fix for empty mib at beginning of execution

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_bch.c

@@ -158,10 +158,14 @@ void schedule_nr_mib(module_id_t module_idP, frame_t frameP, sub_frame_t slotP)
     dl_req = &dl_tti_request->dl_tti_request_body;
 
     // get MIB every 8 frames
-    if((slotP == 0) && (frameP & 7) == 0) {
+    if(((slotP == 0) && (frameP & 7) == 0) ||
+       gNB->first_MIB) {
 
       mib_sdu_length = mac_rrc_nr_data_req(module_idP, CC_id, frameP, MIBCH, 0, 1, &cc->MIB_pdu.payload[0]);
 
+      // flag to avoid sending an empty MIB in the first frames of execution since gNB doesn't get at the beginning in frame 0 slot 0
+      gNB->first_MIB = false;
+
       LOG_D(MAC,
             "[gNB %d] Frame %d : MIB->BCH  CC_id %d, Received %d bytes\n",
             module_idP,

openair2/LAYER2/NR_MAC_gNB/main.c

@@ -81,6 +81,8 @@ void mac_top_init_gNB(void)
         
       RC.nrmac[i]->ul_handle = 0;
 
+      RC.nrmac[i]->first_MIB = true;
+
       if (get_softmodem_params()->phy_test) {
         RC.nrmac[i]->pre_processor_dl = nr_preprocessor_phytest;
         RC.nrmac[i]->pre_processor_ul = nr_ul_preprocessor_phytest;

openair2/LAYER2/NR_MAC_gNB/nr_mac_gNB.h

@@ -736,6 +736,7 @@ typedef struct gNB_MAC_INST_s {
   NR_CellGroupConfig_t *secondaryCellGroupCommon;
   NR_Type0_PDCCH_CSS_config_t type0_PDCCH_CSS_config[64];
 
+  bool first_MIB;
 } gNB_MAC_INST;
 
 #endif /*__LAYER2_NR_MAC_GNB_H__ */