/*
 * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The OpenAirInterface Software Alliance licenses this file to You under
 * the OAI Public License, Version 1.1  (the "License"); you may not use this file
 * except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.openairinterface.org/?page_id=698
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *-------------------------------------------------------------------------------
 * For more information about the OpenAirInterface (OAI) Software Alliance:
 *      contact@openairinterface.org
 */

/*! \file     gNB_scheduler_RA.c
 * \brief     primitives used for random access
 * \author    Guido Casati
 * \date      2019
 * \email:    guido.casati@iis.fraunhofer.de
 * \version
 */

#include "common/platform_types.h"
#include "uper_decoder.h"

/* MAC */
#include "nr_mac_gNB.h"
#include "NR_MAC_gNB/mac_proto.h"
#include "NR_MAC_COMMON/nr_mac_extern.h"

/* Utils */
#include "common/utils/LOG/log.h"
#include "common/utils/LOG/vcd_signal_dumper.h"
#include "common/utils/nr/nr_common.h"
#include "UTIL/OPT/opt.h"
#include "SIMULATION/TOOLS/sim.h" // for taus

/* rlc */
#include "openair2/LAYER2/nr_rlc/nr_rlc_oai_api.h"
#include "openair2/LAYER2/RLC/rlc.h"

#include <executables/softmodem-common.h>
extern RAN_CONTEXT_t RC;
extern const uint8_t nr_slots_per_frame[5];
extern uint16_t sl_ahead;

// forward declaration of functions used in this file
static void fill_msg3_pusch_pdu(nfapi_nr_pusch_pdu_t *pusch_pdu,
                                NR_ServingCellConfigCommon_t *scc,
                                int round,
                                int startSymbolAndLength,
                                rnti_t rnti,
                                int scs,
                                int bwp_size,
                                int bwp_start,
                                int mappingtype,
                                int fh,
                                int msg3_first_rb,
                                int msg3_nb_rb);
static void nr_fill_rar(uint8_t Mod_idP, NR_RA_t *ra, uint8_t *dlsch_buffer, nfapi_nr_pusch_pdu_t *pusch_pdu);

static const uint8_t DELTA[4] = {2, 3, 4, 6};

static const float ssb_per_rach_occasion[8] = {0.125, 0.25, 0.5, 1, 2, 4, 8};

static int16_t ssb_index_from_prach(module_id_t module_idP,
                                    frame_t frameP,
                                    sub_frame_t slotP,
                                    uint16_t preamble_index,
                                    uint8_t freq_index,
                                    uint8_t symbol)
{
  gNB_MAC_INST *gNB = RC.nrmac[module_idP];
  NR_COMMON_channels_t *cc = &gNB->common_channels[0];
  NR_ServingCellConfigCommon_t *scc = cc->ServingCellConfigCommon;
  nfapi_nr_config_request_scf_t *cfg = &RC.nrmac[module_idP]->config[0];

  uint8_t config_index = scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->rach_ConfigGeneric.prach_ConfigurationIndex;
  uint8_t fdm = cfg->prach_config.num_prach_fd_occasions.value;
  
  uint8_t total_RApreambles = MAX_NUM_NR_PRACH_PREAMBLES;
  if( scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->totalNumberOfRA_Preambles != NULL)
    total_RApreambles = *scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->totalNumberOfRA_Preambles;	
  
  float  num_ssb_per_RO = ssb_per_rach_occasion[cfg->prach_config.ssb_per_rach.value];	
  uint16_t start_symbol_index = 0;
  uint8_t mu,N_dur=0,N_t_slot=0,start_symbol = 0, temp_start_symbol = 0, N_RA_slot=0;
  uint16_t format,RA_sfn_index = -1;
  uint8_t config_period = 1;
  uint16_t prach_occasion_id = -1;
  uint8_t num_active_ssb = cc->num_active_ssb;

  if (scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->msg1_SubcarrierSpacing)
    mu = *scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->msg1_SubcarrierSpacing;
  else
    mu = scc->downlinkConfigCommon->frequencyInfoDL->scs_SpecificCarrierList.list.array[0]->subcarrierSpacing;

  get_nr_prach_info_from_index(config_index,
			       (int)frameP,
			       (int)slotP,
			       scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencyPointA,
			       mu,
			       cc->frame_type,
			       &format,
			       &start_symbol,
			       &N_t_slot,
			       &N_dur,
			       &RA_sfn_index,
			       &N_RA_slot,
			       &config_period);
  uint8_t index = 0,slot_index = 0;
  for (slot_index = 0;slot_index < N_RA_slot; slot_index++) {
    if (N_RA_slot <= 1) { //1 PRACH slot in a subframe
       if((mu == 1) || (mu == 3))
         slot_index = 1;  //For scs = 30khz and 120khz
    }
    for (int i=0; i< N_t_slot; i++) {
      temp_start_symbol = (start_symbol + i * N_dur + 14 * slot_index) % 14;
      if(symbol == temp_start_symbol) {
        start_symbol_index = i;
        break;
      }
    }
  }
  if (N_RA_slot <= 1) { //1 PRACH slot in a subframe
    if((mu == 1) || (mu == 3))
      slot_index = 0;  //For scs = 30khz and 120khz
  }

  //  prach_occasion_id = subframe_index * N_t_slot * N_RA_slot * fdm + N_RA_slot_index * N_t_slot * fdm + freq_index + fdm * start_symbol_index; 
  prach_occasion_id = (((frameP % (cc->max_association_period * config_period))/config_period)*cc->total_prach_occasions_per_config_period) +
                      (RA_sfn_index + slot_index) * N_t_slot * fdm + start_symbol_index * fdm + freq_index; 

