UE: update PDCCH config if MAC config changes

without this fix, after sync is successful, RAR is not getting decoded.
PDCCH area also changes as SSB offset can change. if MAC configuration changes.

openair2/LAYER2/NR_MAC_UE/config_ue.c

@@ -2106,6 +2106,10 @@ static void handle_reconfiguration_with_sync(NR_UE_MAC_INST_t *mac,
       configure_common_BWP_dl(mac, bwp_id, scc->downlinkConfigCommon->initialDownlinkBWP);
     if (scc->uplinkConfigCommon)
       configure_common_BWP_ul(mac, bwp_id, scc->uplinkConfigCommon->initialUplinkBWP);
+
+    // Update PDCCH config as MAC configuration has changed
+    if (IS_SA_MODE(get_softmodem_params()))
+      update_pdcch_config(mac);
   }
 
   mac->state = UE_NOT_SYNC_RECONF;

openair2/LAYER2/NR_MAC_UE/mac_proto.h

@@ -377,4 +377,5 @@ void nr_ue_sidelink_scheduler(nr_sidelink_indication_t *sl_ind, NR_UE_MAC_INST_t
 
 NR_SearchSpace_t *get_common_search_space(const NR_UE_MAC_INST_t *mac, const NR_SearchSpaceId_t ss_id);
 ssb_ro_preambles_t get_ssb_ro_preambles_4step(struct NR_RACH_ConfigCommon__ssb_perRACH_OccasionAndCB_PreamblesPerSSB *config);
+void update_pdcch_config(NR_UE_MAC_INST_t *mac);
 #endif

openair2/LAYER2/NR_MAC_UE/nr_ue_dci_configuration.c

@@ -422,6 +422,38 @@ static bool monitor_dci_for_other_SI(NR_UE_MAC_INST_t *mac,
   return false;
 }
 
+void update_pdcch_config(NR_UE_MAC_INST_t *mac)
+{
+  int scs = mac->current_DL_BWP ? mac->current_DL_BWP->scs : mac->numerology;
+  const int slots_per_frame = get_slots_per_frame_from_scs(scs);
+  int ssb_sc_offset_norm;
+  if (mac->ssb_subcarrier_offset < 24 && mac->frequency_range == FR1)
+    ssb_sc_offset_norm = mac->ssb_subcarrier_offset >> scs;
+  else
+    ssb_sc_offset_norm = mac->ssb_subcarrier_offset;
+  uint16_t ssb_offset_point_a = (mac->ssb_start_subcarrier - ssb_sc_offset_norm) / 12;
+  int ssb_start_symbol = get_ssb_start_symbol(mac->nr_band, scs, mac->mib_ssb);
+  get_type0_PDCCH_CSS_config_parameters(&mac->type0_PDCCH_CSS_config,
+                                        mac->mib_frame,
+                                        mac->mib,
+                                        slots_per_frame,
+                                        ssb_sc_offset_norm,
+                                        ssb_start_symbol,
+                                        scs,
+                                        mac->frequency_range,
+                                        mac->nr_band,
+                                        273,  // at this point UE in principle doesn't know the grid size (we assume the largest)
+                                        mac->mib_ssb,
+                                        1, // If the UE is not configured with a periodicity, the UE assumes a periodicity of a half frame
+                                        ssb_offset_point_a);
+  if (mac->search_space_zero == NULL)
+    mac->search_space_zero = calloc(1, sizeof(*mac->search_space_zero));
+  if (mac->coreset0 == NULL)
+    mac->coreset0 = calloc(1, sizeof(*mac->coreset0));
+  fill_coresetZero(mac->coreset0, &mac->type0_PDCCH_CSS_config);
+  fill_searchSpaceZero(mac->search_space_zero, slots_per_frame, &mac->type0_PDCCH_CSS_config);
+}
+
 void ue_dci_configuration(NR_UE_MAC_INST_t *mac, fapi_nr_dl_config_request_t *dl_config, const frame_t frame, const int slot)
 {
   const NR_UE_DL_BWP_t *current_DL_BWP = mac->current_DL_BWP;
@@ -430,37 +462,14 @@ void ue_dci_configuration(NR_UE_MAC_INST_t *mac, fapi_nr_dl_config_request_t *dl
   int scs = current_DL_BWP ? current_DL_BWP->scs : mac->numerology;
   const int slots_per_frame = get_slots_per_frame_from_scs(scs);
   if (mac->get_sib1) {
-    int ssb_sc_offset_norm;
-    if (mac->ssb_subcarrier_offset < 24 && mac->frequency_range == FR1)
-      ssb_sc_offset_norm = mac->ssb_subcarrier_offset >> scs;
-    else
-      ssb_sc_offset_norm = mac->ssb_subcarrier_offset;
-    uint16_t ssb_offset_point_a = (mac->ssb_start_subcarrier - ssb_sc_offset_norm) / 12;
-    int ssb_start_symbol = get_ssb_start_symbol(mac->nr_band, scs, mac->mib_ssb);
-    get_type0_PDCCH_CSS_config_parameters(&mac->type0_PDCCH_CSS_config,
-                                          mac->mib_frame,
-                                          mac->mib,
-                                          slots_per_frame,
-                                          ssb_sc_offset_norm,
-                                          ssb_start_symbol,
-                                          scs,
-                                          mac->frequency_range,
-                                          mac->nr_band,
-                                          273,  // at this point UE in principle doesn't know the grid size (we assume the largest)
-                                          mac->mib_ssb,
-                                          1, // If the UE is not configured with a periodicity, the UE assumes a periodicity of a half frame
-                                          ssb_offset_point_a);
-    if (mac->search_space_zero == NULL)
-      mac->search_space_zero = calloc(1, sizeof(*mac->search_space_zero));
-    if (mac->coreset0 == NULL)
-      mac->coreset0 = calloc(1, sizeof(*mac->coreset0));
-    fill_coresetZero(mac->coreset0, &mac->type0_PDCCH_CSS_config);
-    fill_searchSpaceZero(mac->search_space_zero, slots_per_frame, &mac->type0_PDCCH_CSS_config);
-    if (is_ss_monitor_occasion(frame, slot, slots_per_frame, mac->search_space_zero)) {
+    update_pdcch_config(mac);
+    bool is_occasion = is_ss_monitor_occasion(frame, slot, slots_per_frame, mac->search_space_zero);
+    if (is_occasion) {
       LOG_D(NR_MAC_DCI, "Monitoring DCI for SIB1 in frame %d slot %d\n", frame, slot);
       config_dci_pdu(mac, dl_config, TYPE_SI_RNTI_, slot, mac->search_space_zero);
     }
   }
+
   for (int i = 0; i < MAX_SI_GROUPS; i++) {
     if (!mac->get_otherSI[i])
       continue;