absoluteFrequencySSB is the center of SSB (correction of 10 RB in ref to point A needed)

openair2/LAYER2/NR_MAC_UE/config_ue.c

@@ -221,7 +221,7 @@ void config_common_ue(NR_UE_MAC_INST_t *mac,
   if (scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencyPointA > 2016666)
     scs_scaling = scs_scaling>>2;
   uint32_t absolute_diff = (*scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencySSB - scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencyPointA);
-  cfg->ssb_table.ssb_offset_point_a = absolute_diff/(12*scs_scaling);
+  cfg->ssb_table.ssb_offset_point_a = absolute_diff/(12*scs_scaling) - 10;
   cfg->ssb_table.ssb_period = *scc->ssb_periodicityServingCell;
   cfg->ssb_table.ssb_subcarrier_offset = 0; // TODO currently not in RRC?
   switch (scc->ssb_PositionsInBurst->present) {

openair2/LAYER2/NR_MAC_gNB/config.c

@@ -207,7 +207,7 @@ void config_common(int Mod_idP, int pdsch_AntennaPorts, NR_ServingCellConfigComm
   if (scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencyPointA > 2016666)
     scs_scaling = scs_scaling>>2;
   uint32_t absolute_diff = (*scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencySSB - scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencyPointA);
-  cfg->ssb_table.ssb_offset_point_a.value = absolute_diff/(12*scs_scaling);
+  cfg->ssb_table.ssb_offset_point_a.value = absolute_diff/(12*scs_scaling) - 10; //absoluteFrequencySSB is the central frequency of SSB which is made by 20RBs in total
   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;

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_bch.c

@@ -135,7 +135,7 @@ void schedule_nr_mib(module_id_t module_idP, frame_t frameP, sub_frame_t slotP){
         AssertFatal(1==0,"SCS %ld not allowed for SSB \n", *cc->ServingCellConfigCommon->ssbSubcarrierSpacing);
       }
       dl_config_pdu->ssb_pdu.ssb_pdu_rel15.SsbSubcarrierOffset = 0; //kSSB
-      dl_config_pdu->ssb_pdu.ssb_pdu_rel15.ssbOffsetPointA     = ssb_offset0/(ratio*12);
+      dl_config_pdu->ssb_pdu.ssb_pdu_rel15.ssbOffsetPointA     = ssb_offset0/(ratio*12) - 10; // absoluteFrequencySSB is the center of SSB
       dl_config_pdu->ssb_pdu.ssb_pdu_rel15.bchPayloadFlag      = 1;
       dl_config_pdu->ssb_pdu.ssb_pdu_rel15.bchPayload          = (*(uint32_t*)cc->MIB_pdu.payload) & ((1<<24)-1);
       dl_req->nPDUs++;