  //one RO is shared by one or more SSB
  if(num_ssb_per_RO <= 1 )
    index = (int) (prach_occasion_id / (int)(1/num_ssb_per_RO)) % num_active_ssb;
  //one SSB have more than one continuous RO
  else if ( num_ssb_per_RO > 1) {
    index = (prach_occasion_id * (int)num_ssb_per_RO)% num_active_ssb ;
    for(int j = 0;j < num_ssb_per_RO;j++) {
      if(preamble_index <  (((j+1) * total_RApreambles) / num_ssb_per_RO))
        index = index + j;
    }
  }

  LOG_D(NR_MAC, "Frame %d, Slot %d: Prach Occasion id = %d ssb per RO = %f number of active SSB %u index = %d fdm %u symbol index %u freq_index %u total_RApreambles %u\n",
        frameP, slotP, prach_occasion_id, num_ssb_per_RO, num_active_ssb, index, fdm, start_symbol_index, freq_index, total_RApreambles);

  return index;
}

//Compute Total active SSBs and RO available
void find_SSB_and_RO_available(gNB_MAC_INST *nrmac)
{
  /* already mutex protected through nr_mac_config_scc() */
  //NR_SCHED_ENSURE_LOCKED(&nrmac->sched_lock);

  NR_COMMON_channels_t *cc = &nrmac->common_channels[0];
  NR_ServingCellConfigCommon_t *scc = cc->ServingCellConfigCommon;
  nfapi_nr_config_request_scf_t *cfg = &nrmac->config[0];

  uint8_t config_index = scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->rach_ConfigGeneric.prach_ConfigurationIndex;
  uint8_t mu,N_dur=0,N_t_slot=0,start_symbol=0,N_RA_slot = 0;
  uint16_t format,N_RA_sfn = 0,unused_RA_occasion,repetition = 0;
  uint8_t num_active_ssb = 0;
  uint8_t max_association_period = 1;

  struct NR_RACH_ConfigCommon__ssb_perRACH_OccasionAndCB_PreamblesPerSSB *ssb_perRACH_OccasionAndCB_PreamblesPerSSB = scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->ssb_perRACH_OccasionAndCB_PreamblesPerSSB;

  switch (ssb_perRACH_OccasionAndCB_PreamblesPerSSB->present){
    case NR_RACH_ConfigCommon__ssb_perRACH_OccasionAndCB_PreamblesPerSSB_PR_oneEighth:
      cc->cb_preambles_per_ssb = 4 * (ssb_perRACH_OccasionAndCB_PreamblesPerSSB->choice.oneEighth + 1);
      break;
    case NR_RACH_ConfigCommon__ssb_perRACH_OccasionAndCB_PreamblesPerSSB_PR_oneFourth:
      cc->cb_preambles_per_ssb = 4 * (ssb_perRACH_OccasionAndCB_PreamblesPerSSB->choice.oneFourth + 1);
      break;
    case NR_RACH_ConfigCommon__ssb_perRACH_OccasionAndCB_PreamblesPerSSB_PR_oneHalf:
      cc->cb_preambles_per_ssb = 4 * (ssb_perRACH_OccasionAndCB_PreamblesPerSSB->choice.oneHalf + 1);
      break;
    case NR_RACH_ConfigCommon__ssb_perRACH_OccasionAndCB_PreamblesPerSSB_PR_one:
      cc->cb_preambles_per_ssb = 4 * (ssb_perRACH_OccasionAndCB_PreamblesPerSSB->choice.one + 1);
      break;
    case NR_RACH_ConfigCommon__ssb_perRACH_OccasionAndCB_PreamblesPerSSB_PR_two:
      cc->cb_preambles_per_ssb = 4 * (ssb_perRACH_OccasionAndCB_PreamblesPerSSB->choice.two + 1);
      break;
    case NR_RACH_ConfigCommon__ssb_perRACH_OccasionAndCB_PreamblesPerSSB_PR_four:
      cc->cb_preambles_per_ssb = ssb_perRACH_OccasionAndCB_PreamblesPerSSB->choice.four;
      break;
    case NR_RACH_ConfigCommon__ssb_perRACH_OccasionAndCB_PreamblesPerSSB_PR_eight:
      cc->cb_preambles_per_ssb = ssb_perRACH_OccasionAndCB_PreamblesPerSSB->choice.eight;
      break;
    case NR_RACH_ConfigCommon__ssb_perRACH_OccasionAndCB_PreamblesPerSSB_PR_sixteen:
      cc->cb_preambles_per_ssb = ssb_perRACH_OccasionAndCB_PreamblesPerSSB->choice.sixteen;
      break;
    default:
      AssertFatal(1 == 0, "Unsupported ssb_perRACH_config %d\n", ssb_perRACH_OccasionAndCB_PreamblesPerSSB->present);
      break;
    }

  if (scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->msg1_SubcarrierSpacing)
    mu = *scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->msg1_SubcarrierSpacing;
  else
    mu = scc->downlinkConfigCommon->frequencyInfoDL->scs_SpecificCarrierList.list.array[0]->subcarrierSpacing;

  // prach is scheduled according to configuration index and tables 6.3.3.2.2 to 6.3.3.2.4
  get_nr_prach_occasion_info_from_index(config_index,
                                        scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencyPointA,
                                        mu,
                                        cc->frame_type,
                                        &format,
                                        &start_symbol,
                                        &N_t_slot,
                                        &N_dur,
                                        &N_RA_slot,
                                        &N_RA_sfn,
                                        &max_association_period);

  float num_ssb_per_RO = ssb_per_rach_occasion[cfg->prach_config.ssb_per_rach.value];	
  uint8_t fdm = cfg->prach_config.num_prach_fd_occasions.value;
  uint64_t L_ssb = (((uint64_t) cfg->ssb_table.ssb_mask_list[0].ssb_mask.value)<<32) | cfg->ssb_table.ssb_mask_list[1].ssb_mask.value ;
  uint32_t total_RA_occasions = N_RA_sfn * N_t_slot * N_RA_slot * fdm;

