ssb offset to point A bugfix

openair1/SCHED_NR/phy_procedures_nr_gNB.c

@@ -75,7 +75,8 @@ void nr_common_signal_procedures (PHY_VARS_gNB *gNB,int frame,int slot,nfapi_nr_
   // setting the first subcarrier
   const int scs = cfg->ssb_config.scs_common.value;
   const int prb_offset = (fp->freq_range == nr_FR1) ? ssb_pdu.ssb_pdu_rel15.ssbOffsetPointA>>scs : ssb_pdu.ssb_pdu_rel15.ssbOffsetPointA>>(scs-2);
-  const int sc_offset = (fp->freq_range == nr_FR1) ? ssb_pdu.ssb_pdu_rel15.SsbSubcarrierOffset>>scs : ssb_pdu.ssb_pdu_rel15.SsbSubcarrierOffset;
+  const int sc_offset = (fp->freq_range == nr_FR1) ? ssb_pdu.ssb_pdu_rel15.SsbSubcarrierOffset >> scs
+                                                   : ssb_pdu.ssb_pdu_rel15.SsbSubcarrierOffset >> (scs - 2);
   fp->ssb_start_subcarrier = (12 * prb_offset + sc_offset);
   LOG_D(PHY, "SSB first subcarrier %d (%d,%d)\n", fp->ssb_start_subcarrier, prb_offset, sc_offset);
 

openair2/LAYER2/NR_MAC_gNB/config.c

@@ -351,24 +351,27 @@ void config_common(gNB_MAC_INST *nrmac, int pdsch_AntennaPorts, int pusch_Antenn
   cfg->num_tlv++;
 
   // SSB Table Configuration
-  uint32_t absolute_diff = (*frequencyInfoDL->absoluteFrequencySSB - frequencyInfoDL->absoluteFrequencyPointA);
-  const int scaling_5khz = frequencyInfoDL->absoluteFrequencyPointA < 600000 ? 3 : 1;
-  int sco = (absolute_diff/scaling_5khz) % 24;
-  if(frequency_range == FR2)
-    sco >>= 1; // this assumes 120kHz SCS for SSB and subCarrierSpacingCommon (only option supported by OAI for
-  const int scs_scaling = frequency_range == FR2 ? 1 << (*scc->ssbSubcarrierSpacing - 2) : 1 << *scc->ssbSubcarrierSpacing;
-  cfg->ssb_table.ssb_offset_point_a.value = absolute_diff/(12*scaling_5khz) - 10*scs_scaling; //absoluteFrequencySSB is the central frequency of SSB which is made by 20RBs in total
+  
+  cfg->ssb_table.ssb_offset_point_a.value = get_ssb_offset_to_pointA(*scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencySSB,
+                               scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencyPointA,
+                               *scc->ssbSubcarrierSpacing,
+                               frequency_range);
   cfg->ssb_table.ssb_offset_point_a.tl.tag = NFAPI_NR_CONFIG_SSB_OFFSET_POINT_A_TAG;
   cfg->num_tlv++;
   cfg->ssb_table.ssb_period.value = *scc->ssb_periodicityServingCell;
   cfg->ssb_table.ssb_period.tl.tag = NFAPI_NR_CONFIG_SSB_PERIOD_TAG;
   cfg->num_tlv++;
-  cfg->ssb_table.ssb_subcarrier_offset.value = sco;
+  cfg->ssb_table.ssb_subcarrier_offset.value = get_ssb_subcarrier_offset(*scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencySSB,
+                                scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencyPointA);
   cfg->ssb_table.ssb_subcarrier_offset.tl.tag = NFAPI_NR_CONFIG_SSB_SUBCARRIER_OFFSET_TAG;
   cfg->num_tlv++;
 
   nrmac->ssb_SubcarrierOffset = cfg->ssb_table.ssb_subcarrier_offset.value;
   nrmac->ssb_OffsetPointA = cfg->ssb_table.ssb_offset_point_a.value;
+  LOG_I(NR_MAC,
+        "ssb_OffsetPointA %d, ssb_SubcarrierOffset %d\n",
+        cfg->ssb_table.ssb_offset_point_a.value,
+        cfg->ssb_table.ssb_subcarrier_offset.value);
 
   switch (scc->ssb_PositionsInBurst->present) {
     case 1 :

