diff --git a/ci-scripts/conf_files/gnb-du.sa.band1.52prb.usrpb210.conf b/ci-scripts/conf_files/gnb-du.sa.band1.52prb.usrpb210.conf
index ab5cd5ac69..fb227fbaab 100644
--- a/ci-scripts/conf_files/gnb-du.sa.band1.52prb.usrpb210.conf
+++ b/ci-scripts/conf_files/gnb-du.sa.band1.52prb.usrpb210.conf
@@ -118,7 +118,8 @@ gNBs =
         pucchGroupHopping                                              = 0;
         hoppingId                                                      = 40;
         p0_nominal                                                     = -70;
-        n_TimingAdvanceOffset                                          = 0;
+        # TimingAdvanceOffset_n25600
+        n_TimingAdvanceOffset                                          = 1;
 
       ssb_PositionsInBurst_Bitmap                                      = 1;
 
diff --git a/common/utils/nr/nr_common.c b/common/utils/nr/nr_common.c
index f851c26eee..fafc1bcd47 100644
--- a/common/utils/nr/nr_common.c
+++ b/common/utils/nr/nr_common.c
@@ -1149,6 +1149,20 @@ void init_delay_table(uint16_t ofdm_symbol_size,
   }
 }
 
+int set_default_nta_offset(frequency_range_t freq_range, uint32_t samples_per_subframe)
+{
+  // ta_offset_samples : ta_offset = samples_per_subframe : (Δf_max x N_f / 1000)
+  // As described in Section 4.3.1 in 38.211
+
+  // TODO There is no way for the UE to know about LTE-NR coexistence case
+  //      as mentioned in Table 7.1.2-2 of 38.133
+  //      LTE-NR coexistence means the presence of an active LTE service in the same band as NR in current deployment
+  //      We assume no coexistence
+
+  uint64_t numer = (freq_range == FR1 ? 25600 : 13792) * (uint64_t)samples_per_subframe;
+  return numer / (4096 * 480);
+}
+
 void nr_timer_start(NR_timer_t *timer)
 {
   timer->active = true;
diff --git a/common/utils/nr/nr_common.h b/common/utils/nr/nr_common.h
index 3c04bca581..1e4fecc4f5 100644
--- a/common/utils/nr/nr_common.h
+++ b/common/utils/nr/nr_common.h
@@ -177,7 +177,7 @@ bool nr_timer_is_active(const NR_timer_t *timer);
  */
 uint32_t nr_timer_elapsed_time(const NR_timer_t *timer);
 
-
+int set_default_nta_offset(frequency_range_t freq_range, uint32_t samples_per_subframe);
 extern const nr_bandentry_t nr_bandtable[];
 
 static inline int get_num_dmrs(uint16_t dmrs_mask )
diff --git a/doc/SW_archi.md b/doc/SW_archi.md
index 277b4e3a9e..b186bea524 100644
--- a/doc/SW_archi.md
+++ b/doc/SW_archi.md
@@ -98,12 +98,6 @@ The infinite loop:
 raw incoming data is in buffer called "rxdata"  
     We derivate frame number, slot number, ... from the RX timestamp
 {: .func2}
-## nr_fep_full()
-"front end processing" of uplink signal  
-performs DFT on the signal  
-it computes the buffer rxdataF (for frequency) from rxdata (samples over time)  
-rxdataF is the rxdata in frequency domain, phase aligned
-{: .func3}
 ## gNB_top()
 only compute frame numbre, slot number, ...
 {: .func3}
diff --git a/executables/nr-ru.c b/executables/nr-ru.c
index 8a29e6ac2f..7f5d193d34 100644
--- a/executables/nr-ru.c
+++ b/executables/nr-ru.c
@@ -959,43 +959,10 @@ int setup_RU_buffers(RU_t *ru) {
   int mu = config->ssb_config.scs_common.value;
   int N_RB = config->carrier_config.dl_grid_size[config->ssb_config.scs_common.value].value;
 
-  if (config->cell_config.frame_duplex_type.value == TDD) {
-    int N_TA_offset =  config->carrier_config.uplink_frequency.value < 6000000 ? 400 : 431; // reference samples  for 25600Tc @ 30.72 Ms/s for FR1, same @ 61.44 Ms/s for FR2
-    double factor=1;
-
-    switch (mu) {
-      case 0: //15 kHz scs
-        AssertFatal(N_TA_offset == 400, "scs_common 15kHz only for FR1\n");
-        factor = fp->samples_per_subframe / 30720.0;
-        break;
-
-      case 1: //30 kHz sc
-        AssertFatal(N_TA_offset == 400, "scs_common 30kHz only for FR1\n");
-        factor = fp->samples_per_subframe / 30720.0;
-        break;
-
-      case 2: //60 kHz scs
-        AssertFatal(1==0, "scs_common should not be 60 kHz\n");
-        break;
-
-      case 3: //120 kHz scs
-        AssertFatal(N_TA_offset == 431, "scs_common 120kHz only for FR2\n");
-        factor = fp->samples_per_subframe / 61440.0;
-        break;
-
-      case 4: //240 kHz scs
-        AssertFatal(N_TA_offset == 431, "scs_common 240kHz only for FR2\n");
-        factor = fp->samples_per_subframe / 61440.0;
-        break;
-
-      default:
-        AssertFatal(1==0, "Invalid scs_common!\n");
-    }
-
-    ru->N_TA_offset = (int)(N_TA_offset * factor);
-    LOG_I(PHY,"RU %d Setting N_TA_offset to %d samples (factor %f, UL Freq %d, N_RB %d, mu %d)\n",ru->idx,ru->N_TA_offset,factor,
-          config->carrier_config.uplink_frequency.value, N_RB, mu);
-  } else ru->N_TA_offset = 0;
+  ru->N_TA_offset = set_default_nta_offset(fp->freq_range, fp->samples_per_subframe);
+  LOG_I(PHY,
+        "RU %d Setting N_TA_offset to %d samples (UL Freq %d, N_RB %d, mu %d)\n",
+        ru->idx, ru->N_TA_offset, config->carrier_config.uplink_frequency.value, N_RB, mu);
 
   if (ru->openair0_cfg.mmapped_dma == 1) {
     // replace RX signal buffers with mmaped HW versions
diff --git a/nfapi/open-nFAPI/nfapi/public_inc/fapi_nr_ue_interface.h b/nfapi/open-nFAPI/nfapi/public_inc/fapi_nr_ue_interface.h
index 1c0c596253..f0d9b73e63 100644
--- a/nfapi/open-nFAPI/nfapi/public_inc/fapi_nr_ue_interface.h
+++ b/nfapi/open-nFAPI/nfapi/public_inc/fapi_nr_ue_interface.h
@@ -550,6 +550,7 @@ typedef struct {
  int ta_frame;
  int ta_slot;
  int ta_command;
+ int ta_offset;
  bool is_rar;
 } fapi_nr_ta_command_pdu;
 
diff --git a/openair1/PHY/INIT/nr_init_ue.c b/openair1/PHY/INIT/nr_init_ue.c
index 3985efb9b7..577f7a44d8 100644
--- a/openair1/PHY/INIT/nr_init_ue.c
+++ b/openair1/PHY/INIT/nr_init_ue.c
@@ -499,47 +499,21 @@ void clean_UE_harq(PHY_VARS_NR_UE *UE)
 }
 
