Implemented NR SS raster object

lib/include/srsran/common/band_helper.h

@@ -68,6 +68,35 @@ public:
    */
   srsran_duplex_mode_t get_duplex_mode(uint16_t band) const;
 
+  struct sync_raster_t {
+  protected:
+    sync_raster_t(uint32_t f, uint32_t s, uint32_t l) : first(f), step(s), last(l), gscn(f) {}
+    uint32_t gscn;
+
+  private:
+    uint32_t first;
+    uint32_t step;
+    uint32_t last;
+
+  public:
+    bool valid() const { return step != 0; }
+
+    void next()
+    {
+      if (gscn <= last) {
+        gscn += step;
+      }
+    }
+
+    bool end() const { return (gscn > last or step == 0); }
+
+    void reset() { gscn = first; }
+
+    double get_frequency() const;
+  };
+
+  sync_raster_t get_sync_raster(uint16_t band, srsran_subcarrier_spacing_t scs) const;
+
 private:
   // Elements of TS 38.101-1 Table 5.2-1: NR operating bands in FR1
   struct nr_operating_band {
@@ -225,7 +254,7 @@ private:
     {261, KHZ_120, 2070833, 2, 2084999, 2070833, 2, 2084999}
   }};
 
-// Elements of TS 38.101-1 Table 5.4.3.3-1 : Applicable SS raster entries per operating band
+  // Elements of TS 38.101-1 Table 5.4.3.3-1 : Applicable SS raster entries per operating band
   struct nr_band_ss_raster {
     uint16_t                    band;
     srsran_subcarrier_spacing_t scs;
@@ -270,4 +299,4 @@ private:
 
 } // namespace srsran
 
-#endif // SRSRAN_BAND_HELPER_H
+#endif // SRSRAN_BAND_HELPER_H

lib/src/common/band_helper.cc

@@ -12,6 +12,7 @@
 
 #include "srsran/common/band_helper.h"
 #include <algorithm>
+#include <cmath>
 
 namespace srsran {
 
@@ -104,6 +105,59 @@ srsran_duplex_mode_t srsran_band_helper::get_duplex_mode(uint16_t band) const
   return SRSRAN_DUPLEX_MODE_INVALID;
 }
 
+struct sync_raster_impl : public srsran_band_helper::sync_raster_t {
+public:
+  sync_raster_impl(uint32_t f, uint32_t s, uint32_t l) : sync_raster_t(f, s, l)
+  {
+    // Do nothing
+  }
+};
+
+double srsran_band_helper::sync_raster_t::get_frequency() const
+{
+  // Row 1
+  if (gscn >= 2 and gscn <= 7498) {
+    double N = std::ceil((gscn - 1) / 3.0);
+    double M = (gscn - 3 * N) / 2.0 + 3.0;
+    return N * 1200e3 + M * 50e3;
+  }
+
+  // Row 2
+  if (gscn >= 7499 and gscn <= 22255) {
+    double N = gscn - 7499;
+    return 3000e6 + N * 1.44e6;
+  }
+
+  // Row 3
+  if (gscn >= 22256 and gscn <= 26639) {
+    double N = gscn - 22256;
+    return 2425.08e6 + N * 17.28e6;
+  }
+
+  // Unhandled case
+  return NAN;
+}
+
+srsran_band_helper::sync_raster_t srsran_band_helper::get_sync_raster(uint16_t                    band,
+                                                                      srsran_subcarrier_spacing_t scs) const
+{
+  // Look for the given band and SCS
+  for (const nr_band_ss_raster& ss_raster : nr_band_ss_raster_table) {
+    // Check if band and SCS match!
+    if (ss_raster.band == band && ss_raster.scs == scs) {
+      return sync_raster_impl(ss_raster.gscn_first, ss_raster.gscn_step, ss_raster.gscn_last);
+    }
+
+    // As bands are in ascending order, do not waste more time if the current band is bigger
+    if (ss_raster.band > band) {
+      return sync_raster_impl(0, 0, 0);
+    }
+  }
+
+  // Band is out of range, so consider invalid
+  return sync_raster_impl(0, 0, 0);
+}
+
 srsran_band_helper::nr_raster_params srsran_band_helper::get_raster_params(uint32_t nr_arfcn)
 {
   for (auto& fr : nr_fr_params) {
@@ -114,4 +168,4 @@ srsran_band_helper::nr_raster_params srsran_band_helper::get_raster_params(uint3
   return {}; // return empty params
 }
 
-} // namespace srsran
+} // namespace srsran