  for(int i = 0;i < 64;i++) {
    if ((L_ssb >> (63-i)) & 0x01) { // only if the bit of L_ssb at current ssb index is 1
      cc->ssb_index[num_active_ssb] = i; 
      num_active_ssb++;
    }
  }

  cc->total_prach_occasions_per_config_period = total_RA_occasions;
  for(int i=1; (1 << (i-1)) <= max_association_period; i++) {
    cc->max_association_period = (1 <<(i-1));
    total_RA_occasions = total_RA_occasions * cc->max_association_period;
    if(total_RA_occasions >= (int) (num_active_ssb/num_ssb_per_RO)) {
      repetition = (uint16_t)((total_RA_occasions * num_ssb_per_RO )/num_active_ssb);
      break;
    }
  }

  unused_RA_occasion = total_RA_occasions - (int)((num_active_ssb * repetition)/num_ssb_per_RO);
  cc->total_prach_occasions = total_RA_occasions - unused_RA_occasion;
  cc->num_active_ssb = num_active_ssb;

  LOG_D(NR_MAC,
        "Total available RO %d, num of active SSB %d: unused RO = %d association_period %u N_RA_sfn %u total_prach_occasions_per_config_period %u\n",
        cc->total_prach_occasions,
        cc->num_active_ssb,
        unused_RA_occasion,
        cc->max_association_period,
        N_RA_sfn,
        cc->total_prach_occasions_per_config_period);
}		
		
void schedule_nr_prach(module_id_t module_idP, frame_t frameP, sub_frame_t slotP)
{
  gNB_MAC_INST *gNB = RC.nrmac[module_idP];
  /* already mutex protected: held in gNB_dlsch_ulsch_scheduler() */
  NR_SCHED_ENSURE_LOCKED(&gNB->sched_lock);

  NR_COMMON_channels_t *cc = gNB->common_channels;
  NR_ServingCellConfigCommon_t *scc = cc->ServingCellConfigCommon;
  int mu;
  if (scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->msg1_SubcarrierSpacing)
    mu = *scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->msg1_SubcarrierSpacing;
  else
    mu = scc->downlinkConfigCommon->frequencyInfoDL->scs_SpecificCarrierList.list.array[0]->subcarrierSpacing;
  int index = ul_buffer_index(frameP, slotP, mu, gNB->UL_tti_req_ahead_size);
  nfapi_nr_ul_tti_request_t *UL_tti_req = &RC.nrmac[module_idP]->UL_tti_req_ahead[0][index];
  nfapi_nr_config_request_scf_t *cfg = &RC.nrmac[module_idP]->config[0];

  if (is_nr_UL_slot(scc->tdd_UL_DL_ConfigurationCommon, slotP, cc->frame_type)) {

    uint8_t config_index = scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->rach_ConfigGeneric.prach_ConfigurationIndex;
    uint8_t N_dur, N_t_slot, start_symbol = 0, N_RA_slot;
    uint16_t RA_sfn_index = -1;
    uint8_t config_period = 1;
    uint16_t format;
    int slot_index = 0;
    uint16_t prach_occasion_id = -1;

    int bwp_start = NRRIV2PRBOFFSET(scc->uplinkConfigCommon->initialUplinkBWP->genericParameters.locationAndBandwidth, MAX_BWP_SIZE);

    uint8_t fdm = cfg->prach_config.num_prach_fd_occasions.value;
    // prach is scheduled according to configuration index and tables 6.3.3.2.2 to 6.3.3.2.4
    if ( get_nr_prach_info_from_index(config_index,
                                      (int)frameP,
                                      (int)slotP,
                                      scc->downlinkConfigCommon->frequencyInfoDL->absoluteFrequencyPointA,
                                      mu,
                                      cc->frame_type,
                                      &format,
                                      &start_symbol,
                                      &N_t_slot,
                                      &N_dur,
                                      &RA_sfn_index,
                                      &N_RA_slot,
                                      &config_period) ) {

      uint16_t format0 = format&0xff;      // first column of format from table
      uint16_t format1 = (format>>8)&0xff; // second column of format from table

      if (N_RA_slot > 1) { //more than 1 PRACH slot in a subframe
        if (slotP%2 == 1)
          slot_index = 1;
        else
          slot_index = 0;
      }else if (N_RA_slot <= 1) { //1 PRACH slot in a subframe
        slot_index = 0;
      }

      UL_tti_req->SFN = frameP;
      UL_tti_req->Slot = slotP;
      for (int fdm_index=0; fdm_index < fdm; fdm_index++) { // one structure per frequency domain occasion
        for (int td_index=0; td_index<N_t_slot; td_index++) {

          prach_occasion_id = (((frameP % (cc->max_association_period * config_period))/config_period) * cc->total_prach_occasions_per_config_period) +
                              (RA_sfn_index + slot_index) * N_t_slot * fdm + td_index * fdm + fdm_index;

          if((prach_occasion_id < cc->total_prach_occasions) && (td_index == 0)){
            AssertFatal(UL_tti_req->n_pdus < sizeof(UL_tti_req->pdus_list) / sizeof(UL_tti_req->pdus_list[0]),
                        "Invalid UL_tti_req->n_pdus %d\n", UL_tti_req->n_pdus);

            UL_tti_req->pdus_list[UL_tti_req->n_pdus].pdu_type = NFAPI_NR_UL_CONFIG_PRACH_PDU_TYPE;
            UL_tti_req->pdus_list[UL_tti_req->n_pdus].pdu_size = sizeof(nfapi_nr_prach_pdu_t);
            nfapi_nr_prach_pdu_t  *prach_pdu = &UL_tti_req->pdus_list[UL_tti_req->n_pdus].prach_pdu;
            memset(prach_pdu,0,sizeof(nfapi_nr_prach_pdu_t));
            UL_tti_req->n_pdus+=1;

