SRSUE RRC: new PHY unknown sync state, cell select waits for PHY in-sync

srsue/hdr/stack/rrc/rrc.h

@@ -260,7 +260,6 @@ class cell_t
   }
 
   phy_interface_rrc_lte::phy_cell_t phy_cell = {};
-  bool                              in_sync  = false;
   bool                              has_mcch = false;
   asn1::rrc::sib_type1_s            sib1;
   asn1::rrc::sib_type2_s            sib2;
@@ -328,9 +327,9 @@ public:
   void     paging_completed(bool outcome) final;
 
   // PHY interface
-  void in_sync();
-  void out_of_sync();
-  void new_phy_meas(float rsrp, float rsrq, uint32_t tti, int earfcn, int pci);
+  void in_sync() final;
+  void out_of_sync() final;
+  void new_phy_meas(float rsrp, float rsrq, uint32_t tti, int earfcn, int pci) final;
 
   // MAC interface
   void ho_ra_completed(bool ra_successful);
@@ -390,6 +389,9 @@ private:
 
   bool drb_up = false;
 
+  typedef enum { phy_unknown_sync = 0, phy_in_sync, phy_out_of_sync } phy_sync_state_t;
+  phy_sync_state_t phy_sync_state = phy_unknown_sync;
+
   rrc_args_t args = {};
 
   uint32_t cell_clean_cnt = 0;

srsue/hdr/stack/rrc/rrc_procedures.h

@@ -117,6 +117,7 @@ public:
 
 private:
   srslte::proc_outcome_t step_cell_selection();
+  srslte::proc_outcome_t step_wait_in_sync();
   srslte::proc_outcome_t step_cell_search();
   srslte::proc_outcome_t step_cell_config();
 
@@ -124,7 +125,7 @@ private:
   rrc* rrc_ptr;
 
   // state variables
-  enum class search_state_t { cell_selection, cell_config, cell_search };
+  enum class search_state_t { cell_selection, wait_in_sync, cell_config, cell_search };
   cs_result_t                                                     cs_result;
   search_state_t                                                  state;
   uint32_t                                                        neigh_index;

srsue/src/phy/sync.cc

@@ -330,6 +330,7 @@ bool sync::cell_select(phy_interface_rrc_lte::phy_cell_t* new_cell)
   phy_state.run_sfn_sync();
   if (phy_state.is_camping()) {
     Info("Cell Select: SFN synchronized. CAMPING...\n");
+    stack->in_sync();
     ret = true;
   } else {
     Info("Cell Select: Could not synchronize SFN\n");

srsue/src/stack/rrc/rrc.cc

@@ -201,6 +201,8 @@ void rrc::run_tti(uint32_t tti)
     return;
   }
 
+  rrc_log->step(tti);
+
   if (simulate_rlf) {
     radio_link_failure();
     simulate_rlf = false;
@@ -425,7 +427,7 @@ void rrc::out_of_sync()
 {
   // CAUTION: We do not lock in this function since they are called from real-time threads
   if (serving_cell && timers && rrc_log) {
-    serving_cell->in_sync = false;
+    phy_sync_state = phy_out_of_sync;
 
     // upon receiving N310 consecutive "out-of-sync" indications for the PCell from lower layers while neither T300,
     //   T301, T304 nor T311 is running:
@@ -452,7 +454,7 @@ void rrc::out_of_sync()
 void rrc::in_sync()
 {
   // CAUTION: We do not lock in this function since they are called from real-time threads
-  serving_cell->in_sync = true;
+  phy_sync_state = phy_in_sync;
   if (t310.is_running()) {
     n311_cnt++;
     if (n311_cnt == N311) {
@@ -1346,7 +1348,7 @@ void rrc::start_con_restablishment(asn1::rrc::reest_cause_e cause)
 
