moved cell search to background task thread pool, and provided a stack interface to rrc to call "start_cell_search". Once completed, the background task signals back to RRC

lib/include/srslte/interfaces/ue_interfaces.h

@@ -632,6 +632,13 @@ public:
   virtual void wait_ra_completion(uint16_t rnti) = 0;
 };
 
+// STACK interface for RRC
+class stack_interface_rrc
+{
+public:
+  virtual void start_cell_search() = 0;
+};
+
 // Combined interface for PHY to access stack (MAC and RRC)
 class stack_interface_phy_lte : public mac_interface_phy_lte, public rrc_interface_phy_lte
 {

srsue/hdr/stack/rrc/rrc.h

@@ -299,6 +299,7 @@ public:
             usim_interface_rrc*    usim_,
             gw_interface_rrc*      gw_,
             srslte::timers*        timers_,
+            stack_interface_rrc*   stack_,
             const rrc_args_t&      args_);
 
   void stop();
@@ -349,8 +350,11 @@ public:
   void write_pdu_pcch(srslte::unique_byte_buffer_t pdu);
   void write_pdu_mch(uint32_t lcid, srslte::unique_byte_buffer_t pdu);
 
-private:
+  // STACK interface
+  void cell_search_completed(const phy_interface_rrc_lte::cell_search_ret_t& cs_ret,
+                             const phy_interface_rrc_lte::phy_cell_t&        found_cell);
 
+private:
   typedef struct {
     enum { PDU, PCCH, PDU_MCH, RLF, PDU_BCCH_DLSCH, STOP } command;
     srslte::unique_byte_buffer_t pdu;
@@ -371,6 +375,7 @@ private:
   nas_interface_rrc*        nas     = nullptr;
   usim_interface_rrc*       usim    = nullptr;
   gw_interface_rrc*         gw      = nullptr;
+  stack_interface_rrc*      stack   = nullptr;
 
   srslte::unique_byte_buffer_t dedicated_info_nas;
 

srsue/hdr/stack/rrc/rrc_procedures.h

@@ -32,12 +32,17 @@ namespace srsue {
 class rrc::cell_search_proc : public srslte::proc_impl_t
 {
 public:
+  struct cell_search_event_t {
+    phy_interface_rrc_lte::cell_search_ret_t cs_ret;
+    phy_interface_rrc_lte::phy_cell_t        found_cell;
+  };
   enum class state_t { phy_cell_search, si_acquire };
 
   srslte::proc_outcome_t init(rrc* parent_);
   srslte::proc_outcome_t step() final;
+  srslte::proc_outcome_t trigger_event(const cell_search_event_t& event);
 
-  phy_interface_rrc_lte::cell_search_ret_t get_cs_ret() { return cs_ret; }
+  phy_interface_rrc_lte::cell_search_ret_t get_cs_ret() { return search_result.cs_ret; }
   static const char*                       name() { return "Cell Search"; }
 
 private:
@@ -48,8 +53,8 @@ private:
   srslte::log* log_h;
 
   // state vars
-  phy_interface_rrc_lte::cell_search_ret_t cs_ret;
-  state_t                                  state;
+  cell_search_event_t search_result;
+  state_t             state;
 };
 
 class rrc::si_acquire_proc : public srslte::proc_impl_t

srsue/hdr/stack/ue_stack_lte.h

@@ -54,6 +54,7 @@ class ue_stack_lte final : public ue_stack_base,
                            public stack_interface_phy_lte,
                            public stack_interface_gw,
                            public stack_interface_mac,
+                           public stack_interface_rrc,
                            public thread
 {
 public:
@@ -117,6 +118,9 @@ public:
   void process_pdus() final;
   void wait_ra_completion(uint16_t rnti) final;
 
