NR_UE: consider sync position (1/8 CP) in initial sync and UL write timestamp

executables/nr-ue.c

@@ -657,7 +657,7 @@ void *UE_thread(void *arg) {
 
     // use previous timing_advance value to compute writeTimestamp
     writeTimestamp = timestamp + UE->frame_parms.get_samples_slot_timestamp(slot_nr, &UE->frame_parms,DURATION_RX_TO_TX - RX_NB_TH) -
-                     firstSymSamp - openair0_cfg[0].tx_sample_advance - UE->N_TA_offset - timing_advance;
+                     firstSymSamp - openair0_cfg[0].tx_sample_advance - UE->N_TA_offset - timing_advance + UE->frame_parms.nb_prefix_samples / 8;
 
     // but use current UE->timing_advance value to compute writeBlockSize
     if (UE->timing_advance != timing_advance) {

openair1/PHY/NR_UE_TRANSPORT/nr_initial_sync.c

@@ -309,6 +309,7 @@ int nr_initial_sync(UE_nr_rxtx_proc_t *proc, PHY_VARS_NR_UE *ue, int n_frames)
         // every 7*(1<<mu) symbols there is a different prefix length (38.211 5.3.1)
         int n_symb_prefix0 = (ue->symbol_offset/(7*(1<<mu)))+1;
         sync_pos_frame = n_symb_prefix0*(fp->ofdm_symbol_size + fp->nb_prefix_samples0)+(ue->symbol_offset-n_symb_prefix0)*(fp->ofdm_symbol_size + fp->nb_prefix_samples);
+        sync_pos_frame += fp->nb_prefix_samples / 8; // shift sync position ahead by 1/8th of cyclic prefix, same as in nr_adjust_synch_ue()
         if (ue->ssb_offset < sync_pos_frame)
           ue->rx_offset = fp->samples_per_frame - sync_pos_frame + ue->ssb_offset;
         else