diff --git a/lib/include/srslte/common/common.h b/lib/include/srslte/common/common.h
index c6ad06402..9d3d56569 100644
--- a/lib/include/srslte/common/common.h
+++ b/lib/include/srslte/common/common.h
@@ -44,13 +44,15 @@
 #define SRSLTE_N_DRB           8
 #define SRSLTE_N_RADIO_BEARERS 11
 
-#define HARQ_DELAY_MS 4
-#define MSG3_DELAY_MS 6
-#define HARQ_TX(tti) ((tti+HARQ_DELAY_MS)%10240)
-#define HARQ_RX(tti) ((tti+(2*HARQ_DELAY_MS))%10240)
+#define HARQ_DELAY_MS   6
+#define MSG3_DELAY_MS   6
+#define TTI_TX(tti)     ((tti+HARQ_DELAY_MS)%10240)
+#define TTI_RX_ACK(tti) ((tti+(2*HARQ_DELAY_MS))%10240)
 
-#define TTIMOD_SZ   10
-#define TTIMOD(tti)  (tti%TTIMOD_SZ)
+#define TTIMOD_SZ       20
+#define TTIMOD(tti)     (tti%TTIMOD_SZ)
+
+#define ASYNC_DL_SCHED  (HARQ_DELAY_MS <= 4)
 
 // Cat 3 UE - Max number of DL-SCH transport block bits received within a TTI
 // 3GPP 36.306 Table 4.1.1
diff --git a/srsenb/hdr/phy/phch_worker.h b/srsenb/hdr/phy/phch_worker.h
index a84045920..3194751e8 100644
--- a/srsenb/hdr/phy/phch_worker.h
+++ b/srsenb/hdr/phy/phch_worker.h
@@ -89,9 +89,9 @@ private:
 
   cf_t          *signal_buffer_rx; 
   cf_t          *signal_buffer_tx; 
-  uint32_t       tti_rx, tti_tx, tti_sched_ul;
+  uint32_t       tti_rx, tti_tx_dl, tti_tx_ul;
   uint32_t       sf_rx, sf_tx, tx_mutex_cnt;
-  uint32_t       t_rx, t_tx, t_sched_ul;
+  uint32_t       t_rx, t_tx_dl, t_tx_ul;
   srslte_enb_dl_t enb_dl;
   srslte_enb_ul_t enb_ul;
   
diff --git a/srsenb/src/mac/scheduler.cc b/srsenb/src/mac/scheduler.cc
index 73f121424..ab499efb0 100644
--- a/srsenb/src/mac/scheduler.cc
+++ b/srsenb/src/mac/scheduler.cc
@@ -677,14 +677,14 @@ int sched::ul_sched(uint32_t tti, srsenb::sched_interface::ul_sched_res_t* sched
   pthread_mutex_lock(&mutex);
 
   /* If dl_sched() not yet called this tti (this tti is +4ms advanced), reset CCE state */
-  if (HARQ_TX(current_tti) != tti) {
+  if (TTI_TX(current_tti) != tti) {
     bzero(used_cce, MAX_CCE*sizeof(bool));    
   }
   
   /* Initialize variables */
   current_tti = tti; 
   sfn = tti/10;
-  if (tti > 4) {
+  if (tti > HARQ_DELAY_MS) {
     sf_idx = (tti-HARQ_DELAY_MS)%10;
   } else {
     sf_idx = (tti+10240-HARQ_DELAY_MS)%10;
diff --git a/srsenb/src/mac/scheduler_metric.cc b/srsenb/src/mac/scheduler_metric.cc
index 708ab2dd8..6c50009f7 100644
--- a/srsenb/src/mac/scheduler_metric.cc
+++ b/srsenb/src/mac/scheduler_metric.cc
@@ -142,8 +142,12 @@ dl_harq_proc* dl_metric_rr::get_user_allocation(sched_ue *user)
   dl_harq_proc *h = user->get_pending_dl_harq(current_tti);
 
   // Time-domain RR scheduling
+#if ASYNC_DL_SCHED
   if (pending_data || h) {
-    if (nof_users_with_data) {    
+#else
+  if (pending_data || (h && !h->is_empty())) {
+#endif
+    if (nof_users_with_data) {
       if (nof_users_with_data == 2) {
       }
       if ((current_tti%nof_users_with_data) != user->ue_idx) {      
@@ -153,7 +157,11 @@ dl_harq_proc* dl_metric_rr::get_user_allocation(sched_ue *user)
   }
   
   // Schedule retx if we have space 
+#if ASYNC_DL_SCHED
   if (h) {
+#else
+  if (h && !h->is_empty()) {
+#endif
     uint32_t retx_mask = h->get_rbgmask();
     // If can schedule the same mask, do it
     if (!allocation_is_valid(retx_mask)) {
@@ -170,10 +178,14 @@ dl_harq_proc* dl_metric_rr::get_user_allocation(sched_ue *user)
       }
     }
   } 
-  // If could not schedule the reTx, or there wasn't any pending retx, find an empty PID 
+  // If could not schedule the reTx, or there wasn't any pending retx, find an empty PID
+#if ASYNC_DL_SCHED
   h = user->get_empty_dl_harq(); 
   if (h) {
-    // Allocate resources based on pending data 
+#else
+  if (h && h->is_empty()) {
+#endif
+    // Allocate resources based on pending data
     if (pending_data) {
       uint32_t pending_rb = user->get_required_prb_dl(pending_data, nof_ctrl_symbols);
       uint32_t newtx_mask = 0; 
diff --git a/srsenb/src/mac/scheduler_ue.cc b/srsenb/src/mac/scheduler_ue.cc
index 525494ad2..7f4042849 100644
--- a/srsenb/src/mac/scheduler_ue.cc
+++ b/srsenb/src/mac/scheduler_ue.cc
@@ -248,7 +248,7 @@ bool sched_ue::get_pucch_sched(uint32_t current_tti, uint32_t prb_idx[2])
   
   // First check if it has pending ACKs 
   for (int i=0;i<SCHED_MAX_HARQ_PROC;i++) {
-    if (HARQ_TX(dl_harq[i].get_tti()) == current_tti) {
+    if (TTI_TX(dl_harq[i].get_tti()) == current_tti) {
       uint32_t n_pucch = srslte_pucch_get_npucch(dl_harq[i].get_n_cce(), SRSLTE_PUCCH_FORMAT_1A, has_sr, &pucch_sched);
       if (prb_idx) {
         for (int i=0;i<2;i++) {
@@ -288,7 +288,7 @@ bool sched_ue::get_pucch_sched(uint32_t current_tti, uint32_t prb_idx[2])
 int sched_ue::set_ack_info(uint32_t tti, bool ack)
 {
   for (int i=0;i<SCHED_MAX_HARQ_PROC;i++) {
-    if (HARQ_TX(dl_harq[i].get_tti()) == tti) {
+    if (TTI_TX(dl_harq[i].get_tti()) == tti) {
       Debug("SCHED: Set ACK=%d for rnti=0x%x, pid=%d, tti=%d\n", ack, rnti, i, tti);
       dl_harq[i].set_ack(ack); 
       return dl_harq[i].get_tbs();
@@ -656,6 +656,7 @@ bool sched_ue::is_sr_triggered()
 /* Gets HARQ process with oldest pending retx */
 dl_harq_proc* sched_ue::get_pending_dl_harq(uint32_t tti)
 {
+#if ASYNC_DL_SCHED
   int oldest_idx=-1; 
   uint32_t oldest_tti = 0; 
   for (int i=0;i<SCHED_MAX_HARQ_PROC;i++) {
@@ -671,7 +672,10 @@ dl_harq_proc* sched_ue::get_pending_dl_harq(uint32_t tti)
     return &dl_harq[oldest_idx]; 
   } else {
     return NULL; 
-  }  
+  }
+#else
+  return &dl_harq[tti%SCHED_MAX_HARQ_PROC];
+#endif
 }
 
