[develop] Added: timing offset compensation at UE

     - post-compensation for DL and pre-compensation for UL

executables/nr-ue.c

@@ -762,6 +762,8 @@ void *UE_thread(void *arg)
 
   int timing_advance = UE->timing_advance;
   NR_UE_MAC_INST_t *mac = get_mac_inst(0);
+  int rx_offset_slot = 0; //samples to be shifted for the current slot
+  int UL_TO_Tx_ofs = 0;
 
   bool syncRunning=false;
   const int nb_slot_frame = UE->frame_parms.slots_per_frame;
@@ -869,14 +871,21 @@ void *UE_thread(void *arg)
 
     int readBlockSize, writeBlockSize;
 
-    readBlockSize = get_readBlockSize(slot_nr, &UE->frame_parms);
-    writeBlockSize = UE->frame_parms.get_samples_per_slot((slot_nr + DURATION_RX_TO_TX) % nb_slot_frame, &UE->frame_parms);
-    if (UE->apply_timing_offset && (slot_nr == nb_slot_frame - 1)) {
+    rx_offset_slot = UE->rx_offset_TO * UE->rx_offset_slot / nb_slot_frame - UE->rx_offset_comp;
+    UE->rx_offset_comp += rx_offset_slot;
+    UE->rx_offset_slot++;
+    UL_TO_Tx_ofs += 2*rx_offset_slot; //to adapt the UE's transmission time in order to get aligned at gNB
+
+    readBlockSize=get_readBlockSize(slot_nr, &UE->frame_parms) + rx_offset_slot;
+    writeBlockSize=UE->frame_parms.get_samples_per_slot((slot_nr + DURATION_RX_TO_TX) % nb_slot_frame, &UE->frame_parms);
+    /*
+    if (UE->apply_timing_offset && (slot_nr == nb_slot_frame-1)) {
       const int sampShift = -(UE->rx_offset>>1);
       readBlockSize -= sampShift;
       writeBlockSize -= sampShift;
       UE->apply_timing_offset = false;
     }
+    */
 
     AssertFatal(readBlockSize ==
                 UE->rfdevice.trx_read_func(&UE->rfdevice,
@@ -885,9 +894,9 @@ void *UE_thread(void *arg)
                                            readBlockSize,
                                            UE->frame_parms.nb_antennas_rx),"");
 
-    if(slot_nr == (nb_slot_frame - 1)) {
-      // read in first symbol of next frame and adjust for timing drift
-      int first_symbols = UE->frame_parms.ofdm_symbol_size + UE->frame_parms.nb_prefix_samples0; // first symbol of every frames
+    if( slot_nr==(nb_slot_frame-1)) {
+      // read in first symbol of next frame
+      int first_symbols=UE->frame_parms.ofdm_symbol_size+UE->frame_parms.nb_prefix_samples0; // first symbol of every frames
 
       if (first_symbols > 0) {
         openair0_timestamp ignore_timestamp;

openair1/PHY/NR_UE_ESTIMATION/nr_adjust_synch_ue.c

@@ -114,11 +114,6 @@ void nr_adjust_synch_ue(NR_DL_FRAME_PARMS *frame_parms,
     ue->rx_offset_comp = 0;
   }
 
-
-  const int sample_shift = -(ue->rx_offset>>1);
-  // reset IIR filter for next offset calculation
-  ue->max_pos_fil += sample_shift * 32768;
-
   if(abs(diff)<5)
     count_max_pos_ok ++;
   else