 void rrc::start_cell_reselection()
 {
-  if (neighbour_cells.empty() and serving_cell->in_sync and phy->cell_is_camping()) {
+  if (neighbour_cells.empty() and phy_sync_state == phy_in_sync and phy->cell_is_camping()) {
     // don't bother with cell selection if there are no neighbours and we are already camping
     return;
   }

srsue/src/stack/rrc/rrc_procedures.cc

@@ -116,6 +116,7 @@ proc_outcome_t rrc::cell_search_proc::react(const cell_search_event_t& event)
       return handle_cell_found(search_result.found_cell);
     }
     case phy_interface_rrc_lte::cell_search_ret_t::CELL_NOT_FOUND:
+      rrc_ptr->phy_sync_state = phy_unknown_sync;
       Info("No cells found.\n");
       // do nothing
       return proc_outcome_t::success;
@@ -329,7 +330,7 @@ rrc::cell_selection_proc::cell_selection_proc(rrc* parent_) : rrc_ptr(parent_) {
  */
 proc_outcome_t rrc::cell_selection_proc::init()
 {
-  if (rrc_ptr->neighbour_cells.empty() and rrc_ptr->serving_cell->in_sync and rrc_ptr->phy->cell_is_camping()) {
+  if (rrc_ptr->neighbour_cells.empty() and rrc_ptr->phy_sync_state == phy_in_sync and rrc_ptr->phy->cell_is_camping()) {
     // don't bother with cell selection if there are no neighbours and we are already camping
     Debug("Skipping Cell Selection Procedure ..\n");
     cs_result = cs_result_t::same_cell;
@@ -350,11 +351,10 @@ proc_outcome_t rrc::cell_selection_proc::step_cell_selection()
   for (; neigh_index < rrc_ptr->neighbour_cells.size(); ++neigh_index) {
     /*TODO: CHECK that PLMN matches. Currently we don't receive SIB1 of neighbour cells
      * neighbour_cells[i]->plmn_equals(selected_plmn_id) && */
-    if (rrc_ptr->neighbour_cells.at(neigh_index)->in_sync) {
     // Matches S criteria
     float rsrp = rrc_ptr->neighbour_cells.at(neigh_index)->get_rsrp();
 
-      if (not rrc_ptr->serving_cell->in_sync or
+    if (rrc_ptr->phy_sync_state != phy_in_sync or
         (rrc_ptr->cell_selection_criteria(rsrp) and rsrp > rrc_ptr->serving_cell->get_rsrp() + 5)) {
       // currently connected and verifies cell selection criteria
       // Try to select Cell
@@ -364,21 +364,17 @@ proc_outcome_t rrc::cell_selection_proc::step_cell_selection()
 
       /* BLOCKING CALL */
       if (rrc_ptr->phy->cell_select(&rrc_ptr->serving_cell->phy_cell)) {
-          serv_cell_cfg_fut = rrc_ptr->serv_cell_cfg.get_future();
-          if (not rrc_ptr->serv_cell_cfg.launch(rrc_ptr->ue_required_sibs)) {
-            return proc_outcome_t::error;
-          }
-          state = search_state_t::cell_config;
+        Info("Wait PHY to be in-synch\n");
+        state = search_state_t::wait_in_sync;
         return proc_outcome_t::repeat;
       } else {
-          rrc_ptr->serving_cell->in_sync = false;
+        rrc_ptr->phy_sync_state = phy_unknown_sync;
         Error("Could not camp on serving cell.\n");
         // Continue to next neighbour cell
       }
     }
   }
-  }
-  if (rrc_ptr->serving_cell->in_sync) {
+  if (rrc_ptr->phy_sync_state == phy_in_sync) {
     if (not rrc_ptr->phy->cell_is_camping()) {
       Info("Serving cell %s is in-sync but not camping. Selecting it...\n", rrc_ptr->serving_cell->print().c_str());
 
