First draft implementation of CBRA

openair1/PHY/NR_TRANSPORT/nr_prach.c

@@ -678,10 +678,19 @@ void rx_nr_prach(PHY_VARS_gNB *gNB,
       }
       
       else {
-        preamble_shift  -= NCS;
-	
-        if (preamble_shift < 0)
-          preamble_shift+=N_ZC;
+
+        // FIXME: It is working, but we need to differentiate between odd and even preamble index
+        //  Check why preamble_shift does not match with UE
+        //  TS 38.211 Section 6.3.3.1 Sequence generation
+        if(preamble_index%2==0) {
+          preamble_shift  = (NCS==0)? 0 : (preamble_index % (N_ZC/NCS));
+          preamble_shift *= NCS;
+        } else {
+          preamble_shift  -= 2*NCS;
+          if (preamble_shift < 0)
+            preamble_shift+=N_ZC;
+        }
+
       }
     } else { // This is the high-speed case
       new_dft = 0;

openair2/LAYER2/NR_MAC_UE/config_ue.c

@@ -529,11 +529,13 @@ int nr_rrc_mac_config_req_ue(
       mac->servCellIndex = *cell_group_config->spCellConfig->servCellIndex;
       config_control_ue(mac);
       if (cell_group_config->spCellConfig->reconfigurationWithSync) {
-        ra->rach_ConfigDedicated = cell_group_config->spCellConfig->reconfigurationWithSync->rach_ConfigDedicated->choice.uplink;
-	mac->scc = cell_group_config->spCellConfig->reconfigurationWithSync->spCellConfigCommon;
-	config_common_ue(mac,module_id,cc_idP);
-	mac->crnti = cell_group_config->spCellConfig->reconfigurationWithSync->newUE_Identity;
-	LOG_I(MAC,"Configuring CRNTI %x\n",mac->crnti);
+        if (cell_group_config->spCellConfig->reconfigurationWithSync->rach_ConfigDedicated) {
+          ra->rach_ConfigDedicated = cell_group_config->spCellConfig->reconfigurationWithSync->rach_ConfigDedicated->choice.uplink;
+        }
+        mac->scc = cell_group_config->spCellConfig->reconfigurationWithSync->spCellConfigCommon;
+        config_common_ue(mac,module_id,cc_idP);
+        mac->crnti = cell_group_config->spCellConfig->reconfigurationWithSync->newUE_Identity;
+        LOG_I(MAC,"Configuring CRNTI %x\n",mac->crnti);
       }
 
       // Setup the SSB to Rach Occasions mapping according to the config

openair2/LAYER2/NR_MAC_UE/nr_ra_procedures.c

@@ -79,8 +79,8 @@ void init_RA(module_id_t mod_id,
 
   if (rach_ConfigDedicated) {
     if (rach_ConfigDedicated->cfra){
-      LOG_I(MAC, "Initialization of 4-step contention-free random access procedure\n");
-      prach_resources->RA_TYPE = RA_4STEP;
+      LOG_I(MAC, "Initialization of 2-step contention-free random access procedure\n");
+      prach_resources->RA_TYPE = RA_2STEP;
       ra->cfra = 1;
     } else if (rach_ConfigDedicated->ext1){
       if (rach_ConfigDedicated->ext1->cfra_TwoStep_r16){
@@ -93,6 +93,10 @@ void init_RA(module_id_t mod_id,
     } else {
       LOG_E(MAC, "In %s: config not handled\n", __FUNCTION__);
     }
+  } else if (nr_rach_ConfigCommon){
+    LOG_I(MAC, "Initialization of 4-step contention-based random access procedure\n");
+    prach_resources->RA_TYPE = RA_4STEP;
+    ra->cfra = 0;
   } else {
     LOG_E(MAC, "In %s: config not handled\n", __FUNCTION__);
   }
@@ -366,6 +370,12 @@ void ra_preambles_config(NR_PRACH_RESOURCES_t *prach_resources, NR_UE_MAC_INST_t
       prach_resources->ra_PreambleIndex = ra->starting_preamble_nb + sizeOfRA_PreamblesGroupA + ((taus()) % (ra->cb_preambles_per_ssb - sizeOfRA_PreamblesGroupA));
       ra->RA_usedGroupA = 0;
     }
+
+    // TODO: Remove to generate random ra_PreambleIndex
+    printf("prach_resources->ra_PreambleIndex = %i\n", prach_resources->ra_PreambleIndex);
+    prach_resources->ra_PreambleIndex = 21;
+    ra->RA_usedGroupA = 1;
+
   } else { // Msg3 is being retransmitted
     if (ra->RA_usedGroupA && noGroupB) {
       prach_resources->ra_PreambleIndex = ra->starting_preamble_nb + ((taus()) % ra->cb_preambles_per_ssb);

