Baseline implementation of RA 2-Step MsgA procedures at UE

openair1/PHY/NR_UE_TRANSPORT/nr_prach.c

@@ -225,7 +225,9 @@ int32_t generate_nr_prach(PHY_VARS_NR_UE *ue, uint8_t gNB_id, int frame, uint8_t
   k += kbar;
   k *= 2;
 
-  LOG_I(PHY, "PRACH [UE %d] in frame.slot %d.%d, placing PRACH in position %d, msg1 frequency start %d (k1 %d), preamble_offset %d, first_nonzero_root_idx %d\n",
+  LOG_I(PHY,
+        "PRACH [UE %d] in frame.slot %d.%d, placing PRACH in position %d, Msg1/MsgA-Preamble frequency start %d (k1 %d), "
+        "preamble_offset %d, first_nonzero_root_idx %d\n",
         Mod_id,
         frame,
         slot,

openair2/LAYER2/NR_MAC_UE/mac_defs.h

@@ -263,16 +263,17 @@ typedef struct {
 } NR_UE_SCHEDULING_INFO;
 
 typedef enum {
-  nrRA_UE_IDLE = 0,
-  nrRA_GENERATE_PREAMBLE = 1,
-  nrRA_WAIT_RAR = 2,
-  nrRA_WAIT_CONTENTION_RESOLUTION = 3,
-  nrRA_SUCCEEDED = 4,
-  nrRA_FAILED = 5
+  nrRA_UE_IDLE,
+  nrRA_GENERATE_PREAMBLE,
+  nrRA_WAIT_RAR,
+  nrRA_WAIT_MSGB,
+  nrRA_WAIT_CONTENTION_RESOLUTION,
+  nrRA_SUCCEEDED,
+  nrRA_FAILED,
 } nrRA_UE_state_t;
 
 static const char *const nrra_ue_text[] =
-    {"UE_IDLE", "GENERATE_PREAMBLE", "WAIT_RAR", "WAIT_CONTENTION_RESOLUTION", "RA_SUCCEEDED", "RA_FAILED"};
+    {"UE_IDLE", "GENERATE_PREAMBLE", "WAIT_RAR", "WAIT_MSGB", "WAIT_CONTENTION_RESOLUTION", "RA_SUCCEEDED", "RA_FAILED"};
 
 typedef struct {
   /// PRACH format retrieved from prach_ConfigIndex
@@ -311,8 +312,10 @@ typedef struct {
   nr_ra_type_t ra_type;
   /// RA rx frame offset: compensate RA rx offset introduced by OAI gNB.
   uint8_t RA_offset;
-  /// RA-rnti
-  uint16_t ra_rnti;
+  /// RA-RNTI
+  rnti_t ra_rnti;
+  /// MsgB-RNTI
+  rnti_t MsgB_rnti;
   /// Temporary CRNTI
   uint16_t t_crnti;
   /// number of attempt for rach

openair2/LAYER2/NR_MAC_UE/mac_proto.h

@@ -304,6 +304,10 @@ void nr_ra_failed(NR_UE_MAC_INST_t *mac, uint8_t CC_id, NR_PRACH_RESOURCES_t *pr
 
 void nr_ra_succeeded(NR_UE_MAC_INST_t *mac, const uint8_t gNB_index, const frame_t frame, const int slot);
 
+int16_t nr_get_RA_window_2Step(const NR_MsgA_ConfigCommon_r16_t *msgA_ConfigCommon_r16);
+
+int16_t nr_get_RA_window_4Step(const NR_RACH_ConfigCommon_t *rach_ConfigCommon);
+
 void nr_get_RA_window(NR_UE_MAC_INST_t *mac);
 
 /* \brief Function called by PHY to retrieve information to be transmitted using the RA procedure.
@@ -331,7 +335,7 @@ void nr_get_prach_resources(NR_UE_MAC_INST_t *mac,
                             NR_PRACH_RESOURCES_t *prach_resources,
                             NR_RACH_ConfigDedicated_t * rach_ConfigDedicated);
 