@@ -386,7 +382,7 @@ proc_outcome_t rrc::cell_selection_proc::step_cell_selection()
       if (rrc_ptr->phy->cell_select(&rrc_ptr->serving_cell->phy_cell)) {
         Info("Selected serving cell OK.\n");
       } else {
-        rrc_ptr->serving_cell->in_sync = false;
+        rrc_ptr->phy_sync_state = phy_unknown_sync;
         Error("Could not camp on serving cell.\n");
         return proc_outcome_t::error;
       }
@@ -405,6 +401,19 @@ proc_outcome_t rrc::cell_selection_proc::step_cell_selection()
   return proc_outcome_t::repeat;
 }
 
+proc_outcome_t rrc::cell_selection_proc::step_wait_in_sync()
+{
+  if (rrc_ptr->phy_sync_state == phy_in_sync) {
+    Info("PHY is in SYNC\n");
+    serv_cell_cfg_fut = rrc_ptr->serv_cell_cfg.get_future();
+    if (not rrc_ptr->serv_cell_cfg.launch(rrc_ptr->ue_required_sibs)) {
+      return proc_outcome_t::error;
+    }
+    state = search_state_t::cell_config;
+  }
+  return proc_outcome_t::yield;
+}
+
 proc_outcome_t rrc::cell_selection_proc::step_cell_search()
 {
   if (rrc_ptr->cell_searcher.run()) {
@@ -443,6 +452,8 @@ proc_outcome_t rrc::cell_selection_proc::step()
   switch (state) {
     case search_state_t::cell_selection:
       return step_cell_selection();
+    case search_state_t::wait_in_sync:
+      return step_wait_in_sync();
     case search_state_t::cell_config:
       return step_cell_config();
     case search_state_t::cell_search:
@@ -684,11 +695,11 @@ srslte::proc_outcome_t rrc::connection_request_proc::react(const cell_selection_
     switch (cs_ret) {
       case cs_result_t::same_cell:
         log_h->warning("Did not reselect cell but serving cell is out-of-sync.\n");
-        rrc_ptr->serving_cell->in_sync = false;
+        rrc_ptr->phy_sync_state = phy_unknown_sync;
         break;
       case cs_result_t::changed_cell:
         log_h->warning("Selected a new cell but could not camp on. Setting out-of-sync.\n");
-        rrc_ptr->serving_cell->in_sync = false;
+        rrc_ptr->phy_sync_state = phy_unknown_sync;
         break;
       default:
         log_h->warning("Could not find any suitable cell to connect\n");
@@ -861,7 +872,7 @@ proc_outcome_t rrc::cell_reselection_proc::step()
     case cs_result_t::same_cell:
       if (!rrc_ptr->phy->cell_is_camping()) {
         Warning("Did not reselect cell but serving cell is out-of-sync.\n");
-        rrc_ptr->serving_cell->in_sync = false;
+        rrc_ptr->phy_sync_state = phy_unknown_sync;
       }
       break;
   }
@@ -945,7 +956,7 @@ srslte::proc_outcome_t rrc::connection_reest_proc::step_cell_reselection()
   // Run cell reselection
   if (not rrc_ptr->cell_reselector.run()) {
     // Cell reselection finished or not started
-    if (rrc_ptr->serving_cell->in_sync) {
+    if (rrc_ptr->phy_sync_state == phy_in_sync) {
       // In-sync, check SIBs
       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");
@@ -978,7 +989,7 @@ proc_outcome_t rrc::connection_reest_proc::step_cell_configuration()
 {
   if (not rrc_ptr->serv_cell_cfg.run()) {
     // SIBs adquisition not started or finished
-    if (rrc_ptr->serving_cell->in_sync) {
+    if (rrc_ptr->phy_sync_state == phy_in_sync) {
       // In-sync
       if (rrc_ptr->serving_cell->has_sib1() && rrc_ptr->serving_cell->has_sib2() && rrc_ptr->serving_cell->has_sib3()) {
         // All SIBs are available