 dl_harq_proc* sched_ue::get_empty_dl_harq()
@@ -681,7 +685,7 @@ dl_harq_proc* sched_ue::get_empty_dl_harq()
       return &dl_harq[i]; 
     }
   }
-  return NULL; 
+  return NULL;
 }
 
 ul_harq_proc* sched_ue::get_ul_harq(uint32_t tti)
diff --git a/srsenb/src/phy/phch_common.cc b/srsenb/src/phy/phch_common.cc
index 719064324..c4b94153c 100644
--- a/srsenb/src/phy/phch_common.cc
+++ b/srsenb/src/phy/phch_common.cc
@@ -104,7 +104,7 @@ void phch_common::ack_clear(uint32_t sf_idx)
 
 void phch_common::ack_add_rnti(uint16_t rnti)
 {
-  for (int sf_idx=0;sf_idx<10;sf_idx++) {
+  for (int sf_idx=0;sf_idx<TTIMOD_SZ;sf_idx++) {
     pending_ack[rnti].is_pending[sf_idx] = false; 
   }
 }
@@ -126,14 +126,18 @@ bool phch_common::ack_is_pending(uint32_t sf_idx, uint16_t rnti, uint32_t *last_
 {
   if (pending_ack.count(rnti)) {
     bool ret = pending_ack[rnti].is_pending[sf_idx];  
-    pending_ack[rnti].is_pending[sf_idx] = false; 
+    pending_ack[rnti].is_pending[sf_idx] = false;
+
+    if (ret) {
+
+    }
     
     if (ret && last_n_pdcch) {
       *last_n_pdcch = pending_ack[rnti].n_pdcch[sf_idx];
     }
     return ret; 
   } else {
-    return false; 
+    return false;
   }
 }
 
diff --git a/srsenb/src/phy/phch_worker.cc b/srsenb/src/phy/phch_worker.cc
index 9cc87ddd9..52b617fd5 100644
--- a/srsenb/src/phy/phch_worker.cc
+++ b/srsenb/src/phy/phch_worker.cc
@@ -176,16 +176,16 @@ cf_t* phch_worker::get_buffer_rx()
 void phch_worker::set_time(uint32_t tti_, uint32_t tx_mutex_cnt_, srslte_timestamp_t tx_time_)
 {
   tti_rx       = tti_; 
-  tti_tx       = HARQ_TX(tti_rx);
-  tti_sched_ul = HARQ_RX(tti_rx);
-  
+  tti_tx_dl    = TTI_TX(tti_rx);
+  tti_tx_ul    = TTI_RX_ACK(tti_rx);
+
   sf_rx        = tti_rx%10;
-  sf_tx        = tti_tx%10;
-  
-  t_tx         = TTIMOD(tti_tx);
+  sf_tx        = tti_tx_dl%10;
+
+  t_tx_dl      = TTIMOD(tti_tx_dl);
   t_rx         = TTIMOD(tti_rx);
-  t_sched_ul   = TTIMOD(tti_sched_ul);
-  
+  t_tx_ul      = TTIMOD(tti_tx_ul);
+
   tx_mutex_cnt = tx_mutex_cnt_;
   memcpy(&tx_time, &tx_time_, sizeof(srslte_timestamp_t));
 }
@@ -194,16 +194,16 @@ int phch_worker::add_rnti(uint16_t rnti)
 {
 
   if (srslte_enb_dl_add_rnti(&enb_dl, rnti)) {
-    return -1; 
+    return -1;
   }
   if (srslte_enb_ul_add_rnti(&enb_ul, rnti)) {
-    return -1; 
+    return -1;
   }
 
-  // Create user 
-  ue_db[rnti].rnti = rnti; 
-    
-  return SRSLTE_SUCCESS; 
+  // Create user
+  ue_db[rnti].rnti = rnti;
+
+  return SRSLTE_SUCCESS;
 
 }
 
@@ -211,61 +211,61 @@ uint32_t phch_worker::get_nof_rnti() {
   return ue_db.size();
 }
 
-void phch_worker::set_config_dedicated(uint16_t rnti, 
-                                       srslte_uci_cfg_t *uci_cfg, 
+void phch_worker::set_config_dedicated(uint16_t rnti,
+                                       srslte_uci_cfg_t *uci_cfg,
                                        srslte_pucch_sched_t *pucch_sched,
-                                       srslte_refsignal_srs_cfg_t *srs_cfg, 
+                                       srslte_refsignal_srs_cfg_t *srs_cfg,
                                        uint32_t I_sr, bool pucch_cqi, uint32_t pmi_idx, bool pucch_cqi_ack)
 {
-  pthread_mutex_lock(&mutex); 
+  pthread_mutex_lock(&mutex);
   if (ue_db.count(rnti)) {
     pucch_sched->N_pucch_1 = phy->pucch_cfg.n1_pucch_an;
     srslte_enb_ul_cfg_ue(&enb_ul, rnti, uci_cfg, pucch_sched, srs_cfg);
-        
-    ue_db[rnti].I_sr    = I_sr; 
+
+    ue_db[rnti].I_sr    = I_sr;
     ue_db[rnti].I_sr_en = true;
 
     if (pucch_cqi) {
-      ue_db[rnti].pmi_idx = pmi_idx; 
-      ue_db[rnti].cqi_en  = true;       
-      ue_db[rnti].pucch_cqi_ack = pucch_cqi_ack; 
+      ue_db[rnti].pmi_idx = pmi_idx;
+      ue_db[rnti].cqi_en  = true;
+      ue_db[rnti].pucch_cqi_ack = pucch_cqi_ack;
     } else {
-      ue_db[rnti].pmi_idx = 0; 
-      ue_db[rnti].cqi_en  = false;             
+      ue_db[rnti].pmi_idx = 0;
+      ue_db[rnti].cqi_en  = false;
     }
-    
+
   } else {
     Error("Setting config dedicated: rnti=0x%x does not exist\n");
   }
-  pthread_mutex_unlock(&mutex); 
+  pthread_mutex_unlock(&mutex);
 }
 