-void prepare_msg4_feedback(NR_UE_MAC_INST_t *mac, int pid, int ack_nack);
+void prepare_msg4_msgb_feedback(NR_UE_MAC_INST_t *mac, int pid, int ack_nack);
 void configure_initial_pucch(PUCCH_sched_t *pucch, int res_ind);
 void release_PUCCH_SRS(NR_UE_MAC_INST_t *mac);
 void nr_ue_reset_sync_state(NR_UE_MAC_INST_t *mac);
@@ -356,7 +360,7 @@ void schedule_RA_after_SR_failure(NR_UE_MAC_INST_t *mac);
 void nr_Msg1_transmitted(NR_UE_MAC_INST_t *mac);
 void nr_Msg3_transmitted(NR_UE_MAC_INST_t *mac, uint8_t CC_id, frame_t frameP, slot_t slotP, uint8_t gNB_id);
 void trigger_MAC_UE_RA(NR_UE_MAC_INST_t *mac);
-void nr_get_msg3_payload(NR_UE_MAC_INST_t *mac, uint8_t *buf, int TBS_max);
+void nr_get_Msg3_MsgA_PUSCH_payload(NR_UE_MAC_INST_t *mac, uint8_t *buf, int TBS_max);
 void handle_time_alignment_timer_expired(NR_UE_MAC_INST_t *mac);
 int8_t nr_ue_process_dci_freq_dom_resource_assignment(nfapi_nr_ue_pusch_pdu_t *pusch_config_pdu,
                                                       fapi_nr_dl_config_dlsch_pdu_rel15_t *dlsch_config_pdu,
@@ -410,7 +414,7 @@ int nr_config_pusch_pdu(NR_UE_MAC_INST_t *mac,
                         dci_pdu_rel15_t *dci,
                         csi_payload_t *csi_report,
                         RAR_grant_t *rar_grant,
-                        uint16_t rnti,
+                        rnti_t rnti,
                         int ss_type,
                         const nr_dci_format_t dci_format);
 

openair2/LAYER2/NR_MAC_UE/nr_ue_scheduler.c

@@ -574,7 +574,7 @@ int nr_config_pusch_pdu(NR_UE_MAC_INST_t *mac,
                         dci_pdu_rel15_t *dci,
                         csi_payload_t *csi_report,
                         RAR_grant_t *rar_grant,
-                        uint16_t rnti,
+                        rnti_t rnti,
                         int ss_type,
                         const nr_dci_format_t dci_format)
 {
@@ -584,6 +584,7 @@ int nr_config_pusch_pdu(NR_UE_MAC_INST_t *mac,
   int rnti_type = get_rnti_type(mac, rnti);
   NR_UE_UL_BWP_t *current_UL_BWP = mac->current_UL_BWP;
   NR_UE_ServingCell_Info_t *sc_info = &mac->sc_info;
+  int scs = current_UL_BWP->scs;
 
   // Common configuration
   pusch_config_pdu->dmrs_config_type = pusch_dmrs_type1;
@@ -596,8 +597,69 @@ int nr_config_pusch_pdu(NR_UE_MAC_INST_t *mac,
   int dmrslength = 1;
   NR_PUSCH_Config_t *pusch_Config = current_UL_BWP->pusch_Config;
 
