Use command line option for sell search

There is already a command line option called 'ue-scan-carrier' which
seemed to blindly look for SSB by changing the center frequency by
+/-100Hz if the previous attempt failed. This is probably copied from
LTE and is not suitable for NR. This commit uses this option to either
1. Perform initial sync on one GSCN if the SSB position if known
2. Or scan the all GSCN (if the SSB postion is unknown)

Also, the following is done for re-synchronization
1. Scan all GSCN when UE comes back from IDLE state
2. Scan one GSCN when UE does re-estabishment

Removed dependency of lte-softmodem.h in nr-softmodem.c.
CONFIG_HLP_UESCAN is declared also in lte-softmodem.h.

executables/nr-softmodem-common.h

@@ -47,7 +47,7 @@
 #define CONFIG_HLP_UETXG         "set UE TX gain\n"
 #define CONFIG_HLP_UENANTR       "set UE number of rx antennas\n"
 #define CONFIG_HLP_UENANTT       "set UE number of tx antennas\n"
-#define CONFIG_HLP_UESCAN        "set UE to scan around carrier\n"
+#define CONFIG_HLP_UESCAN "set UE to scan all possible GSCN in current bandwidth\n"
 #define CONFIG_HLP_UEFO          "set UE to enable estimation and compensation of frequency offset\n"
 #define CONFIG_HLP_DUMPFRAME     "dump UE received frame to rxsig_frame0.dat and exit\n"
 #define CONFIG_HLP_DLSHIFT       "dynamic shift for LLR compuation for TM3/4 (default 0)\n"

executables/nr-softmodem.c

@@ -49,7 +49,6 @@
 #include "PHY_INTERFACE/phy_interface_vars.h"
 #include "gnb_config.h"
 #include "SIMULATION/TOOLS/sim.h"
-#include "executables/lte-softmodem.h"
 
 #ifdef SMBV
 #include "PHY/TOOLS/smbv.h"
@@ -604,6 +603,7 @@ static void initialize_agent(ngran_node_t node_type, e2_agent_args_t oai_args)
 }
 #endif
 
+void init_eNB_afterRU(void);
 configmodule_interface_t *uniqCfg = NULL;
 int main( int argc, char **argv ) {
   int ru_id, CC_id = 0;

executables/nr-ue.c

@@ -348,7 +348,13 @@ static void *NRUE_phy_stub_standalone_pnf_task(void *arg)
  * \param arg is a pointer to a \ref PHY_VARS_NR_UE structure.
  */
 
-typedef nr_rxtx_thread_data_t syncData_t;
+typedef struct {
+  PHY_VARS_NR_UE *UE;
+  UE_nr_rxtx_proc_t proc;
+  nr_gscn_info_t gscnInfo[MAX_GSCN_BAND];
+  int numGscn;
+  int rx_offset;
+} syncData_t;
 
 static void UE_synch(void *arg) {
   syncData_t *syncD=(syncData_t *) arg;
@@ -431,7 +437,7 @@ static void UE_synch(void *arg) {
 
       uint64_t dl_carrier, ul_carrier;
       nr_get_carrier_frequencies(UE, &dl_carrier, &ul_carrier);
-      nr_initial_sync_t ret = nr_initial_sync(&syncD->proc, UE, 2, get_softmodem_params()->sa);
+      nr_initial_sync_t ret = nr_initial_sync(&syncD->proc, UE, 2, get_softmodem_params()->sa, syncD->gscnInfo, syncD->numGscn);
       if (ret.cell_detected) {
         syncD->rx_offset = ret.rx_offset;
         freq_offset = UE->common_vars.freq_offset; // frequency offset computed with pss in initial sync
@@ -451,24 +457,7 @@ static void UE_synch(void *arg) {
               openair0_cfg[UE->rf_map.card].tx_freq[0]);
 
         UE->rfdevice.trx_set_freq_func(&UE->rfdevice,&openair0_cfg[0]);
-        if (UE->UE_scan_carrier == 1)
-          UE->UE_scan_carrier = 0;
-        else
-          UE->is_synchronized = 1;
-      } else {
-        if (UE->UE_scan_carrier == 1) {
-
-          if (freq_offset >= 0)
-            freq_offset += 100;
-
-          freq_offset *= -1;
-
-          nr_rf_card_config_freq(&openair0_cfg[UE->rf_map.card], ul_carrier, dl_carrier, freq_offset);
-
-          LOG_I(PHY, "Initial sync failed: trying carrier off %d Hz\n", freq_offset);
-
-          UE->rfdevice.trx_set_freq_func(&UE->rfdevice,&openair0_cfg[0]);
-        }
+        UE->is_synchronized = 1;
       }
       break;
 
@@ -601,6 +590,7 @@ static int UE_dl_preprocessing(PHY_VARS_NR_UE *UE, const UE_nr_rxtx_proc_t *proc
     // Start synchronization with a target gNB
     if (UE->synch_request.received_synch_request == 1) {
       UE->is_synchronized = 0;
+      UE->UE_scan_carrier = UE->synch_request.synch_req.ssb_bw_scan;
       UE->target_Nid_cell = UE->synch_request.synch_req.target_Nid_cell;
       clean_UE_harq(UE);
       UE->synch_request.received_synch_request = 0;
@@ -818,6 +808,20 @@ void *UE_thread(void *arg)
       readFrame(UE, &sync_timestamp, false);
       notifiedFIFO_elt_t *Msg = newNotifiedFIFO_elt(sizeof(syncData_t), 0, &nf, UE_synch);
       syncData_t *syncMsg = (syncData_t *)NotifiedFifoData(Msg);
+      NR_DL_FRAME_PARMS *fp = &UE->frame_parms;
+      if (UE->UE_scan_carrier) {
+        // Get list of GSCN in this band for UE's bandwidth and center frequency.
+        LOG_W(PHY, "UE set to scan all GSCN in current bandwidth\n");
+        syncMsg->numGscn =
+            get_scan_ssb_first_sc(fp->dl_CarrierFreq, fp->N_RB_DL, fp->nr_band, fp->numerology_index, syncMsg->gscnInfo);
+      } else {
+        LOG_W(PHY, "SSB position provided\n");
+        nr_gscn_info_t *g = syncMsg->gscnInfo;
+        g->ssbFirstSC = fp->ssb_start_subcarrier;
+        g->gscn = 0;
+        g->ssRef = 0;
+        syncMsg->numGscn = 1;
+      }
       syncMsg->UE = UE;
       memset(&syncMsg->proc, 0, sizeof(syncMsg->proc));
       pushTpool(&(get_nrUE_params()->Tpool), Msg);