 void phch_worker::rem_rnti(uint16_t rnti)
 {
-  pthread_mutex_lock(&mutex); 
+  pthread_mutex_lock(&mutex);
   if (ue_db.count(rnti)) {
     ue_db.erase(rnti);
-    
-    srslte_enb_dl_rem_rnti(&enb_dl, rnti); 
+
+    srslte_enb_dl_rem_rnti(&enb_dl, rnti);
     srslte_enb_ul_rem_rnti(&enb_ul, rnti);
-    
-    // remove any pending grant for each subframe 
+
+    // remove any pending grant for each subframe
     for (uint32_t i=0;i<TTIMOD_SZ;i++) {
       for (uint32_t j=0;j<phy->ul_grants[i].nof_grants;j++) {
         if (phy->ul_grants[i].sched_grants[j].rnti == rnti) {
-          phy->ul_grants[i].sched_grants[j].rnti = 0; 
+          phy->ul_grants[i].sched_grants[j].rnti = 0;
         }
       }
       for (uint32_t j=0;j<phy->dl_grants[i].nof_grants;j++) {
         if (phy->dl_grants[i].sched_grants[j].rnti == rnti) {
-          phy->dl_grants[i].sched_grants[j].rnti = 0; 
+          phy->dl_grants[i].sched_grants[j].rnti = 0;
         }
       }
     }
   } else {
     Error("Removing user: rnti=0x%x does not exist\n", rnti);
   }
-  pthread_mutex_unlock(&mutex); 
+  pthread_mutex_unlock(&mutex);
 }
 
 void phch_worker::work_imp()
@@ -275,18 +275,18 @@ void phch_worker::work_imp()
   }
 
   pthread_mutex_lock(&mutex);
-  
+
   mac_interface_phy::ul_sched_t *ul_grants = phy->ul_grants;
-  mac_interface_phy::dl_sched_t *dl_grants = phy->dl_grants; 
-  mac_interface_phy *mac = phy->mac; 
-  
+  mac_interface_phy::dl_sched_t *dl_grants = phy->dl_grants;
+  mac_interface_phy *mac = phy->mac;
+
   log_h->step(tti_rx);
-  
+
   Debug("Worker %d running\n", get_id());
-  
+
   for(std::map<uint16_t, ue>::iterator iter=ue_db.begin(); iter!=ue_db.end(); ++iter) {
     uint16_t rnti = (uint16_t) iter->first;
-    ue_db[rnti].has_grant_tti = -1; 
+    ue_db[rnti].has_grant_tti = -1;
   }
 
   // Process UL signal
@@ -294,51 +294,51 @@ void phch_worker::work_imp()
 
   // Decode pending UL grants for the tti they were scheduled
   decode_pusch(ul_grants[t_rx].sched_grants, ul_grants[t_rx].nof_grants);
-  
+
   // Decode remaining PUCCH ACKs not associated with PUSCH transmission and SR signals
   decode_pucch();
-      
+
   // Get DL scheduling for the TX TTI from MAC
-  if (mac->get_dl_sched(tti_tx, &dl_grants[t_tx]) < 0) {
+  if (mac->get_dl_sched(tti_tx_dl, &dl_grants[t_tx_dl]) < 0) {
     Error("Getting DL scheduling from MAC\n");
     goto unlock;
-  } 
-  
-  if (dl_grants[t_tx].cfi < 1 || dl_grants[t_tx].cfi > 3) {
-    Error("Invalid CFI=%d\n", dl_grants[t_tx].cfi);
+  }
+
+  if (dl_grants[t_tx_dl].cfi < 1 || dl_grants[t_tx_dl].cfi > 3) {
+    Error("Invalid CFI=%d\n", dl_grants[t_tx_dl].cfi);
     goto unlock;
   }
-  
+
   // Get UL scheduling for the TX TTI from MAC
-  if (mac->get_ul_sched(tti_sched_ul, &ul_grants[t_sched_ul]) < 0) {
+  if (mac->get_ul_sched(tti_tx_ul, &ul_grants[t_tx_ul]) < 0) {
     Error("Getting UL scheduling from MAC\n");
     goto unlock;
-  } 
-  
+  }
+
   // Put base signals (references, PBCH, PCFICH and PSS/SSS) into the resource grid
   srslte_enb_dl_clear_sf(&enb_dl);
-  srslte_enb_dl_set_cfi(&enb_dl, dl_grants[t_tx].cfi);
-  srslte_enb_dl_put_base(&enb_dl, tti_tx);
+  srslte_enb_dl_set_cfi(&enb_dl, dl_grants[t_tx_dl].cfi);
+  srslte_enb_dl_put_base(&enb_dl, tti_tx_dl);
+
+  // Put UL/DL grants to resource grid. PDSCH data will be encoded as well.
+  encode_pdcch_dl(dl_grants[t_tx_dl].sched_grants, dl_grants[t_tx_dl].nof_grants);
+  encode_pdcch_ul(ul_grants[t_tx_ul].sched_grants, ul_grants[t_tx_ul].nof_grants);
+  encode_pdsch(dl_grants[t_tx_dl].sched_grants, dl_grants[t_tx_dl].nof_grants);
 
-  // Put UL/DL grants to resource grid. PDSCH data will be encoded as well. 
-  encode_pdcch_dl(dl_grants[t_tx].sched_grants, dl_grants[t_tx].nof_grants);
-  encode_pdcch_ul(ul_grants[t_sched_ul].sched_grants, ul_grants[t_sched_ul].nof_grants);
-  encode_pdsch(dl_grants[t_tx].sched_grants, dl_grants[t_tx].nof_grants);
-  
   // Put pending PHICH HARQ ACK/NACK indications into subframe
-  encode_phich(ul_grants[t_sched_ul].phich, ul_grants[t_sched_ul].nof_phich);
-  
-  // Prepare for receive ACK for DL grants in t_tx+4
-  phy->ack_clear(TTIMOD(HARQ_TX(sf_tx)));
-  for (uint32_t i=0;i<dl_grants[t_tx].nof_grants;i++) {
+  encode_phich(ul_grants[t_tx_ul].phich, ul_grants[t_tx_ul].nof_phich);
+
+  // Prepare for receive ACK for DL grants in t_tx_dl+4
+  phy->ack_clear(TTIMOD(TTI_TX(t_tx_dl)));
+  for (uint32_t i=0;i<dl_grants[t_tx_dl].nof_grants;i++) {
     // SI-RNTI and RAR-RNTI do not have ACK
-    if (dl_grants[t_tx].sched_grants[i].rnti >= SRSLTE_CRNTI_START && dl_grants[t_tx].sched_grants[i].rnti <= SRSLTE_CRNTI_END) {
-      phy->ack_set_pending(TTIMOD(HARQ_TX(sf_tx)), dl_grants[t_tx].sched_grants[i].rnti, dl_grants[t_tx].sched_grants[i].location.ncce);
+    if (dl_grants[t_tx_dl].sched_grants[i].rnti >= SRSLTE_CRNTI_START && dl_grants[t_tx_dl].sched_grants[i].rnti <= SRSLTE_CRNTI_END) {
+      phy->ack_set_pending(TTIMOD(TTI_TX(t_tx_dl)), dl_grants[t_tx_dl].sched_grants[i].rnti, dl_grants[t_tx_dl].sched_grants[i].location.ncce);
     }
   }
-  
+
   // Generate signal and transmit
-  srslte_enb_dl_gen_signal(&enb_dl, signal_buffer_tx);  
+  srslte_enb_dl_gen_signal(&enb_dl, signal_buffer_tx);
   Debug("Sending to radio\n");
   phy->worker_end(tx_mutex_cnt, signal_buffer_tx, SRSLTE_SF_LEN_PRB(phy->cell.nof_prb), tx_time);
 