            // filling the prach fapi structure
            prach_pdu->phys_cell_id = *scc->physCellId;
            prach_pdu->num_prach_ocas = N_t_slot;
            prach_pdu->prach_start_symbol = start_symbol;
            prach_pdu->num_ra = fdm_index;
            prach_pdu->num_cs = get_NCS(scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->rach_ConfigGeneric.zeroCorrelationZoneConfig,
                                        format0,
                                        scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->restrictedSetConfig);

            LOG_D(NR_MAC, "Frame %d, Slot %d: Prach Occasion id = %u  fdm index = %u start symbol = %u slot index = %u subframe index = %u \n",
                  frameP, slotP,
                  prach_occasion_id, prach_pdu->num_ra,
                  prach_pdu->prach_start_symbol,
                  slot_index, RA_sfn_index);
            // SCF PRACH PDU format field does not consider A1/B1 etc. possibilities
            // We added 9 = A1/B1 10 = A2/B2 11 A3/B3
            if (format1!=0xff) {
              switch(format0) {
                case 0xa1:
                  prach_pdu->prach_format = 11;
                  break;
                case 0xa2:
                  prach_pdu->prach_format = 12;
                  break;
                case 0xa3:
                  prach_pdu->prach_format = 13;
                  break;
              default:
                AssertFatal(1==0,"Only formats A1/B1 A2/B2 A3/B3 are valid for dual format");
              }
            }
            else{
              switch(format0) {
                case 0:
                  prach_pdu->prach_format = 0;
                  break;
                case 1:
                  prach_pdu->prach_format = 1;
                  break;
                case 2:
                  prach_pdu->prach_format = 2;
                  break;
                case 3:
                  prach_pdu->prach_format = 3;
                  break;
                case 0xa1:
                  prach_pdu->prach_format = 4;
                  break;
                case 0xa2:
                  prach_pdu->prach_format = 5;
                  break;
                case 0xa3:
                  prach_pdu->prach_format = 6;
                  break;
                case 0xb1:
                  prach_pdu->prach_format = 7;
                  break;
                case 0xb4:
                  prach_pdu->prach_format = 8;
                  break;
                case 0xc0:
                  prach_pdu->prach_format = 9;
                  break;
                case 0xc2:
                  prach_pdu->prach_format = 10;
                  break;
              default:
                AssertFatal(1==0,"Invalid PRACH format");
              }
            }
          }
        }
      }

      // block resources in vrb_map_UL
      const NR_RACH_ConfigGeneric_t *rach_ConfigGeneric =
          &scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->rach_ConfigGeneric;
      const uint8_t mu_pusch =
          scc->uplinkConfigCommon->frequencyInfoUL->scs_SpecificCarrierList.list.array[0]->subcarrierSpacing;
      const int16_t N_RA_RB = get_N_RA_RB(cfg->prach_config.prach_sub_c_spacing.value, mu_pusch);
      index = ul_buffer_index(frameP, slotP, mu, gNB->vrb_map_UL_size);
      uint16_t *vrb_map_UL = &cc->vrb_map_UL[index * MAX_BWP_SIZE];
      for (int i = 0; i < N_RA_RB * fdm; ++i)
        vrb_map_UL[bwp_start + rach_ConfigGeneric->msg1_FrequencyStart + i] |= SL_to_bitmap(start_symbol, N_t_slot*N_dur);
    }
  }
}

static void nr_schedule_msg2(uint16_t rach_frame,
                             uint16_t rach_slot,
                             uint16_t *msg2_frame,
                             uint16_t *msg2_slot,
                             int mu,
                             NR_ServingCellConfigCommon_t *scc,
                             frame_type_t frame_type,
                             uint16_t monitoring_slot_period,
                             uint16_t monitoring_offset,
                             uint8_t beam_index,
                             uint8_t num_active_ssb,
                             int16_t *tdd_beam_association,
                             int sl_ahead)
{
  // preferentially we schedule the msg2 in the mixed slot or in the last dl slot
  // if they are allowed by search space configuration
  uint8_t response_window = scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->rach_ConfigGeneric.ra_ResponseWindow;
  uint8_t slot_window;
  const int n_slots_frame = nr_slots_per_frame[mu];
  const NR_TDD_UL_DL_Pattern_t *tdd = scc->tdd_UL_DL_ConfigurationCommon ? &scc->tdd_UL_DL_ConfigurationCommon->pattern1 : NULL;
  // number of mixed slot or of last dl slot if there is no mixed slot
  uint8_t last_dl_slot_period = n_slots_frame-1;
  // lenght of tdd period in slots
  uint8_t tdd_period_slot = n_slots_frame;

  if (tdd) {
    last_dl_slot_period = tdd->nrofDownlinkSymbols == 0? (tdd->nrofDownlinkSlots-1) : tdd->nrofDownlinkSlots;
    tdd_period_slot = n_slots_frame/get_nb_periods_per_frame(tdd->dl_UL_TransmissionPeriodicity);
  }
  else{
    if(frame_type == TDD)
      AssertFatal(frame_type == FDD, "Dynamic TDD not handled yet\n");
  }


  switch(response_window){
    case NR_RACH_ConfigGeneric__ra_ResponseWindow_sl1:
      slot_window = 1;
      break;
    case NR_RACH_ConfigGeneric__ra_ResponseWindow_sl2:
      slot_window = 2;
      break;
    case NR_RACH_ConfigGeneric__ra_ResponseWindow_sl4:
      slot_window = 4;
      break;
    case NR_RACH_ConfigGeneric__ra_ResponseWindow_sl8:
      slot_window = 8;
      break;
    case NR_RACH_ConfigGeneric__ra_ResponseWindow_sl10:
      slot_window = 10;
      break;
    case NR_RACH_ConfigGeneric__ra_ResponseWindow_sl20:
      slot_window = 20;
      break;
    case NR_RACH_ConfigGeneric__ra_ResponseWindow_sl40:
      slot_window = 40;
      break;
    case NR_RACH_ConfigGeneric__ra_ResponseWindow_sl80:
      slot_window = 80;
      break;
    default:
      AssertFatal(1==0,"Invalid response window value %d\n",response_window);
  }
  AssertFatal(slot_window<=nr_slots_per_frame[mu],"Msg2 response window needs to be lower or equal to 10ms");