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_RA.c

@@ -454,11 +454,15 @@ void nr_initiate_ra_proc(module_id_t module_idP,
   // if the preamble received correspond to one of the listed
   // the UE sent a RACH either for starting RA procedure or RA procedure failed and UE retries
   int pr_found=0;
-  for (int i = 0; i < ra->preambles.num_preambles; i++) {
-    if (preamble_index == ra->preambles.preamble_list[i]) {
-      pr_found=1;
-      break;
+  if(ra->preambles.num_preambles > 0) {
+    for (int i = 0; i < ra->preambles.num_preambles; i++) {
+      if (preamble_index == ra->preambles.preamble_list[i]) {
+        pr_found=1;
+        break;
+      }
     }
+  } else {
+    pr_found=1;
   }
 
   if (!pr_found) {

openair2/RRC/NR/rrc_gNB_reconfig.c

@@ -226,7 +226,9 @@ void fill_default_secondaryCellGroup(NR_ServingCellConfigCommon_t *servingcellco
   secondaryCellGroup->spCellConfig->reconfigurationWithSync->t304=NR_ReconfigurationWithSync__t304_ms2000;
   secondaryCellGroup->spCellConfig->reconfigurationWithSync->rach_ConfigDedicated = NULL;
   secondaryCellGroup->spCellConfig->reconfigurationWithSync->ext1                 = NULL;
-  /* contention free ra */
+
+  // For 2-step contention-free random access procedure
+#if 0
   secondaryCellGroup->spCellConfig->reconfigurationWithSync->rach_ConfigDedicated = calloc(1,sizeof(struct NR_ReconfigurationWithSync__rach_ConfigDedicated));
   secondaryCellGroup->spCellConfig->reconfigurationWithSync->rach_ConfigDedicated->present= NR_ReconfigurationWithSync__rach_ConfigDedicated_PR_uplink;
   secondaryCellGroup->spCellConfig->reconfigurationWithSync->rach_ConfigDedicated->choice.uplink= calloc(1,sizeof(struct NR_RACH_ConfigDedicated));
@@ -240,12 +242,13 @@ void fill_default_secondaryCellGroup(NR_ServingCellConfigCommon_t *servingcellco
   secondaryCellGroup->spCellConfig->reconfigurationWithSync->rach_ConfigDedicated->choice.uplink->cfra->resources.present = NR_CFRA__resources_PR_ssb;
   secondaryCellGroup->spCellConfig->reconfigurationWithSync->rach_ConfigDedicated->choice.uplink->cfra->resources.choice.ssb = calloc(1,sizeof(struct NR_CFRA__resources__ssb));
   secondaryCellGroup->spCellConfig->reconfigurationWithSync->rach_ConfigDedicated->choice.uplink->cfra->resources.choice.ssb->ra_ssb_OccasionMaskIndex = 0;
+
   struct NR_CFRA_SSB_Resource *ssbElem[8];
+
   ssbElem[0] = calloc(1,sizeof(struct NR_CFRA_SSB_Resource));
   ssbElem[0]->ssb = 0;
   ssbElem[0]->ra_PreambleIndex = 63;
   ASN_SEQUENCE_ADD(&secondaryCellGroup->spCellConfig->reconfigurationWithSync->rach_ConfigDedicated->choice.uplink->cfra->resources.choice.ssb->ssb_ResourceList.list,ssbElem[0]);
-#if 0
   ssbElem[1] = calloc(1,sizeof(struct NR_CFRA_SSB_Resource));
   ssbElem[1]->ssb = 1;
   ssbElem[1]->ra_PreambleIndex = 62;
@@ -274,8 +277,10 @@ void fill_default_secondaryCellGroup(NR_ServingCellConfigCommon_t *servingcellco
   ssbElem[7]->ssb = 7;
   ssbElem[7]->ra_PreambleIndex = 63;
   ASN_SEQUENCE_ADD(&secondaryCellGroup->spCellConfig->reconfigurationWithSync->rach_ConfigDedicated->choice.uplink->cfra->resources.choice.ssb->ssb_ResourceList.list,ssbElem[7]);
-#endif
+
   secondaryCellGroup->spCellConfig->reconfigurationWithSync->rach_ConfigDedicated->choice.uplink->cfra->ext1 = NULL;
+#endif
+
   secondaryCellGroup->spCellConfig->rlf_TimersAndConstants = calloc(1,sizeof(*secondaryCellGroup->spCellConfig->rlf_TimersAndConstants));
   secondaryCellGroup->spCellConfig->rlf_TimersAndConstants->present = NR_SetupRelease_RLF_TimersAndConstants_PR_setup;
   secondaryCellGroup->spCellConfig->rlf_TimersAndConstants->choice.setup=calloc(1,sizeof(*secondaryCellGroup->spCellConfig->rlf_TimersAndConstants->choice.setup));