Merge remote-tracking branch 'origin/fix-a3-event' into integration_2026_w04 (!3789)

fix A3 event configuration

See commit message for more information.
As a reference, for comparison purpose, PCAPs and TXT files for various tests
done in develop and in this MR are available in the MR description.

openair2/RRC/NR/MESSAGES/asn1_msg.c

@@ -1121,7 +1121,8 @@ NR_MeasConfig_t *get_MeasConfig(const NR_MeasTiming_t *mt,
                                 NR_ReportConfigToAddMod_t *rc_PER,
                                 NR_ReportConfigToAddMod_t *rc_A2,
                                 seq_arr_t *rc_A3_seq,
-                                seq_arr_t *neigh_seq)
+                                seq_arr_t *neigh_seq,
+                                int *neigh_a3_id)
 {
   DevAssert(mt != NULL && mt->frequencyAndTiming != NULL);
   const struct NR_MeasTiming__frequencyAndTiming *ft = mt->frequencyAndTiming;
@@ -1207,7 +1208,10 @@ NR_MeasConfig_t *get_MeasConfig(const NR_MeasTiming_t *mt,
   if (neigh_seq) {
     int i = 0;
     FOR_EACH_SEQ_ARR(nr_neighbour_cell_t *, neigh_cell, neigh_seq) {
-      NR_ReportConfigId_t reportConfigId = neigh_cell->physicalCellId == -1 ? 3 : i + 4;
+      NR_ReportConfigId_t reportConfigId = neigh_a3_id[i];
+      /* check that there is a A3 configured for this neighbour */
+      if (reportConfigId == -1)
+        continue;
       NR_MeasIdToAddMod_t *measid_A3 = get_MeasId(meas_idx + 1, reportConfigId, i + 2);
       meas_idx++;
       asn1cSeqAdd(&mc->measIdToAddModList->list, measid_A3);

openair2/RRC/NR/MESSAGES/asn1_msg.h

@@ -164,7 +164,8 @@ NR_MeasConfig_t *get_MeasConfig(const NR_MeasTiming_t *mt,
                                 NR_ReportConfigToAddMod_t *rc_PER,
                                 NR_ReportConfigToAddMod_t *rc_A2,
                                 seq_arr_t *rc_A3_seq,
-                                seq_arr_t *neigh_seq);
+                                seq_arr_t *neigh_seq,
+                                int *neigh_a3_id);
 void free_MeasConfig(NR_MeasConfig_t *mc);
 int do_NR_Paging(uint8_t Mod_id, uint8_t *buffer, uint32_t tmsi);
 

openair2/RRC/NR/rrc_gNB.c

@@ -622,9 +622,6 @@ static nr_a3_event_t *get_a3_configuration(gNB_RRC_INST *rrc, int pci)
       return a3_event;
   }
 
-  if (measurementConfiguration->is_default_a3_configuration_exists)
-    return get_a3_configuration(rrc, -1);
-
   return NULL;
 }
 
@@ -750,6 +747,10 @@ NR_MeasConfig_t *nr_rrc_get_measconfig(const gNB_RRC_INST *rrc, uint64_t nr_cell
     if (neighbour_config)
       neighbour_cells = neighbour_config->neighbour_cells;
 
+    int *neigh_a3_id = NULL;
+    if (neighbour_cells && neighbour_cells->size)
+      neigh_a3_id = calloc_or_fail(neighbour_cells->size, sizeof(int));
+
     if (neighbour_cells && rrc->measurementConfiguration.a3_event_list && rrc->measurementConfiguration.a3_event_list->size > 0) {
       /* Loop through neighbours and find related A3 configuration
          If no related A3 but there is default add the default one.
@@ -759,16 +760,31 @@ NR_MeasConfig_t *nr_rrc_get_measconfig(const gNB_RRC_INST *rrc, uint64_t nr_cell
       bool default_a3_added = false; // To ensure that the default configuration is only added once
       for (int i = 0; i < neighbour_cells->size; i++) {
         nr_neighbour_cell_t *neighbourCell = (nr_neighbour_cell_t *)seq_arr_at(neighbour_cells, i);
-        if (default_a3_added && neighbourCell->physicalCellId == -1)
-          continue;
         seq_arr_push_back(&neigh_seq, neighbourCell, sizeof(nr_neighbour_cell_t));
         const nr_a3_event_t *a3Event = get_a3_configuration((gNB_RRC_INST *)rrc, neighbourCell->physicalCellId);
-        if (a3Event) {
+        if (!a3Event) {
-          NR_ReportConfigId_t reportConfigId = neighbourCell->physicalCellId == -1 ? 3 : i + 4;
+          /* no A3 event configured for this neighbour, let's try the default one, if it exists */
-          seq_arr_push_back(&rc_A3_seq, prepare_a3_event_report(a3Event, reportConfigId), sizeof(NR_ReportConfigToAddMod_t));
+          if (default_a3_added) {
-          if (neighbourCell->physicalCellId == -1)
+            /* default A3 exists and is already added, use it for this neighbour */
-            default_a3_added = true;
+            neigh_a3_id[i] = 3;
+            continue;
+          }
+          /* try to get the default A3 config */
+          a3Event = get_a3_configuration((gNB_RRC_INST *)rrc, -1);
+          if (!a3Event) {
+            /* no default A3 config found, so no A3 config for this neighbour */
+            neigh_a3_id[i] = -1;
+            continue;
+          }
+          default_a3_added = true;
+          /* default A3 report config ID is 3 */
+          neigh_a3_id[i] = 3;
+        } else {
+          /* specific A3 report config ID are 4, 5, ... */
+          neigh_a3_id[i] = i + 4;
         }
+        NR_ReportConfigId_t reportConfigId = neigh_a3_id[i];
+        seq_arr_push_back(&rc_A3_seq, prepare_a3_event_report(a3Event, reportConfigId), sizeof(NR_ReportConfigToAddMod_t));
       }
     }
     if (rrc->measurementConfiguration.per_event)
@@ -776,12 +792,14 @@ NR_MeasConfig_t *nr_rrc_get_measconfig(const gNB_RRC_INST *rrc, uint64_t nr_cell
     if (rrc->measurementConfiguration.a2_event)
       rc_A2 = prepare_a2_event_report(rrc->measurementConfiguration.a2_event);
 
-    NR_MeasConfig_t *result = get_MeasConfig(mt, band, scs, cell_info->nr_pci, rc_PER, rc_A2, &rc_A3_seq, &neigh_seq);
+    NR_MeasConfig_t *result = get_MeasConfig(mt, band, scs, cell_info->nr_pci, rc_PER, rc_A2, &rc_A3_seq, &neigh_seq, neigh_a3_id);
 
     // Clean up sequence arrays
     seq_arr_free(&rc_A3_seq, NULL);
     seq_arr_free(&neigh_seq, NULL);
 
+    free(neigh_a3_id);
+
     return result;
   }
   return NULL;
@@ -1620,6 +1638,9 @@ static void process_Event_Based_Measurement_Report(gNB_RRC_INST *rrc,
         if (!neigh_cell && neighbour) {
           // No F1 connection but static neighbour configuration is available
           const nr_a3_event_t *a3_event_configuration = get_a3_configuration(rrc, neighbour->physicalCellId);
+          /* if no A3 event configured for this physical cell ID, try to get the default one */
+          if (!a3_event_configuration)
+            a3_event_configuration = get_a3_configuration(rrc, -1);
           // Additional check - This part can be modified according to additional cell specific Handover Margin
           // a3-Offset: The actual value is field value * 0.5 dB.
           if (a3_event_configuration