Imrpovements for extracting UL DCI, remove hardcoding, blind decoding of DCI

nfapi/open-nFAPI/nfapi/public_inc/fapi_nr_ue_interface.h

@@ -415,8 +415,14 @@ typedef struct {
   uint8_t number_of_candidates;
   uint16_t CCE[64];
   uint8_t L[64];
-  uint8_t dci_length;
-  uint8_t dci_format;
+  // 3GPP TS 38.212 Sec. 7.3.1.0, 3GPP TS 138.131 sec. 6.3.2 (SearchSpace)
+  // The maximum number of DCI lengths allowed by the spec are 4, with max 3 for C-RNTI.
+  // But a given search space may only support a maximum of 2 DCI formats at a time
+  // depending on its search space type configured by RRC. Hence for blind decoding, UE
+  // needs to monitor only upto 2 DCI lengths for a given search space.
+  uint8_t num_dci_options;  // Num DCIs the UE actually needs to decode (1 or 2)
+  uint8_t dci_length_options[2];
+  uint8_t dci_format_options[2];
 } fapi_nr_dl_config_dci_dl_pdu_rel15_t;
 
 typedef struct {

openair1/PHY/NR_UE_TRANSPORT/dci_nr.c

@@ -845,7 +845,6 @@ uint8_t nr_dci_decoding_procedure(PHY_VARS_NR_UE *ue,
   for (int i=0;i<pdcch_vars->nb_search_space;i++) {
 
     rel15 = &pdcch_vars->pdcch_config[i];
-    int dci_length = rel15->dci_length;
     //int gNB_id = 0;
     int16_t tmp_e[16*108];
     rnti_t n_rnti;
@@ -853,6 +852,10 @@ uint8_t nr_dci_decoding_procedure(PHY_VARS_NR_UE *ue,
     for (int j=0;j<rel15->number_of_candidates;j++) {
       int CCEind = rel15->CCE[j];
       int L = rel15->L[j];
+
+      // Loop over possible DCI lengths
+      for (int k = 0; k < rel15->num_dci_options; k++) {
+        int dci_length = rel15->dci_length_options[k];
         uint64_t dci_estimation[2]= {0};
         const t_nrPolar_params *currentPtrDCI = nr_polar_params(NR_POLAR_DCI_MESSAGE_TYPE, dci_length, L, 1, &ue->polarList);
 
@@ -877,17 +880,19 @@ uint8_t nr_dci_decoding_procedure(PHY_VARS_NR_UE *ue,
         n_rnti = rel15->rnti;
 
         if (crc == n_rnti) {
-        LOG_D(PHY,"Decoded crc %x matches rnti %x for DCI format %d\n", crc, n_rnti, rel15->dci_format);
+          LOG_D(PHY,"Decoded crc %x matches rnti %x for DCI format %d\n", crc, n_rnti, rel15->dci_format_options[k]);
           dci_ind->SFN = frame;
           dci_ind->slot = slot;
           dci_ind->dci_list[dci_ind->number_of_dcis].rnti        = n_rnti;
           dci_ind->dci_list[dci_ind->number_of_dcis].n_CCE       = CCEind;
-	dci_ind->dci_list[dci_ind->number_of_dcis].dci_format  = rel15->dci_format;
+          dci_ind->dci_list[dci_ind->number_of_dcis].dci_format  = rel15->dci_format_options[k];
           dci_ind->dci_list[dci_ind->number_of_dcis].payloadSize = dci_length;
           memcpy((void*)dci_ind->dci_list[dci_ind->number_of_dcis].payloadBits,(void*)dci_estimation,8);
           dci_ind->number_of_dcis++;
+          break;    // If DCI is found, no need to check for remaining DCI lengths
         } else {
-        LOG_D(PHY,"Decoded crc %x does not match rnti %x for DCI format %d\n", crc, n_rnti, rel15->dci_format);
+          LOG_D(PHY,"Decoded crc %x does not match rnti %x for DCI format %d\n", crc, n_rnti, rel15->dci_format_options[k]);
+        }
       }
     }
   }

openair2/LAYER2/NR_MAC_UE/nr_ue_dci_configuration.c

@@ -64,7 +64,7 @@ void fill_dci_search_candidates(NR_SearchSpace_t *ss,fapi_nr_dl_config_dci_dl_pd
 
 }
 
-void config_dci_pdu(NR_UE_MAC_INST_t *mac, fapi_nr_dl_config_dci_dl_pdu_rel15_t *rel15, fapi_nr_dl_config_request_t *dl_config, int rnti_type, int ss_id, uint8_t dci_format){
+void config_dci_pdu(NR_UE_MAC_INST_t *mac, fapi_nr_dl_config_dci_dl_pdu_rel15_t *rel15, fapi_nr_dl_config_request_t *dl_config, int rnti_type, int ss_id){
 
   uint16_t monitoringSymbolsWithinSlot;
   uint8_t bwp_id = 1, coreset_id = 1;
@@ -76,9 +76,6 @@ void config_dci_pdu(NR_UE_MAC_INST_t *mac, fapi_nr_dl_config_dci_dl_pdu_rel15_t
   NR_BWP_DownlinkCommon_t *initialDownlinkBWP = scc->downlinkConfigCommon->initialDownlinkBWP;
   NR_SearchSpace_t *ss = mac->SSpace[bwp_id - 1][coreset_id - 1][ss_id];
 
