Perform 2 Step frequency adjustment in the USRP and reset frequency offset...

Perform 2 Step frequency adjustment in the USRP and reset frequency offset after changing the RF card frequency

executables/nr-ue.c

@@ -450,25 +450,43 @@ static void UE_synch(void *arg) {
 
         // rerun with new cell parameters and frequency-offset
         // todo: the freq_offset computed on DL shall be scaled before being applied to UL
-        nr_rf_card_config_freq(&openair0_cfg[UE->rf_map.card], ul_carrier, dl_carrier, freq_offset);
+        nr_rf_card_config_freq(&openair0_cfg[UE->rf_map.card],
+                               (uint64_t)openair0_cfg[UE->rf_map.card].tx_freq[0],
+                               (uint64_t)openair0_cfg[UE->rf_map.card].rx_freq[0],
+                               freq_offset);
 
-        LOG_I(PHY,"Got synch: hw_slot_offset %d, carrier off %d Hz, rxgain %f (DL %f Hz, UL %f Hz)\n",
+        LOG_I(PHY,
+              "Got synch: hw_slot_offset %d, carrier off %d Hz, rxgain %f (DL %f Hz, UL %f Hz)\n",
               hw_slot_offset,
               freq_offset,
               openair0_cfg[UE->rf_map.card].rx_gain[0],
               openair0_cfg[UE->rf_map.card].rx_freq[0],
               openair0_cfg[UE->rf_map.card].tx_freq[0]);
 
-        UE->rfdevice.trx_set_freq_func(&UE->rfdevice,&openair0_cfg[0]);
-        if (UE->UE_scan_carrier == 1) {
+        UE->rfdevice.trx_set_freq_func(&UE->rfdevice, &openair0_cfg[0]);
+
+        LOG_A(PHY,
+              "Adjusting hardware frequency offset to %d Hz (computed SSB offset %d Hz)\n",
+              (int)((double)dl_carrier - openair0_cfg[UE->rf_map.card].rx_freq[0]),
+              UE->common_vars.freq_offset);
+
+        if (abs(UE->common_vars.freq_offset) > abs(UE->frame_parms.subcarrier_spacing / 100)) {
+          LOG_W(PHY,
+                "Computed SSB offset %d Hz > %d Hz, resynchronizing again...\n",
+                UE->common_vars.freq_offset,
+                (UE->frame_parms.subcarrier_spacing / 100));
+          // Reset frequency offset after applying new frequency with nr_rf_card_config_freq
+          UE->common_vars.freq_offset = 0;
+          return;
+        }
+
+        // Reset frequency offset after applying new frequency with nr_rf_card_config_freq
+        UE->common_vars.freq_offset = 0;
+
+        if (UE->UE_scan_carrier == 1)
           UE->UE_scan_carrier = 0;
-        } else {
+        else
           UE->is_synchronized = 1;
-        }
-        if (UE->synch_request.received_synch_request == 1) {
-          UE->is_synchronized = 0;
-          UE->synch_request.received_synch_request = 0;
-        }
       } else {
 
         if (UE->UE_scan_carrier == 1) {
@@ -602,6 +620,8 @@ nr_phy_data_t UE_dl_preprocessing(PHY_VARS_NR_UE *UE, UE_nr_rxtx_proc_t *proc)
         UE->frame_parms.ul_CarrierFreq = dl_CarrierFreq - diff;
 
         nr_rf_card_config_freq(&openair0_cfg[UE->rf_map.card], UE->frame_parms.ul_CarrierFreq, UE->frame_parms.dl_CarrierFreq, 0);
+        // Reset frequency offset
+        UE->common_vars.freq_offset = 0;
         UE->rfdevice.trx_set_freq_func(&UE->rfdevice, &openair0_cfg[0]);
         init_symbol_rotation(&UE->frame_parms);
       }