Fix logic for UL HARQ retx causing Msg3 adaptive retx to be identified as a new transmission

lib/include/srslte/interfaces/ue_interfaces.h

@@ -345,6 +345,7 @@ public:
     uint16_t rnti;
     bool     phich_available;
     bool     hi_value;
+    bool     is_rar;
     uint32_t tti_tx;
   } mac_grant_ul_t;
 

lib/include/srslte/phy/common/phy_common.h

@@ -267,6 +267,7 @@ typedef enum {
   SRSLTE_DCI_FORMATN0,
   SRSLTE_DCI_FORMATN1,
   SRSLTE_DCI_FORMATN2,
+  SRSLTE_DCI_FORMAT_RAR, // Not a real LTE format. Used internally to indicate RAR grant
   SRSLTE_DCI_NOF_FORMATS
 } srslte_dci_format_t;
 

srsue/src/phy/cc_worker.cc

@@ -721,6 +721,7 @@ void cc_worker::ul_phy_to_mac_grant(srslte_pusch_grant_t*
   mac_grant->tb.tbs         = phy_grant->tb.tbs / (uint32_t)8;
   mac_grant->tb.rv          = phy_grant->tb.rv;
   mac_grant->pid            = pid;
+  mac_grant->is_rar         = dci_ul->format == SRSLTE_DCI_FORMAT_RAR;
   mac_grant->tti_tx         = CURRENT_TTI_TX;
 }
 

srsue/src/phy/phy_common.cc

@@ -159,6 +159,8 @@ void phy_common::set_rar_grant(uint8_t             grant_payload[SRSLTE_RAR_GRAN
     Error("Converting RAR message to UL dci\n");
     return;
   }
+
+  dci_ul.format = SRSLTE_DCI_FORMAT_RAR; // Use this format to identify a RAR grant
   dci_ul.rnti   = rnti;
 
   uint32_t msg3_tx_tti;

srsue/src/stack/mac/ul_harq.cc

@@ -187,8 +187,6 @@ void ul_harq_entity::ul_harq_process::reset_ndi()
   cur_grant.tb.ndi = false;
 }
 
-#define grant_is_rar() (grant.rnti == harq_entity->rntis->temp_rnti)
-
 void ul_harq_entity::ul_harq_process::new_grant_ul(mac_interface_phy_lte::mac_grant_ul_t  grant,
                                                    mac_interface_phy_lte::tb_action_ul_t* action)
 {
@@ -201,7 +199,7 @@ void ul_harq_entity::ul_harq_process::new_grant_ul(mac_interface_phy_lte::mac_gr
 
     // Get maximum retransmissions
     uint32_t max_retx;
-    if (grant_is_rar()) {
+    if (grant.rnti == harq_entity->rntis->temp_rnti) {
       max_retx = harq_entity->harq_cfg.max_harq_msg3_tx;
     } else {
       max_retx = harq_entity->harq_cfg.max_harq_tx;
@@ -210,11 +208,11 @@ void ul_harq_entity::ul_harq_process::new_grant_ul(mac_interface_phy_lte::mac_gr
     // Check maximum retransmissions, do not consider last retx ACK
     if (current_tx_nb >= max_retx && !grant.hi_value) {
       Info("UL %d:  Maximum number of ReTX reached (%d). Discarding TB.\n", pid, max_retx);
-      if (grant_is_rar()) {
+      if (grant.rnti == harq_entity->rntis->temp_rnti) {
         harq_entity->ra_procedure->harq_max_retx();
       }
       reset();
-    } else if (grant_is_rar() && current_tx_nb) {
+    } else if (grant.rnti == harq_entity->rntis->temp_rnti && current_tx_nb) {
       harq_entity->ra_procedure->harq_retx();
     }
   }
@@ -233,9 +231,10 @@ void ul_harq_entity::ul_harq_process::new_grant_ul(mac_interface_phy_lte::mac_gr
     if (grant.tb.tbs == 0) {
       action->tb.enabled = true;
 
-    } else if ((grant.rnti == harq_entity->rntis->crnti &&        // If C-RNTI
+      // Decide if adaptive retx or new tx. 3 checks in 5.4.2.1
-                ((grant.tb.ndi != get_ndi()) || !has_grant())) || // if NDI toggled or is first dci is a new tx
+    } else if ((grant.rnti != harq_entity->rntis->temp_rnti && grant.tb.ndi != get_ndi()) || // If not addressed to T-CRNTI and NDI toggled
-               grant_is_rar())                                    // If T-CRNTI received in RAR has no RV information
+               (grant.rnti == harq_entity->rntis->crnti     && !has_grant())              || // If addressed to C-RNTI and buffer is empty
+               (grant.is_rar))                                                               // Grant received in a RAR
     {
       // New transmission
       reset();
@@ -251,7 +250,7 @@ void ul_harq_entity::ul_harq_process::new_grant_ul(mac_interface_phy_lte::mac_gr
       }
 
