SRSUE: RRC Reest Procedure Refactor

srsue/hdr/stack/rrc/rrc_procedures.h

@@ -239,17 +239,16 @@ public:
   static const char*     name() { return "Connection re-establishment"; }
 
 private:
-  enum class state_t { init, cell_reselection, cell_configuration, cell_criteria, success, error } state;
+  enum class state_t { cell_reselection, cell_configuration } state;
 
   rrc*                     rrc_ptr          = nullptr;
   asn1::rrc::reest_cause_e reest_cause      = asn1::rrc::reest_cause_e::nulltype;
   uint16_t                 reest_rnti       = 0;
   uint16_t                 reest_source_pci = 0;
 
-  void step_init();
+  srslte::proc_outcome_t step_cell_reselection();
-  void step_cell_reselection();
+  srslte::proc_outcome_t step_cell_configuration();
-  void step_cell_configuration();
+  srslte::proc_outcome_t cell_criteria();
-  void step_cell_criteria();
 };
 
 } // namespace srsue

srsue/src/stack/rrc/rrc_procedures.cc

@@ -873,7 +873,7 @@ proc_outcome_t rrc::cell_reselection_proc::step()
  *    RRC Connection Re-establishment procedure
  *************************************/
 
-rrc::connection_reest_proc::connection_reest_proc(srsue::rrc* rrc_) : rrc_ptr(rrc_), state(state_t::init) {}
+rrc::connection_reest_proc::connection_reest_proc(srsue::rrc* rrc_) : rrc_ptr(rrc_), state(state_t::cell_reselection) {}
 
 proc_outcome_t rrc::connection_reest_proc::init(asn1::rrc::reest_cause_e cause)
 {
@@ -892,25 +892,7 @@ proc_outcome_t rrc::connection_reest_proc::init(asn1::rrc::reest_cause_e cause)
 
     // the initiation of reestablishment procedure as indicates in 3GPP 36.331 Section 5.3.7.2
     // Cannot be called from here because it has PHY-MAC re-configuration that should be performed in a different thread
-    Info("Conditions are meet\n");
+    Info("Conditions are meet. Initiating RRC Connection Reestablishment Procedure\n");
-    state = state_t::init;
-
-  } else {
-    // 3GPP 36.331 Section 5.3.7.1
-    // If AS security has not been activated, the UE does not initiate the procedure but instead
-    // moves to RRC_IDLE directly
-    Info("Conditions are NOT meet\n");
-    rrc_ptr->start_go_idle();
-    state = state_t::success;
-  }
-
-  return proc_outcome_t::yield;
-}
-
-void rrc::connection_reest_proc::step_init()
-{
-  // initiation of reestablishment procedure as indicates in 3GPP 36.331 Section 5.3.7.2
-  Info("Initiating RRC Connection Reestablishment Procedure\n");
 
     // stop timer T310, if running;
     rrc_ptr->t310.stop();
@@ -938,81 +920,91 @@ void rrc::connection_reest_proc::step_init()
     rrc_ptr->apply_mac_config_dedicated_default();
 
     // Launch cell reselection
-  if (rrc_ptr->cell_reselector.launch()) {
+    if (not rrc_ptr->cell_reselector.launch()) {
+      Error("Failed to initiate a Cell re-selection procedure...\n");
+      return proc_outcome_t::error;
+    }
     state = state_t::cell_reselection;
+
   } else {
-    Error("Failed to initiate a Cell re-selection procedure...\n");
+    // 3GPP 36.331 Section 5.3.7.1
-    state = state_t::error;
+    // If AS security has not been activated, the UE does not initiate the procedure but instead
+    // moves to RRC_IDLE directly
+    Info("Conditions are NOT meet\n");
+    rrc_ptr->start_go_idle();
+    return proc_outcome_t::success;
   }
+
+  return proc_outcome_t::yield;
 }
 
-void rrc::connection_reest_proc::step_cell_reselection()
+srslte::proc_outcome_t rrc::connection_reest_proc::step_cell_reselection()
 {
-  if (!rrc_ptr->t311.is_running()) {
+
-    Info("During cell reselection, T311 expired. Aborting.\n");
+  // Run cell reselection
-    state = state_t::success;
+  if (not rrc_ptr->cell_reselector.run()) {
-  } else if (rrc_ptr->cell_reselector.run()) {
+    // Cell reselection finished or not started
-    // Keep running, do nothing
+    if (rrc_ptr->serving_cell->in_sync) {
-  } else if (!rrc_ptr->serving_cell->in_sync) {
+      // In-sync, check SIBs
-    Info("Serving cell is out-of-sync, re-launching re-selection procedure\n");
+      if (rrc_ptr->serving_cell->has_sib1() && rrc_ptr->serving_cell->has_sib2() && rrc_ptr->serving_cell->has_sib3()) {
-    if (rrc_ptr->cell_reselector.launch()) {
-      state = state_t::cell_reselection;
-    } else {
-      // Error launching procedure
-      state = state_t::error;
-    }
-  } else if (rrc_ptr->serving_cell->has_sib1() && rrc_ptr->serving_cell->has_sib2() &&
-             rrc_ptr->serving_cell->has_sib3()) {
         Info("In-sync, SIBs available. Going to cell criteria\n");
-    state = state_t::cell_criteria;
+        return cell_criteria();
       } else {
         Info("SIBs missing (%d, %d, %d), launching serving cell configuration procedure\n",
              rrc_ptr->serving_cell->has_sib1(),
              rrc_ptr->serving_cell->has_sib2(),
              rrc_ptr->serving_cell->has_sib3());
         std::vector<uint32_t> required_sibs = {1, 2, 3};
-    if (rrc_ptr->serv_cell_cfg.launch(required_sibs)) {
+        if (!rrc_ptr->serv_cell_cfg.launch(required_sibs)) {
+          Error("Failed to initiate configure serving cell\n");
+          return proc_outcome_t::error;
+        }
         state = state_t::cell_configuration;
+      }
     } else {
-      Error("Failed to initiate configure serving cell\n");
+      // Out-of-sync, relaunch reselection
-      state = state_t::error;
+      Info("Serving cell is out-of-sync, re-launching re-selection procedure\n");
+      if (!rrc_ptr->cell_reselector.launch()) {
+        return proc_outcome_t::error;
+      }
     }
   }
+
+  return proc_outcome_t::yield;
 }
 