 
-void init_N_TA_offset(PHY_VARS_NR_UE *ue){
-
+void init_N_TA_offset(PHY_VARS_NR_UE *ue)
+{
   NR_DL_FRAME_PARMS *fp = &ue->frame_parms;
 
   // No timing offset for Sidelink, refer to 3GPP 38.211 Section 8.5
-  if (fp->frame_type == FDD || ue->sl_mode == 2) {
+  if (ue->sl_mode == 2)
     ue->N_TA_offset = 0;
-  } else {
-    int N_TA_offset = fp->ul_CarrierFreq < 6e9 ? 400 : 431; // reference samples  for 25600Tc @ 30.72 Ms/s for FR1, same @ 61.44 Ms/s for FR2
+  else
+    ue->N_TA_offset = set_default_nta_offset(fp->freq_range, fp->samples_per_subframe);
+  ue->ta_frame = -1;
+  ue->ta_slot = -1;
 
-    double factor = 1.0;
-    switch (fp->numerology_index) {
-      case 0: //15 kHz scs
-        AssertFatal(N_TA_offset == 400, "scs_common 15kHz only for FR1\n");
-        factor = fp->samples_per_subframe / 30720.0;
-        break;
-      case 1: //30 kHz sc
-        AssertFatal(N_TA_offset == 400, "scs_common 30kHz only for FR1\n");
-        factor = fp->samples_per_subframe / 30720.0;
-        break;
-      case 2: //60 kHz scs
-        AssertFatal(1==0, "scs_common should not be 60 kHz\n");
-        break;
-      case 3: //120 kHz scs
-        AssertFatal(N_TA_offset == 431, "scs_common 120kHz only for FR2\n");
-        factor = fp->samples_per_subframe / 61440.0;
-        break;
-      case 4: //240 kHz scs
-        AssertFatal(N_TA_offset == 431, "scs_common 240kHz only for FR2\n");
-        factor = fp->samples_per_subframe / 61440.0;
-        break;
-      default:
-        AssertFatal(1==0, "Invalid scs_common!\n");
-    }
-
-    ue->N_TA_offset = (int)(N_TA_offset * factor);
-    ue->ta_frame = -1;
-    ue->ta_slot = -1;
-
-    LOG_I(PHY,"UE %d Setting N_TA_offset to %d samples (factor %f, UL Freq %lu, N_RB %d, mu %d)\n", ue->Mod_id, ue->N_TA_offset, factor, fp->ul_CarrierFreq, fp->N_RB_DL, fp->numerology_index);
-  }
+  LOG_I(PHY,
+        "UE %d Setting N_TA_offset to %d samples (UL Freq %lu, N_RB %d, mu %d)\n",
+        ue->Mod_id, ue->N_TA_offset, fp->ul_CarrierFreq, fp->N_RB_DL, fp->numerology_index);
 }
 
 void phy_init_nr_top(PHY_VARS_NR_UE *ue) {
diff --git a/openair1/PHY/INIT/nr_parms.c b/openair1/PHY/INIT/nr_parms.c
index 6a2c300b72..939478f35c 100644
--- a/openair1/PHY/INIT/nr_parms.c
+++ b/openair1/PHY/INIT/nr_parms.c
@@ -316,7 +316,7 @@ void nr_init_frame_parms(nfapi_nr_config_request_scf_t* cfg, NR_DL_FRAME_PARMS *
   fp->get_samples_slot_timestamp = &get_samples_slot_timestamp;
   fp->get_slot_from_timestamp = &get_slot_from_timestamp;
   fp->samples_per_frame = 10 * fp->samples_per_subframe;
-  fp->freq_range = (fp->dl_CarrierFreq < 6e9)? FR1 : FR2;
+  fp->freq_range = (fp->dl_CarrierFreq < 6e9) ? FR1 : FR2;
 
   fp->Ncp = Ncp;
 
@@ -400,7 +400,7 @@ int nr_init_frame_parms_ue(NR_DL_FRAME_PARMS *fp,
   fp->get_samples_per_slot = &get_samples_per_slot;
   fp->get_samples_slot_timestamp = &get_samples_slot_timestamp;
   fp->samples_per_frame = 10 * fp->samples_per_subframe;
-  fp->freq_range = (fp->dl_CarrierFreq < 6e9)? FR1 : FR2;
+  fp->freq_range = (fp->dl_CarrierFreq < 6e9) ? FR1 : FR2;
 
   uint8_t sco = 0;
   if (((fp->freq_range == FR1) && (config->ssb_table.ssb_subcarrier_offset < 24)) ||
diff --git a/openair1/SCHED_NR/nr_ru_procedures.c b/openair1/SCHED_NR/nr_ru_procedures.c
index 16a06c6e97..2b26848170 100644
--- a/openair1/SCHED_NR/nr_ru_procedures.c
+++ b/openair1/SCHED_NR/nr_ru_procedures.c
@@ -224,42 +224,6 @@ void nr_feptx_prec(RU_t *ru,int frame_tx,int tti_tx) {
   stop_meas(&ru->precoding_stats);
 }
 
-
-void nr_fep_full(RU_t *ru, int slot) {
-
-  RU_proc_t *proc = &ru->proc;
-  int l, aa;
-  NR_DL_FRAME_PARMS *fp = ru->nr_frame_parms;
-
-  // if ((fp->frame_type == TDD) && 
-     // (subframe_select(fp,proc->tti_rx) != NR_UPLINK_SLOT)) return;
-
-  LOG_D(PHY,"In fep_full for slot = %d\n", proc->tti_rx);
-
-  start_meas(&ru->ofdm_demod_stats);
-  if (ru->idx == 0) VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME( VCD_SIGNAL_DUMPER_FUNCTIONS_PHY_PROCEDURES_RU_FEPRX, 1 );
-
-
-  // remove_7_5_kHz(ru,proc->tti_rx<<1);
-  // remove_7_5_kHz(ru,1+(proc->tti_rx<<1));
-  int offset = (proc->tti_rx % RU_RX_SLOT_DEPTH) * (fp->symbols_per_slot * fp->ofdm_symbol_size);
-  for (l = 0; l < fp->symbols_per_slot; l++) {
-    for (aa = 0; aa < fp->nb_antennas_rx; aa++) {
-      nr_slot_fep_ul(fp,
-                     ru->common.rxdata[aa],
-                     &ru->common.rxdataF[aa][offset],
-                     l,
-                     proc->tti_rx,
-                     ru->N_TA_offset);
-    }
-  }
-
-  if (ru->idx == 0) VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME( VCD_SIGNAL_DUMPER_FUNCTIONS_PHY_PROCEDURES_RU_FEPRX, 0 );
-  stop_meas(&ru->ofdm_demod_stats);
-  
-  
-}
-
 // core routine for FEP TX, called from threads in RU TX thread-pool 
 void nr_feptx(void *arg) {
 
@@ -363,8 +327,8 @@ void nr_feptx_tp(RU_t *ru, int frame_tx, int slot) {
 }
 
 // core RX FEP routine, called by threads in RU thread-pool
-void nr_fep(void* arg) {
-	
+void nr_fep(void* arg)
+{
   feprx_cmd_t *feprx_cmd = (feprx_cmd_t *)arg;
 
