SRSUE: Make sure PHY reset is done when SYNC is IDLE

srsue/hdr/phy/sync.h

@@ -73,6 +73,13 @@ public:
   bool                                     cell_select_start(phy_cell_t cell);
   bool                                     cell_is_camping();
 
+  /**
+   * @brief Interface for monitoring UE's synchronization transition to IDLE. In addition to IDLE transitioning, this
+   * method waits for workers to finish processing and ends the current RF transmission burst.
+   * @return true if SYNC transitioned to IDLE, false otherwise
+   */
+  bool wait_idle();
+
   // RRC interface for controlling the neighbour cell measurement
   void set_cells_to_meas(uint32_t earfcn, const std::set<uint32_t>& pci);
   void set_inter_frequency_measurement(uint32_t cc_idx, uint32_t earfcn_, srsran_cell_t cell_);
@@ -190,7 +197,7 @@ private:
   bool set_cell(float cfo);
 
   std::atomic<bool> running     = {false};
-  bool is_overflow = false;
+  bool              is_overflow = false;
 
   srsran::rf_timestamp_t last_rx_time;
   bool                   forced_rx_time_init = true; // Rx time sync after first receive from radio
@@ -232,7 +239,7 @@ private:
   std::atomic<float> sfo     = {}; // SFO estimate updated after each sync-cycle
   std::atomic<float> cfo     = {}; // CFO estimate updated after each sync-cycle
   std::atomic<float> ref_cfo = {}; // provided adjustment value applied before sync
-  sync_metrics_t metrics = {};
+  sync_metrics_t     metrics = {};
 
   // in-sync / out-of-sync counters
   std::atomic<uint32_t> out_of_sync_cnt = {0};
@@ -274,7 +281,7 @@ private:
   const static int MIN_TTI_JUMP       = 1;    ///< Time gap reported to stack after receiving subframe
   const static int MAX_TTI_JUMP       = 1000; ///< Maximum time gap tolerance in RF stream metadata
   const uint8_t    SYNC_CC_IDX        = 0;    ///< From the sync POV, the CC idx is always the first
-  const uint32_t   TIMEOUT_TO_IDLE_MS = 2;    ///< Timeout in milliseconds for transitioning to IDLE
+  const uint32_t   TIMEOUT_TO_IDLE_MS = 2000; ///< Timeout in milliseconds for transitioning to IDLE
 };
 
 } // namespace srsue

srsue/src/phy/phy.cc

@@ -304,10 +304,15 @@ bool phy::cell_select(phy_cell_t cell)
 {
   sfsync.scell_sync_stop();
   if (sfsync.cell_select_init(cell)) {
-    reset();
     // Update PCI before starting the background command to make sure PRACH gets the updated value
     selected_cell.id = cell.pci;
     cmd_worker_cell.add_cmd([this, cell]() {
+      // Wait SYNC transitions to IDLE
+      sfsync.wait_idle();
+
+      // Reset worker once SYNC is IDLE to flush any PHY state including measurements, pending ACKs and pending grants
+      reset();
+
       bool ret = sfsync.cell_select_start(cell);
       if (ret) {
         srsran_cell_t sync_cell;
@@ -330,8 +335,13 @@ bool phy::cell_search()
 {
   sfsync.scell_sync_stop();
   if (sfsync.cell_search_init()) {
-    reset();
     cmd_worker_cell.add_cmd([this]() {
+      // Wait SYNC transitions to IDLE
+      sfsync.wait_idle();
+
+      // Reset worker once SYNC is IDLE to flush any PHY state including measurements, pending ACKs and pending grants
+      reset();
+
       phy_cell_t                               found_cell = {};
       rrc_interface_phy_lte::cell_search_ret_t ret        = sfsync.cell_search_start(&found_cell);
       stack->cell_search_complete(ret, found_cell);

srsue/src/phy/phy_common.cc

@@ -873,12 +873,15 @@ void phy_common::reset()
   pcell_report_period = 20;
   last_ri             = 0;
 
