Solved bug: when a retransmission of a succesfully decoded block was received

lib/include/srslte/interfaces/ue_interfaces.h

@@ -303,11 +303,11 @@ public:
   } mac_grant_t; 
   
   typedef struct {
-    bool                    decode_enabled;
+    bool                    decode_enabled[SRSLTE_MAX_TB];
     int                     rv[SRSLTE_MAX_TB];
     uint16_t                rnti; 
     bool                    generate_ack; 
-    bool                    default_ack; 
+    bool                    default_ack[SRSLTE_MAX_TB];
     // If non-null, called after tb_decoded_ok to determine if ack needs to be sent
     bool                  (*generate_ack_callback)(void*); 
     void                   *generate_ack_callback_arg;

lib/src/phy/phch/pdsch.c

@@ -613,7 +613,7 @@ static int srslte_pdsch_codeword_decode(srslte_pdsch_t *q, srslte_pdsch_cfg_t *c
       ret = SRSLTE_SUCCESS;
     }
   } else {
-    ERROR("Detected NULL pointer");
+    ERROR("Detected NULL pointer in TB%d &softbuffer=%p &data=%p &ack=%p", codeword_idx, softbuffer, (void*)data, ack);
   }
 
   return ret;
@@ -689,7 +689,8 @@ int srslte_pdsch_decode(srslte_pdsch_t *q,
 
     // Codeword decoding
     for (uint32_t tb = 0; tb < SRSLTE_MAX_CODEWORDS; tb ++) {
-      if (cfg->grant.tb_en[tb]) {
+      /* Decode only if transport block is enabled and the default ACK is not true */
+      if (cfg->grant.tb_en[tb] && !acks[tb]) {
         int ret = srslte_pdsch_codeword_decode(q, cfg, softbuffers[tb], rnti, data[tb], tb, &acks[tb]);
 
         /* Check if there has been any execution error */

lib/src/phy/phch/test/pdsch_test.c

@@ -460,6 +460,10 @@ int main(int argc, char **argv) {
         srslte_softbuffer_rx_reset_tbs(softbuffers_rx[i], (uint32_t) grant.mcs[i].tbs);
       }
     }
+
+    /* Set ACKs to zero, otherwise will not decode if there are positive ACKs*/
+    bzero(acks, sizeof(acks));
+
     r = srslte_pdsch_decode(&pdsch_rx, &pdsch_cfg, softbuffers_rx, rx_slot_symbols, ce, 0, rnti, data_rx, acks);
   }
   gettimeofday(&t[2], NULL);

srsue/hdr/mac/dl_harq.h

@@ -168,12 +168,14 @@ private:
     void new_grant_dl(Tgrant grant, Taction *action) {
       /* Fill action structure */
       bzero(action, sizeof(Taction));
-      action->default_ack = false;
       action->generate_ack = true;
-      action->decode_enabled = false;
+      action->rnti = grant.rnti;
 
       /* For each subprocess... */
       for (uint32_t tb = 0; tb < SRSLTE_MAX_TB; tb++) {
+        action->default_ack[tb] = false;
+        action->decode_enabled[tb] = false;
+        action->phy_grant.dl.tb_en[tb] = grant.tb_en[tb];
         if (grant.tb_en[tb]) {
           subproc[tb].new_grant_dl(grant, action);
         }
@@ -258,20 +260,19 @@ private:
                                                                        cur_grant.n_bytes[tid]);
           action->payload_ptr[tid] = payload_buffer_ptr;
           if (!action->payload_ptr) {
-            action->decode_enabled = false;
+            action->decode_enabled[tid] = false;
             Error("Can't get a buffer for TBS=%d\n", cur_grant.n_bytes[tid]);
             return;
           }
-          action->decode_enabled = true;
+          action->decode_enabled[tid]= true;
           action->rv[tid] = cur_grant.rv[tid];
-          action->rnti = cur_grant.rnti;
           action->softbuffers[tid] = &softbuffer;
           memcpy(&action->phy_grant, &cur_grant.phy_grant, sizeof(Tphygrant));
           n_retx++;
 
         } else {
+          action->default_ack[tid] = true;
           Warning("DL PID %d: Received duplicate TB. Discarting and retransmitting ACK\n", pid);
-          action->phy_grant.dl.tb_en[tid] = false;
         }
 
         if (pid == HARQ_BCCH_PID || harq_entity->timers_db->get(TIME_ALIGNMENT)->is_expired()) {

srsue/src/mac/mac.cc

@@ -268,7 +268,7 @@ void mac::new_grant_dl(mac_interface_phy::mac_grant_t grant, mac_interface_phy::
 
     memcpy(&action->phy_grant, &grant.phy_grant, sizeof(srslte_phy_grant_t));
     action->generate_ack = false; 
-    action->decode_enabled = true; 
+    action->decode_enabled[0] = true;
     srslte_softbuffer_rx_reset_cb(&pch_softbuffer, 1);
     action->payload_ptr[0] = pch_payload_buffer;
     action->softbuffers[0]  = &pch_softbuffer;
@@ -276,7 +276,7 @@ void mac::new_grant_dl(mac_interface_phy::mac_grant_t grant, mac_interface_phy::
     action->rv[0]   = grant.rv[0];
     if (grant.n_bytes[0] > pch_payload_buffer_sz) {
       Error("Received grant for PCH (%d bytes) exceeds buffer (%d bytes)\n", grant.n_bytes[0], pch_payload_buffer_sz);
-      action->decode_enabled = false; 
+      action->decode_enabled[0] = false;
     }
   } else {
     // If PDCCH for C-RNTI and RA procedure in Contention Resolution, notify it