@@ -347,35 +347,35 @@ void phch_worker::work_imp()
 #endif
 
 #ifdef DEBUG_WRITE_FILE
-  if (tti_tx == 10) {
+  if (tti_tx_dl == 10) {
     fclose(f);
     exit(-1);
   }
-#endif    
-  
+#endif
+
   /* Tell the plotting thread to draw the plots */
 #ifdef ENABLE_GUI
   if ((int) get_id() == plot_worker_id) {
-    sem_post(&plot_sem);    
+    sem_post(&plot_sem);
   }
 #endif
 
 unlock:
-  pthread_mutex_unlock(&mutex); 
+  pthread_mutex_unlock(&mutex);
 
 }
 
 
 int phch_worker::decode_pusch(srslte_enb_ul_pusch_t *grants, uint32_t nof_pusch)
 {
-  srslte_uci_data_t uci_data; 
+  srslte_uci_data_t uci_data;
   bzero(&uci_data, sizeof(srslte_uci_data_t));
-  
-  uint32_t wideband_cqi_value = 0; 
-  
-  uint32_t n_rb_ho = 0; 
+
+  uint32_t wideband_cqi_value = 0;
+
+  uint32_t n_rb_ho = 0;
   for (uint32_t i=0;i<nof_pusch;i++) {
-    uint16_t rnti = grants[i].rnti; 
+    uint16_t rnti = grants[i].rnti;
     if (rnti) {
 
     #ifdef LOG_EXECTIME
@@ -386,27 +386,27 @@ int phch_worker::decode_pusch(srslte_enb_ul_pusch_t *grants, uint32_t nof_pusch)
 
       // Get pending ACKs with an associated PUSCH transmission
       if (phy->ack_is_pending(t_rx, rnti)) {
-        uci_data.uci_ack_len = 1; 
+        uci_data.uci_ack_len = 1;
       }
-      // Configure PUSCH CQI channel 
+      // Configure PUSCH CQI channel
       srslte_cqi_value_t cqi_value;
-      bool cqi_enabled = false; 
+      bool cqi_enabled = false;
       if (ue_db[rnti].cqi_en && srslte_cqi_send(ue_db[rnti].pmi_idx, tti_rx)) {
         cqi_value.type = SRSLTE_CQI_TYPE_WIDEBAND;
-        cqi_enabled = true; 
+        cqi_enabled = true;
       } else if (grants[i].grant.cqi_request) {
         cqi_value.type = SRSLTE_CQI_TYPE_SUBBAND_HL;
         cqi_value.subband_hl.N = (phy->cell.nof_prb > 7) ? srslte_cqi_hl_get_no_subbands(phy->cell.nof_prb) : 0;
-        cqi_enabled = true; 
+        cqi_enabled = true;
       }
       if (cqi_enabled) {
         uci_data.uci_cqi_len = srslte_cqi_size(&cqi_value);
       }
-      
-      // mark this tti as having an ul grant to avoid pucch 
-      ue_db[rnti].has_grant_tti = tti_rx; 
-      
-      srslte_ra_ul_grant_t phy_grant; 
+
+      // mark this tti as having an ul grant to avoid pucch
+      ue_db[rnti].has_grant_tti = tti_rx;
+
+      srslte_ra_ul_grant_t phy_grant;
       int res = -1;
       if (!srslte_ra_ul_dci_to_grant(&grants[i].grant, enb_ul.cell.nof_prb, n_rb_ho, &phy_grant, tti_rx%8)) {
         if (phy_grant.mcs.mod == SRSLTE_MOD_64QAM) {
@@ -414,27 +414,27 @@ int phch_worker::decode_pusch(srslte_enb_ul_pusch_t *grants, uint32_t nof_pusch)
         }
         phy_grant.Qm = SRSLTE_MIN(phy_grant.Qm, 4);
         res = srslte_enb_ul_get_pusch(&enb_ul, &phy_grant, grants[i].softbuffer,
-                                                rnti, grants[i].rv_idx, 
-                                                grants[i].current_tx_nb, 
-                                                grants[i].data, 
-                                                &uci_data, 
+                                                rnti, grants[i].rv_idx,
+                                                grants[i].current_tx_nb,
+                                                grants[i].data,
+                                                &uci_data,
                                                 sf_rx);
       } else {
         Error("Computing PUSCH grant\n");
-        return SRSLTE_ERROR; 
+        return SRSLTE_ERROR;
       }
-      
+
     #ifdef LOG_EXECTIME
       gettimeofday(&t[2], NULL);
       get_time_interval(t);
       snprintf(timestr, 64, ", dec_time=%4d us", (int) t[0].tv_usec);
     #endif
-      
-      bool crc_res = (res == 0); 
-                   
+
+      bool crc_res = (res == 0);
+
       // Save PHICH scheduling for this user. Each user can have just 1 PUSCH grant per TTI
-      ue_db[rnti].phich_info.n_prb_lowest = enb_ul.pusch_cfg.grant.n_prb_tilde[0];                                           
-      ue_db[rnti].phich_info.n_dmrs       = phy_grant.ncs_dmrs;                                           
+      ue_db[rnti].phich_info.n_prb_lowest = enb_ul.pusch_cfg.grant.n_prb_tilde[0];
+      ue_db[rnti].phich_info.n_dmrs       = phy_grant.ncs_dmrs;
 
       char cqi_str[64];
       if (cqi_enabled) {
@@ -446,8 +446,8 @@ int phch_worker::decode_pusch(srslte_enb_ul_pusch_t *grants, uint32_t nof_pusch)
         }
         snprintf(cqi_str, 64, ", cqi=%d", wideband_cqi_value);
       }
-      
-      float snr_db  = 10*log10(srslte_chest_ul_get_snr(&enb_ul.chest)); 
+
+      float snr_db  = 10*log10(srslte_chest_ul_get_snr(&enb_ul.chest));
 