-  ZERO_OBJECT(pathloss);
+  {
-  ZERO_OBJECT(avg_sinr_db);
+    std::unique_lock<std::mutex> lock(meas_mutex);
-  ZERO_OBJECT(avg_snr_db);
+    ZERO_OBJECT(pathloss);
-  ZERO_OBJECT(avg_rsrp);
+    ZERO_OBJECT(avg_sinr_db);
-  ZERO_OBJECT(avg_rsrp_dbm);
+    ZERO_OBJECT(avg_snr_db);
-  ZERO_OBJECT(avg_rsrq_db);
+    ZERO_OBJECT(avg_rsrp);
+    ZERO_OBJECT(avg_rsrp_dbm);
+    ZERO_OBJECT(avg_rsrq_db);
+  }
   cell_state.reset();
 
   reset_neighbour_cells();

srsue/src/phy/sync.cc

@@ -219,18 +219,6 @@ rrc_interface_phy_lte::cell_search_ret_t sync::cell_search_start(phy_cell_t* fou
 
   rrc_proc_state = PROC_SEARCH_RUNNING;
 
-  // Wait for SYNC thread to transition to IDLE (max. 2000ms)
-  if (not phy_state.wait_idle(TIMEOUT_TO_IDLE_MS)) {
-    Error("SYNC: Error transitioning to IDLE. Cell search cannot start.");
-    return ret;
-  }
-
-  // Wait for workers to finish PHY processing
-  worker_com->semaphore.wait_all();
-
-  // Reset worker once SYNC is IDLE to flush any worker states such as ACKs and pending grants
-  worker_com->reset();
-
   if (srate_mode != SRATE_FIND) {
     srate_mode = SRATE_FIND;
     radio_h->set_rx_srate(1.92e6);
@@ -392,6 +380,26 @@ bool sync::cell_is_camping()
   return phy_state.is_camping();
 }
 
+bool sync::wait_idle()
+{
+  // Wait for SYNC thread to transition to IDLE (max. 2000ms)
+  if (not phy_state.wait_idle(TIMEOUT_TO_IDLE_MS)) {
+    Error("SYNC: Failed transitioning to IDLE");
+    return false;
+  }
+
+  // Reset UE sync. Attention: doing this reset when the FSM is NOT IDLE can cause PSS/SSS out-of-sync
+  srsran_ue_sync_reset(&ue_sync);
+
+  // Wait for workers to finish PHY processing
+  worker_com->semaphore.wait_all();
+
+  // As workers have finished, make sure the Tx burst is ended
+  radio_h->tx_end();
+
+  return true;
+}
+
 void sync::run_cell_search_state()
 {
   cell_search_ret = search_p.run(&cell, mib);
@@ -802,23 +810,8 @@ void sync::set_ue_sync_opts(srsran_ue_sync_t* q, float cfo)
   srsran_sync_set_sss_algorithm(&q->sfind, (sss_alg_t)sss_alg);
 }
 
-bool sync::set_cell(float cfo)
+bool sync::set_cell(float cfo_in)
 {
-  // Wait for SYNC thread to transition to IDLE (max. 2000ms)
-  if (not phy_state.wait_idle(TIMEOUT_TO_IDLE_MS)) {
-    Error("SYNC: Can not change Cell while not in IDLE");
-    return false;
-  }
-
-  // Reset UE sync. Attention: doing this reset when the FSM is NOT IDLE can cause PSS/SSS out-of-sync
-  srsran_ue_sync_reset(&ue_sync);
-
-  // Wait for workers to finish PHY processing
-  worker_com->semaphore.wait_all();
-
-  // Reset worker once SYNC is IDLE to flush any worker states such as ACKs and pending grants
-  worker_com->reset();
-
   if (!srsran_cell_isvalid(&cell)) {
     Error("SYNC:  Setting cell: invalid cell (nof_prb=%d, pci=%d, ports=%d)", cell.nof_prb, cell.id, cell.nof_ports);
     return false;
@@ -851,7 +844,7 @@ bool sync::set_cell(float cfo)
   }
 
   // Set options defined in expert section
-  set_ue_sync_opts(&ue_sync, cfo);
+  set_ue_sync_opts(&ue_sync, cfo_in);
 
   // Reset ue_sync and set CFO/gain from search procedure
   srsran_ue_sync_reset(&ue_sync);