Paging UE (MAC): parse and store SIB1 PCCH config

Populate UE MAC paging state from SIB1 PCCH-Config so PF/PO-related
parameters are available to the rest of the UE MAC.

Changes:
- Add nr_ue_paging_cfg_t to NR_UE_MAC_INST_s with parsed paging fields
  (T, N, Ns, PF_offset, X) and the optional
  firstPDCCH-MonitoringOccasionOfPO list (first_mo_of_po[],
  first_mo_of_po_count)
- Add configure_pcch_config() to decode SIB1 PCCH-Config via the
  common helpers nr_pcch_default_paging_cycle_rf,
  nr_pcch_n_and_paging_frame_offset, nr_pcch_ns_per_pf and
  nr_pcch_first_pdcch_start_mo
- Add NR_PCCH_MAX_PO constant (TS 38.331 PCCH-Config) and size the
  first_mo_of_po[]
- Invoke configure_pcch_config() from nr_rrc_mac_config_req_sib1()

Signed-off-by: Guido Casati <guido.casati@openairinterface.org>

common/platform_constants.h

@@ -52,6 +52,9 @@
 /** Maximum value of nrofPDCCH-MonitoringOccasionPerSSB-InPO-r16 (TS 38.331 PCCH-Config) */
 #define NR_PCCH_MAX_MO_PER_SSB_IN_PO 4
 
+/** Maximum number of Paging Occasions per Paging Frame (TS 38.331 PCCH-Config) */
+#define NR_PCCH_MAX_PO 4
+
 #define NB_RB_MBMS_MAX (29 * 16) /* 29 = LTE_maxSessionPerPMCH + 16 = LTE_maxServiceCount from LTE_asn_constant.h */
 
 #define NB_RAB_MAX 11 /* from LTE_maxDRB in LTE_asn_constant.h */

openair2/LAYER2/NR_MAC_UE/config_ue.c

@@ -1973,6 +1973,57 @@ static void configure_si_schedulingInfo(NR_UE_MAC_INST_t *mac,
   }
 }
 