-  // DCI format configuration
-  rel15->dci_format = dci_format;
-
   // CORESET configuration
   NR_ControlResourceSet_t *coreset = mac->coreset[bwp_id - 1][coreset_id - 1];
   rel15->coreset.duration = coreset->duration;
@@ -123,7 +120,9 @@ void config_dci_pdu(NR_UE_MAC_INST_t *mac, fapi_nr_dl_config_dci_dl_pdu_rel15_t
     rel15->BWPSize = NRRIV2BW(bwp_Common->genericParameters.locationAndBandwidth, 275);
     rel15->BWPStart = NRRIV2PRBOFFSET(bwp_Common->genericParameters.locationAndBandwidth, 275);
     rel15->SubcarrierSpacing = bwp_Common->genericParameters.subcarrierSpacing;
-    rel15->dci_length = nr_dci_size(scc, mac->scg, def_dci_pdu_rel15, rel15->dci_format, NR_RNTI_C, rel15->BWPSize, bwp_id);
+    for (int i = 0; i < rel15->num_dci_options; i++) {
+      rel15->dci_length_options[i] = nr_dci_size(scc, mac->scg, def_dci_pdu_rel15, rel15->dci_format_options[i], NR_RNTI_C, rel15->BWPSize, bwp_id);
+    }
     break;
     case NR_RNTI_RA:
     // we use the initial DL BWP
@@ -133,7 +132,7 @@ void config_dci_pdu(NR_UE_MAC_INST_t *mac, fapi_nr_dl_config_dci_dl_pdu_rel15_t
     rel15->BWPSize = NRRIV2BW(initialDownlinkBWP->genericParameters.locationAndBandwidth, 275);
     rel15->BWPStart = NRRIV2PRBOFFSET(bwp_Common->genericParameters.locationAndBandwidth, 275); //NRRIV2PRBOFFSET(initialDownlinkBWP->genericParameters.locationAndBandwidth, 275);
     rel15->SubcarrierSpacing = initialDownlinkBWP->genericParameters.subcarrierSpacing;
-    rel15->dci_length = nr_dci_size(scc, mac->scg, def_dci_pdu_rel15, rel15->dci_format, NR_RNTI_RA, rel15->BWPSize, bwp_id);
+    rel15->dci_length_options[0] = nr_dci_size(scc, mac->scg, def_dci_pdu_rel15, rel15->dci_format_options[0], NR_RNTI_RA, rel15->BWPSize, bwp_id);
     break;
     case NR_RNTI_P:
     break;
@@ -215,7 +214,9 @@ void ue_dci_configuration(NR_UE_MAC_INST_t *mac, fapi_nr_dl_config_request_t *dl
             LOG_D(MAC, "[DCI_CONFIG] Configure monitoring of PDCCH candidates in Type1-PDCCH common random access search space\n");
             switch(mac->ra_state){
               case WAIT_RAR:
-              config_dci_pdu(mac, rel15, dl_config, NR_RNTI_RA, ss_id, NR_DL_DCI_FORMAT_1_0);
+              rel15->num_dci_options = 1;
+              rel15->dci_format_options[0] = NR_DL_DCI_FORMAT_1_0;
+              config_dci_pdu(mac, rel15, dl_config, NR_RNTI_RA, ss_id);
               fill_dci_search_candidates(ss, rel15);
               break;
               case WAIT_CONTENTION_RESOLUTION:
@@ -286,7 +287,10 @@ void ue_dci_configuration(NR_UE_MAC_INST_t *mac, fapi_nr_dl_config_request_t *dl
           // Monitors DCI 01 and 11 scrambled with C-RNTI, or CS-RNTI(s), or SP-CSI-RNTI
           if (get_softmodem_params()->phy_test == 1 && mac->crnti > 0) {
             LOG_D(MAC, "[DCI_CONFIG] Configure monitoring of PDCCH candidates in the user specific search space\n");
-            config_dci_pdu(mac, rel15, dl_config, NR_RNTI_C, ss_id, NR_DL_DCI_FORMAT_1_1);
+            rel15->num_dci_options = 2;
+            rel15->dci_format_options[0] = NR_DL_DCI_FORMAT_1_1;
+            rel15->dci_format_options[1] = NR_UL_DCI_FORMAT_0_1;
+            config_dci_pdu(mac, rel15, dl_config, NR_RNTI_C, ss_id);
             fill_dci_search_candidates(ss, rel15);
 
             #ifdef DEBUG_DCI

openair2/NR_UE_PHY_INTERFACE/NR_IF_Module.c

@@ -155,7 +155,7 @@ int nr_ue_dl_indication(nr_downlink_indication_t *dl_info, NR_UL_TIME_ALIGNMENT_
     ul_config->number_pdus = 0;
     //hook up pointers
     mac->scheduled_response.dl_config = dl_config;
-    mac->scheduled_response.ul_config = ul_config;
+    mac->scheduled_response.ul_config = NULL;
     mac->scheduled_response.tx_request = &mac->tx_request;
     mac->scheduled_response.module_id = dl_info->module_id;
     mac->scheduled_response.CC_id = dl_info->cc_id;