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_bch.c

@@ -218,7 +218,7 @@ void schedule_nr_mib(module_id_t module_idP, frame_t frameP, sub_frame_t slotP,
               if ((ssb_start_symbol/14) == rel_slot){
                 const int prb_offset = offset_pointa >> (scs-2); // reference 60kHz
                 schedule_ssb(frameP, slotP, scc, dl_req, i_ssb, ssbSubcarrierOffset, offset_pointa, (*(uint32_t*)cc->MIB_pdu.payload) & ((1<<24)-1));
-                fill_ssb_vrb_map(cc, prb_offset, ssbSubcarrierOffset, ssb_start_symbol, CC_id);
+                fill_ssb_vrb_map(cc, prb_offset, ssbSubcarrierOffset >> (scs - 2), ssb_start_symbol, CC_id);
                 const NR_TDD_UL_DL_Pattern_t *tdd = &scc->tdd_UL_DL_ConfigurationCommon->pattern1;
                 const int n_slots_frame = nr_slots_per_frame[*scc->ssbSubcarrierSpacing];
                 // FR2 is only TDD, to be fixed for flexible TDD

openair2/RRC/NR/nr_rrc_config.c

@@ -1646,15 +1646,8 @@ NR_BCCH_BCH_Message_t *get_new_MIB_NR(const NR_ServingCellConfigCommon_t *scc)
   frequency_range_t frequency_range = band < 100 ? FR1 : FR2;
   int ssb_subcarrier_offset = 31; // default value for NSA
   if (get_softmodem_params()->sa) {
-    uint32_t absolute_diff = (*scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencySSB
-                              - scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencyPointA);
-    int scs_scaling = scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencyPointA < 600000 ? 3 : 1;
-    ssb_subcarrier_offset = (absolute_diff / scs_scaling) % 24;
-    if (frequency_range == FR2) {
-      // this assumes 120kHz SCS for SSB and subCarrierSpacingCommon (only
-      // option supported by OAI for now)
-      ssb_subcarrier_offset >>= 1;
-    }
+    ssb_subcarrier_offset = get_ssb_subcarrier_offset(*scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencySSB,
+                                                      scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencyPointA);
   }
   mib->message.choice.mib->ssb_SubcarrierOffset = ssb_subcarrier_offset & 15;
 
@@ -1839,32 +1832,17 @@ NR_BCCH_DL_SCH_Message_t *get_SIB1_NR(const gNB_RrcConfigurationReq *configurati
         frequencyInfoDL->frequencyBandList.list.array[i];
   }
 
-  int scs_scaling0 = 1 << (configuration->scc->downlinkConfigCommon->initialDownlinkBWP->genericParameters.subcarrierSpacing);
-  int scs_scaling = scs_scaling0;
-  int scs_scaling2 = scs_scaling0;
-  if (frequencyInfoDL->absoluteFrequencyPointA < 600000) {
-    scs_scaling = scs_scaling0 * 3;
-  }
-  if (frequencyInfoDL->absoluteFrequencyPointA > 2016666) {
-    scs_scaling = scs_scaling0 >> 2;
-    scs_scaling2 = scs_scaling0 >> 2;
-  }
-  uint32_t absolute_diff = (*frequencyInfoDL->absoluteFrequencySSB - frequencyInfoDL->absoluteFrequencyPointA);
-
-  sib1->servingCellConfigCommon->downlinkConfigCommon.frequencyInfoDL.offsetToPointA =
-      scs_scaling2 * (absolute_diff / (12 * scs_scaling) - 10);
+  const NR_FreqBandIndicatorNR_t band = *configuration->scc->downlinkConfigCommon->frequencyInfoDL->frequencyBandList.list.array[0];
+  frequency_range_t frequency_range = band < 100 ? FR1 : FR2;
+  sib1->servingCellConfigCommon->downlinkConfigCommon.frequencyInfoDL.offsetToPointA = get_ssb_offset_to_pointA(*configuration->scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencySSB,
+                               configuration->scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencyPointA,
+                               configuration->scc->downlinkConfigCommon->initialDownlinkBWP->genericParameters.subcarrierSpacing,
+                               frequency_range);
 
   LOG_I(NR_RRC,
-        "SIB1 freq: absoluteFrequencySSB %ld, absoluteFrequencyPointA %ld\n",
-        *frequencyInfoDL->absoluteFrequencySSB,
-        frequencyInfoDL->absoluteFrequencyPointA);
-  LOG_I(NR_RRC,
-        "SIB1 freq: absolute_diff %d, %d*(absolute_diff/(12*%d) - 10) %d\n",
-        absolute_diff,
-        scs_scaling2,
-        scs_scaling,
+	"SIB1 freq: offsetToPointA %d\n",
         (int)sib1->servingCellConfigCommon->downlinkConfigCommon.frequencyInfoDL.offsetToPointA);
-
+  
   for (int i = 0; i < frequencyInfoDL->scs_SpecificCarrierList.list.count; i++) {
     asn1cSeqAdd(&ServCellCom->downlinkConfigCommon.frequencyInfoDL.scs_SpecificCarrierList.list,
                 frequencyInfoDL->scs_SpecificCarrierList.list.array[i]);