srsENB: Derive inactivity timeout from T310 and T311 and N310.

srsenb/enb.conf.example

@@ -277,6 +277,7 @@ pusch_max_mcs    = 16
 # metrics_csv_filename: File path to use for CSV metrics.
 # pregenerate_signals:  Pregenerate uplink signals after attach. Improves CPU performance.
 # tx_amplitude:         Transmit amplitude factor (set 0-1 to reduce PAPR)
+# rrc_inactivity_timer  Inactivity timeout used to remove UE context from RRC (in milliseconds). With -1 the timeout is automatically derived.
 # max_prach_offset_us:  Maximum allowed RACH offset (in us)
 # eea_pref_list:        Ordered preference list for the selection of encryption algorithm (EEA) (default: EEA0, EEA2, EEA1).
 # eia_pref_list:        Ordered preference list for the selection of integrity algorithm (EIA) (default: EIA2, EIA1, EIA0).
@@ -291,7 +292,7 @@ pusch_max_mcs    = 16
 #metrics_csv_filename = /tmp/enb_metrics.csv
 #pregenerate_signals  = false
 #tx_amplitude         = 0.6
-#rrc_inactivity_timer = 60000
+#rrc_inactivity_timer = -1
 #max_prach_offset_us  = 30
 #eea_pref_list = EEA0, EEA2, EEA1
 #eia_pref_list = EIA2, EIA1, EIA0

srsenb/hdr/enb.h

@@ -88,7 +88,7 @@ struct gui_args_t {
 };
 
 struct general_args_t {
-  uint32_t    rrc_inactivity_timer;
+  int32_t     rrc_inactivity_timer;
   float       metrics_period_secs;
   bool        metrics_csv_enable;
   std::string metrics_csv_filename;

srsenb/src/enb_cfg_parser.cc

@@ -954,7 +954,14 @@ int set_derived_args(all_args_t* args_, rrc_cfg_t* rrc_cfg_, phy_cfg_t* phy_cfg_
     rrc_cfg_->sibs[1].sib2().rr_cfg_common.pdsch_cfg_common.p_b = 1;
   }
 
+  if (args_->general.rrc_inactivity_timer == -1) {
+    uint32_t t310                   = rrc_cfg_->sibs[1].sib2().ue_timers_and_consts.t310.to_number();
+    uint32_t t311                   = rrc_cfg_->sibs[1].sib2().ue_timers_and_consts.t311.to_number();
+    uint32_t n310                   = rrc_cfg_->sibs[1].sib2().ue_timers_and_consts.n310.to_number();
+    rrc_cfg_->inactivity_timeout_ms = t310 + t311 + n310 + 50;
+  } else {
     rrc_cfg_->inactivity_timeout_ms = args_->general.rrc_inactivity_timer;
+  }
   rrc_cfg_->enable_mbsfn = args_->stack.embms.enable;
   rrc_cfg_->mbms_mcs     = args_->stack.embms.mcs;
 

srsenb/src/main.cc

@@ -187,7 +187,7 @@ void parse_args(all_args_t* args, int argc, char* argv[])
     ("expert.max_prach_offset_us", bpo::value<float>(&args->phy.max_prach_offset_us)->default_value(30), "Maximum allowed RACH offset (in us)")
     ("expert.equalizer_mode", bpo::value<string>(&args->phy.equalizer_mode)->default_value("mmse"), "Equalizer mode")
     ("expert.estimator_fil_w", bpo::value<float>(&args->phy.estimator_fil_w)->default_value(0.1), "Chooses the coefficients for the 3-tap channel estimator centered filter.")
-    ("expert.rrc_inactivity_timer", bpo::value<uint32_t>(&args->general.rrc_inactivity_timer)->default_value(60000), "Inactivity timer in ms")
+    ("expert.rrc_inactivity_timer", bpo::value<int32_t>(&args->general.rrc_inactivity_timer)->default_value(-1), "Inactivity timer in ms. With -1 the timeout is automatically derived.")
     ("expert.print_buffer_state", bpo::value<bool>(&args->general.print_buffer_state)->default_value(false), "Prints on the console the buffer state every 10 seconds")
     ("expert.eea_pref_list", bpo::value<string>(&args->general.eea_pref_list)->default_value("EEA0, EEA2, EEA1"), "Ordered preference list for the selection of encryption algorithm (EEA) (default: EEA0, EEA2, EEA1).")
     ("expert.eia_pref_list", bpo::value<string>(&args->general.eia_pref_list)->default_value("EIA2, EIA1, EIA0"), "Ordered preference list for the selection of integrity algorithm (EIA) (default: EIA2, EIA1, EIA0).")

srsenb/src/stack/rrc/rrc.cc

@@ -79,6 +79,8 @@ void rrc::init(const rrc_cfg_t&       cfg_,
   config_mac();
   enb_mobility_cfg.reset(new enb_mobility_handler(this));
 
+  rrc_log->info("Inactivity timeout: %d ms\n", cfg.inactivity_timeout_ms);
+
   running = true;
 }