mac,nr: avoid repacking NR DL retxs

srsenb/hdr/stack/mac/mac.h

@@ -139,7 +139,7 @@ private:
   /* Map of active UEs */
   static const uint16_t            FIRST_RNTI = 0x46;
   rnti_map_t<unique_rnti_ptr<ue> > ue_db;
-  std::atomic<uint16_t>            ue_counter;
+  std::atomic<uint16_t>            ue_counter{0};
 
   uint8_t* assemble_rar(sched_interface::dl_sched_rar_grant_t* grants,
                         uint32_t                               enb_cc_idx,

srsenb/hdr/stack/mac/nr/sched_nr_harq.h

@@ -56,12 +56,11 @@ public:
   bool new_retx(slot_point slot_tx, slot_point slot_ack, const prb_grant& grant);
   bool new_retx(slot_point slot_tx, slot_point slot_ack);
 
-  const uint32_t pid;
-
-protected:
   // NOTE: Has to be used before first tx is dispatched
   bool set_tbs(uint32_t tbs);
 
+  const uint32_t pid;
+
 private:
   struct tb_t {
     bool     active    = false;
@@ -84,16 +83,15 @@ class dl_harq_proc : public harq_proc
 public:
   dl_harq_proc(uint32_t id_, uint32_t nprb);
 
-  tx_harq_softbuffer& get_softbuffer() { return *softbuffer; }
+  tx_harq_softbuffer&           get_softbuffer() { return *softbuffer; }
   srsran::unique_byte_buffer_t* get_tx_pdu() { return &pdu; }
 
-  // clear and reset softbuffer and PDU for new tx
-  bool set_tbs(uint32_t tbs)
-  {
-    softbuffer->reset();
-    pdu->clear();
-    return harq_proc::set_tbs(tbs);
-  }
+  bool new_tx(slot_point       slot_tx,
+              slot_point       slot_ack,
+              const prb_grant& grant,
+              uint32_t         mcs,
+              uint32_t         tbs,
+              uint32_t         max_retx);
 
 private:
   srsran::unique_pool_ptr<tx_harq_softbuffer> softbuffer;

srsenb/src/stack/mac/nr/mac_nr.cc

@@ -281,7 +281,7 @@ int mac_nr::get_dl_sched(const srsran_slot_cfg_t& slot_cfg, dl_sched_t& dl_sched
         continue;
       }
       for (auto& tb_data : pdsch.data) {
-        if (tb_data != nullptr) {
+        if (tb_data != nullptr and tb_data->N_bytes == 0) {
           // TODO: exclude retx from packing
           ue_db[rnti]->generate_pdu(tb_data, pdsch.sch.grant.tb->tbs / 8);
 

srsenb/src/stack/mac/nr/sched_nr_harq.cc

@@ -105,6 +105,21 @@ dl_harq_proc::dl_harq_proc(uint32_t id_, uint32_t nprb) :
   harq_proc(id_), softbuffer(harq_softbuffer_pool::get_instance().get_tx(nprb)), pdu(srsran::make_byte_buffer())
 {}
 
+bool dl_harq_proc::new_tx(slot_point       slot_tx,
+                          slot_point       slot_ack,
+                          const prb_grant& grant,
+                          uint32_t         mcs,
+                          uint32_t         tbs,
+                          uint32_t         max_retx)
+{
+  if (harq_proc::new_tx(slot_tx, slot_ack, grant, mcs, tbs, max_retx)) {
+    softbuffer->reset();
+    pdu->clear();
+    return true;
+  }
+  return false;
+}
+
 harq_entity::harq_entity(uint32_t nprb, uint32_t nof_harq_procs)
 {
   // Create HARQs