   RU_t *ru         = feprx_cmd->ru;
diff --git a/openair1/SCHED_NR/sched_nr.h b/openair1/SCHED_NR/sched_nr.h
index 4e1c7e2509..c31d3669a4 100644
--- a/openair1/SCHED_NR/sched_nr.h
+++ b/openair1/SCHED_NR/sched_nr.h
@@ -40,10 +40,8 @@ void nr_common_signal_procedures (PHY_VARS_gNB *gNB,int frame,int slot,nfapi_nr_
 void nr_feptx_ofdm(RU_t *ru,int frame_tx,int tti_tx);
 void nr_feptx0(RU_t *ru,int tti_tx,int first_symbol, int num_symbols, int aa);
 
-void fep_full(RU_t *ru,int slot);
 void nr_feptx_prec(RU_t *ru,int frame_tx,int tti_tx);
 void nr_feptx_prec_control(RU_t *ru,int frame,int tti_tx);
-void nr_fep_full(RU_t *ru, int slot);
 void nr_fep_tp(RU_t *ru, int slot);
 void nr_feptx_tp(RU_t *ru, int frame_tx, int slot);
 void feptx_prec(RU_t *ru,int frame_tx,int tti_tx);
diff --git a/openair1/SCHED_NR_UE/fapi_nr_ue_l1.c b/openair1/SCHED_NR_UE/fapi_nr_ue_l1.c
index 312d5778b3..32fa53cc60 100644
--- a/openair1/SCHED_NR_UE/fapi_nr_ue_l1.c
+++ b/openair1/SCHED_NR_UE/fapi_nr_ue_l1.c
@@ -328,7 +328,6 @@ static void configure_dlsch(NR_UE_DLSCH_t *dlsch0,
 
 static void configure_ta_command(PHY_VARS_NR_UE *ue, fapi_nr_ta_command_pdu *ta_command_pdu)
 {
-
   /* Time Alignment procedure
   // - UE processing capability 1
   // - Setting the TA update to be applied after the reception of the TA command
@@ -369,7 +368,7 @@ static void configure_ta_command(PHY_VARS_NR_UE *ue, fapi_nr_ta_command_pdu *ta_
   /* Time alignment procedure */
   // N_t_1 + N_t_2 + N_TA_max must be in msec
   const double t_subframe = 1.0; // subframe duration of 1 msec
-  const int ul_tx_timing_adjustment = 1 + (int)ceil(slots_per_subframe*(N_t_1 + N_t_2 + N_TA_max + 0.5)/t_subframe);
+  const int ul_tx_timing_adjustment = 1 + (int)ceil(slots_per_subframe * (N_t_1 + N_t_2 + N_TA_max + 0.5) / t_subframe);
 
   if (ta_command_pdu->is_rar) {
     ue->ta_slot = ta_command_pdu->ta_slot;
@@ -383,8 +382,19 @@ static void configure_ta_command(PHY_VARS_NR_UE *ue, fapi_nr_ta_command_pdu *ta_
       ue->ta_frame = ta_command_pdu->ta_frame;
     ue->ta_command = ta_command_pdu->ta_command;
   }
-  LOG_D(PHY,"TA command received in Frame.Slot %d.%d -- Starting UL time alignment procedures. TA update will be applied at frame %d slot %d\n",
+
+  LOG_D(PHY,
+        "TA command received in %d.%d Starting UL time alignment procedures. TA update will be applied at frame %d slot %d\n",
         ta_command_pdu->ta_frame, ta_command_pdu->ta_slot, ue->ta_frame, ue->ta_slot);
+
+  if (ta_command_pdu->ta_offset != -1) {
+    // ta_offset_samples : ta_offset = samples_per_subframe : (Δf_max x N_f / 1000)
+    // As described in Section 4.3.1 in 38.211
+    int ta_offset_samples = (ta_command_pdu->ta_offset * samples_per_subframe) / (4096 * 480);
+    ue->N_TA_offset = ta_offset_samples;
+    LOG_D(PHY, "Received N_TA offset %d from upper layers. Corresponds to %d samples.\n",
+          ta_command_pdu->ta_offset, ta_offset_samples);
+  }
 }
 
 static void nr_ue_scheduled_response_dl(NR_UE_MAC_INST_t *mac,
diff --git a/openair2/LAYER2/NR_MAC_UE/config_ue.c b/openair2/LAYER2/NR_MAC_UE/config_ue.c
index 0958172537..fab0fb7a7c 100644
--- a/openair2/LAYER2/NR_MAC_UE/config_ue.c
+++ b/openair2/LAYER2/NR_MAC_UE/config_ue.c
@@ -1545,6 +1545,45 @@ static void configure_common_BWP_ul(NR_UE_MAC_INST_t *mac, int bwp_id, NR_BWP_Up
   }
 }
 
+static void configure_timeAlignmentTimer(NR_timer_t *time_alignment_timer, NR_TimeAlignmentTimer_t timer_config, int scs)
+{
+  uint32_t timer_ms = 0;
+  switch (timer_config) {
+    case NR_TimeAlignmentTimer_ms500 :
+      timer_ms = 500;
+      break;
+    case NR_TimeAlignmentTimer_ms750 :
+      timer_ms = 750;
+      break;
+    case NR_TimeAlignmentTimer_ms1280 :
+      timer_ms = 1280;
+      break;
+    case NR_TimeAlignmentTimer_ms1920 :
+      timer_ms = 1920;
+      break;
+    case NR_TimeAlignmentTimer_ms2560 :
+      timer_ms = 2560;
+      break;
+    case NR_TimeAlignmentTimer_ms5120 :
+      timer_ms = 5120;
+      break;
+    case NR_TimeAlignmentTimer_ms10240 :
+      timer_ms = 10240;
+      break;
+    case NR_TimeAlignmentTimer_infinity :
+      timer_ms = UINT_MAX;
+      break;
+    default :
+      AssertFatal(false, "Invalid timeAlignmentTimer\n");
+  }
+  // length of slot is (1/2^scs)ms
+  uint32_t n_slots = timer_ms != UINT_MAX ? (timer_ms << scs) : UINT_MAX;
+  bool timer_was_active = nr_timer_is_active(time_alignment_timer);
+  nr_timer_setup(time_alignment_timer, n_slots, 1); // 1 slot update rate
+  if (timer_was_active)
+    nr_timer_start(time_alignment_timer);
+}
+
 void nr_rrc_mac_config_req_reset(module_id_t module_id,
                                  NR_UE_MAC_reset_cause_t cause)
 {
@@ -1577,6 +1616,8 @@ void nr_rrc_mac_config_req_reset(module_id_t module_id,
       nr_ue_mac_default_configs(mac);
       nr_ue_reset_sync_state(mac);
       release_mac_configuration(mac, cause);
+      // apply the timeAlignmentTimerCommon included in SIB1
+      configure_timeAlignmentTimer(&mac->time_alignment_timer, mac->timeAlignmentTimerCommon, mac->current_UL_BWP->scs);
       // new sync with old cell ID (re-establishment on the same cell)
       sync_req.target_Nid_cell = mac->physCellId;
       sync_req.ssb_bw_scan = false;
@@ -1587,6 +1628,24 @@ void nr_rrc_mac_config_req_reset(module_id_t module_id,
   }
 }
 