       /*
       if (!crc_res && enb_ul.pusch_cfg.grant.L_prb == 1 && enb_ul.pusch_cfg.grant.n_prb[0] == 0 && snr_db > 5) {
@@ -456,8 +456,8 @@ int phch_worker::decode_pusch(srslte_enb_ul_pusch_t *grants, uint32_t nof_pusch)
         srslte_vec_save_file("d", enb_ul.pusch.d, sizeof(cf_t)*enb_ul.pusch_cfg.nbits.nof_re);
         srslte_vec_save_file("ce2", enb_ul.pusch.ce, sizeof(cf_t)*enb_ul.pusch_cfg.nbits.nof_re);
         srslte_vec_save_file("z", enb_ul.pusch.z, sizeof(cf_t)*enb_ul.pusch_cfg.nbits.nof_re);
-        printf("saved sf_idx=%d, mcs=%d, tbs=%d, rnti=%d, rv=%d, snr=%.1f\n", tti%10, 
-               grants[i].grant.mcs_idx, enb_ul.pusch_cfg.cb_segm.tbs, rnti, grants[i].rv_idx, snr_db); 
+        printf("saved sf_idx=%d, mcs=%d, tbs=%d, rnti=%d, rv=%d, snr=%.1f\n", tti%10,
+               grants[i].grant.mcs_idx, enb_ul.pusch_cfg.cb_segm.tbs, rnti, grants[i].rv_idx, snr_db);
         exit(-1);
       }
       */
@@ -465,120 +465,121 @@ int phch_worker::decode_pusch(srslte_enb_ul_pusch_t *grants, uint32_t nof_pusch)
           "PUSCH: rnti=0x%x, prb=(%d,%d), tbs=%d, mcs=%d, rv=%d, snr=%.1f dB, n_iter=%d, crc=%s%s%s%s\n",
           rnti, phy_grant.n_prb[0], phy_grant.n_prb[0]+phy_grant.L_prb,
           phy_grant.mcs.tbs/8, phy_grant.mcs.idx, grants[i].grant.rv_idx,
-          snr_db, 
+          snr_db,
           srslte_pusch_last_noi(&enb_ul.pusch),
           crc_res?"OK":"KO",
           uci_data.uci_ack_len>0?(uci_data.uci_ack?", ack=1":", ack=0"):"",
-          uci_data.uci_cqi_len>0?cqi_str:"",         
-          timestr);    
-      
-      // Notify MAC of RL status 
+          uci_data.uci_cqi_len>0?cqi_str:"",
+          timestr);
+
+      // Notify MAC of RL status
       if (grants[i].grant.rv_idx == 0) {
         if (res && snr_db < PUSCH_RL_SNR_DB_TH) {
           Debug("PUSCH: Radio-Link failure snr=%.1f dB\n", snr_db);
           phy->mac->rl_failure(rnti);
         } else {
           phy->mac->rl_ok(rnti);
-        }        
+        }
       }
-      
+
       // Notify MAC new received data and HARQ Indication value
-      phy->mac->crc_info(tti_rx, rnti, phy_grant.mcs.tbs/8, crc_res);    
+      phy->mac->crc_info(tti_rx, rnti, phy_grant.mcs.tbs/8, crc_res);
       if (uci_data.uci_ack_len) {
         phy->mac->ack_info(tti_rx, rnti, uci_data.uci_ack && (crc_res || snr_db > PUSCH_RL_SNR_DB_TH));
       }
-      
-      // Notify MAC of UL SNR and DL CQI 
+
+      // Notify MAC of UL SNR and DL CQI
       if (snr_db >= PUSCH_RL_SNR_DB_TH) {
         phy->mac->snr_info(tti_rx, rnti, snr_db);
       }
       if (uci_data.uci_cqi_len>0 && crc_res) {
         phy->mac->cqi_info(tti_rx, rnti, wideband_cqi_value);
       }
-      
-      // Save metrics stats 
+
+      // Save metrics stats
       ue_db[rnti].metrics_ul(phy_grant.mcs.idx, 0, snr_db, srslte_pusch_last_noi(&enb_ul.pusch));
-    }    
+    }
   }
-  return SRSLTE_SUCCESS; 
+  return SRSLTE_SUCCESS;
 }
 
 
 int phch_worker::decode_pucch()
 {
   srslte_uci_data_t uci_data;
-  
+
   for(std::map<uint16_t, ue>::iterator iter=ue_db.begin(); iter!=ue_db.end(); ++iter) {
     uint16_t rnti = (uint16_t) iter->first;
 
     if (rnti >= SRSLTE_CRNTI_START && rnti <= SRSLTE_CRNTI_END && ue_db[rnti].has_grant_tti != (int) tti_rx) {
-      // Check if user needs to receive PUCCH 
-      bool needs_pucch = false, needs_ack=false, needs_sr=false, needs_cqi=false; 
+      // Check if user needs to receive PUCCH
+      bool needs_pucch = false, needs_ack=false, needs_sr=false, needs_cqi=false;
       uint32_t last_n_pdcch = 0;
       bzero(&uci_data, sizeof(srslte_uci_data_t));
-      
+
       if (ue_db[rnti].I_sr_en) {
         if (srslte_ue_ul_sr_send_tti(ue_db[rnti].I_sr, tti_rx)) {
-          needs_pucch = true; 
-          needs_sr = true; 
-          uci_data.scheduling_request = true; 
+          needs_pucch = true;
+          needs_sr = true;
+          uci_data.scheduling_request = true;
         }
-      }      
+      }
+
       if (phy->ack_is_pending(t_rx, rnti, &last_n_pdcch)) {
-        needs_pucch = true; 
-        needs_ack = true; 
-        uci_data.uci_ack_len = 1; 
+        needs_pucch = true;
+        needs_ack = true;
+        uci_data.uci_ack_len = 1;
       }
       srslte_cqi_value_t cqi_value;
       if (ue_db[rnti].cqi_en && (ue_db[rnti].pucch_cqi_ack || !needs_ack)) {
         if (srslte_cqi_send(ue_db[rnti].pmi_idx, tti_rx)) {
-          needs_pucch = true; 
-          needs_cqi = true; 
-          cqi_value.type = SRSLTE_CQI_TYPE_WIDEBAND; 
+          needs_pucch = true;
+          needs_cqi = true;
+          cqi_value.type = SRSLTE_CQI_TYPE_WIDEBAND;
           uci_data.uci_cqi_len = srslte_cqi_size(&cqi_value);
         }
       }
-      
+
       if (needs_pucch) {
-        if (srslte_enb_ul_get_pucch(&enb_ul, rnti, last_n_pdcch, t_rx, &uci_data)) {
+        if (srslte_enb_ul_get_pucch(&enb_ul, rnti, last_n_pdcch, sf_rx, &uci_data)) {
           fprintf(stderr, "Error getting PUCCH\n");
-          return SRSLTE_ERROR; 
+          return SRSLTE_ERROR;
         }
         if (uci_data.uci_ack_len > 0) {
-          phy->mac->ack_info(tti_rx, rnti, uci_data.uci_ack && (srslte_pucch_get_last_corr(&enb_ul.pucch) >= PUCCH_RL_CORR_TH));      
+          phy->mac->ack_info(tti_rx, rnti, uci_data.uci_ack && (srslte_pucch_get_last_corr(&enb_ul.pucch) >= PUCCH_RL_CORR_TH));
         }
         if (uci_data.scheduling_request) {
-          phy->mac->sr_detected(tti_rx, rnti);                
+          phy->mac->sr_detected(tti_rx, rnti);
         }
-        
+
         char cqi_str[64];
         if (uci_data.uci_cqi_len) {
           srslte_cqi_value_unpack(uci_data.uci_cqi, &cqi_value);
           phy->mac->cqi_info(tti_rx, rnti, cqi_value.wideband.wideband_cqi);
           sprintf(cqi_str, ", cqi=%d", cqi_value.wideband.wideband_cqi);
         }
-        log_h->info("PUCCH: rnti=0x%x, corr=%.2f, n_pucch=%d, n_prb=%d%s%s%s\n", 
-                    rnti, 
+        log_h->info("PUCCH: rnti=0x%x, corr=%.2f, n_pucch=%d, n_prb=%d%s%s%s\n",
+                    rnti,
                     srslte_pucch_get_last_corr(&enb_ul.pucch),
                     enb_ul.pucch.last_n_pucch, enb_ul.pucch.last_n_prb,
-                    needs_ack?(uci_data.uci_ack?", ack=1":", ack=0"):"", 
-                    needs_sr?(uci_data.scheduling_request?", sr=yes":", sr=no"):"", 
-                    needs_cqi?cqi_str:"");                
+                    needs_ack?(uci_data.uci_ack?", ack=1":", ack=0"):"",
+                    needs_sr?(uci_data.scheduling_request?", sr=yes":", sr=no"):"",
+                    needs_cqi?cqi_str:"");
 