  // slot and frame limit to transmit msg2 according to response window
  uint8_t slot_limit = (rach_slot + slot_window)%nr_slots_per_frame[mu];
  uint16_t frame_limit = rach_frame + (rach_slot + slot_window)/nr_slots_per_frame[mu];

  // computing start of next period
  uint8_t start_next_period = rach_slot-(rach_slot%tdd_period_slot)+tdd_period_slot;
  int eff_slot = start_next_period + last_dl_slot_period; // initializing scheduling of slot to next mixed (or last dl) slot

  // we can't schedule msg2 before sl_ahead since prach
  while ((eff_slot-rach_slot)<=sl_ahead) {
    eff_slot += tdd_period_slot;
  }

  int FR = *scc->downlinkConfigCommon->frequencyInfoDL->frequencyBandList.list.array[0] >= 257 ? nr_FR2 : nr_FR1;
  if (FR==nr_FR2) {
    int num_tdd_period = (eff_slot%nr_slots_per_frame[mu])/tdd_period_slot;
    while((tdd_beam_association[num_tdd_period]!=-1)&&(tdd_beam_association[num_tdd_period]!=beam_index)) {
      eff_slot += tdd_period_slot;
      num_tdd_period = (eff_slot % nr_slots_per_frame[mu])/tdd_period_slot;
    }
    if(tdd_beam_association[num_tdd_period] == -1)
      tdd_beam_association[num_tdd_period] = beam_index;
  }

  *msg2_frame = rach_frame + eff_slot / nr_slots_per_frame[mu];
  *msg2_slot = eff_slot % nr_slots_per_frame[mu];

  // go to previous slot if the current scheduled slot is beyond the response window
  // and if the slot is not among the PDCCH monitored ones (38.213 10.1)
  while (*msg2_frame > frame_limit
         || (*msg2_frame == frame_limit && *msg2_slot > slot_limit)
         || ((*msg2_frame * nr_slots_per_frame[mu] + *msg2_slot - monitoring_offset) % monitoring_slot_period != 0)) {

    if((frame_type == FDD) || ((*msg2_slot%tdd_period_slot) > 0)) {
      if (*msg2_slot==0) {
        (*msg2_frame)--;
        *msg2_slot = nr_slots_per_frame[mu] - 1;
      }
      else
        (*msg2_slot)--;
    }
    else
      AssertFatal(1==0,"No available DL slot to schedule msg2 has been found");
  }

  // calculate frame number considering wrap-around
  *msg2_frame = *msg2_frame % 1024;
}


void nr_initiate_ra_proc(module_id_t module_idP,
                         int CC_id,
                         frame_t frameP,
                         sub_frame_t slotP,
                         uint16_t preamble_index,
                         uint8_t freq_index,
                         uint8_t symbol,
                         int16_t timing_offset)
{
  gNB_MAC_INST *nr_mac = RC.nrmac[module_idP];
  NR_SCHED_LOCK(&nr_mac->sched_lock);

  uint8_t ul_carrier_id = 0; // 0 for NUL 1 for SUL
  uint16_t msg2_frame, msg2_slot,monitoring_slot_period,monitoring_offset;
  NR_COMMON_channels_t *cc = &nr_mac->common_channels[CC_id];
  NR_ServingCellConfigCommon_t *scc = cc->ServingCellConfigCommon;
  frame_type_t frame_type = cc->frame_type;

  uint8_t total_RApreambles = MAX_NUM_NR_PRACH_PREAMBLES;
  uint8_t  num_ssb_per_RO = scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->ssb_perRACH_OccasionAndCB_PreamblesPerSSB->present;
  int pr_found;

  if( scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->totalNumberOfRA_Preambles != NULL)
    total_RApreambles = *scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->totalNumberOfRA_Preambles;

  if(num_ssb_per_RO > 3) { /*num of ssb per RO >= 1*/
    num_ssb_per_RO -= 3;
    total_RApreambles = total_RApreambles/num_ssb_per_RO ;
  }

  for (int i = 0; i < NR_NB_RA_PROC_MAX; i++) {

    NR_RA_t *ra = &cc->ra[i];
    if (ra->state != RA_IDLE)
      continue;

    pr_found = 0;

    for(int j = 0; j < ra->preambles.num_preambles; j++) {
      //check if the preamble received correspond to one of the listed or configured preambles
      if (preamble_index == ra->preambles.preamble_list[j]) {
        if (ra->rnti == 0 && get_softmodem_params()->nsa)
          continue;
        pr_found=1;
        break;
      }
    }
    if (pr_found == 0) {
       continue;
    }

    uint16_t ra_rnti;

    // ra_rnti from 5.1.3 in 38.321
    // FK: in case of long PRACH the phone seems to expect the subframe number instead of the slot number here.
    if (scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->prach_RootSequenceIndex.present
        == NR_RACH_ConfigCommon__prach_RootSequenceIndex_PR_l839)
      ra_rnti = 1 + symbol + (9 /*slotP*/ * 14) + (freq_index * 14 * 80) + (ul_carrier_id * 14 * 80 * 8);
    else
      ra_rnti = 1 + symbol + (slotP * 14) + (freq_index * 14 * 80) + (ul_carrier_id * 14 * 80 * 8);

    // Configure RA BWP
    configure_UE_BWP(nr_mac, scc, NULL, ra, NULL, -1, -1);

    VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME(VCD_SIGNAL_DUMPER_FUNCTIONS_INITIATE_RA_PROC, 1);

    LOG_D(NR_MAC,
          "[gNB %d][RAPROC] CC_id %d Frame %d, Slot %d  Initiating RA procedure for preamble index %d\n",
          module_idP,
          CC_id,
          frameP,
          slotP,
          preamble_index);

    uint8_t beam_index = ssb_index_from_prach(module_idP, frameP, slotP, preamble_index, freq_index, symbol);

    // the UE sent a RACH either for starting RA procedure or RA procedure failed and UE retries
    if (ra->cfra) {
      // if the preamble received correspond to one of the listed
      if (!(preamble_index == ra->preambles.preamble_list[beam_index])) {
        LOG_E(
            NR_MAC,
            "[gNB %d][RAPROC] FAILURE: preamble %d does not correspond to any of the ones in rach_ConfigDedicated\n",
            module_idP,
            preamble_index);
        continue; // if the PRACH preamble does not correspond to any of the ones sent through RRC abort RA proc
      }
    }
    LOG_D(NR_MAC, "Frame %d, Slot %d: Activating RA process \n", frameP, slotP);
    ra->state = Msg2;
    ra->timing_offset = timing_offset;
    ra->preamble_slot = slotP;

    // retrieving ra pdcch monitoring period and offset
    find_monitoring_periodicity_offset_common(ra->ra_ss, &monitoring_slot_period, &monitoring_offset);

    nr_schedule_msg2(frameP,
                     slotP,
                     &msg2_frame,
                     &msg2_slot,
                     ra->DL_BWP.scs,
                     scc,
                     frame_type,
                     monitoring_slot_period,
                     monitoring_offset,
                     beam_index,
                     cc->num_active_ssb,
                     nr_mac->tdd_beam_association,
                     nr_mac->if_inst->sl_ahead);

    ra->Msg2_frame = msg2_frame;
    ra->Msg2_slot = msg2_slot;

    LOG_D(NR_MAC, "%s() Msg2[%04d%d] SFN/SF:%04d%d\n", __FUNCTION__, ra->Msg2_frame, ra->Msg2_slot, frameP, slotP);

    int loop = 0;
    if (ra->rnti == 0) { // This condition allows for the usage of a preconfigured rnti for the CFRA
      do {
        // 3GPP TS 38.321 version 15.13.0 Section 7.1 Table 7.1-1: RNTI values
        ra->rnti = (taus() % 0xffef) + 1;
        loop++;
      } while (loop != 100
               && !((find_nr_UE(&nr_mac->UE_info, ra->rnti) == NULL) && (find_nr_RA_id(module_idP, CC_id, ra->rnti) == -1)
                    && ra->rnti >= 0x1 && ra->rnti <= 0xffef));
      if (loop == 100) {
        LOG_E(NR_MAC, "%s:%d:%s: [RAPROC] initialisation random access aborted\n", __FILE__, __LINE__, __FUNCTION__);
        abort();
      }
    }

    ra->RA_rnti = ra_rnti;
    ra->preamble_index = preamble_index;
    ra->beam_id = cc->ssb_index[beam_index];

    LOG_I(NR_MAC,
          "[gNB %d][RAPROC] CC_id %d Frame %d Activating Msg2 generation in frame %d, slot %d using RA rnti %x SSB, new rnti %04x "
          "index %u RA index %d\n",
          module_idP,
          CC_id,
          frameP,
          ra->Msg2_frame,
          ra->Msg2_slot,
          ra->RA_rnti,
          ra->rnti,
          cc->ssb_index[beam_index],
          i);

    NR_SCHED_UNLOCK(&nr_mac->sched_lock);
    return;
  }

  NR_SCHED_UNLOCK(&nr_mac->sched_lock);
  LOG_E(NR_MAC, "[gNB %d][RAPROC] FAILURE: CC_id %d %4d.%2d initiating RA procedure for preamble index %d: no free RA process\n", module_idP, CC_id, frameP, slotP, preamble_index);

  VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME(VCD_SIGNAL_DUMPER_FUNCTIONS_INITIATE_RA_PROC, 0);
}

static void start_ra_contention_resolution_timer(NR_RA_t *ra, const long ra_ContentionResolutionTimer, const int K2, const int scs)
{
  // 3GPP TS 38.331 Section 6.3.2 Radio resource control information elements
  // ra-ContentionResolutionTimer ENUMERATED {sf8, sf16, sf24, sf32, sf40, sf48, sf56, sf64}
  // The initial value for the contention resolution timer.
  // Value sf8 corresponds to 8 subframes, value sf16 corresponds to 16 subframes, and so on.
  // We add K2 because we start the timer in the DL slot that schedules Msg3/Msg3 retransmission
  ra->contention_resolution_timer = ((((int)ra_ContentionResolutionTimer + 1) * 8) << scs) + K2;
  LOG_D(NR_MAC,
        "Starting RA Contention Resolution timer with %d ms + %d K2 (%d slots) duration\n",
        ((int)ra_ContentionResolutionTimer + 1) * 8,
        K2,
        ra->contention_resolution_timer);
}

static void nr_generate_Msg3_retransmission(module_id_t module_idP,
                                            int CC_id,
                                            frame_t frame,
                                            sub_frame_t slot,
                                            NR_RA_t *ra,
                                            nfapi_nr_ul_dci_request_t *ul_dci_req)
{
  gNB_MAC_INST *nr_mac = RC.nrmac[module_idP];
  NR_COMMON_channels_t *cc = &nr_mac->common_channels[CC_id];
  NR_ServingCellConfigCommon_t *scc = cc->ServingCellConfigCommon;
  NR_UE_UL_BWP_t *ul_bwp = &ra->UL_BWP;
  NR_UE_ServingCell_Info_t *sc_info = &ra->sc_info;