+static int get_ta_offset(long *n_TimingAdvanceOffset)
+{
+  if (!n_TimingAdvanceOffset)
+    return -1;
+
+  switch (*n_TimingAdvanceOffset) {
+    case NR_ServingCellConfigCommonSIB__n_TimingAdvanceOffset_n0 :
+      return 0;
+    case NR_ServingCellConfigCommonSIB__n_TimingAdvanceOffset_n25600 :
+      return 25600;
+    case NR_ServingCellConfigCommonSIB__n_TimingAdvanceOffset_n39936 :
+      return 39936;
+    default :
+      AssertFatal(false, "Invalid n-TimingAdvanceOffset\n");
+  }
+  return -1;
+}
+
 void nr_rrc_mac_config_req_sib1(module_id_t module_id,
                                 int cc_idP,
                                 NR_SI_SchedulingInfo_t *si_SchedulingInfo,
@@ -1599,15 +1658,18 @@ void nr_rrc_mac_config_req_sib1(module_id_t module_id,
   UPDATE_IE(mac->tdd_UL_DL_ConfigurationCommon, scc->tdd_UL_DL_ConfigurationCommon, NR_TDD_UL_DL_ConfigCommon_t);
   UPDATE_IE(mac->si_SchedulingInfo, si_SchedulingInfo, NR_SI_SchedulingInfo_t);
   UPDATE_IE(mac->si_SchedulingInfo_v1700, si_SchedulingInfo_v1700, NR_SI_SchedulingInfo_v1700_t);
+  mac->n_ta_offset = get_ta_offset(scc->n_TimingAdvanceOffset);
 
   config_common_ue_sa(mac, scc, cc_idP);
   configure_common_BWP_dl(mac,
                           0, // bwp-id
                           &scc->downlinkConfigCommon.initialDownlinkBWP);
-  if (scc->uplinkConfigCommon)
+  if (scc->uplinkConfigCommon) {
+    mac->timeAlignmentTimerCommon = scc->uplinkConfigCommon->timeAlignmentTimerCommon;
     configure_common_BWP_ul(mac,
                             0, // bwp-id
                             &scc->uplinkConfigCommon->initialUplinkBWP);
+  }
   // set current BWP only if coming from non-connected state
   // otherwise it is just a periodically update of the SIB1 content
   if (mac->state < UE_CONNECTED) {
@@ -1615,6 +1677,7 @@ void nr_rrc_mac_config_req_sib1(module_id_t module_id,
     AssertFatal(mac->current_DL_BWP, "Couldn't find DL-BWP0\n");
     mac->current_UL_BWP = get_ul_bwp_structure(mac, 0, false);
     AssertFatal(mac->current_UL_BWP, "Couldn't find DL-BWP0\n");
+    configure_timeAlignmentTimer(&mac->time_alignment_timer, mac->timeAlignmentTimerCommon, mac->current_UL_BWP->scs);
   }
 
   // Setup the SSB to Rach Occasions mapping according to the config
@@ -1652,6 +1715,7 @@ static void handle_reconfiguration_with_sync(NR_UE_MAC_INST_t *mac,
 
   if (reconfigurationWithSync->spCellConfigCommon) {
     NR_ServingCellConfigCommon_t *scc = reconfigurationWithSync->spCellConfigCommon;
+    mac->n_ta_offset = get_ta_offset(scc->n_TimingAdvanceOffset);
     if (scc->physCellId)
       mac->physCellId = *scc->physCellId;
     mac->dmrs_TypeA_Position = scc->dmrs_TypeA_Position;
@@ -1939,12 +2003,29 @@ static void configure_maccellgroup(NR_UE_MAC_INST_t *mac, const NR_MAC_CellGroup
     }
   }
   if (mcg->tag_Config) {
-    // TODO TAG not handled
-    if(mcg->tag_Config->tag_ToAddModList) {
+    if (mcg->tag_Config->tag_ToReleaseList) {
+      for (int i = 0; i < mcg->tag_Config->tag_ToReleaseList->list.count; i++) {
+        for (int j = 0; j < mac->TAG_list.count; j++) {
+          if (*mcg->tag_Config->tag_ToReleaseList->list.array[i] == mac->TAG_list.array[j]->tag_Id)
+            asn_sequence_del(&mac->TAG_list, j, 1);
+        }
+      }
+    }
+    if (mcg->tag_Config->tag_ToAddModList) {
       for (int i = 0; i < mcg->tag_Config->tag_ToAddModList->list.count; i++) {
-        if (mcg->tag_Config->tag_ToAddModList->list.array[i]->timeAlignmentTimer !=
-            NR_TimeAlignmentTimer_infinity)
-          LOG_E(NR_MAC, "TimeAlignmentTimer not handled\n");
+        int j;
+        for (j = 0; j < mac->TAG_list.count; j++) {
+          if (mac->TAG_list.array[j]->tag_Id == mcg->tag_Config->tag_ToAddModList->list.array[i]->tag_Id)
+            break;
+        }
+        if (j < mac->TAG_list.count) {
+          UPDATE_IE(mac->TAG_list.array[j], mcg->tag_Config->tag_ToAddModList->list.array[i], NR_TAG_t);
+        }
+        else {
+          NR_TAG_t *local_tag = NULL;
+          UPDATE_IE(local_tag, mcg->tag_Config->tag_ToAddModList->list.array[i], NR_TAG_t);
+          ASN_SEQUENCE_ADD(&mac->TAG_list, local_tag);
+        }
       }
     }
   }
@@ -2428,6 +2509,7 @@ void nr_rrc_mac_config_req_cg(module_id_t module_id,
       handle_reconfiguration_with_sync(mac, cc_idP, spCellConfig->reconfigurationWithSync);
     }
     if (scd) {
+      mac->tag_Id = scd->tag_Id;
       configure_servingcell_info(mac, scd);
       configure_BWPs(mac, scd);
     }
@@ -2436,6 +2518,12 @@ void nr_rrc_mac_config_req_cg(module_id_t module_id,
   if (cell_group_config->mac_CellGroupConfig)
     configure_maccellgroup(mac, cell_group_config->mac_CellGroupConfig);
 
+  for (int j = 0; j < mac->TAG_list.count; j++) {
+    // apply the Timing Advance Command for the indicated TAG
+    if (mac->TAG_list.array[j]->tag_Id == mac->tag_Id)
+      configure_timeAlignmentTimer(&mac->time_alignment_timer, mac->TAG_list.array[j]->timeAlignmentTimer, mac->current_UL_BWP->scs);
+  }
+
   configure_logicalChannelBearer(mac,
                                  cell_group_config->rlc_BearerToAddModList,
                                  cell_group_config->rlc_BearerToReleaseList);
diff --git a/openair2/LAYER2/NR_MAC_UE/mac_defs.h b/openair2/LAYER2/NR_MAC_UE/mac_defs.h
index fb727aeb5e..d9c5fa2345 100644
--- a/openair2/LAYER2/NR_MAC_UE/mac_defs.h
+++ b/openair2/LAYER2/NR_MAC_UE/mac_defs.h
@@ -76,7 +76,6 @@
 #define NR_INVALID_LCGID (NR_MAX_NUM_LCGID)
 
 #define MAX_NUM_BWP_UE 5
-#define NUM_SLOT_FRAME 10
 #define NR_MAX_SR_ID 8  // SchedulingRequestId ::= INTEGER (0..7)
 
