diff --git a/common/utils/nr/nr_common.h b/common/utils/nr/nr_common.h
index 9087f335c5..5f4c58d386 100644
--- a/common/utils/nr/nr_common.h
+++ b/common/utils/nr/nr_common.h
@@ -53,6 +53,7 @@
   R(TYPE_P_RNTI_) /* Paging RNTI */                                \
   R(TYPE_SI_RNTI_) /* System information RNTI */                   \
   R(TYPE_RA_RNTI_) /* Random Access RNTI */                        \
+  R(TYPE_MSGB_RNTI_) /* Random Access MsgB RNTI */                 \
   R(TYPE_SP_CSI_RNTI_) /* Semipersistent CSI reporting on PUSCH */ \
   R(TYPE_SFI_RNTI_) /* Slot Format Indication on the given cell */ \
   R(TYPE_INT_RNTI_) /* Indication pre-emption in DL */            \
diff --git a/openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.c b/openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.c
index cbdcb51d22..835df85c04 100644
--- a/openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.c
+++ b/openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.c
@@ -655,6 +655,7 @@ NR_tda_info_t get_dl_tda_info(const NR_UE_DL_BWP_t *dl_BWP,
     case TYPE_CS_RNTI_:
     case TYPE_MCS_C_RNTI_:
     case TYPE_RA_RNTI_:
+    case TYPE_MSGB_RNTI_:
     case TYPE_TC_RNTI_:
       if(tdalist)
         tda_info = set_tda_info_from_list(tdalist, tda_index);
diff --git a/openair2/LAYER2/NR_MAC_UE/nr_ue_dci_configuration.c b/openair2/LAYER2/NR_MAC_UE/nr_ue_dci_configuration.c
index 550ae2b8da..1c01f84d4d 100644
--- a/openair2/LAYER2/NR_MAC_UE/nr_ue_dci_configuration.c
+++ b/openair2/LAYER2/NR_MAC_UE/nr_ue_dci_configuration.c
@@ -266,6 +266,14 @@ void config_dci_pdu(NR_UE_MAC_INST_t *mac,
       rel15->rnti = mac->ra.ra_rnti;
       rel15->SubcarrierSpacing = current_DL_BWP->scs;
       break;
+    case TYPE_MSGB_RNTI_:
+      // we use the initial DL BWP
+      sps = current_DL_BWP->cyclicprefix == NULL ? 14 : 12;
+      monitoringSymbolsWithinSlot =
+          (ss->monitoringSymbolsWithinSlot->buf[0] << (sps - 8)) | (ss->monitoringSymbolsWithinSlot->buf[1] >> (16 - sps));
+      rel15->rnti = mac->ra.MsgB_rnti;
+      rel15->SubcarrierSpacing = current_DL_BWP->scs;
+      break;
     case TYPE_P_RNTI_:
       break;
     case TYPE_CS_RNTI_:
@@ -571,7 +579,12 @@ void ue_dci_configuration(NR_UE_MAC_INST_t *mac, fapi_nr_dl_config_request_t *dl
   if (mac->state == UE_PERFORMING_RA && mac->ra.ra_state >= nrRA_WAIT_RAR) {
     // if RA is ongoing use RA search space
     if (is_ss_monitor_occasion(frame, slot, slots_per_frame, pdcch_config->ra_SS)) {
-      int rnti_type = mac->ra.ra_state == nrRA_WAIT_RAR ? TYPE_RA_RNTI_ : TYPE_TC_RNTI_;
+      nr_rnti_type_t rnti_type = 0;
+      if (mac->ra.ra_type == RA_4_STEP) {
+        rnti_type = mac->ra.ra_state == nrRA_WAIT_RAR ? TYPE_RA_RNTI_ : TYPE_TC_RNTI_;
+      } else {
+        rnti_type = TYPE_MSGB_RNTI_;
+      }
       config_dci_pdu(mac, dl_config, rnti_type, slot, pdcch_config->ra_SS);
     }
   } else if (mac->state == UE_CONNECTED) {
diff --git a/openair2/LAYER2/NR_MAC_UE/nr_ue_procedures.c b/openair2/LAYER2/NR_MAC_UE/nr_ue_procedures.c
index 7844b31132..cdec17bce6 100644
--- a/openair2/LAYER2/NR_MAC_UE/nr_ue_procedures.c
+++ b/openair2/LAYER2/NR_MAC_UE/nr_ue_procedures.c
@@ -161,6 +161,8 @@ int get_rnti_type(const NR_UE_MAC_INST_t *mac, const uint16_t rnti)
 
   if (rnti == ra->ra_rnti) {
     rnti_type = TYPE_RA_RNTI_;
+  } else if (rnti == ra->MsgB_rnti && (ra->ra_state == nrRA_WAIT_MSGB || ra->ra_state == nrRA_WAIT_CONTENTION_RESOLUTION)) {
+    rnti_type = TYPE_MSGB_RNTI_;
   } else if (rnti == ra->t_crnti && (ra->ra_state == nrRA_WAIT_RAR || ra->ra_state == nrRA_WAIT_CONTENTION_RESOLUTION)) {
     rnti_type = TYPE_TC_RNTI_;
   } else if (rnti == mac->crnti) {
@@ -3347,6 +3349,7 @@ static nr_dci_format_t nr_extract_dci_00_10(NR_UE_MAC_INST_t *mac,
       dci_pdu_rel15->format_indicator = format_indicator;
       break;
     case TYPE_TC_RNTI_ :
+    case TYPE_MSGB_RNTI_:
       // Identifier for DCI formats
       EXTRACT_DCI_ITEM(format_indicator, 1);
       if (format_indicator == 1) {