diff --git a/openair1/PHY/NR_UE_ESTIMATION/nr_adjust_synch_ue.c b/openair1/PHY/NR_UE_ESTIMATION/nr_adjust_synch_ue.c
index d140442523..b49443c03c 100644
--- a/openair1/PHY/NR_UE_ESTIMATION/nr_adjust_synch_ue.c
+++ b/openair1/PHY/NR_UE_ESTIMATION/nr_adjust_synch_ue.c
@@ -35,6 +35,7 @@
 void nr_adjust_synch_ue(NR_DL_FRAME_PARMS *frame_parms,
                       PHY_VARS_NR_UE *ue,
                       module_id_t gNB_id,
+                      uint8_t frame,
                       uint8_t subframe,
                       unsigned char clear,
                       short coef)
@@ -104,6 +105,8 @@ void nr_adjust_synch_ue(NR_DL_FRAME_PARMS *frame_parms,
               //mac_resynch();
               //dl_phy_sync_success(ue->Mod_id,ue->proc.proc_rxtx[0].frame_rx,0,1);//ue->common_vars.eNb_id);
               ue->UE_mode[0] = PRACH;
+              ue->prach_resources[gNB_id]->sync_frame = frame;
+              ue->prach_resources[gNB_id]->init_msg1 = 0;
           }
           else {
               ue->UE_mode[0] = PUSCH;
diff --git a/openair1/PHY/NR_UE_ESTIMATION/nr_estimation.h b/openair1/PHY/NR_UE_ESTIMATION/nr_estimation.h
index 6326ed9446..1837664391 100644
--- a/openair1/PHY/NR_UE_ESTIMATION/nr_estimation.h
+++ b/openair1/PHY/NR_UE_ESTIMATION/nr_estimation.h
@@ -75,6 +75,7 @@ int nr_pdsch_channel_estimation(PHY_VARS_NR_UE *ue,
 void nr_adjust_synch_ue(NR_DL_FRAME_PARMS *frame_parms,
                         PHY_VARS_NR_UE *ue,
                         module_id_t eNB_id,
+                        uint8_t frame,
                         uint8_t subframe,
                         unsigned char clear,
                         short coef);
diff --git a/openair1/PHY/defs_nr_common.h b/openair1/PHY/defs_nr_common.h
index 9caf3bc682..6531f582ac 100644
--- a/openair1/PHY/defs_nr_common.h
+++ b/openair1/PHY/defs_nr_common.h
@@ -221,8 +221,12 @@ typedef struct {
   uint16_t ra_RNTI;
   /// Pointer to Msg3 payload for UL-grant
   uint8_t *Msg3;
-  /// Flag for the Msg1 generation
+  /// Flag for the Msg1 generation: it is enabled every time it is nr prach slot
   uint8_t generate_nr_prach;
+  /// Frame of last completed synch
+  uint8_t sync_frame;
+  /// Flag to indicate that prach is ready to start: it is enabled with an initial delay after the sync
+  uint8_t init_msg1;
 } NR_PRACH_RESOURCES_t;
 
 typedef struct NR_DL_FRAME_PARMS NR_DL_FRAME_PARMS;
diff --git a/openair1/SCHED_NR_UE/phy_procedures_nr_ue.c b/openair1/SCHED_NR_UE/phy_procedures_nr_ue.c
index b7922993cf..ced577b16e 100644
--- a/openair1/SCHED_NR_UE/phy_procedures_nr_ue.c
+++ b/openair1/SCHED_NR_UE/phy_procedures_nr_ue.c
@@ -2482,8 +2482,11 @@ void nr_ue_pbch_procedures(uint8_t gNB_id,
     ue->pbch_vars[gNB_id]->pdu_errors_conseq = 0;
 
     // Switch to PRACH state if it is first PBCH after initial synch and no timing correction is performed
-    if (ue->UE_mode[gNB_id] == NOT_SYNCHED && ue->no_timing_correction == 1)
+    if (ue->UE_mode[gNB_id] == NOT_SYNCHED && ue->no_timing_correction == 1){
       ue->UE_mode[gNB_id] = PRACH;
+      ue->prach_resources[gNB_id]->sync_frame = frame_rx;
+      ue->prach_resources[gNB_id]->init_msg1 = 0;
+    }
 
 #ifdef DEBUG_PHY_PROC
     uint16_t frame_tx;
@@ -4079,6 +4082,7 @@ int phy_procedures_nrUE_RX(PHY_VARS_NR_UE *ue,
         nr_adjust_synch_ue(fp,
       		           ue,
   			   eNB_id,
+                           frame_rx,
   			   nr_tti_rx,
   			   0,
   			   16384);
@@ -4523,7 +4527,10 @@ void nr_ue_prach_procedures(PHY_VARS_NR_UE *ue, UE_nr_rxtx_proc_t *proc, uint8_t
     }
   }
 
-  if (ue->prach_resources[gNB_id] != NULL && prach_resources->generate_nr_prach == 1) {
+  if (!prach_resources->init_msg1 && (frame_tx > ue->prach_resources[gNB_id]->sync_frame + 150))
+    prach_resources->init_msg1 = 1;
+
+  if (ue->prach_resources[gNB_id] != NULL && prach_resources->generate_nr_prach == 1 && prach_resources->init_msg1) {
 
     ue->prach_cnt = 0;
     pathloss = get_nr_PL(mod_id, ue->CC_id, gNB_id);
diff --git a/openair1/SIMULATION/NR_PHY/prachsim.c b/openair1/SIMULATION/NR_PHY/prachsim.c
index 4c37e49fb2..014813aae5 100644
--- a/openair1/SIMULATION/NR_PHY/prachsim.c
+++ b/openair1/SIMULATION/NR_PHY/prachsim.c
@@ -501,6 +501,7 @@ int main(int argc, char **argv){
     printf("raPreamble %d\n",preamble_tx);
 
   UE->prach_resources[0]->ra_PreambleIndex = preamble_tx;
+  UE->prach_resources[0]->init_msg1 = 1;
 
   // Configure channel
   bw = N_RB_UL*(180e3)*(1 << frame_parms->numerology_index);
diff --git a/openair2/LAYER2/NR_MAC_UE/nr_ra_procedures.c b/openair2/LAYER2/NR_MAC_UE/nr_ra_procedures.c
index 75091d49e2..00eaa56855 100644
--- a/openair2/LAYER2/NR_MAC_UE/nr_ra_procedures.c
+++ b/openair2/LAYER2/NR_MAC_UE/nr_ra_procedures.c
@@ -353,7 +353,7 @@ void nr_ue_get_rach(NR_PRACH_RESOURCES_t *prach_resources,
 
   AssertFatal(CC_id == 0,"Transmission on secondary CCs is not supported yet\n");
 
-  if (UE_mode == PRACH) {
+  if (UE_mode == PRACH && prach_resources->init_msg1) {
 
     LOG_D(MAC, "nr_ue_get_rach, RA_active value: %d", mac->RA_active);