 /*!\brief value for indicating BSR Timer is not running */
@@ -424,10 +423,9 @@ typedef enum ta_type {
 } ta_type_t;
 
 typedef struct NR_UL_TIME_ALIGNMENT {
-  /// TA command and TAGID received from the gNB
+  /// TA command received from the gNB
   ta_type_t ta_apply;
   int ta_command;
-  uint32_t tag_id;
   int frame;
   int slot;
 } NR_UL_TIME_ALIGNMENT_t;
@@ -576,6 +574,7 @@ typedef struct NR_UE_MAC_INST_s {
   int dmrs_TypeA_Position;
   int p_Max;
   int p_Max_alt;
+  int n_ta_offset; // -1 not present, otherwise value to be applied
 
   long pdsch_HARQ_ACK_Codebook;
 
@@ -594,6 +593,11 @@ typedef struct NR_UE_MAC_INST_s {
   NR_UE_HARQ_STATUS_t dl_harq_info[NR_MAX_HARQ_PROCESSES];
   NR_UL_HARQ_INFO_t ul_harq_info[NR_MAX_HARQ_PROCESSES];
 
+  NR_TAG_Id_t tag_Id;
+  A_SEQUENCE_OF(NR_TAG_t) TAG_list;
+  NR_TimeAlignmentTimer_t timeAlignmentTimerCommon;
+  NR_timer_t time_alignment_timer;
+
   nr_emulated_l1_t nr_ue_emul_l1;
 
   pthread_mutex_t mutex_dl_info;
diff --git a/openair2/LAYER2/NR_MAC_UE/mac_proto.h b/openair2/LAYER2/NR_MAC_UE/mac_proto.h
index bb42701ec3..e2d6125145 100644
--- a/openair2/LAYER2/NR_MAC_UE/mac_proto.h
+++ b/openair2/LAYER2/NR_MAC_UE/mac_proto.h
@@ -349,8 +349,9 @@ void free_rach_structures(NR_UE_MAC_INST_t *nr_mac, int bwp_id);
 void schedule_RA_after_SR_failure(NR_UE_MAC_INST_t *mac);
 void nr_Msg1_transmitted(NR_UE_MAC_INST_t *mac);
 void nr_Msg3_transmitted(NR_UE_MAC_INST_t *mac, uint8_t CC_id, frame_t frameP, slot_t slotP, uint8_t gNB_id);
+void trigger_MAC_UE_RA(NR_UE_MAC_INST_t *mac);
 void nr_get_msg3_payload(NR_UE_MAC_INST_t *mac, uint8_t *buf, int TBS_max);
-
+void handle_time_alignment_timer_expired(NR_UE_MAC_INST_t *mac);
 int8_t nr_ue_process_dci_freq_dom_resource_assignment(nfapi_nr_ue_pusch_pdu_t *pusch_config_pdu,
                                                       fapi_nr_dl_config_dlsch_pdu_rel15_t *dlsch_config_pdu,
                                                       NR_PDSCH_Config_t *pdsch_Config,
diff --git a/openair2/LAYER2/NR_MAC_UE/main_ue_nr.c b/openair2/LAYER2/NR_MAC_UE/main_ue_nr.c
index e60c163236..a60d8d2c43 100644
--- a/openair2/LAYER2/NR_MAC_UE/main_ue_nr.c
+++ b/openair2/LAYER2/NR_MAC_UE/main_ue_nr.c
@@ -69,6 +69,7 @@ void nr_ue_init_mac(NR_UE_MAC_INST_t *mac)
   mac->uecap_maxMIMO_PUSCH_layers_nocb = 0;
   mac->p_Max = INT_MIN;
   mac->p_Max_alt = INT_MIN;
+  mac->n_ta_offset = -1;
   reset_mac_inst(mac);
 
   // need to inizialize because might not been setup (optional timer)
@@ -201,6 +202,7 @@ void reset_mac_inst(NR_UE_MAC_INST_t *nr_mac)
   }
   if (nr_mac->data_inactivity_timer)
     nr_timer_stop(nr_mac->data_inactivity_timer);
+  nr_timer_stop(&nr_mac->time_alignment_timer);
   nr_timer_stop(&nr_mac->ra.contention_resolution_timer);
   nr_timer_stop(&nr_mac->scheduling_info.sr_DelayTimer);
   nr_timer_stop(&nr_mac->scheduling_info.retxBSR_Timer);
@@ -208,7 +210,7 @@ void reset_mac_inst(NR_UE_MAC_INST_t *nr_mac)
     nr_timer_stop(&nr_mac->scheduling_info.sr_info[i].prohibitTimer);
 
   // consider all timeAlignmentTimers as expired and perform the corresponding actions in clause 5.2
-  // TODO
+  handle_time_alignment_timer_expired(nr_mac);
 
   // set the NDIs for all uplink HARQ processes to the value 0
   for (int k = 0; k < NR_MAX_HARQ_PROCESSES; k++)
@@ -320,6 +322,8 @@ void release_mac_configuration(NR_UE_MAC_INST_t *mac, NR_UE_MAC_reset_cause_t ca
   memset(&mac->ssb_measurements, 0, sizeof(mac->ssb_measurements));
   memset(&mac->csirs_measurements, 0, sizeof(mac->csirs_measurements));
   memset(&mac->ul_time_alignment, 0, sizeof(mac->ul_time_alignment));
+  for (int i = mac->TAG_list.count; i > 0 ; i--)
+    asn_sequence_del(&mac->TAG_list, i - 1, 1);
 }
 
 void free_rach_structures(NR_UE_MAC_INST_t *nr_mac, int bwp_id)
diff --git a/openair2/LAYER2/NR_MAC_UE/nr_ra_procedures.c b/openair2/LAYER2/NR_MAC_UE/nr_ra_procedures.c
index c52a67c5a2..6272c4c33f 100644
--- a/openair2/LAYER2/NR_MAC_UE/nr_ra_procedures.c
+++ b/openair2/LAYER2/NR_MAC_UE/nr_ra_procedures.c
@@ -912,9 +912,14 @@ void nr_ra_failed(NR_UE_MAC_INST_t *mac, uint8_t CC_id, NR_PRACH_RESOURCES_t *pr
 
   prach_resources->RA_PREAMBLE_TRANSMISSION_COUNTER++;
 
-  if (prach_resources->RA_PREAMBLE_TRANSMISSION_COUNTER == ra->preambleTransMax + 1){
+  // when the Contention Resolution is considered not successful
+  // stop timeAlignmentTimer
+  nr_timer_stop(&mac->time_alignment_timer);
 
-    LOG_D(MAC, "[UE %d][%d.%d] Maximum number of RACH attempts (%d) reached, selecting backoff time...\n",
+  if (prach_resources->RA_PREAMBLE_TRANSMISSION_COUNTER == ra->preambleTransMax + 1) {
+
+    LOG_D(NR_MAC,
+          "[UE %d][%d.%d] Maximum number of RACH attempts (%d) reached, selecting backoff time...\n",
           mac->ue_id,
           frame,
           slot,
@@ -931,23 +936,12 @@ void nr_ra_failed(NR_UE_MAC_INST_t *mac, uint8_t CC_id, NR_PRACH_RESOURCES_t *pr
   }
 }
 
