adressing the comments

common/utils/nr/nr_common.c

@@ -706,3 +706,27 @@ void SLIV2SL(int SLIV,int *S,int *L) {
   }
 }
 
+int get_ssb_subcarrier_offset(uint32_t absoluteFrequencySSB, uint32_t absoluteFrequencyPointA)
+{
+  uint32_t absolute_diff = (absoluteFrequencySSB - absoluteFrequencyPointA);
+  const int scaling_5khz = absoluteFrequencyPointA < 600000 ? 3 : 1;
+  return ((absolute_diff / scaling_5khz) % 24);
+}
+
+uint32_t get_ssb_offset_to_pointA(uint32_t absoluteFrequencySSB,
+                                  uint32_t absoluteFrequencyPointA,
+                                  int ssbSubcarrierSpacing,
+                                  int frequency_range)
+{
+  uint32_t absolute_diff = (absoluteFrequencySSB - absoluteFrequencyPointA);
+  const int scaling_5khz = absoluteFrequencyPointA < 600000 ? 3 : 1;
+  int sco = get_ssb_subcarrier_offset(absoluteFrequencySSB, absoluteFrequencyPointA);
+  const int scs_scaling = frequency_range == FR2 ? 1 << (ssbSubcarrierSpacing - 2) : 1 << ssbSubcarrierSpacing;
+  const int scaled_abs_diff = absolute_diff / scaling_5khz;
+  const int ssb_offset_point_a =
+      (scaled_abs_diff - sco) / 12
+      - 10 * scs_scaling; // absoluteFrequencySSB is the central frequency of SSB which is made by 20RBs in total
+  AssertFatal(ssb_offset_point_a % scs_scaling == 0, "PRB offset %d can create frequency offset\n", ssb_offset_point_a);
+  AssertFatal(sco % scs_scaling == 0, "ssb offset %d can create frequency offset\n", sco);
+  return ssb_offset_point_a;
+}

common/utils/nr/nr_common.h

@@ -101,7 +101,11 @@ void get_samplerate_and_bw(int mu,
                            unsigned int *samples_per_frame,
                            double *tx_bw,
                            double *rx_bw);
-
+uint32_t get_ssb_offset_to_pointA(uint32_t absoluteFrequencySSB,
+                                  uint32_t absoluteFrequencyPointA,
+                                  int ssbSubcarrierSpacing,
+                                  int frequency_range);
+int get_ssb_subcarrier_offset(uint32_t absoluteFrequencySSB, uint32_t absoluteFrequencyPointA);
 #define CEILIDIV(a,b) ((a+b-1)/b)
 #define ROUNDIDIV(a,b) (((a<<1)+b)/(b<<1))
 

openair2/LAYER2/NR_MAC_gNB/config.c

@@ -352,7 +352,8 @@ void config_common(gNB_MAC_INST *nrmac, int pdsch_AntennaPorts, int pusch_Antenn
 
   // SSB Table Configuration
   
-  cfg->ssb_table.ssb_offset_point_a.value = get_ssb_offset_to_pointA(*scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencySSB,
+  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);
@@ -361,7 +362,8 @@ void config_common(gNB_MAC_INST *nrmac, int pdsch_AntennaPorts, int pusch_Antenn
   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 = get_ssb_subcarrier_offset(*scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencySSB,
+  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++;

openair2/RRC/NR/nr_rrc_config.c

@@ -1642,8 +1642,6 @@ NR_BCCH_BCH_Message_t *get_new_MIB_NR(const NR_ServingCellConfigCommon_t *scc)
   mib->message.choice.mib->spare.bits_unused = 7; // This makes a spare of 1 bits
 
   AssertFatal(scc->ssbSubcarrierSpacing != NULL, "scc->ssbSubcarrierSpacing is null\n");
-  int band = *scc->downlinkConfigCommon->frequencyInfoDL->frequencyBandList.list.array[0];
-  frequency_range_t frequency_range = band < 100 ? FR1 : FR2;
   int ssb_subcarrier_offset = 31; // default value for NSA
   if (get_softmodem_params()->sa) {
     ssb_subcarrier_offset = get_ssb_subcarrier_offset(*scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencySSB,