diff --git a/openair1/PHY/INIT/nr_init_ue.c b/openair1/PHY/INIT/nr_init_ue.c
index dafee33838..641c8a1f67 100644
--- a/openair1/PHY/INIT/nr_init_ue.c
+++ b/openair1/PHY/INIT/nr_init_ue.c
@@ -615,7 +615,6 @@ void nr_init_ul_harq_processes(NR_UL_UE_HARQ_t harq_list[NR_MAX_ULSCH_HARQ_PROCE
     DevAssert(harq_list[i].f);
     bzero(harq_list[i].f,14*num_rb*12*16);
 
-    harq_list[i].first_tx = 1;
     harq_list[i].round = 0;
   }
 }
@@ -642,7 +641,6 @@ void clean_UE_harq(PHY_VARS_NR_UE *UE)
     ul_harq_process->tx_status = NEW_TRANSMISSION_HARQ;
     ul_harq_process->status = SCH_IDLE;
     ul_harq_process->round = 0;
-    ul_harq_process->first_tx = 1;
   }
 }
 
diff --git a/openair1/PHY/NR_UE_TRANSPORT/nr_transport_ue.h b/openair1/PHY/NR_UE_TRANSPORT/nr_transport_ue.h
index c60fdb6a6d..b03764696f 100644
--- a/openair1/PHY/NR_UE_TRANSPORT/nr_transport_ue.h
+++ b/openair1/PHY/NR_UE_TRANSPORT/nr_transport_ue.h
@@ -45,8 +45,6 @@ typedef enum {
 } harq_result_t;
 
 typedef struct {
-  /// Indicator of first transmission
-  uint8_t first_tx;
   /// HARQ tx status
   harq_result_t tx_status;
   /// Status Flag indicating for this ULSCH (idle,active,disabled)
@@ -57,8 +55,6 @@ typedef struct {
   uint8_t O_ACK;
   /// Index of current HARQ round for this ULSCH
   uint8_t round;
-  /// Last Ndi for this harq process
-  uint8_t ndi;
   /// pointer to pdu from MAC interface (TS 36.212 V15.4.0, Sec 5.1 p. 8)
   unsigned char *a;
   /// Pointer to the payload + CRC 
diff --git a/openair1/PHY/NR_UE_TRANSPORT/nr_ulsch_coding.c b/openair1/PHY/NR_UE_TRANSPORT/nr_ulsch_coding.c
index 961da87922..95aa63d3bd 100644
--- a/openair1/PHY/NR_UE_TRANSPORT/nr_ulsch_coding.c
+++ b/openair1/PHY/NR_UE_TRANSPORT/nr_ulsch_coding.c
@@ -71,17 +71,11 @@ int nr_ulsch_encoding(PHY_VARS_NR_UE *ue,
 
   LOG_D(NR_PHY, "ulsch coding nb_rb %d, Nl = %d\n", nb_rb, ulsch->pusch_pdu.nrOfLayers);
   LOG_D(NR_PHY, "ulsch coding A %d G %d mod_order %d Coderate %f\n", A, G, mod_order, Coderate);
-  LOG_D(NR_PHY,
-        "harq_pid %d harq_process->ndi %d, pusch_data.new_data_indicator %d\n",
-        harq_pid,
-        harq_process->ndi,
-        ulsch->pusch_pdu.pusch_data.new_data_indicator);
-  if (harq_process->first_tx == 1 ||
-      harq_process->ndi != ulsch->pusch_pdu.pusch_data.new_data_indicator) {  // this is a new packet
+  LOG_D(NR_PHY, "harq_pid %d, pusch_data.new_data_indicator %d\n", harq_pid, ulsch->pusch_pdu.pusch_data.new_data_indicator);
+  if (ulsch->pusch_pdu.pusch_data.new_data_indicator) {  // this is a new packet
 #ifdef DEBUG_ULSCH_CODING
   printf("encoding thinks this is a new packet \n");
 #endif
-    harq_process->first_tx = 0;
 ///////////////////////// a---->| add CRC |---->b /////////////////////////
 ///////////
    /* 
@@ -227,8 +221,6 @@ int nr_ulsch_encoding(PHY_VARS_NR_UE *ue,
 
