NR UE scan for SSB within current bandwidth

Till this commit, the UE gets the position of SSB in frequency from
command line and does the syncronization by locating the SSB in time. It
does this by generating a PSS time signal during initialization with the
SSB offset given via command line. Then PSS detection is done by
correlation.

In this commit, the UE computes a list of GSCN in the current NR band
that falls within the current bandwidth for the set center frequency.
For each GSCN in the list, the UE starts a thread and performs the
following:
1. Generate PSS time signal with SSB offset for current GSCN.
2. Detect PSS, SSS and decode PBCH (this step remains the same).
After all threads finishes, the results are collected.

For now, only the first detected PBCH is used to proceed further. So
this PBCH is indicated to MAC and UE exits initial sync.

Future work: The cell search can be standalone feature where the UE
could scan for SSB in the entire NR band. This would require changing
radio's frequency on the fly as the UE's bandwidth would not cover an
entire NR band. The cell detection can futher be imporved by looking
for SIB1 for each decoded PBCH.

common/utils/nr/nr_common.h

@@ -77,6 +77,9 @@ static inline const char *rnti_types(nr_rnti_type_t rr)
 }
 #undef R
 
+#define MU_SCS(m) (15 << m)
+#define MAX_GSCN_BAND 620 // n78 has the highest GSCN range of 619
+
 #define NR_MAX_NB_LAYERS 4 // 8
 
 typedef struct nr_bandentry_s {
@@ -98,6 +101,12 @@ typedef struct {
   int last_gscn;
 } sync_raster_t;
 
+typedef struct {
+  int gscn;
+  double ssRef;
+  int ssbFirstSC;
+} nr_gscn_info_t;
+
 typedef enum frequency_range_e {
   FR1 = 0,
   FR2
@@ -232,6 +241,14 @@ void freq2time(uint16_t ofdm_symbol_size,
 
 void nr_est_delay(int ofdm_symbol_size, const c16_t *ls_est, c16_t *ch_estimates_time, delay_t *delay);
 
+int get_scan_ssb_first_sc(const double fc,
+                          const int nbRB,
+                          const int nrBand,
+                          const int mu,
+                          nr_gscn_info_t ssbStartSC[MAX_GSCN_BAND]);
+
+void check_ssb_raster(uint64_t freq, int band, int scs);
+
 #define CEILIDIV(a,b) ((a+b-1)/b)
 #define ROUNDIDIV(a,b) (((a<<1)+b)/(b<<1))