARS_NR_UE *UE) {
-
-  // compute TO compensation that should be applied for this frame
-  if ( UE->rx_offset < UE->frame_parms.samples_per_frame/2  &&
-       UE->rx_offset > 0 ) {
-    LOG_I(PHY,"!!!adjusting -1 samples!!! rx_offset == %d\n", UE->rx_offset);
+  int samples_shift = -(UE->rx_offset>>1);
   UE->rx_offset   = 0; // reset so that it is not applied falsely in case of SSB being only in every second frame
   UE->max_pos_fil = 0; // reset IIR filter when sample shift is applied
-    return -1 ;
-  }
-
-  if ( UE->rx_offset > UE->frame_parms.samples_per_frame/2 &&
-       UE->rx_offset < UE->frame_parms.samples_per_frame ) {
-    int rx_offset = UE->rx_offset - UE->frame_parms.samples_per_frame;
-    LOG_I(PHY,"!!!adjusting +1 samples!!! rx_offset == %d\n", rx_offset);
-    UE->rx_offset   = 0; // reset so that it is not applied falsely in case of SSB being only in every second frame
-    UE->max_pos_fil = 0; // reset IIR filter when sample shift is applied
-    return 1;
-  }
-
-  return 0;
+  return samples_shift;
 }
 
 static inline int get_firstSymSamp(uint16_t slot, NR_DL_FRAME_PARMS *fp) {
@@ -642,6 +626,7 @@ void *UE_thread(void *arg) {
       readBlockSize=get_readBlockSize(slot_nr, &UE->frame_parms);
       writeBlockSize=UE->frame_parms.get_samples_per_slot((slot_nr + DURATION_RX_TO_TX - NR_RX_NB_TH) % nb_slot_frame, &UE->frame_parms);
     } else {
+      UE->rx_offset_diff = computeSamplesShift(UE);
       readBlockSize=get_readBlockSize(slot_nr, &UE->frame_parms) -
                     UE->rx_offset_diff;
       writeBlockSize=UE->frame_parms.get_samples_per_slot((slot_nr + DURATION_RX_TO_TX - NR_RX_NB_TH) % nb_slot_frame, &UE->frame_parms)- UE->rx_offset_diff;

openair1/PHY/NR_REFSIG/pss_nr.h

@@ -141,8 +141,6 @@ int pss_search_time_nr(int **rxdata, ///rx data in time domain
                        int *eNB_id,
 		       int *f_off);
 
-int nr_adjust_pss_synch(PHY_VARS_NR_UE *ue);
-
 #endif
 #undef EXTERN
 

openair1/PHY/NR_UE_ESTIMATION/nr_adjust_synch_ue.c

@@ -115,12 +115,6 @@ void nr_adjust_synch_ue(NR_DL_FRAME_PARMS *frame_parms,
     }
   }
 
-  if (ue->rx_offset < 0)
-    ue->rx_offset += frame_parms->samples_per_frame;
-
-  if (ue->rx_offset >= frame_parms->samples_per_frame)
-    ue->rx_offset -= frame_parms->samples_per_frame;
-
 #ifdef DEBUG_PHY
   LOG_D(PHY,"AbsSubframe %d: diff = %i, rx_offset (final) = %i : clear = %d, max_pos = %d, max_pos_fil = %d, max_val = %d, sync_pos %d\n",
         subframe,

openair1/PHY/NR_UE_TRANSPORT/pss_nr.c

@@ -976,62 +976,3 @@ int pss_search_time_nr(int **rxdata, ///rx data in time domain
   return(peak_position);
 }
 