  NR_PUSCH_TimeDomainResourceAllocationList_t *pusch_TimeDomainAllocationList = ul_bwp->tdaList_Common;
  int mu = ul_bwp->scs;
  uint8_t K2 = *pusch_TimeDomainAllocationList->list.array[ra->Msg3_tda_id]->k2;
  const int sched_frame = (frame + (slot + K2 >= nr_slots_per_frame[mu])) % 1024;
  const int sched_slot = (slot + K2) % nr_slots_per_frame[mu];

  if (is_xlsch_in_slot(nr_mac->ulsch_slot_bitmap[sched_slot / 64], sched_slot)) {
    // beam association for FR2
    int16_t *tdd_beam_association = nr_mac->tdd_beam_association;
    if (*scc->downlinkConfigCommon->frequencyInfoDL->frequencyBandList.list.array[0] >= 257) {
      // FR2
      const int n_slots_frame = nr_slots_per_frame[mu];
      const NR_TDD_UL_DL_Pattern_t *tdd = scc->tdd_UL_DL_ConfigurationCommon ? &scc->tdd_UL_DL_ConfigurationCommon->pattern1 : NULL;
      AssertFatal(tdd,"Dynamic TDD not handled yet\n");
      uint8_t tdd_period_slot = n_slots_frame/get_nb_periods_per_frame(tdd->dl_UL_TransmissionPeriodicity);
      int num_tdd_period = sched_slot/tdd_period_slot;

      if((tdd_beam_association[num_tdd_period]!=-1)&&(tdd_beam_association[num_tdd_period]!=ra->beam_id))
        return; // can't schedule retransmission in this slot
      else
        tdd_beam_association[num_tdd_period] = ra->beam_id;
    }

    int fh = 0;
    int startSymbolAndLength = pusch_TimeDomainAllocationList->list.array[ra->Msg3_tda_id]->startSymbolAndLength;
    int StartSymbolIndex, NrOfSymbols;
    SLIV2SL(startSymbolAndLength, &StartSymbolIndex, &NrOfSymbols);
    int mappingtype = pusch_TimeDomainAllocationList->list.array[ra->Msg3_tda_id]->mappingType;

    int buffer_index = ul_buffer_index(sched_frame, sched_slot, mu, nr_mac->vrb_map_UL_size);
    uint16_t *vrb_map_UL = &nr_mac->common_channels[CC_id].vrb_map_UL[buffer_index * MAX_BWP_SIZE];

    const int BWPSize = sc_info->initial_ul_BWPSize;
    const int BWPStart = sc_info->initial_ul_BWPStart;

    int rbStart = 0;
    for (int i = 0; (i < ra->msg3_nb_rb) && (rbStart <= (BWPSize - ra->msg3_nb_rb)); i++) {
      if (vrb_map_UL[rbStart + BWPStart + i]&SL_to_bitmap(StartSymbolIndex, NrOfSymbols)) {
        rbStart += i;
        i = 0;
      }
    }
    if (rbStart > (BWPSize - ra->msg3_nb_rb)) {
      // cannot find free vrb_map for msg3 retransmission in this slot
      return;
    }

    LOG_I(NR_MAC,
          "%4d%2d: RA RNTI %04x CC_id %d Scheduling retransmission of Msg3 in (%d,%d)\n",
          frame,
          slot,
          ra->rnti,
          CC_id,
          sched_frame,
          sched_slot);

    buffer_index = ul_buffer_index(sched_frame, sched_slot, mu, nr_mac->UL_tti_req_ahead_size);
    nfapi_nr_ul_tti_request_t *future_ul_tti_req = &nr_mac->UL_tti_req_ahead[CC_id][buffer_index];
    AssertFatal(future_ul_tti_req->SFN == sched_frame
                && future_ul_tti_req->Slot == sched_slot,
                "future UL_tti_req's frame.slot %d.%d does not match PUSCH %d.%d\n",
                future_ul_tti_req->SFN,
                future_ul_tti_req->Slot,
                sched_frame,
                sched_slot);
    AssertFatal(future_ul_tti_req->n_pdus <
                sizeof(future_ul_tti_req->pdus_list) / sizeof(future_ul_tti_req->pdus_list[0]),
                "Invalid future_ul_tti_req->n_pdus %d\n", future_ul_tti_req->n_pdus);
    future_ul_tti_req->pdus_list[future_ul_tti_req->n_pdus].pdu_type = NFAPI_NR_UL_CONFIG_PUSCH_PDU_TYPE;
    future_ul_tti_req->pdus_list[future_ul_tti_req->n_pdus].pdu_size = sizeof(nfapi_nr_pusch_pdu_t);
    nfapi_nr_pusch_pdu_t *pusch_pdu = &future_ul_tti_req->pdus_list[future_ul_tti_req->n_pdus].pusch_pdu;
    memset(pusch_pdu, 0, sizeof(nfapi_nr_pusch_pdu_t));

    fill_msg3_pusch_pdu(pusch_pdu, scc,
                        ra->msg3_round,
                        startSymbolAndLength,
                        ra->rnti, mu,
                        BWPSize, BWPStart,
                        mappingtype, fh,
                        rbStart, ra->msg3_nb_rb);
    future_ul_tti_req->n_pdus += 1;

