allowing TA CE commands in Msg4

srsenb/src/stack/mac/scheduler_ue.cc

@@ -444,16 +444,13 @@ int sched_ue::generate_format1(dl_harq_proc*                     h,
       data->nof_pdu_elems[0]++;
       conres_ce_pending = false;
       Info("SCHED: Added MAC Contention Resolution CE for rnti=0x%x\n", rnti);
-    } else {
-      // Add TA CE
-      // TODO: Can't put it in Msg4 because current srsUE doesn't read it
-      while (nof_ta_cmd > 0 && rem_tbs > 2) {
-        data->pdu[0][data->nof_pdu_elems[0]].lcid = srslte::sch_subh::TA_CMD;
-        data->nof_pdu_elems[0]++;
-        Info("SCHED: Added MAC TA CMD CE for rnti=0x%x\n", rnti);
-        nof_ta_cmd--;
-        rem_tbs -= 2;
-      }
+    }
+    while (nof_ta_cmd > 0 && rem_tbs > 2) {
+      data->pdu[0][data->nof_pdu_elems[0]].lcid = srslte::sch_subh::TA_CMD;
+      data->nof_pdu_elems[0]++;
+      Info("SCHED: Added MAC TA CMD CE for rnti=0x%x\n", rnti);
+      nof_ta_cmd--;
+      rem_tbs -= 2;
     }
 
     do {
@@ -805,7 +802,7 @@ uint32_t sched_ue::get_pending_dl_new_data_unlocked()
       pending_data += lch[i].buf_retx + lch[i].buf_tx;
     }
   }
-  if (not is_first_dl_tx() and nof_ta_cmd > 0) {
+  if (nof_ta_cmd > 0) {
     pending_data += nof_ta_cmd * 2;
   }
   return pending_data;

srsue/src/stack/mac/demux.cc

@@ -97,12 +97,20 @@ void demux::push_pdu_temp_crnti(uint8_t* buff, uint32_t nof_bytes)
     pending_mac_msg.init_rx(nof_bytes);
     pending_mac_msg.parse_packet(buff);
 
-    // Look for Contention Resolution UE ID
+    // Look for Contention Resolution UE ID and TA commands
     is_uecrid_successful = false;
-    while (pending_mac_msg.next() && !is_uecrid_successful) {
+    while (pending_mac_msg.next()) {
       if (pending_mac_msg.get()->ce_type() == srslte::sch_subh::CON_RES_ID) {
         Debug("Found Contention Resolution ID CE\n");
         is_uecrid_successful = mac->contention_resolution_id_rcv(pending_mac_msg.get()->get_con_res_id());
+      } else if (pending_mac_msg.get()->ce_type() == srslte::sch_subh::TA_CMD) {
+        phy_h->set_timeadv(pending_mac_msg.get()->get_ta_cmd());
+        Info("Received TA=%d (%d/%d) \n", pending_mac_msg.get()->get_ta_cmd(),
+             time_alignment_timer->value(), time_alignment_timer->duration());
+        // Start or restart timeAlignmentTimer only if set
+        if (time_alignment_timer->is_set()) {
+          time_alignment_timer->run();
+        }
       }
     }
     pending_mac_msg.reset();