add support for periodic airplane mode simulation in srsUE

srsue/hdr/stack/ue_stack_base.h

@@ -57,6 +57,11 @@ typedef struct {
   int usim_hex_limit;
 } stack_log_args_t;
 
+typedef struct {
+  int airplane_t_on_ms;
+  int airplane_t_off_ms;
+} ue_sim_args_t;
+
 typedef struct {
   std::string      type;
   pcap_args_t      pcap;
@@ -67,6 +72,7 @@ typedef struct {
   nas_args_t       nas;
   gw_args_t        gw;
   bool             have_tti_time_stats;
+  ue_sim_args_t    sim;
 } stack_args_t;
 
 class ue_stack_base

srsue/hdr/stack/upper/nas.h

@@ -132,10 +132,13 @@ private:
   srslte::timer_handler*              timers = nullptr;
   srslte::timer_handler::unique_timer t3410; // started when attach request is sent, on expiry, start t3411
   srslte::timer_handler::unique_timer t3411; // started when attach failed
+  srslte::timer_handler::unique_timer t3421; // started when detach request is sent
   srslte::timer_handler::unique_timer reattach_timer; // started to trigger delayed re-attach
 
-  const uint32_t t3410_duration_ms = 15 * 1000; // 15s according to TS 24.301 Sec 10.2
+  // Values according to TS 24.301 Sec 10.2
-  const uint32_t t3411_duration_ms = 10 * 1000; // 10s according to TS 24.301 Sec 10.2
+  const uint32_t t3410_duration_ms          = 15 * 1000; // 15s
+  const uint32_t t3411_duration_ms          = 10 * 1000; // 10s
+  const uint32_t t3421_duration_ms          = 1 * 1000;  // 15s (here 1s to allow quick reattach)
   const uint32_t reattach_timer_duration_ms = 2 * 1000;  // 2s (arbitrarily chosen to delay re-attach)
 
   // TS 23.003 Sec. 6.2.2 IMEISV's last two octets are Software Version Number (SVN)

srsue/src/main.cc

@@ -375,7 +375,16 @@ static int parse_args(all_args_t* args, int argc, char* argv[])
      bpo::value<uint32_t>(&args->phy.nof_out_of_sync_events)->default_value(20),
      "Number of PHY out-sync events before sending an out-sync event to RRC")
 
-    /* general options */
+    // UE simulation args
+    ("sim.airplane_t_on_ms",
+     bpo::value<int>(&args->stack.sim.airplane_t_on_ms)->default_value(-1),
+     "On-time for airplane mode (in ms)")
+
+    ("sim.airplane_t_off_ms",
+     bpo::value<int>(&args->stack.sim.airplane_t_off_ms)->default_value(-1),
+     "Off-time for airplane mode (in ms)")
+
+     /* general options */
     ("general.metrics_period_secs",
        bpo::value<float>(&args->general.metrics_period_secs)->default_value(1.0),
       "Periodicity for metrics in seconds")

srsue/src/stack/ue_stack_lte.cc

@@ -181,6 +181,15 @@ bool ue_stack_lte::switch_on()
   if (running) {
     pending_tasks.try_push(ue_queue_id,
                            [this]() { nas.start_attach_request(nullptr, srslte::establishment_cause_t::mo_data); });
+
+    // schedule airplane mode on command
+    if (args.sim.airplane_t_on_ms > 0) {
+      timers.defer_callback(args.sim.airplane_t_on_ms, [&]() {
+        // Enable air-plane mode
+        disable_data();
+      });
+    }
+
     return true;
   }
   return false;
@@ -210,13 +219,24 @@ bool ue_stack_lte::switch_off()
 bool ue_stack_lte::enable_data()
 {
   // perform attach request
+  log.console("Turning off airplane mode.\n");
   return switch_on();
 }
 
 bool ue_stack_lte::disable_data()
 {
   // generate detach request
-  return nas.detach_request(false);
+  log.console("Turning on airplane mode.\n");
+  int ret = nas.detach_request(false);
+
+  // schedule airplane mode off command
+  if (args.sim.airplane_t_off_ms > 0) {
+    timers.defer_callback(args.sim.airplane_t_off_ms, [&]() {
+      // Disable airplane mode again
+      enable_data();
+    });
+  }
+  return ret;
 }
 
 bool ue_stack_lte::get_metrics(stack_metrics_t* metrics)

srsue/src/stack/upper/nas.cc

@@ -228,6 +228,7 @@ nas::nas(srslte::timer_handler* timers_) :
   timers(timers_),
   t3410(timers_->get_unique_timer()),
   t3411(timers_->get_unique_timer()),
+  t3421(timers_->get_unique_timer()),
   reattach_timer(timers_->get_unique_timer())
 {
 }
@@ -281,9 +282,10 @@ void nas::init(usim_interface_nas* usim_, rrc_interface_nas* rrc_, gw_interface_
     have_ctxt = true;
   }
 
-  // Configure T3410 and T3411
+  // Configure timers
   t3410.set(t3410_duration_ms, [this](uint32_t tid) { timer_expired(tid); });
   t3411.set(t3411_duration_ms, [this](uint32_t tid) { timer_expired(tid); });
+  t3421.set(t3421_duration_ms, [this](uint32_t tid) { timer_expired(tid); });
   reattach_timer.set(reattach_timer_duration_ms, [this](uint32_t tid) { timer_expired(tid); });
 
   running = true;
@@ -321,6 +323,11 @@ void nas::timer_expired(uint32_t timeout_id)
   } else if (timeout_id == t3411.id()) {
     nas_log->info("Timer T3411 expired: trying to attach again\n");
     start_attach_request(nullptr, srslte::establishment_cause_t::mo_sig);
+  } else if (timeout_id == t3421.id()) {
+    nas_log->info("Timer T3421 expired: entering EMM_STATE_DEREGISTERED\n");
+    // TODO: TS 24.301 says to resend detach request but doesn't say how often before entering EMM_STATE_DEREGISTERED
+    // In order to allow reattaching the UE, we switch into EMM_STATE_DEREGISTERED straight
+    enter_emm_deregistered();
   } else if (timeout_id == reattach_timer.id()) {
     nas_log->info("Reattach timer expired: trying to attach again\n");
     start_attach_request(nullptr, srslte::establishment_cause_t::mo_sig);
@@ -1822,6 +1829,9 @@ void nas::send_detach_request(bool switch_off)
   } else {
     // we are expecting a response from the core
     state = EMM_STATE_DEREGISTERED_INITIATED;
+
+    // start T3421
+    t3421.run();
   }
 
   if (rrc->is_connected()) {

srsue/ue.conf.example

@@ -335,6 +335,21 @@ enable = false
 #nof_in_sync_events     = 10
 #nof_out_of_sync_events = 20
 
+#####################################################################
+# Simulation configuration options
+#
+# The UE simulation supports turning on and off airplane mode in the UE.
+# The actions are carried periodically until the UE is stopped.
+#
+# airplane_t_on_ms:   Time to leave airplane mode turned on (in ms)
+#
+# airplane_t_off_ms:  Time to leave airplane mode turned off (in ms)
+#
+#####################################################################
+[sim]
+#airplane_t_on_ms  = -1
+#airplane_t_off_ms = -1
+
 #####################################################################
 # General configuration options
 #