 ///////////
 ///////////////////////////////////////////////////////////////////////////////
-    LOG_D(PHY,"setting ndi to %d from pusch_data\n", ulsch->pusch_pdu.pusch_data.new_data_indicator);
-    harq_process->ndi = ulsch->pusch_pdu.pusch_data.new_data_indicator;
   }
   F = harq_process->F;
   Kr = harq_process->K;
diff --git a/openair1/SCHED_NR_UE/harq_nr.c b/openair1/SCHED_NR_UE/harq_nr.c
index 2cffd3f484..caf6898f88 100644
--- a/openair1/SCHED_NR_UE/harq_nr.c
+++ b/openair1/SCHED_NR_UE/harq_nr.c
@@ -98,75 +98,6 @@
 #define DL_DCI              (1)
 #define UL_DCI              (0)
 
-/*******************************************************************
-*
-* NAME :         uplink_harq_process
-*
-* PARAMETERS :   ue context
-*                slot_tx slot for transmission
-*                gNB_id identifier
-*                ndi from DCI
-*                rnti_type from DCI
-*
-* RETURN :      true it a new transmission
-*               false it is a retransmission
-*
-* DESCRIPTION : manage uplink grant information for transmissions/retransmissions
-*               TS 38.321 5.4.1 UL Grant reception
-*               TS 38.321 5.4.2.1 HARQ Entity
-*
-*********************************************************************/
-
-harq_result_t uplink_harq_process(NR_UE_ULSCH_t *ulsch, int harq_pid, NR_UL_UE_HARQ_t harq_processes[NR_MAX_ULSCH_HARQ_PROCESSES], int ndi, uint8_t rnti_type)
-{
-  harq_result_t result_harq = RETRANSMISSION_HARQ;
-
-  if (rnti_type == _CS_RNTI_) {
-    LOG_E(PHY, "Fatal error in HARQ entity due to not supported CS_RNTI at line %d in function %s of file %s \n", __LINE__ , __func__, __FILE__);
- 	return(NEW_TRANSMISSION_HARQ);
-  }
-  else if ((rnti_type != _C_RNTI_) && (rnti_type != _TC_RNTI_)) {
-    /* harq mechanism is not relevant for other rnti */
-    return(NEW_TRANSMISSION_HARQ);
-  }
-  else if (harq_pid > ulsch->number_harq_processes_for_pusch) {
-    LOG_E(PHY, "Fatal error in HARQ entity due to unknown process identity %d at line %d in function %s of file %s \n", harq_pid, __LINE__ , __func__, __FILE__);
-    assert(0);
-  }
-
-  /* 38.321 5.4.2.1  2>  if the uplink grant was received on PDCCH for the C-RNTI and the HARQ buffer of the identified process is empty */
-  if ((harq_processes[harq_pid].first_tx == 1) && (rnti_type == _C_RNTI_)) {  /* no transmission yet on this process so consider its harq buffer as empty */
-   harq_processes[harq_pid].first_tx = 0;
-    harq_processes[harq_pid].ndi = ndi;             /* store first value of ndi */
-    harq_processes[harq_pid].round = 0;
-
-    result_harq = NEW_TRANSMISSION_HARQ;
-
-    LOG_D(PHY, "[HARQ-UL-PUSCH harqId : %d] first new transmission \n", harq_pid);
-  }
-  /* 38.321 5.4.2.1  2> if the received grant was not addressed to a Temporary C-RNTI on PDCCH, and the NDI provided in the associated HARQ */
-  /* information has been toggled compared to the value in the previous transmission of this TB of this HARQ process */
-  else if ((harq_processes[harq_pid].ndi != ndi) && (rnti_type != _TC_RNTI_)) {   /* is ndi toogled so this is a new grant ? */
-    harq_processes[harq_pid].ndi = ndi;             /* store first value of ndi */
-    harq_processes[harq_pid].round = 0;
-
-    result_harq = NEW_TRANSMISSION_HARQ;
-
-    LOG_D(PHY, "[HARQ-UL-PUSCH harqId : %d] new transmission due to toogle of ndi \n", harq_pid);
-   }
-   /* 38.321 5.4.2.1 2> else (i.e. retransmission): */
-   else {
-     harq_processes[harq_pid].ndi = ndi;             /* ndi has not toggled si this is a retransmission */
-     harq_processes[harq_pid].round++;                  /* increment number of retransmission */
-
-     result_harq = RETRANSMISSION_HARQ;
-
-     LOG_D(PHY, "[HARQ-UL-PUSCH harqId : %d] retransmission \n", harq_pid);
-   }
-
-  return (result_harq);
-}
-
 /*******************************************************************
 *
 * NAME :         init_downlink_harq_status
diff --git a/openair1/SCHED_NR_UE/harq_nr.h b/openair1/SCHED_NR_UE/harq_nr.h
index 1e7faf23e0..4c39772948 100644
--- a/openair1/SCHED_NR_UE/harq_nr.h
+++ b/openair1/SCHED_NR_UE/harq_nr.h
@@ -55,13 +55,6 @@
 
 /*************** FUNCTIONS ****************************************/
 
-/** \brief This function update uplink harq context and return transmission type (new transmission or retransmission)
-    @param ulsch uplink harq context
-    @param harq process identifier harq_pid
-    @returns retransmission or new transmission */
-
-harq_result_t uplink_harq_process(NR_UE_ULSCH_t *ulsch, int harq_pid, NR_UL_UE_HARQ_t harq_processes[NR_MAX_ULSCH_HARQ_PROCESSES], int ndi, uint8_t rnti_type);
-
 /** \brief This function initialises downlink HARQ status
     @param pointer to downlink harq status
     @returns none */
diff --git a/openair1/SIMULATION/NR_PHY/ulsim.c b/openair1/SIMULATION/NR_PHY/ulsim.c
index 57e88bd666..d3ecbdccdb 100644
--- a/openair1/SIMULATION/NR_PHY/ulsim.c
+++ b/openair1/SIMULATION/NR_PHY/ulsim.c
@@ -1117,7 +1117,7 @@ int main(int argc, char *argv[])
         pusch_config_pdu->target_code_rate = code_rate;
         pusch_config_pdu->tbslbrm = tbslbrm;
         pusch_config_pdu->pusch_data.tb_size = TBS / 8;
-        pusch_config_pdu->pusch_data.new_data_indicator = trial & 0x1;
+        pusch_config_pdu->pusch_data.new_data_indicator = round == 0 ? true : false;
         pusch_config_pdu->pusch_data.rv_index = rv_index;
         pusch_config_pdu->pusch_data.harq_process_id = harq_pid;
         pusch_config_pdu->pusch_ptrs.ptrs_time_density = ptrs_time_density;
diff --git a/openair1/SIMULATION/NR_UE_PHY/unit_tests/src/harq_test.c b/openair1/SIMULATION/NR_UE_PHY/unit_tests/src/harq_test.c
index 96d7382f2b..dc182b2106 100644
--- a/openair1/SIMULATION/NR_UE_PHY/unit_tests/src/harq_test.c
+++ b/openair1/SIMULATION/NR_UE_PHY/unit_tests/src/harq_test.c
@@ -25,7 +25,7 @@
 *
 * MODULE      :  UE test bench for hard (hybrid repeat request acknowledgment)
 *
-* DESCRIPTION :  it allows unitary tests for uplink and downlink harq
+* DESCRIPTION :  it allows unitary tests for downlink harq
 *
 ************************************************************************/
 
@@ -39,65 +39,6 @@
 //#include "PHY/vars.h"
 //#include "LAYER2/MAC/vars.h"
 
-/*******************************************************************
-*
-* NAME :         test_harq_uplink
-*
-* PARAMETERS :   none
-*
-* RETURN :       none
-*
-* DESCRIPTION :  test of HARQ uplink feature
-*
-*********************************************************************/
-
-int test_harq_uplink(PHY_VARS_NR_UE *phy_vars_ue)
-{
-  int gNB_id = 0;
-  int thread_number = 0;
-  int code_word_idx = 0;
-  int harq_pid = 0;
-  int ndi = 1;
-  uint8_t rnti_type = _C_RNTI_;
-  int number_steps = 5;
-
-  printf("\nHARQ Uplink \n");
-
-  config_uplink_harq_process(phy_vars_ue , gNB_id, thread_number, code_word_idx, NR_DEFAULT_DLSCH_HARQ_PROCESSES);
-
-  NR_UE_ULSCH_t *ulsch_harq = phy_vars_ue->ulsch[gNB_id];
-
-  /* reach maximum number of retransmissions */
-  printf("First sequence ndi does not toggle \n");
-  for (int i = 0 ; i < number_steps; i++) {
-    uplink_harq_process(ulsch_harq, harq_pid, ndi, rnti_type);
-  }
-
-  harq_pid++; /* next harq */
-
-  /* new grant so new transmission each try */
-  printf("Second sequence ndi toggle each transmission \n");
-  for (int i = 0 ; i < number_steps; i++) {
-    uplink_harq_process(ulsch_harq, harq_pid, ndi, rnti_type);
-    ndi ^= 1; /* toogle ndi each try */
-  }
-
-  harq_pid++; /* next harq */
-
-  /* new grant so new transmission each try */
-  printf("Third sequence ndi toggle each two transmissions \n");
-  for (int i = 0 ; i < number_steps; i++) {
-    uplink_harq_process(ulsch_harq, harq_pid, ndi, rnti_type);
-    if (i & 0x1) {
-      ndi ^= 1; /* toogle ndi each try */
-    }
-  }
-
-  release_uplink_harq_process(phy_vars_ue , gNB_id, thread_number, code_word_idx);
-
-  return 0;
-}
-
 /*******************************************************************
 *
 * NAME :         test_harq_downlink
@@ -175,11 +116,7 @@ int test_harq(PHY_VARS_NR_UE *phy_vars_ue)
 {
   int result = -1;
 