srsue/src/mac/proc_ra.cc

@@ -275,8 +275,9 @@ void ra_proc::new_grant_dl(mac_interface_phy::mac_grant_t grant, mac_interface_p
 {
   if (grant.n_bytes[0] < MAX_RAR_PDU_LEN) {
     rDebug("DL grant found RA-RNTI=%d\n", ra_rnti);        
-    action->decode_enabled = true; 
-    action->default_ack = false; 
+    action->decode_enabled[0] = true;
+    action->decode_enabled[1] = false;
+    action->default_ack[0] = false;
     action->generate_ack = false; 
     action->payload_ptr[0] = rar_pdu_buffer;
     action->rnti = grant.rnti; 
@@ -290,7 +291,8 @@ void ra_proc::new_grant_dl(mac_interface_phy::mac_grant_t grant, mac_interface_p
     }
   } else {
     rError("Received RAR grant exceeds buffer length (%d>%d)\n", grant.n_bytes[0], MAX_RAR_PDU_LEN);
-    action->decode_enabled = false; 
+    action->decode_enabled[0] = false;
+    action->decode_enabled[1] = false;
     state = RESPONSE_ERROR;
   }
 }

srsue/src/phy/phch_worker.cc

@@ -230,18 +230,18 @@ void phch_worker::work_imp()
 
       /* Set DL ACKs to default */
       for (uint32_t tb = 0; tb < SRSLTE_MAX_CODEWORDS; tb++) {
-        dl_ack[tb] = dl_action.default_ack;
+        dl_ack[tb] = dl_action.default_ack[tb];
       }
 
       /* Decode PDSCH if instructed to do so */
-      if (dl_action.decode_enabled) {
+      if (dl_action.decode_enabled[0] || dl_action.decode_enabled[1]) {
         decode_pdsch(&dl_action.phy_grant.dl, dl_action.payload_ptr,
                       dl_action.softbuffers, dl_action.rv, dl_action.rnti,
                       dl_mac_grant.pid, dl_ack);
       }
-      if (dl_action.generate_ack_callback && dl_action.decode_enabled) {
+      if (dl_action.generate_ack_callback) {
         for (uint32_t tb = 0; tb < SRSLTE_MAX_TB; tb++) {
-          if (dl_mac_grant.tb_en[tb]) {
+          if (dl_action.decode_enabled[tb]) {
             phy->mac->tb_decoded(dl_ack[tb], tb, dl_mac_grant.rnti_type, dl_mac_grant.pid);
             dl_ack[tb] = dl_action.generate_ack_callback(dl_action.generate_ack_callback_arg);
             Debug("Calling generate ACK callback for TB %d returned=%d\n", tb, dl_ack[tb]);
@@ -332,12 +332,12 @@ void phch_worker::work_imp()
   
   phy->worker_end(tx_tti, signal_ready, signal_buffer[0], SRSLTE_SF_LEN_PRB(cell.nof_prb), tx_time);
   
-  if (dl_action.decode_enabled && !dl_action.generate_ack_callback) {
-    if (dl_mac_grant.rnti_type == SRSLTE_RNTI_PCH) {
+  if (!dl_action.generate_ack_callback) {
+    if (dl_mac_grant.rnti_type == SRSLTE_RNTI_PCH && dl_action.decode_enabled[0]) {
       phy->mac->pch_decoded_ok(dl_mac_grant.n_bytes[0]);
     } else {
       for (uint32_t tb = 0; tb < SRSLTE_MAX_TB; tb++) {
-        if (dl_mac_grant.tb_en[tb]) {
+        if (dl_action.decode_enabled[tb]) {
           phy->mac->tb_decoded(dl_ack[tb], tb, dl_mac_grant.rnti_type, dl_mac_grant.pid);
         }
       }

srsue/test/phy/ue_itf_test_prach.cc

@@ -277,8 +277,8 @@ public:
   }
 
   void new_grant_dl(mac_grant_t grant, tb_action_dl_t *action) {
-    action->decode_enabled = true; 
-    action->default_ack = false; 
+    action->decode_enabled[0] = true;
+    action->default_ack[0] = false;
     if (grant.rnti == 2) {
       action->generate_ack = false; 
     } else {

srsue/test/phy/ue_itf_test_sib1.cc

@@ -116,8 +116,8 @@ public:
     total_dci++; 
     
 
-    action->decode_enabled = true; 
-    action->default_ack = false; 
+    action->decode_enabled[0] = true;
+    action->default_ack[0] = false;
     action->generate_ack = false;
     for (uint32_t tb = 0; tb < SRSLTE_MAX_TB; tb++) {
       action->payload_ptr[tb] = payload[tb];