lib,rlc_am_nr: added t_poll_retransmit to tx entity

lib/include/srsran/rlc/rlc_am_nr.h

@@ -98,6 +98,7 @@ public:
 
   bool sdu_queue_is_full() final;
   void reestablish() final;
+  void stop() final;
 
   int  write_sdu(unique_byte_buffer_t sdu);
   void empty_queue() final;
@@ -125,8 +126,10 @@ public:
   // Polling
   uint8_t get_pdu_poll(bool is_retx, uint32_t sdu_bytes);
 
-  void stop() final;
+  // Timers
+  void timer_expired(uint32_t timeout_id);
 
+  // Window helpers
   bool inside_tx_window(uint32_t sn) const;
 
 private:
@@ -166,6 +169,12 @@ private:
    ***************************************************************************/
   inline uint32_t tx_window_size() const;
 
+  /****************************************************************************
+   * TX timers
+   * Ref: 3GPP TS 38.322 version 16.2.0 Section 7.3
+   ***************************************************************************/
+  srsran::timer_handler::unique_timer poll_retransmit_timer;
+
 public:
   // Getters/Setters
   void set_tx_state(const rlc_am_nr_tx_state_t& st_) { st = st_; }   // This should only be used for testing.

lib/src/rlc/rlc_am_nr.cc

@@ -32,7 +32,9 @@ const static uint32_t so_end_of_sdu     = 0xFFFF;
 /***************************************************************************
  *  Tx subclass implementation
  ***************************************************************************/
-rlc_am_nr_tx::rlc_am_nr_tx(rlc_am* parent_) : parent(parent_), rlc_am_base_tx(parent_->logger) {}
+rlc_am_nr_tx::rlc_am_nr_tx(rlc_am* parent_) :
+  parent(parent_), rlc_am_base_tx(parent_->logger), poll_retransmit_timer(parent->timers->get_unique_timer())
+{}
 
 bool rlc_am_nr_tx::configure(const rlc_config_t& cfg_)
 {
@@ -73,6 +75,19 @@ bool rlc_am_nr_tx::configure(const rlc_config_t& cfg_)
   empty_queue_no_lock();
   tx_sdu_queue.resize(cfg_.tx_queue_length);
 
+  // Check timers are valid
+  if (not poll_retransmit_timer.is_valid()) {
+    RlcError("Configuring TX: timers not configured");
+    return false;
+  }
+
+  // Configure t_poll_retransmission timer
+  if (cfg.t_poll_retx > 0) {
+    poll_retransmit_timer.set(static_cast<uint32_t>(cfg.t_poll_retx),
+                              [this](uint32_t timerid) { timer_expired(timerid); });
+    RlcInfo("configured poll retransmission timer. t-pollRetransmission=%d ms", cfg.t_poll_retx);
+  }
+
   tx_enabled = true;
 
   RlcDebug("RLC AM NR configured tx entity.");
@@ -1112,6 +1127,17 @@ void rlc_am_nr_tx::empty_queue_no_lock()
 }
 void rlc_am_nr_tx::stop() {}
 
+void rlc_am_nr_tx::timer_expired(uint32_t timeout_id)
+{
+  std::unique_lock<std::mutex> lock(mutex);
+
+  // Status Prohibit
+  if (poll_retransmit_timer.is_valid() && poll_retransmit_timer.id() == timeout_id) {
+    RlcDebug("Status prohibit timer expired after %dms", poll_retransmit_timer.duration());
+    return;
+  }
+}
+
 /*
  * Window helpers
  */