Hack to make FDD compatible with current UL scheduling design

- temporary solution since scheduler does not support FDD
- modified is_NR_UL_slot to return always 1 when is FDD mode
- this is necessary because currently the scheduler assumes that is TDD
  and tdd_UL_DL_ConfigurationCommon is always initialied

openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.c

@@ -2808,11 +2808,15 @@ int is_nr_DL_slot(NR_ServingCellConfigCommon_t *scc,slot_t slot) {
   else return(slot_in_period <= slots1+scc->tdd_UL_DL_ConfigurationCommon->pattern2->nrofDownlinkSlots ? 1 : 0);    
 }
 
-int is_nr_UL_slot(NR_ServingCellConfigCommon_t *scc,slot_t slot) {
+int is_nr_UL_slot(NR_ServingCellConfigCommon_t *scc, slot_t slot, lte_frame_type_t frame_type) {
 
   int period,period1,period2=0;
 
-  if (scc->tdd_UL_DL_ConfigurationCommon==NULL) return(1);
+  // Note: condition on frame_type
+  // goal: the UL scheduler assumes mode is TDD therefore this hack is needed to make FDD work
+  if (scc->tdd_UL_DL_ConfigurationCommon == NULL || frame_type == FDD) {
+    return(1);
+  }
 
   if (scc->tdd_UL_DL_ConfigurationCommon->pattern1.ext1 &&
       scc->tdd_UL_DL_ConfigurationCommon->pattern1.ext1->dl_UL_TransmissionPeriodicity_v1530)

openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.h

@@ -174,7 +174,7 @@ int16_t fill_dmrs_mask(NR_PDSCH_Config_t *pdsch_Config,int dmrs_TypeA_Position,i
 
 int is_nr_DL_slot(NR_ServingCellConfigCommon_t *scc,slot_t slotP);
 
-int is_nr_UL_slot(NR_ServingCellConfigCommon_t *scc,slot_t slotP);
+int is_nr_UL_slot(NR_ServingCellConfigCommon_t *scc, slot_t slotP, lte_frame_type_t frame_type);
 
 uint16_t nr_dci_size(NR_ServingCellConfigCommon_t *scc,
                      NR_CellGroupConfig_t *secondaryCellGroup,

openair2/LAYER2/NR_MAC_UE/nr_ue_procedures.c

@@ -1054,8 +1054,9 @@ long get_k2(NR_UE_MAC_INST_t *mac, uint8_t time_domain_ind) {
  * from MAC instance .
  */
 fapi_nr_ul_config_request_t *get_ul_config_request(NR_UE_MAC_INST_t *mac, int slot) {
+
   //Check if request to access ul_config is for a UL slot
-  if (is_nr_UL_slot(mac->scc, slot) == 0) {
+  if (is_nr_UL_slot(mac->scc, slot, mac->phy_config.config_req.cell_config.frame_duplex_type) == 0) {
     LOG_W(MAC, "Slot %d is not a UL slot. get_ul_config_request() called for wrong slot!!!\n", slot);
     return NULL;
   }
@@ -1509,7 +1510,7 @@ void nr_ue_prach_scheduler(module_id_t module_idP, frame_t frameP, sub_frame_t s
   mac->RA_offset = 2; // to compensate the rx frame offset at the gNB
   mac->generate_nr_prach = 0; // Reset flag for PRACH generation
 
-  if (is_nr_UL_slot(scc, slotP)) {
+  if (is_nr_UL_slot(scc, slotP, mac->phy_config.config_req.cell_config.frame_duplex_type)) {
 
     uint8_t selected_gnb_ssb_idx = mac->mib_ssb;
 

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_RA.c

@@ -210,7 +210,8 @@ void schedule_nr_prach(module_id_t module_idP, frame_t frameP, sub_frame_t slotP
   nfapi_nr_ul_tti_request_t *UL_tti_req = &RC.nrmac[module_idP]->UL_tti_req_ahead[0][slotP];
   nfapi_nr_config_request_scf_t *cfg = &RC.nrmac[module_idP]->config[0];
 
-  if (is_nr_UL_slot(scc,slotP)) {
+  if (is_nr_UL_slot(scc, slotP, cc->frame_type)) {
+
     uint8_t config_index = scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->rach_ConfigGeneric.prach_ConfigurationIndex;
     uint8_t mu,N_dur,N_t_slot,start_symbol = 0,N_RA_slot;
     uint16_t RA_sfn_index = -1;

openair2/NR_UE_PHY_INTERFACE/NR_IF_Module.c

@@ -109,7 +109,7 @@ int nr_ue_ul_indication(nr_uplink_indication_t *ul_info){
 
   ret = nr_ue_scheduler(NULL, ul_info);
 
-  if (is_nr_UL_slot(mac->scc, ul_info->slot_tx) && get_softmodem_params()->do_ra)
+  if (is_nr_UL_slot(mac->scc, ul_info->slot_tx, mac->phy_config.config_req.cell_config.frame_duplex_type) && get_softmodem_params()->do_ra)
     nr_ue_prach_scheduler(module_id, ul_info->frame_tx, ul_info->slot_tx, ul_info->thread_id);
 
   switch(ret){