-void rrc::connection_reest_proc::step_cell_configuration()
+proc_outcome_t rrc::connection_reest_proc::step_cell_configuration()
 {
-  if (!rrc_ptr->t311.is_running()) {
+  if (not rrc_ptr->serv_cell_cfg.run()) {
-    Info("During cell configuration, T311 expired. Aborting.\n");
+    // SIBs adquisition not started or finished
-    state = state_t::success;
+    if (rrc_ptr->serving_cell->in_sync) {
-  } else if (rrc_ptr->serv_cell_cfg.run()) {
+      // In-sync
-    // Keep running, do nothing
+      if (rrc_ptr->serving_cell->has_sib1() && rrc_ptr->serving_cell->has_sib2() && rrc_ptr->serving_cell->has_sib3()) {
-  } else if (!rrc_ptr->serving_cell->in_sync) {
+        // All SIBs are available
-    Info("Serving cell is out-of-sync, re-launching re-selection procedure\n");
+        return cell_criteria();
-    if (rrc_ptr->cell_reselector.launch()) {
-      state = state_t::cell_reselection;
       } else {
-      Error("Failed to initiate a Cell re-selection procedure...\n");
+        // Required SIBs are not available
-      state = state_t::error;
+        Error("Failed to configure serving cell\n");
+        return proc_outcome_t::error;
       }
-  } else if (rrc_ptr->serving_cell->has_sib1() && rrc_ptr->serving_cell->has_sib2() &&
-             rrc_ptr->serving_cell->has_sib3()) {
-    Info("SIBs available. Going to cell criteria\n");
-    state = state_t::cell_criteria;
     } else {
-    Error("Failed to configure serving cell\n");
+      // Out-of-sync, relaunch reselection
-    state = state_t::error;
+      Info("Serving cell is out-of-sync, re-launching re-selection procedure\n");
+      if (!rrc_ptr->cell_reselector.launch()) {
+        Error("Failed to initiate a Cell re-selection procedure...\n");
+        return proc_outcome_t::error;
       }
+      state = state_t::cell_reselection;
+    }
+  }
+
+  return proc_outcome_t::yield;
 }
 
-void rrc::connection_reest_proc::step_cell_criteria()
+srslte::proc_outcome_t rrc::connection_reest_proc::cell_criteria()
 {
-  // Wait until we're synced and have obtained SIBs
   // Perform cell selection in accordance to 36.304
-  if (!rrc_ptr->t311.is_running()) {
+  if (rrc_ptr->cell_selection_criteria(rrc_ptr->serving_cell->get_rsrp())) {
-    Info("During cell selection criteria, T311 expired. Aborting.\n");
-    state = state_t::success;
-  } else if (rrc_ptr->cell_selection_criteria(rrc_ptr->serving_cell->get_rsrp())) {
     // Actions following cell reselection while T311 is running 5.3.7.3
     // Upon selecting a suitable E-UTRA cell, the UE shall:
     Info("Cell Selection criteria passed after %dms. Sending RRC Connection Reestablishment Request\n",
@@ -1025,55 +1017,38 @@ void rrc::connection_reest_proc::step_cell_criteria()
     rrc_ptr->t301.run();
 
     // apply the timeAlignmentTimerCommon included in SystemInformationBlockType2;
-    // TODO
+    // Not implemented yet.
 
     // initiate transmission of the RRCConnectionReestablishmentRequest message in accordance with 5.3.7.4;
     rrc_ptr->send_con_restablish_request(reest_cause, reest_rnti, reest_source_pci);
   } else {
     // Upon selecting an inter-RAT cell
-    Warning("Reestablishment Cell Selection criteria failed.\n");
+    Info("Reestablishment Cell Selection criteria failed.\n");
     rrc_ptr->leave_connected();
   }
-  state = state_t::success;
+  return proc_outcome_t::success;
 }
 
 proc_outcome_t rrc::connection_reest_proc::step()
 {
-  proc_outcome_t proc_outcome = srslte::proc_outcome_t::yield;
+  // Abort procedure if T311 expires
+  if (!rrc_ptr->t311.is_running()) {
+    Info("T311 expired. Aborting.\n");
+    return proc_outcome_t::success;
+  }
 
   /*
    * Implementation of procedure in 3GPP 36.331 Section 5.3.7.3: Actions following cell selection while T311 is running
    */
   switch (state) {
-
-    case state_t::init:
-      step_init();
-      break;
-
     case state_t::cell_reselection:
-      step_cell_reselection();
+      return step_cell_reselection();
-      break;
 
     case state_t::cell_configuration:
-      step_cell_configuration();
+      return step_cell_configuration();
-      break;
-
-    case state_t::cell_criteria:
-      step_cell_criteria();
-      break;
-
-    case state_t::success:
-      Info("Finished successfully\n");
-      proc_outcome = srslte::proc_outcome_t::success;
-      break;
-
-    case state_t::error:
-      Info("Finished with error\n");
-      proc_outcome = srslte::proc_outcome_t::error;
-      break;
   }
 
-  return proc_outcome;
+  return proc_outcome_t::error;
 }
 
 } // namespace srsue