-void schedule_RA_after_SR_failure(NR_UE_MAC_INST_t *mac)
+void trigger_MAC_UE_RA(NR_UE_MAC_INST_t *mac)
 {
   LOG_W(NR_MAC, "Triggering new RA procedure for UE with RNTI %x\n", mac->crnti);
   mac->state = UE_SYNC;
   reset_ra(mac, false);
   mac->ra.msg3_C_RNTI = true;
-  // release PUCCH for all Serving Cells;
-  // release SRS for all Serving Cells;
-  release_PUCCH_SRS(mac);
-  // clear any configured downlink assignments and uplink grants;
-  int scs = mac->current_UL_BWP->scs;
-  if (mac->dl_config_request)
-    memset(mac->dl_config_request, 0, sizeof(*mac->dl_config_request));
-  if (mac->ul_config_request)
-    clear_ul_config_request(mac, scs);
-  // clear any PUSCH resources for semi-persistent CSI reporting
-  // TODO we don't have semi-persistent CSI reporting
 }
 
 void prepare_msg4_feedback(NR_UE_MAC_INST_t *mac, int pid, int ack_nack)
diff --git a/openair2/LAYER2/NR_MAC_UE/nr_ue_procedures.c b/openair2/LAYER2/NR_MAC_UE/nr_ue_procedures.c
index ccfa861587..32d0dc72cf 100644
--- a/openair2/LAYER2/NR_MAC_UE/nr_ue_procedures.c
+++ b/openair2/LAYER2/NR_MAC_UE/nr_ue_procedures.c
@@ -2953,8 +2953,11 @@ void nr_ue_send_sdu(NR_UE_MAC_INST_t *mac, nr_downlink_indication_t *dl_info, in
 {
   VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME(VCD_SIGNAL_DUMPER_FUNCTIONS_UE_SEND_SDU, VCD_FUNCTION_IN);
 
-  LOG_D(MAC, "In [%d.%d] Handling DLSCH PDU type %d\n",
-        dl_info->frame, dl_info->slot, dl_info->rx_ind->rx_indication_body[pdu_id].pdu_type);
+  LOG_D(NR_MAC,
+        "In [%d.%d] Handling DLSCH PDU type %d\n",
+        dl_info->frame,
+        dl_info->slot,
+        dl_info->rx_ind->rx_indication_body[pdu_id].pdu_type);
 
   // Processing MAC PDU
   // it parses MAC CEs subheaders, MAC CEs, SDU subheaderds and SDUs
@@ -2964,15 +2967,19 @@ void nr_ue_send_sdu(NR_UE_MAC_INST_t *mac, nr_downlink_indication_t *dl_info, in
       // DCCH logical channel, or CCCH logical channel
       if (mac->data_inactivity_timer)
         nr_timer_start(mac->data_inactivity_timer);
+      // DL data arrival during RRC_CONNECTED when UL synchronisation status is "non-synchronised"
+      if (!nr_timer_is_active(&mac->time_alignment_timer) && mac->state == UE_CONNECTED && !get_softmodem_params()->phy_test) {
+        trigger_MAC_UE_RA(mac);
+        break;
+      }
       nr_ue_process_mac_pdu(mac, dl_info, pdu_id);
       break;
     case FAPI_NR_RX_PDU_TYPE_RAR :
       nr_ue_process_rar(mac, dl_info, pdu_id);
       break;
-    default:
-      AssertFatal(false, "Invalid PDU type\n");
+    default :
+      AssertFatal(false, "Invalid DLSCH PDU type\n");
   }
-
   VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME(VCD_SIGNAL_DUMPER_FUNCTIONS_UE_SEND_SDU, VCD_FUNCTION_OUT);
 }
 
@@ -3412,6 +3419,21 @@ static nr_dci_format_t nr_extract_dci_info(NR_UE_MAC_INST_t *mac,
   return format;
 }
 
+static void set_time_alignment(NR_UE_MAC_INST_t *mac, int ta, ta_type_t type, int frame, int slot)
+{
+  NR_UL_TIME_ALIGNMENT_t *ul_time_alignment = &mac->ul_time_alignment;
+  ul_time_alignment->ta_command = ta;
+  ul_time_alignment->ta_apply = type;
+
+  const int ntn_ue_koffset = get_NTN_UE_Koffset(mac->sc_info.ntn_Config_r17, mac->current_UL_BWP->scs);
+  const int n_slots_frame = nr_slots_per_frame[mac->current_UL_BWP->scs];
+  ul_time_alignment->frame = (frame + (slot + ntn_ue_koffset) / n_slots_frame) % MAX_FRAME_NUMBER;
+  ul_time_alignment->slot = (slot + ntn_ue_koffset) % n_slots_frame;
+
+  // start or restart the timeAlignmentTimer associated with the indicated TAG
+  nr_timer_start(&mac->time_alignment_timer);
+}
+
 ///////////////////////////////////
 // brief:     nr_ue_process_mac_pdu
 // function:  parsing DL PDU header
@@ -3563,33 +3585,21 @@ void nr_ue_process_mac_pdu(NR_UE_MAC_INST_t *mac, nr_downlink_indication_t *dl_i
         //  38.321 Ch6.1.3.4
         mac_len = 1;
 
-        /*uint8_t ta_command = ((NR_MAC_CE_TA *)pduP)[1].TA_COMMAND;
-          uint8_t tag_id = ((NR_MAC_CE_TA *)pduP)[1].TAGID;*/
-
         const int ta = ((NR_MAC_CE_TA *)pduP)[1].TA_COMMAND;
         const int tag = ((NR_MAC_CE_TA *)pduP)[1].TAGID;
 
-        NR_UL_TIME_ALIGNMENT_t *ul_time_alignment = &mac->ul_time_alignment;
-        ul_time_alignment->tag_id = tag;
-        ul_time_alignment->ta_command = ta;
-        ul_time_alignment->ta_apply = adjustment_ta;
+        if (tag != mac->tag_Id) {
+          LOG_E(NR_MAC, "MAC CE TAG %d does not correspond to the one configured at MAC %ld\n", tag, mac->tag_Id);
+          done = 1;
+          break;
+        }
 
-        const int ntn_ue_koffset = get_NTN_UE_Koffset(mac->sc_info.ntn_Config_r17, mac->current_UL_BWP->scs);
-        const int n_slots_frame = nr_slots_per_frame[mac->current_UL_BWP->scs];
-        ul_time_alignment->frame = (frameP + (slot + ntn_ue_koffset) / n_slots_frame) % MAX_FRAME_NUMBER;
-        ul_time_alignment->slot = (slot + ntn_ue_koffset) % n_slots_frame;
-
-        /*
-        #ifdef DEBUG_HEADER_PARSING
-        LOG_D(MAC, "[UE] CE %d : UE Timing Advance : %d\n", i, pduP[1]);
-        #endif
-        */
+        set_time_alignment(mac, ta, adjustment_ta, frameP, slot);
 
         if (ta == 31)
           LOG_D(NR_MAC, "[%d.%d] Received TA_COMMAND %u TAGID %u CC_id %d \n", frameP, slot, ta, tag, CC_id);
         else
           LOG_I(NR_MAC, "[%d.%d] Received TA_COMMAND %u TAGID %u CC_id %d \n", frameP, slot, ta, tag, CC_id);
-
         break;
       case DL_SCH_LCID_CON_RES_ID:
         //  Clause 5.1.5 and 6.1.3.3 of 3GPP TS 38.321 version 16.2.1 Release 16
@@ -3933,13 +3943,15 @@ static void nr_ue_process_rar(NR_UE_MAC_INST_t *mac, nr_downlink_indication_t *d
     }
   }
 