-  result = test_harq_uplink(phy_vars_ue);
-
-  if (result == 0) {
-    result = test_harq_downlink(phy_vars_ue);
-  }
+  result = test_harq_downlink(phy_vars_ue);
 
   return (result);
 }
@@ -188,7 +125,7 @@ int test_harq(PHY_VARS_NR_UE *phy_vars_ue)
 *
 * NAME :         main
 *
-* DESCRIPTION :  test of uplink and downlink harq entities
+* DESCRIPTION :  test of downlink harq entities
 *
 *********************************************************************/
 
diff --git a/openair2/LAYER2/NR_MAC_UE/mac_defs.h b/openair2/LAYER2/NR_MAC_UE/mac_defs.h
index 18560f3e92..c7bbee0780 100644
--- a/openair2/LAYER2/NR_MAC_UE/mac_defs.h
+++ b/openair2/LAYER2/NR_MAC_UE/mac_defs.h
@@ -505,9 +505,7 @@ typedef struct {
   fapi_nr_csirs_measurements_t csirs_measurements;
 
   /// Last NDI of UL HARQ processes
-  uint8_t UL_ndi[NR_MAX_HARQ_PROCESSES];
-  /// first ULTX of UL HARQ processes
-  int first_ul_tx[NR_MAX_HARQ_PROCESSES];
+  int UL_ndi[NR_MAX_HARQ_PROCESSES];
   ////	FAPI-like interface message
   fapi_nr_ul_config_request_t *ul_config_request;
   fapi_nr_dl_config_request_t *dl_config_request;
diff --git a/openair2/LAYER2/NR_MAC_UE/nr_ra_procedures.c b/openair2/LAYER2/NR_MAC_UE/nr_ra_procedures.c
index 73228af0d1..ebcb0e601b 100644
--- a/openair2/LAYER2/NR_MAC_UE/nr_ra_procedures.c
+++ b/openair2/LAYER2/NR_MAC_UE/nr_ra_procedures.c
@@ -597,7 +597,7 @@ void nr_Msg3_transmitted(module_id_t mod_id, uint8_t CC_id, frame_t frameP, slot
   // start contention resolution timer (cnt in slots)
   int RA_contention_resolution_timer_subframes = (nr_rach_ConfigCommon->ra_ContentionResolutionTimer + 1)<<3;
 
-  ra->RA_contention_resolution_target_frame = frameP + (RA_contention_resolution_timer_subframes/10);
+  ra->RA_contention_resolution_target_frame = (frameP + (RA_contention_resolution_timer_subframes/10)) % MAX_FRAME_NUMBER;
   ra->RA_contention_resolution_target_slot = (slotP + (RA_contention_resolution_timer_subframes * subframes_per_slot)) % nr_slots_per_frame[mu];
 
   LOG_D(MAC,"In %s: [UE %d] CB-RA: contention resolution timer set in frame.slot %d.%d and expiring in %d.%d\n",
diff --git a/openair2/LAYER2/NR_MAC_UE/nr_ue_procedures.c b/openair2/LAYER2/NR_MAC_UE/nr_ue_procedures.c
index e4bf6a0d26..2bb1691eae 100644
--- a/openair2/LAYER2/NR_MAC_UE/nr_ue_procedures.c
+++ b/openair2/LAYER2/NR_MAC_UE/nr_ue_procedures.c
@@ -197,7 +197,7 @@ void nr_ue_mac_default_configs(NR_UE_MAC_INST_t *mac)
     mac->scheduling_info.lc_sched_info[i].LCID_status = LCID_EMPTY;
     mac->scheduling_info.lc_sched_info[i].LCID_buffer_remain = 0;
     for (int k = 0; k < NR_MAX_HARQ_PROCESSES; k++)
-      mac->first_ul_tx[k] = 1;
+      mac->UL_ndi[k] = -1; // initialize to invalid value
   }
 