-  if (rar_grant) {
+  AssertFatal(!((mac->ra.ra_state < nrRA_SUCCEEDED && mac->ra.ra_type == RA_2_STEP) && rar_grant), "logic error: Is not possible to have both msgA_pusch_resource and rar_grant\n");
+
+  if (mac->ra.ra_state < nrRA_SUCCEEDED && mac->ra.ra_type == RA_2_STEP) {
+    NR_MsgA_PUSCH_Resource_r16_t *msgA_PUSCH_Resource =
+        current_UL_BWP->msgA_ConfigCommon_r16->msgA_PUSCH_Config_r16->msgA_PUSCH_ResourceGroupA_r16;
+    int S = 0;
+    int L = 0;
+    SLIV2SL(*msgA_PUSCH_Resource->startSymbolAndLengthMsgA_PO_r16, &S, &L);
+    tda_info->k2 = msgA_PUSCH_Resource->msgA_PUSCH_TimeDomainOffset_r16;
+    tda_info->startSymbolIndex = S;
+    tda_info->nrOfSymbols = L;
+    l_prime_mask = get_l_prime(tda_info->nrOfSymbols,
+                               tda_info->mapping_type,
+                               add_pos,
+                               dmrslength,
+                               tda_info->startSymbolIndex,
+                               mac->dmrs_TypeA_Position);
+    LOG_I(NR_MAC,
+          "MSGA PUSCH start_sym:%d NR Symb:%d mappingtype:%d, DMRS_MASK:%x\n",
+          pusch_config_pdu->start_symbol_index,
+          pusch_config_pdu->nr_of_symbols,
+          tda_info->mapping_type,
+          l_prime_mask);
+
+    LOG_D(NR_MAC,
+          "sc_info->initial_ul_BWPStart = %d  sc_info->initial_ul_BWPSize = %d\n",
+          sc_info->initial_ul_BWPStart,
+          sc_info->initial_ul_BWPSize);
+    pusch_config_pdu->handle = 0;
+    pusch_config_pdu->rb_size = msgA_PUSCH_Resource->nrofPRBs_PerMsgA_PO_r16;
+    pusch_config_pdu->mcs_table = 0;
+    pusch_config_pdu->frequency_hopping = msgA_PUSCH_Resource->msgA_IntraSlotFrequencyHopping_r16 ? *msgA_PUSCH_Resource->msgA_IntraSlotFrequencyHopping_r16 : 0;
+    pusch_config_pdu->dmrs_ports = 1; // is in SIB1 nrofDMRS_Sequences_r16?
+    pusch_config_pdu->pusch_data.new_data_indicator = 1; // new data
+    pusch_config_pdu->num_dmrs_cdm_grps_no_data = 2;
+    pusch_config_pdu->ul_dmrs_symb_pos = get_l_prime(3, 0, pusch_dmrs_pos2, pusch_len1, 10, mac->dmrs_TypeA_Position);
+    pusch_config_pdu->transform_precoding =
+           *mac->current_UL_BWP->msgA_ConfigCommon_r16->msgA_PUSCH_Config_r16->msgA_TransformPrecoder_r16;
+    pusch_config_pdu->rb_bitmap[0] = 0;
+    pusch_config_pdu->rb_start = msgA_PUSCH_Resource->frequencyStartMsgA_PUSCH_r16; // rb_start depends on the RO
+    pusch_config_pdu->bwp_size = sc_info->initial_ul_BWPSize;
+    pusch_config_pdu->bwp_start = sc_info->initial_ul_BWPStart;
+    pusch_config_pdu->subcarrier_spacing = scs;
+    pusch_config_pdu->cyclic_prefix = 0;
+    pusch_config_pdu->uplink_frequency_shift_7p5khz = 0;
+    pusch_config_pdu->vrb_to_prb_mapping = 0;
+    pusch_config_pdu->dmrs_config_type = 0;
+    pusch_config_pdu->data_scrambling_id = mac->physCellId;
+    pusch_config_pdu->ul_dmrs_scrambling_id = mac->physCellId;
+    pusch_config_pdu->scid = 0;
+    pusch_config_pdu->resource_alloc = 1;
+    pusch_config_pdu->tx_direct_current_location = 0;
+    pusch_config_pdu->mcs_index = msgA_PUSCH_Resource->msgA_MCS_r16;
+    pusch_config_pdu->qam_mod_order = nr_get_Qm_dl(pusch_config_pdu->mcs_index, 0);
+    pusch_config_pdu->start_symbol_index = S;
+    pusch_config_pdu->nr_of_symbols = L;
+    pusch_config_pdu->pusch_data.rv_index = 0; // 8.3 in 38.213
+    pusch_config_pdu->pusch_data.harq_process_id = 0;
+    pusch_config_pdu->pusch_data.num_cb = 0;
+    pusch_config_pdu->tbslbrm = 0;
+    pusch_config_pdu->target_code_rate = nr_get_code_rate_ul(pusch_config_pdu->mcs_index, 0);
 
+  } else if (rar_grant) {
     // Note: for Msg3 or MsgA PUSCH transmission the N_PRB_oh is always set to 0
     int ibwp_start = sc_info->initial_ul_BWPStart;
     int ibwp_size = sc_info->initial_ul_BWPSize;
@@ -1501,8 +1563,8 @@ void nr_ue_ul_scheduler(NR_UE_MAC_INST_t *mac, nr_uplink_indication_t *ul_info)
             TBS_bytes,
             ra->ra_state);
       ulcfg_pdu->pusch_config_pdu.tx_request_body.fapiTxPdu = NULL;
-      if (ra->ra_state == nrRA_WAIT_RAR && !ra->cfra) {
-        nr_get_msg3_payload(mac, ulsch_input_buffer, TBS_bytes);
+      if ((ra->ra_state == nrRA_WAIT_RAR || ra->ra_state == nrRA_WAIT_MSGB) && !ra->cfra) {
+        nr_get_Msg3_MsgA_PUSCH_payload(mac, ulsch_input_buffer, TBS_bytes);
         for (int k = 0; k < TBS_bytes; k++) {
           LOG_D(NR_MAC, "(%i): 0x%x\n", k, ulsch_input_buffer[k]);
         }
@@ -1553,6 +1615,9 @@ void nr_ue_ul_scheduler(NR_UE_MAC_INST_t *mac, nr_uplink_indication_t *ul_info)
         LOG_A(NR_MAC, "[RAPROC][%d.%d] RA-Msg3 transmitted\n", frame_tx, slot_tx);
         nr_Msg3_transmitted(mac, cc_id, frame_tx, slot_tx, gNB_index);
       }
+      if (ra->ra_state == nrRA_WAIT_MSGB && !ra->cfra) {
+        LOG_A(NR_MAC, "[RAPROC][%d.%d] RA-MsgA-PUSCH transmitted\n", frame_tx, slot_tx);
+      }
     }
     ulcfg_pdu++;
   }
@@ -2867,7 +2932,57 @@ static void nr_ue_prach_scheduler(NR_UE_MAC_INST_t *mac, frame_t frameP, sub_fra
       if(mac->if_module != NULL && mac->if_module->scheduled_response != NULL)
         mac->if_module->scheduled_response(&scheduled_response);
 