-  #ifdef DEBUG_RAR
-  LOG_D(MAC, "[DEBUG_RAR] (%d,%d) number of RAR subheader %d; number of RAR pyloads %d\n",
+#ifdef DEBUG_RAR
+  LOG_D(NR_MAC,
+        "[DEBUG_RAR] (%d,%d) number of RAR subheader %d; number of RAR pyloads %d\n",
         frame,
         slot,
         n_subheaders,
         n_subPDUs);
-  LOG_D(MAC, "[DEBUG_RAR] Received RAR (%02x|%02x.%02x.%02x.%02x.%02x.%02x) for preamble %d/%d\n",
+  LOG_D(NR_MAC,
+        "[DEBUG_RAR] Received RAR (%02x|%02x.%02x.%02x.%02x.%02x.%02x) for preamble %d/%d\n",
         *(uint8_t *) rarh,
         rar[0],
         rar[1],
@@ -3949,30 +3961,18 @@ static void nr_ue_process_rar(NR_UE_MAC_INST_t *mac, nr_downlink_indication_t *d
         rar[5],
         rarh->RAPID,
         preamble_index);
-  #endif
+#endif
 
   if (ra->RA_RAPID_found) {
     RAR_grant_t rar_grant;
 
-    unsigned char tpc_command;
-#ifdef DEBUG_RAR
-    unsigned char csi_req;
-#endif
-
-    // TA command
-    NR_UL_TIME_ALIGNMENT_t *ul_time_alignment = &mac->ul_time_alignment;
-    const int ta = rar->TA2 + (rar->TA1 << 5);
-    ul_time_alignment->ta_command = ta;
-    ul_time_alignment->ta_apply = rar_ta;
-
-    LOG_W(MAC, "received TA command %d\n", 31 + ta);
 #ifdef DEBUG_RAR
     // CSI
-    csi_req = (unsigned char) (rar->UL_GRANT_4 & 0x01);
+    unsigned char csi_req = (unsigned char) (rar->UL_GRANT_4 & 0x01);
 #endif
 
     // TPC
-    tpc_command = (unsigned char) ((rar->UL_GRANT_4 >> 1) & 0x07);
+    unsigned char tpc_command = (unsigned char) ((rar->UL_GRANT_4 >> 1) & 0x07);
     switch (tpc_command){
       case 0:
         ra->Msg3_TPC = -6;
@@ -4010,6 +4010,31 @@ static void nr_ue_process_rar(NR_UE_MAC_INST_t *mac, nr_downlink_indication_t *d
     // frequency hopping
     rar_grant.freq_hopping = (unsigned char) (rar->UL_GRANT_1 >> 2);
 
+    // Schedule Msg3
+    const NR_UE_UL_BWP_t *current_UL_BWP = mac->current_UL_BWP;
+    const NR_UE_DL_BWP_t *current_DL_BWP = mac->current_DL_BWP;
+    const NR_BWP_PDCCH_t *pdcch_config = &mac->config_BWP_PDCCH[current_DL_BWP->bwp_id];
+    NR_tda_info_t tda_info = get_ul_tda_info(current_UL_BWP,
+                                             *pdcch_config->ra_SS->controlResourceSetId,
+                                             pdcch_config->ra_SS->searchSpaceType->present,
+                                             TYPE_RA_RNTI_,
+                                             rar_grant.Msg3_t_alloc);
+    if (!tda_info.valid_tda || tda_info.nrOfSymbols == 0) {
+      LOG_E(MAC, "Cannot schedule Msg3. Something wrong in TDA information\n");
+      return;
+    }
+    const int ntn_ue_koffset = get_NTN_UE_Koffset(mac->sc_info.ntn_Config_r17, mac->current_UL_BWP->scs);
+    ret = nr_ue_pusch_scheduler(mac, is_Msg3, frame, slot, &frame_tx, &slot_tx, tda_info.k2 + ntn_ue_koffset);
+
+    // TA command
+    // if the timeAlignmentTimer associated with this TAG is not running
+    if (!nr_timer_is_active(&mac->time_alignment_timer)) {
+      const int ta = rar->TA2 + (rar->TA1 << 5);
+      set_time_alignment(mac, ta, rar_ta, frame_tx, slot_tx);
+      LOG_W(MAC, "received TA command %d\n", 31 + ta);
+    }
+    // else ignore the received Timing Advance Command
+
 #ifdef DEBUG_RAR
     LOG_I(NR_MAC, "rarh->E = 0x%x\n", rarh->E);
     LOG_I(NR_MAC, "rarh->T = 0x%x\n", rarh->T);
@@ -4040,26 +4065,6 @@ static void nr_ue_process_rar(NR_UE_MAC_INST_t *mac, nr_downlink_indication_t *d
           tpc_command);
 #endif
 
-    // Schedule Msg3
-    const NR_UE_UL_BWP_t *current_UL_BWP = mac->current_UL_BWP;
-    const NR_UE_DL_BWP_t *current_DL_BWP = mac->current_DL_BWP;
-    const NR_BWP_PDCCH_t *pdcch_config = &mac->config_BWP_PDCCH[current_DL_BWP->bwp_id];
-    NR_tda_info_t tda_info = get_ul_tda_info(current_UL_BWP,
-                                             *pdcch_config->ra_SS->controlResourceSetId,
-                                             pdcch_config->ra_SS->searchSpaceType->present,
-                                             TYPE_RA_RNTI_,
-                                             rar_grant.Msg3_t_alloc);
-    if (!tda_info.valid_tda || tda_info.nrOfSymbols == 0) {
-      LOG_E(MAC, "Cannot schedule Msg3. Something wrong in TDA information\n");
-      return;
-    }
-    const int ntn_ue_koffset = get_NTN_UE_Koffset(mac->sc_info.ntn_Config_r17, mac->current_UL_BWP->scs);
-    ret = nr_ue_pusch_scheduler(mac, is_Msg3, frame, slot, &frame_tx, &slot_tx, tda_info.k2 + ntn_ue_koffset);
-
-    const int n_slots_frame = nr_slots_per_frame[current_UL_BWP->scs];
-    ul_time_alignment->frame = (frame_tx + (slot_tx + ntn_ue_koffset) / n_slots_frame) % MAX_FRAME_NUMBER;
-    ul_time_alignment->slot = (slot_tx + ntn_ue_koffset) % n_slots_frame;
-
     if (ret != -1) {
       uint16_t rnti = mac->crnti;
       // Upon successful reception, set the T-CRNTI to the RAR value if the RA preamble is selected among the contention-based RA Preambles
@@ -4089,6 +4094,9 @@ static void nr_ue_process_rar(NR_UE_MAC_INST_t *mac, nr_downlink_indication_t *d
 