   memset(&mac->ssb_measurements, 0, sizeof(mac->ssb_measurements));
diff --git a/openair2/LAYER2/NR_MAC_UE/nr_ue_scheduler.c b/openair2/LAYER2/NR_MAC_UE/nr_ue_scheduler.c
index 83ad5e88b1..f688d6c2a4 100644
--- a/openair2/LAYER2/NR_MAC_UE/nr_ue_scheduler.c
+++ b/openair2/LAYER2/NR_MAC_UE/nr_ue_scheduler.c
@@ -627,7 +627,8 @@ int nr_config_pusch_pdu(NR_UE_MAC_INST_t *mac,
     }
 
     /* NDI */
-    pusch_config_pdu->pusch_data.new_data_indicator = dci->ndi;
+    pusch_config_pdu->pusch_data.new_data_indicator = dci->ndi != mac->UL_ndi[dci->harq_pid] ? 1 : 0;
+    mac->UL_ndi[dci->harq_pid] = dci->ndi;
     /* RV */
     pusch_config_pdu->pusch_data.rv_index = dci->rv;
     /* HARQ_PROCESS_NUMBER */
@@ -1032,9 +1033,8 @@ void nr_ue_ul_scheduler(nr_uplink_indication_t *ul_info)
         if (ulcfg_pdu->pdu_type == FAPI_NR_UL_CONFIG_TYPE_PUSCH) {
           int mac_pdu_exist = 0;
           uint16_t TBS_bytes = ulcfg_pdu->pusch_config_pdu.pusch_data.tb_size;
-          LOG_D(NR_MAC,"harq_id %d, NDI %d NDI_DCI %d, TBS_bytes %d (ra_state %d)\n",
+          LOG_D(NR_MAC,"harq_id %d, new_data_indicator %d, TBS_bytes %d (ra_state %d)\n",
                 ulcfg_pdu->pusch_config_pdu.pusch_data.harq_process_id,
-                mac->UL_ndi[ulcfg_pdu->pusch_config_pdu.pusch_data.harq_process_id],
                 ulcfg_pdu->pusch_config_pdu.pusch_data.new_data_indicator,
                 TBS_bytes,ra->ra_state);
           if (ra->ra_state == WAIT_RAR && !ra->cfra) {
@@ -1043,14 +1043,10 @@ void nr_ue_ul_scheduler(nr_uplink_indication_t *ul_info)
             for (int k = 0; k < TBS_bytes; k++) {
               LOG_D(NR_MAC,"(%i): 0x%x\n", k, ulsch_input_buffer[k]);
             }
-            LOG_D(NR_MAC,"Flipping NDI for harq_id %d (Msg3)\n", ulcfg_pdu->pusch_config_pdu.pusch_data.new_data_indicator);
-            mac->UL_ndi[ulcfg_pdu->pusch_config_pdu.pusch_data.harq_process_id] = ulcfg_pdu->pusch_config_pdu.pusch_data.new_data_indicator;
-            mac->first_ul_tx[ulcfg_pdu->pusch_config_pdu.pusch_data.harq_process_id] = 0;
             mac_pdu_exist = 1;
           } else {
 
-            if ((mac->UL_ndi[ulcfg_pdu->pusch_config_pdu.pusch_data.harq_process_id] != ulcfg_pdu->pusch_config_pdu.pusch_data.new_data_indicator ||
-                mac->first_ul_tx[ulcfg_pdu->pusch_config_pdu.pusch_data.harq_process_id] == 1) &&
+            if (ulcfg_pdu->pusch_config_pdu.pusch_data.new_data_indicator &&
                 (mac->state == UE_CONNECTED ||
                 (ra->ra_state == WAIT_RAR && ra->cfra))){
 
@@ -1059,10 +1055,6 @@ void nr_ue_ul_scheduler(nr_uplink_indication_t *ul_info)
               mac_pdu_exist = 1;
             }
 
-            LOG_D(NR_MAC,"Flipping NDI for harq_id %d\n",ulcfg_pdu->pusch_config_pdu.pusch_data.new_data_indicator);
-            mac->UL_ndi[ulcfg_pdu->pusch_config_pdu.pusch_data.harq_process_id] = ulcfg_pdu->pusch_config_pdu.pusch_data.new_data_indicator;
-            mac->first_ul_tx[ulcfg_pdu->pusch_config_pdu.pusch_data.harq_process_id] = 0;
-
           }
 
           // Config UL TX PDU