Fixed bug in dl_harq incorrectly identifying duplicate packets

srsapps/ue/mac/src/dl_harq.cc

@@ -174,7 +174,7 @@ void dl_harq_entity::dl_harq_process::receive_data(uint32_t tti, srslte::ue::dl_
           }
         }
       } else {
-        Warning("DL PID %d: Received duplicate TB. Discarting and retransmitting ACK\n");
+        Warning("DL PID %d: Received duplicate TB. Discarting and retransmitting ACK\n", pid);
       }
       if (pid == HARQ_BCCH_PID || harq_entity->timers_db->get(mac::TIME_ALIGNMENT)->is_expired()) {
         // Do not generate ACK
@@ -203,13 +203,24 @@ void dl_harq_entity::dl_harq_process::receive_data(uint32_t tti, srslte::ue::dl_
 void dl_harq_entity::dl_harq_process::set_harq_info(srslte::ue::dl_sched_grant* new_grant)    {
   bool is_new_transmission = false; 
 
-  if ((new_grant->get_ndi() != cur_grant.get_ndi() && new_grant->get_tbs() == cur_grant.get_tbs()) || // NDI toggled for same TB (assume TB is identified by TBS)
-      (pid == HARQ_BCCH_PID && new_grant->get_rv() == 0)                                           || // Broadcast PID and 1st TX (RV=0)
-      (new_grant->get_tbs() != cur_grant.get_tbs()))                                                  // First transmission for this TB
+  bool is_new_tb = true; 
+  if (srslte_tti_interval(new_grant->get_tti(), cur_grant.get_tti()) <= 8 && 
+      new_grant->get_tbs() == cur_grant.get_tbs())
+  {
+    is_new_tb = false; 
+  }
+  
+  if ((new_grant->get_ndi() != cur_grant.get_ndi() && !is_new_tb) || // NDI toggled for same TB
+      is_new_tb                                                   || // is new TB
+      (pid == HARQ_BCCH_PID && new_grant->get_rv() == 0))            // Broadcast PID and 1st TX (RV=0)
   {
     is_new_transmission = true; 
     Debug("Set HARQ Info for new transmission\n");
   } else {
+    if (!is_new_tb) {
+      Info("old_tbs=%d, new_tbs=%d, old_tti=%d new_tti=%d\n", cur_grant.get_tbs(), new_grant->get_tbs(), 
+           cur_grant.get_tti(), new_grant->get_tti());
+    }
     is_new_transmission = false; 
     Debug("Set HARQ Info for retransmission\n");
   }

srsapps/ue/mac/src/proc_ra.cc

@@ -152,14 +152,6 @@ bool ra_proc::is_error() {
   return state == RA_PROBLEM;
 }
 
-uint32_t interval(uint32_t x1, uint32_t x2) {
-  if (x1 > x2) {
-    return x1-x2; 
-  } else {
-    return 10240-x2+x1;
-  }
-}
-
 const char* state_str[11] = {"Idle",
                             "RA Initializat.: ",
                             "RA Initial.Wait: ",
@@ -277,7 +269,7 @@ void ra_proc::step_response_reception() {
     
     ra_rnti = 1+ra_tti%10; // f_id=0 for FDD 
     dl_sched_grant rar_grant(ra_rnti); 
-    uint32_t interval_ra = interval(tti, ra_tti);
+    uint32_t interval_ra = srslte_tti_interval(tti, ra_tti);
     
     // Try to decode RAR only within the RA response window
     if (interval_ra >= 3 && interval_ra <= 3+responseWindowSize) {        
@@ -402,7 +394,7 @@ void ra_proc::step_response_error() {
 }
 
 void ra_proc::step_backoff_wait() {
-  if (interval(tti, backoff_interval_start) >= backoff_inteval) {
+  if (srslte_tti_interval(tti, backoff_interval_start) >= backoff_inteval) {
     state = RESOURCE_SELECTION; 
   }
 }

srsapps/ue/phy/include/srsapps/ue/phy/sched_grant.h

@@ -80,6 +80,12 @@ namespace ue {
     bool is_tpc_rnti() {
       return (rnti_type == RNTI_TYPE_TPC_PUSCH || rnti_type == RNTI_TYPE_TPC_PUCCH);
     }
+    uint32_t get_tti() {
+      return tti; 
+    }
+    void set_tti(uint32_t tti_) {
+      tti = tti_; 
+    }
     virtual uint32_t get_rv()            = 0; 
     virtual void     set_rv(uint32_t rv) = 0; 
     virtual bool     get_ndi()           = 0; 
@@ -89,6 +95,7 @@ namespace ue {
   protected: 
     uint16_t            rnti; 
     rnti_type_t         rnti_type; 
+    uint32_t            tti; 
   };
  
 }

srsapps/ue/phy/src/dl_buffer.cc

@@ -117,6 +117,8 @@ bool dl_buffer::get_ul_grant(ul_sched_grant *grant)
         return false; 
       }
       
+      grant->set_tti(tti);
+    
       Info("PDCCH: UL DCI Format0 cce_index=%d, n_data_bits=%d\n", ue_dl.last_n_cce, dci_msg.nof_bits);
 
       return grant->create_from_dci(&dci_msg, cell, params_db->get_param(phy_params::PUSCH_HOPPING_OFFSET));     
@@ -167,7 +169,9 @@ bool dl_buffer::get_dl_grant(dl_sched_grant *grant)
     if (srslte_ue_dl_find_dl_dci(&ue_dl, &dci_msg, cfi, tti%10, grant->get_rnti()) != 1) {
       return false; 
     }
-
+    
+    grant->set_tti(tti);
+    
     Info("PDCCH: DL DCI %s cce_index=%d, n_data_bits=%d\n", grant->get_dciformat_string(), ue_dl.last_n_cce, dci_msg.nof_bits);
     
     return grant->create_from_dci(&dci_msg, cell.nof_prb, srslte_ue_dl_get_ncce(&ue_dl));     

srsapps/ue/phy/src/ul_buffer.cc

@@ -299,7 +299,7 @@ void ul_buffer::set_tx_params(float cfo_, float time_adv_sec, srslte_timestamp_t
 
 void ul_buffer::set_end_of_burst()
 {
-  Info("Is end of burst\n");
+  Info("TTI %d Is end of burst\n", tti);
   tti_is_end_of_burst = true; 
 }
 

srslte/include/srslte/common/phy_common.h

@@ -244,6 +244,7 @@ SRSLTE_API int srslte_band_get_fd_region(enum band_geographical_area region,
 SRSLTE_API int srslte_str2mimotype(char *mimo_type_str, 
                                    srslte_mimo_type_t *type);
 
-
+SRSLTE_API uint32_t srslte_tti_interval(uint32_t tti1, 
+                                        uint32_t tti2); 
 
 #endif

srslte/lib/common/src/phy_common.c

@@ -422,3 +422,14 @@ int srslte_band_get_fd_region(enum band_geographical_area region, srslte_earfcn_
   return nof_fd;
 }
 
+
+/* Returns the interval tti1-tti2 mod 10240 */
+uint32_t srslte_tti_interval(uint32_t tti1, uint32_t tti2) {
+  if (tti1 > tti2) {
+    return tti1-tti2; 
+  } else {
+    return 10240-tti2+tti1;
+  }
+}
+
+