srsue: refactor SA mode in RRC, don't initilize NSA-5G in NSA mode

srsue/hdr/stack/rrc_nr/rrc_nr_config.h

@@ -19,7 +19,6 @@
 namespace srsue {
 
 struct rrc_nr_args_t {
-  bool                        sa_mode;
   uint32_t                    sim_nr_meas_pci;
   bool                        pdcp_short_sn_support;
   std::string                 supported_bands_nr_str;

srsue/hdr/stack/ue_stack_base.h

@@ -66,7 +66,7 @@ typedef struct {
   gw_args_t        gw;
   uint32_t         sync_queue_size; // Max allowed difference between PHY and Stack clocks (in TTI)
   bool             have_tti_time_stats;
-  bool             attach_on_nr;
+  bool             sa_mode;
 } stack_args_t;
 
 class ue_stack_base

srsue/src/stack/rrc_nr/rrc_nr.cc

@@ -70,10 +70,11 @@ int rrc_nr::init(phy_interface_rrc_nr*       phy_,
   t310 = task_sched.get_unique_timer();
   t311 = task_sched.get_unique_timer();
 
-  if (args.sa_mode) {
+  if (rrc_eutra == nullptr) {
-    plmn_is_selected = true; // short-cut SA test
+    // SA mode
+    plmn_is_selected = true;
 
-    // for SA mode setup inital HARQ config and SRB0
+    // setup inital HARQ config
     srsran::dl_harq_cfg_nr_t harq_cfg = {};
     harq_cfg.nof_procs                = 8;
     mac->set_config(harq_cfg);
@@ -129,7 +130,7 @@ const char* rrc_nr::get_rb_name(uint32_t lcid)
 void rrc_nr::timer_expired(uint32_t timeout_id)
 {
   logger.debug("Handling Timer Expired");
-  if (timeout_id == sim_measurement_timer.id()) {
+  if (timeout_id == sim_measurement_timer.id() && rrc_eutra != nullptr) {
     logger.debug("Triggered simulated measurement");
 
     phy_meas_nr_t              sim_meas = {};
@@ -2072,7 +2073,11 @@ void rrc_nr::ra_completed()
 
 void rrc_nr::ra_problem()
 {
-  rrc_eutra->nr_scg_failure_information(scg_failure_cause_t::random_access_problem);
+  if (rrc_eutra) {
+    rrc_eutra->nr_scg_failure_information(scg_failure_cause_t::random_access_problem);
+  } else {
+    // TODO: handle RA problem
+  }
 }
 
 void rrc_nr::release_pucch_srs() {}

srsue/src/stack/rrc_nr/rrc_nr_procedures.cc

@@ -142,12 +142,16 @@ void rrc_nr::connection_reconf_no_ho_proc::then(const srsran::proc_state_t& resu
   if (result.is_success()) {
     Info("Finished %s successfully", name());
     srsran::console("RRC NR reconfiguration successful.\n");
-    rrc_handle.rrc_eutra->nr_rrc_con_reconfig_complete(true);
+    if (rrc_handle.rrc_eutra) {
+      rrc_handle.rrc_eutra->nr_rrc_con_reconfig_complete(true);
+    }
   } else {
     // 5.3.5.8.2 Inability to comply with RRCReconfiguration
     switch (initiator) {
       case reconf_initiator_t::mcg_srb1:
-        rrc_handle.rrc_eutra->nr_notify_reconfiguration_failure();
+        if (rrc_handle.rrc_eutra) {
+          rrc_handle.rrc_eutra->nr_notify_reconfiguration_failure();
+        }
         break;
       default:
         Warning("Reconfiguration failure not implemented for initiator %d", initiator);

srsue/src/stack/ue_stack_lte.cc

@@ -221,14 +221,16 @@ int ue_stack_lte::init(const stack_args_t& args_)
               &pdcp_nr,
               gw,
               &nas_5g,
-              &rrc,
+              args.sa_mode ? nullptr : &rrc,
               usim.get(),
               task_sched.get_timer_handler(),
               this,
               args.rrc_nr);
   rrc.init(phy, &mac, &rlc, &pdcp, &nas, usim.get(), gw, &rrc_nr, args.rrc);
 
-  nas_5g.init(usim.get(), &rrc_nr, gw, args.nas_5g);
+  if (args.sa_mode) {
+    nas_5g.init(usim.get(), &rrc_nr, gw, args.nas_5g);
+  }
 
   running = true;
   start(STACK_MAIN_THREAD_PRIO);
@@ -276,7 +278,7 @@ bool ue_stack_lte::switch_on()
   if (running) {
     stack_logger.info("Triggering NAS switch on");
     if (!ue_task_queue.try_push([this]() {
-          if (args.attach_on_nr) {
+          if (args.sa_mode) {
             nas_5g.switch_on();
           } else {
             nas.switch_on();
@@ -329,7 +331,7 @@ bool ue_stack_lte::start_service_request()
 {
   if (running) {
     ue_task_queue.try_push([this]() {
-      if (args.attach_on_nr) {
+      if (args.sa_mode) {
         nas_5g.start_service_request();
       } else {
         nas.start_service_request(srsran::establishment_cause_t::mo_data);

srsue/src/ue.cc

@@ -110,7 +110,7 @@ int ue::init(const all_args_t& args_)
     }
 
     // In SA mode, pass NR PHY pointer to stack
-    args.stack.attach_on_nr = true;
+    args.stack.sa_mode = true;
     if (lte_stack->init(args.stack, dummy_lte_phy.get(), nr_phy.get(), gw_ptr.get())) {
       srsran::console("Error initializing stack.\n");
       ret = SRSRAN_ERROR;
@@ -272,13 +272,12 @@ int ue::parse_args(const all_args_t& args_)
 
   // Make sure fix sampling rate is set for SA mode
   if (args.phy.nof_lte_carriers == 0 and not std::isnormal(args.rf.srate_hz)) {
-    srsran::console("Error. NR Standalone PHY requires a fix RF sampling rate.\n");
+    srsran::console("Error. NR Standalone PHY requires a fixed RF sampling rate.\n");
     return SRSRAN_ERROR;
   }
 
   // SA params
   if (args.phy.nof_lte_carriers == 0 && args.phy.nof_nr_carriers == 1) {
-    args.stack.rrc_nr.sa_mode = true;
     // TODO: expose to UE config
     args.stack.rrc_nr.dl_nr_arfcn  = 368500;
     args.stack.rrc_nr.ssb_nr_arfcn = 368410;