+  // Interface for RRC
+  void start_cell_search() final;
+
 private:
   void run_thread() final;
   void run_tti_impl(uint32_t tti);

srsue/src/stack/rrc/rrc.cc

@@ -98,16 +98,18 @@ void rrc::init(phy_interface_rrc_lte* phy_,
                usim_interface_rrc*    usim_,
                gw_interface_rrc*      gw_,
                srslte::timers*        timers_,
+               stack_interface_rrc*   stack_,
                const rrc_args_t&      args_)
 {
-  pool = byte_buffer_pool::get_instance();
+  pool  = byte_buffer_pool::get_instance();
   phy = phy_;
   mac = mac_;
   rlc = rlc_;
   pdcp = pdcp_;
-  nas = nas_;
-  usim = usim_;
-  gw = gw_;
+  nas   = nas_;
+  usim  = usim_;
+  gw    = gw_;
+  stack = stack_;
 
   args = args_;
 
@@ -325,9 +327,9 @@ void rrc::plmn_select(srslte::plmn_id_t plmn_id)
  * it. Sends connectionRequest message and returns if message transmitted successfully.
  * It does not wait until completition of Connection Establishment procedure
  */
-bool rrc::connection_request(srslte::establishment_cause_t cause, srslte::unique_byte_buffer_t dedicated_info_nas)
+bool rrc::connection_request(srslte::establishment_cause_t cause, srslte::unique_byte_buffer_t dedicated_info_nas_)
 {
-  if (not conn_req_proc.launch(this, cause, std::move(dedicated_info_nas))) {
+  if (not conn_req_proc.launch(this, cause, std::move(dedicated_info_nas_))) {
     rrc_log->error("Failed to initiate connection request procedure\n");
     return false;
   }
@@ -1479,15 +1481,21 @@ void rrc::start_cell_reselection()
   });
 }
 
+void rrc::cell_search_completed(const phy_interface_rrc_lte::cell_search_ret_t& cs_ret,
+                                const phy_interface_rrc_lte::phy_cell_t&        found_cell)
+{
+  cell_searcher.trigger_event(cell_search_proc::cell_search_event_t{cs_ret, found_cell});
+}
+
 /*******************************************************************************
-*
-*
-*
-* Reception of Broadcast messages (MIB and SIBs)
-*
-*
-*
-*******************************************************************************/
+ *
+ *
+ *
+ * Reception of Broadcast messages (MIB and SIBs)
+ *
+ *
+ *
+ *******************************************************************************/
 void rrc::write_pdu_bcch_bch(unique_byte_buffer_t pdu)
 {
   asn1::rrc::bcch_bch_msg_s bch_msg;
@@ -2847,11 +2855,12 @@ void rrc::set_rrc_default()
  *
  ************************************************************************/
 
-void rrc::rrc_meas::init(rrc *parent) {
-  this->parent      = parent;
-  this->log_h       = parent->rrc_log;
-  this->phy         = parent->phy;
-  this->timers      = parent->timers;
+void rrc::rrc_meas::init(rrc* parent_)
+{
+  this->parent      = parent_;
+  this->log_h       = parent_->rrc_log;
+  this->phy         = parent_->phy;
+  this->timers      = parent_->timers;
   s_measure_enabled = false;
   reset();
 }

srsue/src/stack/rrc/rrc_procedures.cc

@@ -43,6 +43,7 @@ proc_outcome_t rrc::cell_search_proc::init(srsue::rrc* parent_)
 
   Info("Starting...\n");
   state = state_t::phy_cell_search;
+  rrc_ptr->stack->start_cell_search();
   return proc_outcome_t::repeat;
 }
 