 
-        // Notify MAC of RL status 
+        // Notify MAC of RL status
         if (!needs_sr) {
           if (srslte_pucch_get_last_corr(&enb_ul.pucch) < PUCCH_RL_CORR_TH) {
             Debug("PUCCH: Radio-Link failure corr=%.1f\n", srslte_pucch_get_last_corr(&enb_ul.pucch));
             phy->mac->rl_failure(rnti);
           } else {
             phy->mac->rl_ok(rnti);
-          }          
-        }                
+          }
+        }
       }
     }
-  }    
-  return 0; 
+  }
+  return 0;
 }
 
 
@@ -587,15 +588,15 @@ int phch_worker::encode_phich(srslte_enb_dl_phich_t *acks, uint32_t nof_acks)
   for (uint32_t i=0;i<nof_acks;i++) {
     uint16_t rnti = acks[i].rnti;
     if (rnti) {
-      srslte_enb_dl_put_phich(&enb_dl, acks[i].ack, 
-                              ue_db[rnti].phich_info.n_prb_lowest, 
-                              ue_db[rnti].phich_info.n_dmrs, 
+      srslte_enb_dl_put_phich(&enb_dl, acks[i].ack,
+                              ue_db[rnti].phich_info.n_prb_lowest,
+                              ue_db[rnti].phich_info.n_dmrs,
                               sf_tx);
-      
-      Info("PHICH: rnti=0x%x, hi=%d, I_lowest=%d, n_dmrs=%d, tti_tx=%d\n", 
-          rnti, acks[i].ack, 
-          ue_db[rnti].phich_info.n_prb_lowest, 
-          ue_db[rnti].phich_info.n_dmrs, tti_tx);
+
+      Info("PHICH: rnti=0x%x, hi=%d, I_lowest=%d, n_dmrs=%d, tti_tx_dl=%d\n",
+          rnti, acks[i].ack,
+          ue_db[rnti].phich_info.n_prb_lowest,
+          ue_db[rnti].phich_info.n_dmrs, tti_tx_dl);
     }
   }
   return SRSLTE_SUCCESS;
@@ -609,14 +610,14 @@ int phch_worker::encode_pdcch_ul(srslte_enb_ul_pusch_t *grants, uint32_t nof_gra
     if (grants[i].needs_pdcch && rnti) {
       if (srslte_enb_dl_put_pdcch_ul(&enb_dl, &grants[i].grant, grants[i].location, rnti, sf_tx)) {
         fprintf(stderr, "Error putting PUSCH %d\n",i);
-        return SRSLTE_ERROR; 
+        return SRSLTE_ERROR;
       }
 
-      Info("PDCCH: UL DCI Format0  rnti=0x%x, cce_index=%d, L=%d, tpc=%d, tti_tx=%d\n",
-           rnti, grants[i].location.ncce, (1<<grants[i].location.L), grants[i].grant.tpc_pusch, tti_tx);
+      Info("PDCCH: UL DCI Format0  rnti=0x%x, cce_index=%d, L=%d, tpc=%d, tti_tx_dl=%d\n",
+           rnti, grants[i].location.ncce, (1<<grants[i].location.L), grants[i].grant.tpc_pusch, tti_tx_dl);
     }
   }
-  return SRSLTE_SUCCESS; 
+  return SRSLTE_SUCCESS;
 }
 
 int phch_worker::encode_pdcch_dl(srslte_enb_dl_pdsch_t *grants, uint32_t nof_grants)
@@ -624,28 +625,28 @@ int phch_worker::encode_pdcch_dl(srslte_enb_dl_pdsch_t *grants, uint32_t nof_gra
   for (uint32_t i=0;i<nof_grants;i++) {
     uint16_t rnti = grants[i].rnti;
     if (rnti) {
-      srslte_dci_format_t format = SRSLTE_DCI_FORMAT1; 
+      srslte_dci_format_t format = SRSLTE_DCI_FORMAT1;
       switch(grants[i].grant.alloc_type) {
         case SRSLTE_RA_ALLOC_TYPE0:
         case SRSLTE_RA_ALLOC_TYPE1:
-          format = SRSLTE_DCI_FORMAT1; 
+          format = SRSLTE_DCI_FORMAT1;
         break;
         case SRSLTE_RA_ALLOC_TYPE2:
-          format = SRSLTE_DCI_FORMAT1A; 
+          format = SRSLTE_DCI_FORMAT1A;
         break;
       }
       if (srslte_enb_dl_put_pdcch_dl(&enb_dl, &grants[i].grant, format, grants[i].location, rnti, sf_tx)) {
         fprintf(stderr, "Error putting PDCCH %d\n",i);
-        return SRSLTE_ERROR; 
-      }      
-      
+        return SRSLTE_ERROR;
+      }
+
       if (LOG_THIS(rnti)) {
-        Info("PDCCH: DL DCI %s rnti=0x%x, cce_index=%d, L=%d, tti_tx=%d\n", srslte_dci_format_string(format), 
-          rnti, grants[i].location.ncce, (1<<grants[i].location.L), tti_tx);
+        Info("PDCCH: DL DCI %s rnti=0x%x, cce_index=%d, L=%d, tti_tx_dl=%d\n", srslte_dci_format_string(format),
+          rnti, grants[i].location.ncce, (1<<grants[i].location.L), tti_tx_dl);
       }
     }
   }
-  return 0; 
+  return 0;
 }
 
 int phch_worker::encode_pdsch(srslte_enb_dl_pdsch_t *grants, uint32_t nof_grants)
@@ -654,14 +655,14 @@ int phch_worker::encode_pdsch(srslte_enb_dl_pdsch_t *grants, uint32_t nof_grants
     uint16_t rnti = grants[i].rnti;
     if (rnti) {
 
