diff --git a/executables/nr-ue.c b/executables/nr-ue.c
index 38932d4833..9e0ca95136 100644
--- a/executables/nr-ue.c
+++ b/executables/nr-ue.c
@@ -436,7 +436,7 @@ static void *NRUE_phy_stub_standalone_pnf_task(void *arg)
     NR_UE_MAC_INST_t *mac = get_mac_inst(mod_id);
     if (mac->mib == NULL)
     {
-      if (get_softmodem_params()->sa && get_softmodem_params()->emulate_l2)
+      if (get_softmodem_params()->sa)
       {
         LOG_D(NR_MAC, "We haven't gotten MIB. Lets see if we received it\n");
         nr_ue_dl_indication(&mac->dl_info, &ul_time_alignment);
diff --git a/openair2/LAYER2/NR_MAC_UE/config_ue.c b/openair2/LAYER2/NR_MAC_UE/config_ue.c
index d223b9ddd7..c8a9516ae3 100755
--- a/openair2/LAYER2/NR_MAC_UE/config_ue.c
+++ b/openair2/LAYER2/NR_MAC_UE/config_ue.c
@@ -650,7 +650,8 @@ int nr_rrc_mac_config_req_ue(
       mac->ul_config_request = (fapi_nr_ul_config_request_t *)calloc(num_slots_ul, sizeof(fapi_nr_ul_config_request_t));
       // Setup the SSB to Rach Occasions mapping according to the config
       build_ssb_to_ro_map(mac);//->scc, mac->phy_config.config_req.cell_config.frame_duplex_type);
-      mac->if_module->phy_config_request(&mac->phy_config);
+      if (!get_softmodem_params()->emulate_l2)
+        mac->if_module->phy_config_request(&mac->phy_config);
       mac->common_configuration_complete = 1;
     }
     if(scell_group_config != NULL ){
diff --git a/openair2/LAYER2/NR_MAC_UE/nr_ra_procedures.c b/openair2/LAYER2/NR_MAC_UE/nr_ra_procedures.c
index b99e0aa0ec..a05128cf29 100644
--- a/openair2/LAYER2/NR_MAC_UE/nr_ra_procedures.c
+++ b/openair2/LAYER2/NR_MAC_UE/nr_ra_procedures.c
@@ -665,10 +665,6 @@ uint8_t nr_ue_get_rach(NR_PRACH_RESOURCES_t *prach_resources,
 
   NR_UE_MAC_INST_t *mac = get_mac_inst(mod_id);
   RA_config_t *ra = &mac->ra;
-  uint8_t mac_sdus[MAX_NR_ULSCH_PAYLOAD_BYTES];
-  uint8_t *payload;
-  uint16_t size_sdu = 0;
-  unsigned short post_padding;
   NR_RACH_ConfigCommon_t *setup;
   if (mac->scc) setup = mac->scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup;
   else          setup = mac->scc_SIB->uplinkConfigCommon->initialUplinkBWP.rach_ConfigCommon->choice.setup;
@@ -676,85 +672,128 @@ uint8_t nr_ue_get_rach(NR_PRACH_RESOURCES_t *prach_resources,
   NR_RACH_ConfigGeneric_t *rach_ConfigGeneric = &setup->rach_ConfigGeneric;
   NR_RACH_ConfigDedicated_t *rach_ConfigDedicated = ra->rach_ConfigDedicated;
 