-      nr_Msg1_transmitted(mac);
+      if (ra->ra_type == RA_4_STEP) {
+        nr_Msg1_transmitted(mac);
+      } else if (ra->ra_type == RA_2_STEP) {
+        const NR_MsgA_ConfigCommon_r16_t *msgacc = mac->current_UL_BWP->msgA_ConfigCommon_r16;
+        int mu = (int)*msgacc->rach_ConfigCommonTwoStepRA_r16.msgA_SubcarrierSpacing_r16;
+
+        NR_MsgA_PUSCH_Resource_r16_t *msgA_PUSCH_Resource =
+            mac->current_UL_BWP->msgA_ConfigCommon_r16->msgA_PUSCH_Config_r16->msgA_PUSCH_ResourceGroupA_r16;
+
+        const int n_slots_frame = nr_slots_per_frame[mu];
+        slot_t msgA_pusch_slot = (slotP + msgA_PUSCH_Resource->msgA_PUSCH_TimeDomainOffset_r16) % n_slots_frame;
+        frame_t msgA_pusch_frame =
+            (frameP + ((slotP + msgA_PUSCH_Resource->msgA_PUSCH_TimeDomainOffset_r16) / n_slots_frame)) % 1024;
+
+        fapi_nr_ul_config_request_pdu_t *pdu =
+            lockGet_ul_config(mac, msgA_pusch_frame, msgA_pusch_slot, FAPI_NR_UL_CONFIG_TYPE_PUSCH);
+        if (!pdu)
+          return;
+
+        // Config Msg3/MsgA-PUSCH PDU
+        NR_tda_info_t tda_info = {0};
+        AssertFatal(msgA_PUSCH_Resource->startSymbolAndLengthMsgA_PO_r16,
+                    "Only SLIV based on startSymbolAndLengthMsgA_PO_r16 implemented\n");
+
+        int ret = nr_config_pusch_pdu(mac,
+                                      &tda_info,
+                                      &pdu->pusch_config_pdu,
+                                      NULL,
+                                      NULL,
+                                      NULL,
+                                      mac->ra.ra_rnti,
+                                      NR_SearchSpace__searchSpaceType_PR_common,
+                                      NR_DCI_NONE);
+
+        if (ret != 0)
+          remove_ul_config_last_item(pdu);
+        release_ul_config(pdu, false);
+
+        // Compute MsgB RNTI
+        ra->MsgB_rnti =
+            nr_get_MsgB_rnti(prach_occasion_info_p->start_symbol, prach_occasion_info_p->slot, prach_occasion_info_p->fdm, 0);
+        LOG_D(NR_MAC, "ra->ra_state %s\n", nrra_ue_text[ra->ra_state]);
+        ra->ra_state = nrRA_WAIT_MSGB;
+        ra->t_crnti = 0;
+        mac->crnti = 0;
+        ra->ra_rnti = 0;
+      } else {
+        AssertFatal(false, "RA type %d not implemented!\n", ra->ra_type);
+      }
+
+      // rnti = ra->t_crnti;
     } // is_nr_prach_slot
   } // if is_nr_UL_slot
 }

openair2/NR_UE_PHY_INTERFACE/NR_IF_Module.c

@@ -1127,7 +1127,7 @@ void update_harq_status(NR_UE_MAC_INST_t *mac, uint8_t harq_pid, uint8_t ack_nac
     LOG_D(PHY,"Updating harq_status for harq_id %d, ack/nak %d\n", harq_pid, current_harq->ack);
     // we can prepare feedback for MSG4 in advance
     if (mac->ra.ra_state == nrRA_WAIT_CONTENTION_RESOLUTION)
-      prepare_msg4_feedback(mac, harq_pid, ack_nack);
+      prepare_msg4_msgb_feedback(mac, harq_pid, ack_nack);
     else {
       current_harq->ack = ack_nack;
       current_harq->ack_received = true;