-      bool rnti_is_user = true; 
+      bool rnti_is_user = true;
       if (rnti == SRSLTE_SIRNTI || rnti == SRSLTE_PRNTI || rnti == SRSLTE_MRNTI) {
-        rnti_is_user = false; 
+        rnti_is_user = false;
       }
-      
-      srslte_ra_dl_grant_t phy_grant; 
+
+      srslte_ra_dl_grant_t phy_grant;
       srslte_ra_dl_dci_to_grant(&grants[i].grant, enb_dl.cell.nof_prb, rnti, &phy_grant);
-      
+
       char grant_str[64];
       switch(grants[i].grant.alloc_type) {
         case SRSLTE_RA_ALLOC_TYPE0:
@@ -674,19 +675,19 @@ int phch_worker::encode_pdsch(srslte_enb_dl_pdsch_t *grants, uint32_t nof_grants
           sprintf(grant_str, "rb_start=%d",grants[i].grant.type2_alloc.RB_start);
         break;
       }
-      
-      if (LOG_THIS(rnti)) { 
+
+      if (LOG_THIS(rnti)) {
         uint8_t x = 0;
         uint8_t *ptr = grants[i].data;
         uint32_t len = phy_grant.mcs[0].tbs / (uint32_t) 8;
-        if (!ptr) {          
+        if (!ptr) {
           ptr = &x;
-          len = 1; 
-        }        
+          len = 1;
+        }
         log_h->info_hex(ptr, len,
-                             "PDSCH: rnti=0x%x, l_crb=%2d, %s, harq=%d, tbs=%d, mcs=%d, rv=%d, tti_tx=%d\n",
-                             rnti, phy_grant.nof_prb, grant_str, grants[i].grant.harq_process, 
-                             phy_grant.mcs[0].tbs/8, phy_grant.mcs[0].idx, grants[i].grant.rv_idx, tti_tx);
+                             "PDSCH: rnti=0x%x, l_crb=%2d, %s, harq=%d, tbs=%d, mcs=%d, rv=%d, tti_tx_dl=%d\n",
+                             rnti, phy_grant.nof_prb, grant_str, grants[i].grant.harq_process,
+                             phy_grant.mcs[0].tbs/8, phy_grant.mcs[0].idx, grants[i].grant.rv_idx, tti_tx_dl);
       }
 
       srslte_softbuffer_tx_t *sb[SRSLTE_MAX_CODEWORDS] = {grants[i].softbuffer, NULL};
diff --git a/srsenb/src/phy/txrx.cc b/srsenb/src/phy/txrx.cc
index 9427e3459..fa14b0b82 100644
--- a/srsenb/src/phy/txrx.cc
+++ b/srsenb/src/phy/txrx.cc
@@ -115,7 +115,7 @@ void txrx::run_thread()
                     
       /* Compute TX time: Any transmission happens in TTI+4 thus advance 4 ms the reception time */
       srslte_timestamp_copy(&tx_time, &rx_time);
-      srslte_timestamp_add(&tx_time, 0, 4e-3);
+      srslte_timestamp_add(&tx_time, 0, HARQ_DELAY_MS*1e-3);
       
       Debug("Settting TTI=%d, tx_mutex=%d, tx_time=%d:%f to worker %d\n", 
             tti, tx_mutex_cnt, 
diff --git a/srsue/hdr/mac/mux.h b/srsue/hdr/mac/mux.h
index 1167af752..ab081070c 100644
--- a/srsue/hdr/mac/mux.h
+++ b/srsue/hdr/mac/mux.h
@@ -82,8 +82,7 @@ private:
   
   const static int MIN_RLC_SDU_LEN = 0; 
   const static int MAX_NOF_SUBHEADERS = 20; 
-  const static int MAX_HARQ_PROC = 8; 
-  
+
   std::vector<lchid_t> lch; 
   
   // Keep track of the PIDs that transmitted BSR reports 
diff --git a/srsue/src/phy/phch_common.cc b/srsue/src/phy/phch_common.cc
index 489d27197..549783fd9 100644
--- a/srsue/src/phy/phch_common.cc
+++ b/srsue/src/phy/phch_common.cc
@@ -136,12 +136,16 @@ srslte::radio* phch_common::get_radio()
 void phch_common::set_rar_grant(uint32_t tti, uint8_t grant_payload[SRSLTE_RAR_GRANT_LEN])
 {
   srslte_dci_rar_grant_unpack(&rar_grant, grant_payload);
-  rar_grant_pending = true; 
-  // PUSCH is at n+6 or n+7 and phch_worker assumes default delay of 4 ttis
+  rar_grant_pending = true;
+  int delay = MSG3_DELAY_MS-HARQ_DELAY_MS;
+  if (delay < 0) {
+    fprintf(stderr, "Error MSG3_DELAY_MS can't be lower than HARQ_DELAY_MS\n");
+    delay = 0;
+  }
   if (rar_grant.ul_delay) {
-    rar_grant_tti     = (tti + 3) % 10240; 
+    rar_grant_tti     = (tti + delay + 1) % 10240;
   } else {
-    rar_grant_tti     = (tti + 2) % 10240; 
+    rar_grant_tti     = (tti + delay) % 10240;
   }
 }
 
diff --git a/srsue/src/phy/phch_worker.cc b/srsue/src/phy/phch_worker.cc
index e6c0050e2..adeb41603 100644
--- a/srsue/src/phy/phch_worker.cc
+++ b/srsue/src/phy/phch_worker.cc
@@ -292,6 +292,13 @@ void phch_worker::work_imp()
       }
     }
   }
+
+  // Process RAR before UL to enable zero-delay Msg3
+  bool rar_delivered = false;
+  if (HARQ_DELAY_MS == MSG3_DELAY_MS && dl_mac_grant.rnti_type == SRSLTE_RNTI_RAR) {
+    rar_delivered = true;
+    phy->mac->tb_decoded(dl_ack[0], 0, dl_mac_grant.rnti_type, dl_mac_grant.pid);
+  }
   
   // Decode PHICH 
   bool ul_ack = false;
@@ -313,8 +320,8 @@ void phch_worker::work_imp()
     set_uci_periodic_cqi();
   }
 
-  /* TTI offset for UL is always 4 for LTE */
-  ul_action.tti_offset = 4;
+  /* TTI offset for UL */
+  ul_action.tti_offset = HARQ_DELAY_MS;
 
   /* Send UL grant or HARQ information (from PHICH) to MAC */
   if (ul_grant_available         && ul_ack_available)  {    
@@ -335,7 +342,7 @@ void phch_worker::work_imp()
                  &ul_action.softbuffers[0], ul_action.rv[0], ul_action.rnti, ul_mac_grant.is_from_rar);
     signal_ready = true; 
     if (ul_action.expect_ack) {
-      phy->set_pending_ack(HARQ_RX(tti), ue_ul.pusch_cfg.grant.n_prb_tilde[0], ul_action.phy_grant.ul.ncs_dmrs);
+      phy->set_pending_ack(TTI_RX_ACK(tti), ue_ul.pusch_cfg.grant.n_prb_tilde[0], ul_action.phy_grant.ul.ncs_dmrs);
     }
 