-int nr_adjust_pss_synch(PHY_VARS_NR_UE *ue) {
-
-  int **rxdata = ue->common_vars.rxdata;
-  NR_DL_FRAME_PARMS *frame_parms = &ue->frame_parms;
-  uint8_t Nid2 = GET_NID2(frame_parms->Nid_cell);
-  int peak_position_ref = ((frame_parms->ofdm_symbol_size + frame_parms->nb_prefix_samples)<<1) + frame_parms->nb_prefix_samples0;
-
-  int maxval=0;
-  for (int i=0;i<2*(frame_parms->ofdm_symbol_size);i++) {
-    maxval = max(maxval,primary_synchro_time_nr[Nid2][i]);
-    maxval = max(maxval,-primary_synchro_time_nr[Nid2][i]);
-  }
-  int shift = log2_approx(maxval);
-
-  /* Search pss in the received buffer each 4 samples which ensures a memory alignment on 128 bits (32 bits x 4 ) */
-  /* This is required by SIMD (single instruction Multiple Data) Extensions of Intel processors. */
-  /* Correlation computation is based on a dot product which is realized thank to SIMS extensions */
-  int64_t peak_value = 0;
-  int peak_position = 0;
-  int64_t result = 0;
-  int64_t avg=0;
-  int start = peak_position_ref - (frame_parms->ofdm_symbol_size>>3);
-  int length = frame_parms->ofdm_symbol_size + (frame_parms->ofdm_symbol_size>>3);
-  memset(pss_corr_ue[Nid2],0,(start+length)*sizeof(int64_t));
-  for (int n=start; n < start+length; n+=4) { //
-    for (int ar=0; ar<frame_parms->nb_antennas_rx; ar++) {
-      result  = dot_product64((short*)primary_synchro_time_nr[Nid2],
-                              (short*) &(rxdata[ar][n]),
-                              frame_parms->ofdm_symbol_size,
-                              shift);
-      pss_corr_ue[Nid2][n] += abs64(result);
-    }
-    avg+=pss_corr_ue[Nid2][n];
-    if (pss_corr_ue[Nid2][n] > peak_value) {
-      peak_value = pss_corr_ue[Nid2][n];
-      peak_position = n;
-    }
-  }
-
-  avg/=(length/4);
-  if (peak_value < 5*avg) {
-    return 0;
-  }
-
-  int peak_position_diff = peak_position_ref - peak_position;
-
-  ue->rx_offset_diff = 0;
-  if(peak_position_diff != 0) {
-    ue->rx_offset_diff = peak_position_diff>>3;
-    if (ue->rx_offset_diff == 0) {
-      ue->rx_offset_diff = peak_position_diff > 0 ? 1 : -1;
-    }
-  }
-
-  LOG_D(NR_PHY,"nr_adjust_pss_synch: peak_position %d, peak_position_diff %d, peak_value %d dB, avg %d dB\n",
-        peak_position, peak_position_diff, dB_fixed64(peak_value),dB_fixed64(avg));
-
-  return peak_position_diff;
-}

openair1/SCHED_NR_UE/phy_procedures_nr_ue.c

@@ -1638,12 +1638,10 @@ int phy_procedures_nrUE_RX(PHY_VARS_NR_UE *ue,
 
     if ((ue->decode_MIB == 1) && slot_pbch) {
 
-      nr_adjust_pss_synch(ue);
-
       LOG_D(PHY," ------  Decode MIB: frame.slot %d.%d ------  \n", frame_rx%1024, nr_slot_rx);
       nr_ue_pbch_procedures(gNB_id, ue, proc, 0);
 
-     /* if (ue->no_timing_correction==0) {
+      if (ue->no_timing_correction==0) {
         LOG_D(PHY,"start adjust sync slot = %d no timing %d\n", nr_slot_rx, ue->no_timing_correction);
         nr_adjust_synch_ue(fp,
                            ue,
@@ -1652,7 +1650,7 @@ int phy_procedures_nrUE_RX(PHY_VARS_NR_UE *ue,
                            nr_slot_rx,
                            0,
                            16384);
-      }*/
+      }
 
       LOG_D(PHY, "Doing N0 measurements in %s\n", __FUNCTION__);
       nr_ue_rrc_measurements(ue, proc, nr_slot_rx);