srsUE: Add option to filter N_id_1 / SSS to configuration

lib/include/srsran/interfaces/ue_phy_interfaces.h

@@ -36,6 +36,7 @@ struct phy_args_t {
   std::map<uint32_t, uint32_t> ul_earfcn_map;    // Map linking DL EARFCN and UL EARFCN
 
   int force_N_id_2 = -1; // Cell identity within the identity group (PSS) to filter.
+  int force_N_id_1 = -1; // Cell identity group (SSS) to filter.
 
   float dl_freq = -1.0f;
   float ul_freq = -1.0f;

srsue/hdr/phy/search.h

@@ -36,7 +36,7 @@ public:
 
   explicit search(srslog::basic_logger& logger) : logger(logger) {}
   ~search();
-  void     init(srsran::rf_buffer_t& buffer_, uint32_t nof_rx_channels, search_callback* parent, int force_N_id_2_);
+  void     init(srsran::rf_buffer_t& buffer_, uint32_t nof_rx_channels, search_callback* parent, int force_N_id_2_, int force_N_id_1_);
   void     reset();
   float    get_last_cfo();
   void     set_agc_enable(bool enable);
@@ -50,6 +50,7 @@ private:
   srsran_ue_cellsearch_t cs           = {};
   srsran_ue_mib_sync_t   ue_mib_sync  = {};
   int                    force_N_id_2 = 0;
+  int                    force_N_id_1 = 0;
 };
 
 }; // namespace srsue

srsue/src/main.cc

@@ -409,6 +409,10 @@ static int parse_args(all_args_t* args, int argc, char* argv[])
      bpo::value<int>(&args->phy.force_N_id_2)->default_value(-1),
      "Force using a specific PSS (set to -1 to allow all PSSs).")
 
+    ("phy.force_N_id_1",
+     bpo::value<int>(&args->phy.force_N_id_1)->default_value(-1),
+     "Force using a specific SSS (set to -1 to allow all SSSs).")
+
     // PHY NR args
     ("phy.nr.store_pdsch_ko",
       bpo::value<bool>(&args->phy.nr_store_pdsch_ko)->default_value(false),

srsue/src/phy/search.cc

@@ -46,7 +46,7 @@ search::~search()
   srsran_ue_cellsearch_free(&cs);
 }
 
-void search::init(srsran::rf_buffer_t& buffer_, uint32_t nof_rx_channels, search_callback* parent, int force_N_id_2_)
+void search::init(srsran::rf_buffer_t& buffer_, uint32_t nof_rx_channels, search_callback* parent, int force_N_id_2_, int force_N_id_1_)
 {
   p = parent;
 
@@ -65,6 +65,7 @@ void search::init(srsran::rf_buffer_t& buffer_, uint32_t nof_rx_channels, search
   p->set_ue_sync_opts(&cs.ue_sync, 0);
 
   force_N_id_2 = force_N_id_2_;
+  force_N_id_1 = force_N_id_1_;
 }
 
 void search::set_cp_en(bool enable)
@@ -125,6 +126,21 @@ search::ret_code search::run(srsran_cell_t* cell_, std::array<uint8_t, SRSRAN_BC
     Info("SYNC:  Could not find any cell in this frequency");
     return CELL_NOT_FOUND;
   }
+
+  if (force_N_id_1 >= 0 && force_N_id_1 < SRSRAN_NOF_NID_1) {
+    bool N_id_1_found = false;
+    for (uint32_t N_id_2 = 0; N_id_2 < SRSRAN_NOF_NID_2; N_id_2++) {
+      if (found_cells[N_id_2].cell_id / SRSRAN_NOF_NID_2 == (uint32_t)force_N_id_1) {
+        N_id_1_found = true;
+        max_peak_cell = N_id_2;
+      }
+    }
+    if (!N_id_1_found) {
+      Info("SYNC:  Could not find any cell in this SSS");
+      return CELL_NOT_FOUND;
+    }
+  }
+
   // Save result
   new_cell.id         = found_cells[max_peak_cell].cell_id;
   new_cell.cp         = found_cells[max_peak_cell].cp;

srsue/src/phy/sync.cc

@@ -82,7 +82,7 @@ void sync::init(srsran::radio_interface_phy* _radio,
   }
 
   // Initialize cell searcher
-  search_p.init(sf_buffer, nof_rf_channels, this, worker_com->args->force_N_id_2);
+  search_p.init(sf_buffer, nof_rf_channels, this, worker_com->args->force_N_id_2, worker_com->args->force_N_id_1);
   search_p.set_cp_en(worker_com->args->detect_cp);
   // Initialize SFN synchronizer, it uses only pcell buffer
   sfn_p.init(&ue_sync, worker_com->args, sf_buffer, sf_buffer.size());

srsue/ue.conf.example

@@ -343,6 +343,9 @@ enable = false
 # nof_in_sync_events:     Number of PHY in-sync events before sending an in-sync event to RRC
 # nof_out_of_sync_events: Number of PHY out-sync events before sending an out-sync event to RRC
 #
+# force_N_id_2: Force using a specific PSS (set to -1 to allow all PSSs).
+# force_N_id_1: Force using a specific SSS (set to -1 to allow all SSSs).
+#
 #####################################################################
 [phy]
 #rx_gain_offset      = 62
@@ -374,6 +377,9 @@ enable = false
 #nof_in_sync_events     = 10
 #nof_out_of_sync_events = 20
 
+#force_N_id_2           = 1
+#force_N_id_1           = 10
+
 #####################################################################
 # PHY NR specific configuration options
 #