-  uint16_t sdu_lengths[NB_RB_MAX] = {0};
-  int offset = 0;
-  int TBS_bytes = 848;
-  int header_length_total=0;
-  int mac_ce_len;
-
   // Delay init RA procedure to allow the convergence of the IIR filter on PRACH noise measurements at gNB side
   if (!prach_resources->init_msg1) {
-    if ((mac->common_configuration_complete > 0 || get_softmodem_params()->do_ra || get_softmodem_params()->nsa) &&
-       ((MAX_FRAME_NUMBER + frame - prach_resources->sync_frame) % MAX_FRAME_NUMBER) > 150) {
+    if ((mac->common_configuration_complete>0 || get_softmodem_params()->do_ra==1) &&
+    ((MAX_FRAME_NUMBER+frame-prach_resources->sync_frame)%MAX_FRAME_NUMBER)>150){
       prach_resources->init_msg1 = 1;
     } else {
-      LOG_D(NR_MAC,"PRACH Condition not met: frame %d, prach_resources->sync_frame %d\n",frame,prach_resources->sync_frame);
+      LOG_I(NR_MAC, "Melissa: mac->common_configuration_complete = %d \n"
+                    " MAX_FRAME_NUMBER (%d) + frame (%d) - prach_resources->sync_frame (%d)"
+                    " = (%d) mod MAX_FRAME_NUMBER (%d)   = %d ??? >150\n",
+                    mac->common_configuration_complete,
+                    MAX_FRAME_NUMBER,
+                    frame,
+                    prach_resources->sync_frame,
+                    MAX_FRAME_NUMBER + frame - prach_resources->sync_frame,
+                    MAX_FRAME_NUMBER,
+                    MAX_FRAME_NUMBER+frame-prach_resources->sync_frame%MAX_FRAME_NUMBER);
+      LOG_D(NR_MAC,"PRACH Condition not met: frame %d, prach_resources->sync_frame %d\n",
+            frame,prach_resources->sync_frame);
       return 0;
     }
   }
 
-  LOG_D(NR_MAC,"frame %d prach_resources->init_msg1 %d, ra->ra_state %d, ra->RA_active %d\n",
-	frame, prach_resources->init_msg1, ra->ra_state, ra->RA_active);
+  LOG_D(NR_MAC, "In %s: [UE %d][%d.%d]: init_msg1 %d, ra_state %d, RA_active %d\n",
+    __FUNCTION__,
+    mod_id,
+    frame,
+    nr_slot_tx,
+    prach_resources->init_msg1,
+    ra->ra_state,
+    ra->RA_active);
 
   if (prach_resources->init_msg1 && ra->ra_state != RA_SUCCEEDED) {
 
     if (ra->RA_active == 0) {
       /* RA not active - checking if RRC is ready to initiate the RA procedure */
 
-      LOG_D(NR_MAC, "RA not active. Checking for data to transmit from upper layers...\n");
+      LOG_D(NR_MAC, "In %s: RA not active. Checking for data to transmit from upper layers...\n", __FUNCTION__);
 
-      int TBS_max = 848; //8 + sizeof(NR_MAC_SUBHEADER_SHORT) + sizeof(NR_MAC_SUBHEADER_SHORT);
-      payload = (uint8_t*) mac->CCCH_pdu.payload;
-      mac_ce_len = 0;
-      post_padding = 1;
+      const uint8_t lcid = UL_SCH_LCID_CCCH;
+      const uint8_t sh_size = sizeof(NR_MAC_SUBHEADER_FIXED);
+      const uint8_t TBS_max = 8 + sizeof(NR_MAC_SUBHEADER_SHORT) + sizeof(NR_MAC_SUBHEADER_SHORT); // Note: unclear the reason behind the selection of such TBS_max
+      int8_t size_sdu = 0;
+      uint8_t mac_ce[16] = {0};
+      uint8_t *pdu = get_softmodem_params()->sa ? mac->CCCH_pdu.payload : mac_ce;
+      uint8_t *payload = pdu;
 
-      // initialisation by RRC
+      // Concerning the C-RNTI MAC CE, it has to be included if the UL transmission (Msg3) is not being made for the CCCH logical channel.
+      // Therefore it has been assumed that this event only occurs only when RA is done and it is not SA mode.
+      if (get_softmodem_params()->sa) {
 