   } else if (dl_action.generate_ack || uci_data.scheduling_request || uci_data.uci_cqi_len > 0) {
@@ -357,7 +364,7 @@ void phch_worker::work_imp()
   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 {
+    } else if (!rar_delivered) {
       for (uint32_t tb = 0; tb < SRSLTE_MAX_TB; tb++) {
         if (dl_action.decode_enabled[tb]) {
           phy->mac->tb_decoded(dl_ack[tb], tb, dl_mac_grant.rnti_type, dl_mac_grant.pid);
@@ -475,7 +482,7 @@ bool phch_worker::decode_pdcch_dl(srsue::mac_interface_phy::mac_grant_t* grant)
     /* Fill MAC grant structure */
     grant->ndi[0] = dci_unpacked.ndi;
     grant->ndi[1] = dci_unpacked.ndi_1;
-    grant->pid = dci_unpacked.harq_process;
+    grant->pid = ASYNC_DL_SCHED?dci_unpacked.harq_process:(tti%(2*HARQ_DELAY_MS));
     grant->n_bytes[0] = grant->phy_grant.dl.mcs[0].tbs / (uint32_t) 8;
     grant->n_bytes[1] = grant->phy_grant.dl.mcs[1].tbs / (uint32_t) 8;
     grant->tti = tti;
@@ -663,7 +670,7 @@ bool phch_worker::decode_pdcch_ul(mac_interface_phy::mac_grant_t* grant)
   char timestr[64];
   timestr[0]='\0';
 
-  phy->reset_pending_ack(HARQ_RX(tti));
+  phy->reset_pending_ack(TTI_RX_ACK(tti));
 
   srslte_dci_msg_t dci_msg; 
   srslte_ra_ul_dci_t dci_unpacked;
@@ -776,7 +783,7 @@ void phch_worker::set_uci_sr()
 {
   uci_data.scheduling_request = false; 
   if (phy->sr_enabled) {
-    uint32_t sr_tx_tti = HARQ_TX(tti);
+    uint32_t sr_tx_tti = TTI_TX(tti);
     // Get I_sr parameter   
     if (srslte_ue_ul_sr_send_tti(I_sr, sr_tx_tti)) {
       Info("PUCCH: SR transmission at TTI=%d, I_sr=%d\n", sr_tx_tti, I_sr);
@@ -793,7 +800,7 @@ void phch_worker::set_uci_periodic_cqi()
   int cqi_max       = phy->args->cqi_max;
   
   if (period_cqi.configured && rnti_is_set) {
-    if (period_cqi.ri_idx_present && srslte_ri_send(period_cqi.pmi_idx, period_cqi.ri_idx, HARQ_TX(tti))) {
+    if (period_cqi.ri_idx_present && srslte_ri_send(period_cqi.pmi_idx, period_cqi.ri_idx, TTI_TX(tti))) {
       if (uci_data.uci_ri_len) {
         uci_data.uci_cqi[0] = uci_data.uci_ri;
         uci_data.uci_cqi_len = uci_data.uci_ri_len;
@@ -802,7 +809,7 @@ void phch_worker::set_uci_periodic_cqi()
         uci_data.uci_pmi_len = 0;
         Info("PUCCH: Periodic RI=%d\n", uci_data.uci_cqi[0]);
       }
-    } else if (srslte_cqi_send(period_cqi.pmi_idx, HARQ_TX(tti))) {
+    } else if (srslte_cqi_send(period_cqi.pmi_idx, TTI_TX(tti))) {
       srslte_cqi_value_t cqi_report;
       if (period_cqi.format_is_subband) {
         // TODO: Implement subband periodic reports
@@ -868,8 +875,8 @@ void phch_worker::set_uci_aperiodic_cqi()
 
 bool phch_worker::srs_is_ready_to_send() {
   if (srs_cfg.configured) {
-    if (srslte_refsignal_srs_send_cs(srs_cfg.subframe_config, HARQ_RX(tti)%10) == 1 &&
-        srslte_refsignal_srs_send_ue(srs_cfg.I_srs, HARQ_TX(tti))        == 1)
+    if (srslte_refsignal_srs_send_cs(srs_cfg.subframe_config, TTI_TX(tti)%10) == 1 &&
+        srslte_refsignal_srs_send_ue(srs_cfg.I_srs, TTI_TX(tti))              == 1)
     {
       return true; 
     }
@@ -889,7 +896,7 @@ void phch_worker::encode_pusch(srslte_ra_ul_grant_t *grant, uint8_t *payload, ui
   char timestr[64];
   timestr[0]='\0';
   
-  if (srslte_ue_ul_cfg_grant(&ue_ul, grant, HARQ_TX(tti), rv, current_tx_nb)) {
+  if (srslte_ue_ul_cfg_grant(&ue_ul, grant, TTI_TX(tti), rv, current_tx_nb)) {
     Error("Configuring UL grant\n");
   }
   
@@ -919,7 +926,7 @@ void phch_worker::encode_pusch(srslte_ra_ul_grant_t *grant, uint8_t *payload, ui
 #endif
 
   Info("PUSCH: tti_tx=%d, n_prb=%d, rb_start=%d, tbs=%d, mod=%d, mcs=%d, rv_idx=%d, ack=%s, ri=%s, cfo=%.1f Hz%s\n",
-         HARQ_TX(tti),
+         TTI_TX(tti),
          grant->L_prb, grant->n_prb[0], 
          grant->mcs.tbs/8, grant->mcs.mod, grant->mcs.idx, rv,
          uci_data.uci_ack_len>0?(uci_data.uci_ack?"1":"0"):"no",
@@ -950,7 +957,7 @@ void phch_worker::encode_pucch()
     gettimeofday(&t[1], NULL);
 #endif
 
-    if (srslte_ue_ul_pucch_encode(&ue_ul, uci_data, last_dl_pdcch_ncce, HARQ_TX(tti), signal_buffer[0])) {
+    if (srslte_ue_ul_pucch_encode(&ue_ul, uci_data, last_dl_pdcch_ncce, TTI_TX(tti), signal_buffer[0])) {
       Error("Encoding PUCCH\n");
     }
 
@@ -966,7 +973,7 @@ void phch_worker::encode_pucch()
   float gain = set_power(tx_power);  
   
   Info("PUCCH: tti_tx=%d, n_cce=%3d, n_pucch=%d, n_prb=%d, ack=%s%s, ri=%s, pmi=%s%s, sr=%s, cfo=%.1f Hz%s\n",
-         HARQ_TX(tti),
+         TTI_TX(tti),
          last_dl_pdcch_ncce, ue_ul.pucch.last_n_pucch, ue_ul.pucch.last_n_prb, 
        uci_data.uci_ack_len>0?(uci_data.uci_ack?"1":"0"):"no",
        uci_data.uci_ack_len>1?(uci_data.uci_ack_2?"1":"0"):"",
@@ -987,7 +994,7 @@ void phch_worker::encode_srs()
   char timestr[64];
   timestr[0]='\0';
   
-  if (srslte_ue_ul_srs_encode(&ue_ul, HARQ_TX(tti), signal_buffer[0]))
+  if (srslte_ue_ul_srs_encode(&ue_ul, TTI_TX(tti), signal_buffer[0]))
   {
     Error("Encoding SRS\n");
   }
@@ -1002,7 +1009,7 @@ void phch_worker::encode_srs()
   float gain = set_power(tx_power);
   uint32_t fi = srslte_vec_max_fi((float*) signal_buffer, SRSLTE_SF_LEN_PRB(cell.nof_prb));
   float *f = (float*) signal_buffer;
-  Info("SRS:   power=%.2f dBm, tti_tx=%d%s\n", tx_power, HARQ_TX(tti), timestr);
+  Info("SRS:   power=%.2f dBm, tti_tx=%d%s\n", tx_power, TTI_TX(tti), timestr);
   
 }