RRC multi-cell (finalise): add informative comments and logging

This commit adds documentation comments and logging to improve
code readability and debugging capabilities for the multi-cell
architecture.

Changes:
- gnb_config.c: Add logging when configuring DU with cell ID and PCI
- rrc_gNB_du.c: Add documentation comment for ssb_arfcn_mtc()
- rrc_gNB_du.c: Add documentation comment for dump_du_info()

openair2/GNB_APP/gnb_config.c

@@ -1684,6 +1684,7 @@ void RCconfig_nr_macrlc(configmodule_interface_t *cfg)
     seq_arr_t *du_SIBs = RC.nrmac[0]->common_channels[0].du_SIBs;
     f1ap_setup_req_t *req = RC_read_F1Setup(gnb_du_id, name, &info, scc, mib, sib1, du_SIBs);
     AssertFatal(req != NULL, "could not read F1 Setup information\n");
+    LOG_I(GNB_APP, "Configured DU: cell ID %lu, PCI %d\n", info.nr_cellid, info.nr_pci);
     RC.nrmac[0]->f1_config.setup_req = req;
     RC.nrmac[0]->f1_config.gnb_id = gnb_id;
 

openair2/RRC/NR/rrc_gNB_du.c

@@ -72,6 +72,9 @@ static NR_SSB_MTC_t *get_ssb_mtc(const NR_MeasurementTimingConfiguration_t *mtc)
   return ssb_mtc;
 }
 
+/** @brief Return the frequency of the SS block of the cell for which this message is included,
+ * or of other SS blocks within the same carrier. MeasurementTimingConfiguration message is
+ * used to convey assistance information for measurement timing between nodes (e.g F1 setup) */
 static int ssb_arfcn_mtc(const NR_MeasurementTimingConfiguration_t *mtc)
 {
   /* format has been verified when accepting MeasurementTimingConfiguration */
@@ -728,6 +731,11 @@ nr_rrc_du_container_t *get_du_for_ue(gNB_RRC_INST *rrc, uint32_t ue_id)
   return get_du_by_assoc_id(rrc, ue_data.du_assoc_id);
 }
 
+/** @brief Dump DU and cell information to file
+ * @param[in] rrc RRC instance
+ * @param[in] f File handle to write to
+ * @note Complexity: O(d + N_CELL) = O(N_CELL) where d = number of DUs, N_CELL = total number of cells across all DUs
+ * @note Called periodically (every 1 second) for stats logging */
 void dump_du_info(const gNB_RRC_INST *rrc, FILE *f)
 {
   fprintf(f, "%ld connected DUs \n", rrc->num_dus);