-      // TODO: To be removed after RA procedures fully implemented
-      if(get_softmodem_params()->do_ra) {
+        NR_MAC_SUBHEADER_FIXED *header = (NR_MAC_SUBHEADER_FIXED *) pdu;
+        pdu += sh_size;
+
+        // initialisation by RRC
         nr_rrc_ue_generate_RRCSetupRequest(mod_id,gNB_id);
-        size_sdu = (uint16_t) nr_mac_rrc_data_req_ue(mod_id, CC_id, gNB_id, frame, CCCH, mac_sdus);
+
         // CCCH PDU
-        sdu_lengths[0] = size_sdu;
-        LOG_D(NR_MAC,"[UE %d] Frame %d: Requested RRCConnectionRequest, got %d bytes\n", mod_id, frame, size_sdu);
-      } else {
-        // fill ulsch_buffer with random data
-        for (int i = 0; i < TBS_bytes; i++){
-          mac_sdus[i] = (unsigned char) (lrand48()&0xff);
+        size_sdu = nr_mac_rrc_data_req_ue(mod_id, CC_id, gNB_id, frame, CCCH, pdu);
+        LOG_D(NR_MAC, "In %s: [UE %d][%d.%d]: Requested RRCConnectionRequest, got %d bytes for LCID 0x%02x \n", __FUNCTION__, mod_id, frame, nr_slot_tx, size_sdu, lcid);
+
+        if (size_sdu > 0) {
+
+          // UE Contention Resolution Identity
+          // Store the first 48 bits belonging to the uplink CCCH SDU within Msg3 to determine whether or not the
+          // Random Access Procedure has been successful after reception of Msg4
+          memcpy(ra->cont_res_id, pdu, sizeof(uint8_t) * 6);
+
+          pdu += size_sdu;
+          ra->Msg3_size = size_sdu + sh_size;
+
+          // Build header
+          header->R = 0;
+          header->LCID = lcid;
+
+        } else {
+          pdu -= sh_size;
         }
-        //Sending SDUs with size 1
-        //Initialize elements of sdu_lengths
-        sdu_lengths[0] = TBS_bytes - 3 - post_padding - mac_ce_len;
-        header_length_total += 2 + (sdu_lengths[0] >= 128);
-        size_sdu += sdu_lengths[0];
+
+      } else {
+
+        size_sdu = nr_write_ce_ulsch_pdu(pdu, mac);
+        pdu += size_sdu;
+        ra->Msg3_size = size_sdu;
+
       }
 
+      if (size_sdu > 0 && ra->generate_nr_prach == GENERATE_PREAMBLE) {
 
-      if (size_sdu > 0) {
-
-        // UE Contention Resolution Identity
-        // Store the first 48 bits belonging to the uplink CCCH SDU within Msg3 to determine whether or not the
-        // Random Access Procedure has been successful after reception of Msg4
-        memcpy(ra->cont_res_id, mac_sdus, sizeof(uint8_t) * 6);
-
-        LOG_D(NR_MAC, "[UE %d][%d.%d]: starting initialisation Random Access Procedure...\n", mod_id, frame, nr_slot_tx);
-
-        ra->Msg3_size = size_sdu + sizeof(NR_MAC_SUBHEADER_SHORT) + sizeof(NR_MAC_SUBHEADER_SHORT);
+        LOG_D(NR_MAC, "In %s: [UE %d][%d.%d]: starting initialisation Random Access Procedure...\n", __FUNCTION__, mod_id, frame, nr_slot_tx);
+        AssertFatal(TBS_max > ra->Msg3_size, "In %s: allocated resources are not enough for Msg3!\n", __FUNCTION__);
 
+        // Init RA procedure
         init_RA(mod_id, prach_resources, setup, rach_ConfigGeneric, rach_ConfigDedicated);
-       // prach_resources->Msg3 = payload;
         nr_get_RA_window(mac);
-
         // Fill in preamble and PRACH resources
-        if (ra->generate_nr_prach == GENERATE_PREAMBLE) {
-          nr_get_prach_resources(mod_id, CC_id, gNB_id, prach_resources, prach_pdu, rach_ConfigDedicated);
-        }
+        nr_get_prach_resources(mod_id, CC_id, gNB_id, prach_resources, prach_pdu, rach_ConfigDedicated);
 