   } else {
     ra->t_crnti = 0;
+    // TODO if the Random Access Preamble was not selected by the MAC entity
+    //      among the contention-based Random Access Preamble
+    //      apply the Timing Advance Command and start or restart the timeAlignmentTimer
   }
   return;
 }
diff --git a/openair2/LAYER2/NR_MAC_UE/nr_ue_scheduler.c b/openair2/LAYER2/NR_MAC_UE/nr_ue_scheduler.c
index e9a2fb58de..84a35dcf52 100644
--- a/openair2/LAYER2/NR_MAC_UE/nr_ue_scheduler.c
+++ b/openair2/LAYER2/NR_MAC_UE/nr_ue_scheduler.c
@@ -61,7 +61,7 @@
   }
 
 static void nr_ue_prach_scheduler(NR_UE_MAC_INST_t *mac, frame_t frameP, sub_frame_t slotP);
-static void schedule_ta_command(fapi_nr_dl_config_request_t *dl_config, NR_UL_TIME_ALIGNMENT_t *ul_time_alignment);
+static void schedule_ta_command(fapi_nr_dl_config_request_t *dl_config, NR_UE_MAC_INST_t *mac);
 static void nr_ue_fill_phr(NR_UE_MAC_INST_t *mac,
                            NR_SINGLE_ENTRY_PHR_MAC_CE *phr,
                            float P_CMAX,
@@ -152,6 +152,30 @@ static void trigger_regular_bsr(NR_UE_MAC_INST_t *mac, NR_LogicalChannelIdentity
     nr_timer_stop(&mac->scheduling_info.sr_DelayTimer);
 }
 
+void handle_time_alignment_timer_expired(NR_UE_MAC_INST_t *mac)
+{
+  // flush all HARQ buffers for all Serving Cells
+  for (int k = 0; k < NR_MAX_HARQ_PROCESSES; k++) {
+    memset(&mac->dl_harq_info[k], 0, sizeof(NR_UE_HARQ_STATUS_t));
+    memset(&mac->ul_harq_info[k], 0, sizeof(NR_UL_HARQ_INFO_t));
+    mac->dl_harq_info[k].last_ndi = -1; // initialize to invalid value
+    mac->ul_harq_info[k].last_ndi = -1; // initialize to invalid value
+  }
+  // release PUCCH for all Serving Cells;
+  // release SRS for all Serving Cells;
+  release_PUCCH_SRS(mac);
+  // clear any configured downlink assignments and uplink grants;
+  int scs = mac->current_UL_BWP ? mac->current_UL_BWP->scs : get_softmodem_params()->numerology;
+  if (mac->dl_config_request)
+    memset(mac->dl_config_request, 0, sizeof(*mac->dl_config_request));
+  if (mac->ul_config_request)
+    clear_ul_config_request(mac, scs);
+  // clear any PUSCH resources for semi-persistent CSI reporting
+  // TODO we don't have semi-persistent CSI reporting
+  // maintain N_TA
+  // TODO not sure what to do here
+}
+
 void update_mac_timers(NR_UE_MAC_INST_t *mac)
 {
   if (mac->data_inactivity_timer) {
@@ -159,6 +183,9 @@ void update_mac_timers(NR_UE_MAC_INST_t *mac)
     if (inactivity_timer_expired)
       nr_mac_rrc_inactivity_timer_ind(mac->ue_id);
   }
+  bool alignment_timer_expired = nr_timer_tick(&mac->time_alignment_timer);
+  if (alignment_timer_expired)
+    handle_time_alignment_timer_expired(mac);
   nr_timer_tick(&mac->ra.contention_resolution_timer);
   for (int j = 0; j < NR_MAX_SR_ID; j++)
     nr_timer_tick(&mac->scheduling_info.sr_info[j].prohibitTimer);
@@ -1245,7 +1272,7 @@ void nr_ue_dl_scheduler(NR_UE_MAC_INST_t *mac, nr_downlink_indication_t *dl_info
   ue_dci_configuration(mac, dl_config, rx_frame, rx_slot);
 
   if (mac->ul_time_alignment.ta_apply != no_ta)
-    schedule_ta_command(dl_config, &mac->ul_time_alignment);
+    schedule_ta_command(dl_config, mac);
 
   nr_scheduled_response_t scheduled_response = {.dl_config = dl_config,
                                                 .module_id = mac->ue_id,
@@ -1271,6 +1298,24 @@ static bool check_pucchres_for_pending_SR(NR_PUCCH_Config_t *pucch_Config, int t
   return false;
 }
 
+void schedule_RA_after_SR_failure(NR_UE_MAC_INST_t *mac)
+{
+  if (get_softmodem_params()->phy_test)
+    return; // cannot trigger RA in phytest mode
+  trigger_MAC_UE_RA(mac);
+  // release PUCCH for all Serving Cells;
+  // release SRS for all Serving Cells;
+  release_PUCCH_SRS(mac);
+  // clear any configured downlink assignments and uplink grants;
+  int scs = mac->current_UL_BWP->scs;
+  if (mac->dl_config_request)
+    memset(mac->dl_config_request, 0, sizeof(*mac->dl_config_request));
+  if (mac->ul_config_request)
+    clear_ul_config_request(mac, scs);
+  // clear any PUSCH resources for semi-persistent CSI reporting
+  // TODO we don't have semi-persistent CSI reporting
+}
+
 static void nr_update_sr(NR_UE_MAC_INST_t *mac)
 {
   NR_UE_SCHEDULING_INFO *sched_info = &mac->scheduling_info;
@@ -1459,6 +1504,11 @@ void nr_ue_ul_scheduler(NR_UE_MAC_INST_t *mac, nr_uplink_indication_t *ul_info)
       } else {
         if (ulcfg_pdu->pusch_config_pdu.pusch_data.new_data_indicator
             && (mac->state == UE_CONNECTED || (ra->ra_state == nrRA_WAIT_RAR && ra->cfra))) {
+          if (!nr_timer_is_active(&mac->time_alignment_timer) && mac->state == UE_CONNECTED && !get_softmodem_params()->phy_test) {
+            // UL data arrival during RRC_CONNECTED when UL synchronisation status is "non-synchronised"
+            trigger_MAC_UE_RA(mac);
+            return;
+          }
           // Getting IP traffic to be transmitted
           int tx_power = ulcfg_pdu->pusch_config_pdu.tx_power;
           int P_CMAX = nr_get_Pcmax(mac->p_Max,
@@ -3534,11 +3584,13 @@ uint8_t nr_ue_get_sdu(NR_UE_MAC_INST_t *mac,
   return num_sdus > 0 ? 1 : 0;
 }
 
-static void schedule_ta_command(fapi_nr_dl_config_request_t *dl_config, NR_UL_TIME_ALIGNMENT_t *ul_time_alignment)
+static void schedule_ta_command(fapi_nr_dl_config_request_t *dl_config, NR_UE_MAC_INST_t *mac)
 {
+  NR_UL_TIME_ALIGNMENT_t *ul_time_alignment = &mac->ul_time_alignment;
   fapi_nr_ta_command_pdu *ta = &dl_config->dl_config_list[dl_config->number_pdus].ta_command_pdu;
   ta->ta_frame = ul_time_alignment->frame;
   ta->ta_slot = ul_time_alignment->slot;
+  ta->ta_offset = mac->n_ta_offset;
   ta->is_rar = ul_time_alignment->ta_apply == rar_ta;
   ta->ta_command = ul_time_alignment->ta_command;
   dl_config->dl_config_list[dl_config->number_pdus].pdu_type = FAPI_NR_CONFIG_TA_COMMAND;