       // Uplink dci in a RAR and there is a PDU in the Msg3 buffer
-      if (grant_is_rar()) {
+      if (grant.is_rar) {
         if (harq_entity->mux_unit->msg3_is_pending()) {
           Debug("Getting Msg3 buffer payload, dci size=%d bytes\n", grant.tb.tbs);
           pdu_ptr = harq_entity->mux_unit->msg3_get(payload_buffer.get(), grant.tb.tbs);
@@ -281,7 +280,7 @@ void ul_harq_entity::ul_harq_process::new_grant_ul(mac_interface_phy_lte::mac_gr
     }
     if (harq_entity->pcap) {
       uint16_t rnti;
-      if (grant_is_rar() && harq_entity->rntis->temp_rnti) {
+      if (grant.rnti == harq_entity->rntis->temp_rnti && harq_entity->rntis->temp_rnti) {
         rnti = harq_entity->rntis->temp_rnti;
       } else {
         rnti = harq_entity->rntis->crnti;
@@ -377,7 +376,7 @@ void ul_harq_entity::ul_harq_process::generate_new_tx(mac_interface_phy_lte::mac
   current_tx_nb             = 0;
   current_irv               = 0;
 
-  Info("UL %d:  New TX%s, RV=%d, TBS=%d\n", pid, grant_is_rar() ? " for Msg3" : "", get_rv(), cur_grant.tb.tbs);
+  Info("UL %d:  New TX%s, RV=%d, TBS=%d\n", pid, grant.rnti == harq_entity->rntis->temp_rnti ? " for Msg3" : "", get_rv(), cur_grant.tb.tbs);
   generate_tx(action);
 }
 

srsue/test/mac_test.cc

@@ -242,23 +242,32 @@ public:
     return 0;
   }
 
-  int ul_grant_and_check_tv(mac* mac_h, bool ack, uint16_t rnti, uint32_t len, const uint8_t* tv)
+  int ul_grant_and_check_tv(mac* mac_h, bool ack, uint16_t rnti, uint32_t len, const uint8_t* tv, bool is_rar = false, bool adaptive_retx = false)
   {
 
     mac_interface_phy_lte::tb_action_ul_t ul_action    = {};
     mac_interface_phy_lte::mac_grant_ul_t ul_mac_grant = {};
 
+    if (ack) {
+      ul_ndi = !ul_ndi;
+    }
+
     // Generate UL Grant
+    if (!adaptive_retx) {
       ul_mac_grant.phich_available = !ack;
-    ul_mac_grant.rnti            = rnti;
       ul_mac_grant.tb.ndi          = ul_ndi;
       ul_mac_grant.tb.ndi_present  = ack;
-    ul_mac_grant.tb.tbs          = len;
+    } else {
-
+      ul_mac_grant.hi_value        = true;
-    if (ack) {
+      ul_mac_grant.phich_available = true;
-      ul_ndi = !ul_ndi;
+      ul_mac_grant.tb.ndi          = ul_ndi;
+      ul_mac_grant.tb.ndi_present  = true;
     }
 
+    ul_mac_grant.is_rar          = is_rar;
+    ul_mac_grant.rnti            = rnti;
+    ul_mac_grant.tb.tbs          = len;
+
     // Send grant to MAC and get action for this TB, then call tb_decoded to unlock MAC
     mac_h->new_grant_ul(0, ul_mac_grant, &ul_action);
 
@@ -1273,9 +1282,9 @@ int run_mac_ra_test(struct ra_test test, mac* mac, phy_dummy* phy, uint32_t* tti
         }
 
         if (test.crnti) {
-          TESTASSERT(!phy->ul_grant_and_check_tv(mac, i == 0, temp_rnti, 3, tv_msg3_ce));
+          TESTASSERT(!phy->ul_grant_and_check_tv(mac, i == 0, temp_rnti, 3, tv_msg3_ce, i == 0));
         } else {
-          TESTASSERT(!phy->ul_grant_and_check_tv(mac, i == 0, temp_rnti, 9, tv_msg3));
+          TESTASSERT(!phy->ul_grant_and_check_tv(mac, i == 0, temp_rnti, 9, tv_msg3, i == 0, i == 1));
         }
       }
 

srsue/test/ttcn3/hdr/ttcn3_syssim.h

@@ -378,6 +378,7 @@ public:
     ul_grant.tb.ndi         = get_ndi_for_new_ul_tx(tti);
     ul_grant.rnti           = crnti;
     ul_grant.pid            = get_pid(tti);
+    ul_grant.is_rar         = true;
     
     ue->new_grant_ul(ul_grant);
   }