@@ -50,25 +51,8 @@ proc_outcome_t rrc::cell_search_proc::init(srsue::rrc* parent_)
 proc_outcome_t rrc::cell_search_proc::step()
 {
   if (state == state_t::phy_cell_search) {
-    // Blocks waiting for result of phy cell search
-    phy_interface_rrc_lte::phy_cell_t new_cell;
-
-    // BLOCKING CALL
-    cs_ret = rrc_ptr->phy->cell_search(&new_cell);
-
-    switch (cs_ret.found) {
-      case phy_interface_rrc_lte::cell_search_ret_t::CELL_FOUND: {
-        return handle_cell_found(new_cell);
-      }
-      case phy_interface_rrc_lte::cell_search_ret_t::CELL_NOT_FOUND:
-        Info("No cells found.\n");
-        // do nothing
-        return proc_outcome_t::success;
-      case phy_interface_rrc_lte::cell_search_ret_t::ERROR:
-        Error("Error while performing cell search\n");
-        // TODO: check what errors can happen (currently not handled in our code)
-        return proc_outcome_t::error;
-    }
+    // Waits for cell search to complete
+    return proc_outcome_t::yield;
   } else if (state == state_t::si_acquire) {
     if (not rrc_ptr->si_acquirer.run()) {
       // SI Acquire has completed
@@ -121,6 +105,32 @@ proc_outcome_t rrc::cell_search_proc::handle_cell_found(const phy_interface_rrc_
   return proc_outcome_t::repeat;
 }
 
+proc_outcome_t rrc::cell_search_proc::trigger_event(const cell_search_event_t& event)
+{
+  if (state != state_t::phy_cell_search) {
+    Error("Received unexpected cell search result\n");
+    return proc_outcome_t::error;
+  }
+  search_result = event;
+
+  Info("PHY cell search completed.\n");
+  // Transition to SI Acquire or finish
+  switch (search_result.cs_ret.found) {
+    case phy_interface_rrc_lte::cell_search_ret_t::CELL_FOUND: {
+      return handle_cell_found(search_result.found_cell);
+    }
+    case phy_interface_rrc_lte::cell_search_ret_t::CELL_NOT_FOUND:
+      Info("No cells found.\n");
+      // do nothing
+      return proc_outcome_t::success;
+    case phy_interface_rrc_lte::cell_search_ret_t::ERROR:
+      Error("Error while performing cell search\n");
+      // TODO: check what errors can happen (currently not handled in our code)
+      return proc_outcome_t::error;
+  }
+  return proc_outcome_t::yield;
+}
+
 /**************************************
  *       SI Acquire Procedure
  *************************************/

srsue/src/stack/ue_stack_lte.cc

@@ -127,7 +127,7 @@ int ue_stack_lte::init(const stack_args_t& args_, srslte::logger* logger_)
   rlc.init(&pdcp, &rrc, &timers, 0 /* RB_ID_SRB0 */);
   pdcp.init(&rlc, &rrc, gw);
   nas.init(usim.get(), &rrc, gw, args.nas);
-  rrc.init(phy, &mac, &rlc, &pdcp, &nas, usim.get(), gw, &timers, args.rrc);
+  rrc.init(phy, &mac, &rlc, &pdcp, &nas, usim.get(), gw, &timers, this, args.rrc);
 
   running = true;
   start(STACK_MAIN_THREAD_PRIO);
@@ -284,11 +284,25 @@ void ue_stack_lte::process_pdus()
 
 void ue_stack_lte::wait_ra_completion(uint16_t rnti)
 {
-  background_tasks.push_task([this, rnti](uint32_t worker_id){
+  background_tasks.push_task([this, rnti](uint32_t worker_id) {
     phy->set_crnti(rnti);
     // signal MAC RA proc to go back to idle
     mac.notify_ra_completed();
   });
 }
 
+/********************
+ *  RRC Interface
+ *******************/
+
+void ue_stack_lte::start_cell_search()
+{
+  background_tasks.push_task([this](uint32_t worker_id) {
+    phy_interface_rrc_lte::phy_cell_t        found_cell;
+    phy_interface_rrc_lte::cell_search_ret_t ret = phy->cell_search(&found_cell);
+    // notify back RRC
+    rrc.cell_search_completed(ret, found_cell);
+  });
+}
+
 } // namespace srsue