+/** @brief Parse SIB1 PCCH-Config (TS 38.331) into UE MAC paging_cfg (T, N, PF_offset, Ns, X and the
+ *  per-PO start-MO list). */
+static void configure_pcch_config(NR_UE_MAC_INST_t *mac, const NR_ServingCellConfigCommonSIB_t *scc)
+{
+  DevAssert(mac);
+  DevAssert(scc);
+  const NR_PCCH_Config_t *pcch = &scc->downlinkConfigCommon.pcch_Config;
+  nr_ue_paging_cfg_t *paging_cfg = &mac->paging_cfg;
+  /* Reset the per-PO start-MO list */
+  paging_cfg->first_mo_of_po_count = 0;
+  memset(paging_cfg->first_mo_of_po, 0, sizeof(paging_cfg->first_mo_of_po));
+
+  paging_cfg->T = nr_pcch_default_paging_cycle_rf(pcch);
+  nr_pcch_n_and_paging_frame_offset(pcch, paging_cfg->T, &paging_cfg->N, &paging_cfg->PF_offset);
+  paging_cfg->Ns = nr_pcch_ns_per_pf(pcch);
+
+  /* TS 38.304 §7.1: X defaults to 1 when nrofPDCCH-MonitoringOccasionPerSSB-InPO-r16 is absent
+   * (one PDCCH MO per SSB in a PO) */
+  paging_cfg->X = 1;
+  if (pcch->ext1 && pcch->ext1->nrofPDCCH_MonitoringOccasionPerSSB_InPO_r16) {
+    const long x = *pcch->ext1->nrofPDCCH_MonitoringOccasionPerSSB_InPO_r16;
+    AssertFatal(x >= 2 && x <= NR_PCCH_MAX_MO_PER_SSB_IN_PO,
+                "TS 38.331 PCCH-Config: nrofPDCCH-MonitoringOccasionPerSSB-InPO-r16=%ld out of range (2..%d)\n",
+                x,
+                NR_PCCH_MAX_MO_PER_SSB_IN_PO);
+    paging_cfg->X = x;
+  }
+
+  // TS 38.304 §7.1 / TS 38.331 PCCH-Config: when firstPDCCH-MonitoringOccasionOfPO is present, it
+  // explicitly defines the starting PDCCH MO index of each PO within the PF, overriding the default
+  // (i_s * S * X) computation.
+  if (pcch->firstPDCCH_MonitoringOccasionOfPO) {
+    for (uint8_t i = 0; i < sizeofArray(paging_cfg->first_mo_of_po); i++) {
+      int v;
+      if (!nr_pcch_first_pdcch_start_mo(pcch->firstPDCCH_MonitoringOccasionOfPO, i, &v))
+        break;
+      paging_cfg->first_mo_of_po[i] = v;
+      paging_cfg->first_mo_of_po_count++;
+    }
+  }
+
+  LOG_D(NR_MAC,
+        "PCCH-Config parsed: T=%u N=%u Ns=%u PF_offset=%u X=%u first_mo_of_po_count=%u\n",
+        paging_cfg->T,
+        paging_cfg->N,
+        paging_cfg->Ns,
+        paging_cfg->PF_offset,
+        paging_cfg->X,
+        paging_cfg->first_mo_of_po_count);
+}
+
 void nr_rrc_mac_config_req_sib1(module_id_t module_id, int cc_idP, NR_SIB1_t *sib1, bool can_start_ra)
 {
   NR_UE_MAC_INST_t *mac = get_mac_inst(module_id);
@@ -1988,6 +2039,7 @@ void nr_rrc_mac_config_req_sib1(module_id_t module_id, int cc_idP, NR_SIB1_t *si
   AssertFatal(scc, "SIB1 SCC should not be NULL\n");
   UPDATE_IE(mac->tdd_UL_DL_ConfigurationCommon, scc->tdd_UL_DL_ConfigurationCommon, NR_TDD_UL_DL_ConfigCommon_t);
   configure_si_schedulingInfo(mac, si_SchedulingInfo, si_SchedulingInfo_v1700);
+  configure_pcch_config(mac, scc);
 
   config_common_ue_sa(mac, scc, cc_idP);
 

openair2/LAYER2/NR_MAC_UE/mac_defs.h

@@ -12,6 +12,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include "common/platform_constants.h"
 #include "common/platform_types.h"
 #include "common/utils/threadPool/notified_fifo.h"
 
@@ -514,6 +515,24 @@ typedef struct {
   A_SEQUENCE_OF(si_schedinfo_config_t) si_SchedInfo_list;
 } si_schedInfo_t;
 
+typedef struct {
+  // Paging Cycle in Radio Frames
+  uint16_t T;
+  // Number of Paging Frames per Paging Cycle
+  uint16_t N;
+  // Number of Paging Occasions per Paging Frame
+  uint8_t Ns;
+  // Offset of the first Paging Frame in the Paging Cycle
+  uint8_t PF_offset;
+  // Number of PDCCH Monitoring Occasions per SSB in the Paging Occasion
+  uint8_t X;
+  // Number of entries in firstPDCCH-MonitoringOccasionOfPO
+  uint8_t first_mo_of_po_count;
+  // First PDCCH MO index of (i_s+1)-th PO within the PF (TS 38.331 PCCH-Config,
+  // firstPDCCH-MonitoringOccasionOfPO list)
+  uint16_t first_mo_of_po[NR_PCCH_MAX_PO];
+} nr_ue_paging_cfg_t;
+
 /*!\brief Top level UE MAC structure */
 typedef struct NR_UE_MAC_INST_s {
   module_id_t ue_id;
@@ -525,6 +544,7 @@ typedef struct NR_UE_MAC_INST_s {
   NR_MIB_t *mib;
 
   si_schedInfo_t si_SchedInfo;
+  nr_ue_paging_cfg_t paging_cfg;
   ssb_list_info_t ssb_list;
 
   NR_UE_ServingCell_Info_t sc_info;