         // Padding: fill remainder with 0
-        if (post_padding > 0){
-          for (int j = 0; j < (TBS_max - offset); j++)
-            payload[offset + j] = 0;
+        if (TBS_max - ra->Msg3_size > 0) {
+          LOG_D(NR_MAC, "In %s: remaining %d bytes, filling with padding\n", __FUNCTION__, TBS_max - ra->Msg3_size);
+          ((NR_MAC_SUBHEADER_FIXED *) pdu)->R = 0;
+          ((NR_MAC_SUBHEADER_FIXED *) pdu)->LCID = UL_SCH_LCID_PADDING;
+          pdu += sizeof(NR_MAC_SUBHEADER_FIXED);
+          for (int j = 0; j < TBS_max - ra->Msg3_size - sizeof(NR_MAC_SUBHEADER_FIXED); j++) {
+            pdu[j] = 0;
+          }
         }
+
+        // Dumping ULSCH payload
+        LOG_D(NR_MAC, "In %s: dumping UL Msg3 MAC PDU with length %d: \n", __FUNCTION__, TBS_max);
+        for(int k = 0; k < TBS_max; k++) {
+          LOG_D(NR_MAC,"(%i): %i\n", k, payload[k]);
+        }
+
+        // Msg3 was initialized with TBS_max bytes because the RA_Msg3_size will only be known after
+        // receiving Msg2 (which contains the Msg3 resource reserve).
+        // Msg3 will be transmitted with RA_Msg3_size bytes, removing unnecessary 0s.
+        mac->ulsch_pdu.Pdu_size = TBS_max;
+        memcpy(mac->ulsch_pdu.payload, payload, TBS_max);
+
+      } else {
+        return 0;
       }
     } else if (ra->RA_window_cnt != -1) { // RACH is active
 
@@ -783,7 +822,7 @@ uint8_t nr_ue_get_rach(NR_PRACH_RESOURCES_t *prach_resources,
 
       } else if (ra->RA_window_cnt > 0) {
 
-        LOG_I(MAC, "[UE %d][%d.%d]: RAR not received yet (RA window count %d) \n", mod_id, frame, nr_slot_tx, ra->RA_window_cnt);
+        LOG_D(MAC, "[UE %d][%d.%d]: RAR not received yet (RA window count %d) \n", mod_id, frame, nr_slot_tx, ra->RA_window_cnt);
 
         // Fill in preamble and PRACH resources
         ra->RA_window_cnt--;
diff --git a/openair2/NR_UE_PHY_INTERFACE/NR_IF_Module.c b/openair2/NR_UE_PHY_INTERFACE/NR_IF_Module.c
index 7ca333135a..33ee64aa1f 100644
--- a/openair2/NR_UE_PHY_INTERFACE/NR_IF_Module.c
+++ b/openair2/NR_UE_PHY_INTERFACE/NR_IF_Module.c
@@ -1092,7 +1092,7 @@ nr_ue_if_module_t *nr_ue_if_module_init(uint32_t module_id){
     nr_ue_if_module_inst[module_id]->current_frame = 0;
     nr_ue_if_module_inst[module_id]->current_slot = 0;
     nr_ue_if_module_inst[module_id]->phy_config_request = nr_ue_phy_config_request;
-    if (get_softmodem_params()->emulate_l2)
+    if (get_softmodem_params()->emulate_l2 || get_softmodem_params()->nsa)
       nr_ue_if_module_inst[module_id]->scheduled_response = nr_ue_scheduled_response_stub;
     else
       nr_ue_if_module_inst[module_id]->scheduled_response = nr_ue_scheduled_response;