    // generation of DCI 0_0 to schedule msg3 retransmission
    NR_SearchSpace_t *ss = ra->ra_ss;
    NR_ControlResourceSet_t *coreset = ra->coreset;
    AssertFatal(coreset!=NULL,"Coreset cannot be null for RA-Msg3 retransmission\n");

    const int coresetid = coreset->controlResourceSetId;
    nfapi_nr_dl_tti_pdcch_pdu_rel15_t *pdcch_pdu_rel15 = nr_mac->pdcch_pdu_idx[CC_id][coresetid];
    if (!pdcch_pdu_rel15) {
      nfapi_nr_ul_dci_request_pdus_t *ul_dci_request_pdu = &ul_dci_req->ul_dci_pdu_list[ul_dci_req->numPdus];
      memset(ul_dci_request_pdu, 0, sizeof(nfapi_nr_ul_dci_request_pdus_t));
      ul_dci_request_pdu->PDUType = NFAPI_NR_DL_TTI_PDCCH_PDU_TYPE;
      ul_dci_request_pdu->PDUSize = (uint8_t)(2+sizeof(nfapi_nr_dl_tti_pdcch_pdu));
      pdcch_pdu_rel15 = &ul_dci_request_pdu->pdcch_pdu.pdcch_pdu_rel15;
      ul_dci_req->numPdus += 1;
      nr_configure_pdcch(pdcch_pdu_rel15, coreset, &ra->sched_pdcch);
      nr_mac->pdcch_pdu_idx[CC_id][coresetid] = pdcch_pdu_rel15;
    }

    uint8_t aggregation_level;
    int CCEIndex = get_cce_index(nr_mac,
                                 CC_id, slot, 0,
                                 &aggregation_level,
                                 ss,
                                 coreset,
                                 &ra->sched_pdcch,
                                 true);
    if (CCEIndex < 0) {
      LOG_E(NR_MAC, "%s(): cannot find free CCE for RA RNTI 0x%04x!\n", __func__, ra->rnti);
      return;
    }

    // Fill PDCCH DL DCI PDU
    nfapi_nr_dl_dci_pdu_t *dci_pdu = &pdcch_pdu_rel15->dci_pdu[pdcch_pdu_rel15->numDlDci];
    pdcch_pdu_rel15->numDlDci++;
    dci_pdu->RNTI = ra->rnti;
    dci_pdu->ScramblingId = *scc->physCellId;
    dci_pdu->ScramblingRNTI = 0;
    dci_pdu->AggregationLevel = aggregation_level;
    dci_pdu->CceIndex = CCEIndex;
    dci_pdu->beta_PDCCH_1_0 = 0;
    dci_pdu->powerControlOffsetSS = 1;

    dci_pdu_rel15_t uldci_payload={0};

    config_uldci(sc_info,
                 pusch_pdu,
                 &uldci_payload,
                 NULL,
                 ra->Msg3_tda_id,
                 ra->msg3_TPC,
                 1, // Not toggling NDI in msg3 retransmissions
                 ul_bwp);

    fill_dci_pdu_rel15(sc_info,
                       &ra->DL_BWP,
                       ul_bwp,
                       dci_pdu,
                       &uldci_payload,
                       NR_UL_DCI_FORMAT_0_0,
                       TYPE_TC_RNTI_,
                       ul_bwp->bwp_id,
                       ss,
                       coreset,
                       0, // parameter not needed for DCI 0_0
                       nr_mac->cset0_bwp_size);

    // Mark the corresponding RBs as used

    fill_pdcch_vrb_map(nr_mac,
                       CC_id,
                       &ra->sched_pdcch,
                       CCEIndex,
                       aggregation_level);

    for (int rb = 0; rb < ra->msg3_nb_rb; rb++) {
      vrb_map_UL[rbStart + BWPStart + rb] |= SL_to_bitmap(StartSymbolIndex, NrOfSymbols);
    }

    // Restart RA contention resolution timer in Msg3 retransmission slot (current slot + K2)
    // 3GPP TS 38.321 Section 5.1.5 Contention Resolution
    start_ra_contention_resolution_timer(
        ra,
        scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->ra_ContentionResolutionTimer,
        K2,
        ra->UL_BWP.scs);

    // reset state to wait msg3
    ra->state = WAIT_Msg3;
    ra->Msg3_frame = sched_frame;
    ra->Msg3_slot = sched_slot;

  }
}

static void nr_get_Msg3alloc(module_id_t module_id,
                             int CC_id,
                             NR_ServingCellConfigCommon_t *scc,
                             sub_frame_t current_slot,
                             frame_t current_frame,
                             NR_RA_t *ra,
                             int16_t *tdd_beam_association)
{
  // msg3 is scheduled in mixed slot in the following TDD period

  uint16_t msg3_nb_rb = 8; // sdu has 6 or 8 bytes
  gNB_MAC_INST *mac = RC.nrmac[module_id];
  frame_type_t frame_type = mac->common_channels->frame_type;

  NR_UE_UL_BWP_t *ul_bwp = &ra->UL_BWP;
  NR_UE_ServingCell_Info_t *sc_info = &ra->sc_info;

  int mu = ul_bwp->scs;
  int StartSymbolIndex = 0;
  int NrOfSymbols = 0;
  int startSymbolAndLength = 0;
  int abs_slot = 0;
  int Msg3maxsymb = 14, Msg3start = 0;
  ra->Msg3_tda_id = 16; // initialization to a value above limit

  NR_PUSCH_TimeDomainResourceAllocationList_t *pusch_TimeDomainAllocationList = ul_bwp->tdaList_Common;

  const NR_TDD_UL_DL_Pattern_t *tdd = scc->tdd_UL_DL_ConfigurationCommon ? &scc->tdd_UL_DL_ConfigurationCommon->pattern1 : NULL;
  const int n_slots_frame = nr_slots_per_frame[mu];
  uint8_t k2 = 0;
  if (frame_type == TDD) {
    int msg3_slot = get_first_ul_slot(tdd->nrofDownlinkSlots, tdd->nrofDownlinkSymbols, tdd->nrofUplinkSymbols);
    if (tdd->nrofUplinkSymbols != 0) {
      if (tdd->nrofUplinkSymbols < 3)
        msg3_slot++; // we can't trasmit msg3 in mixed slot if there are less than 3 symbols
      else {
        Msg3maxsymb = tdd->nrofUplinkSymbols;
        Msg3start = 14 - tdd->nrofUplinkSymbols;
      }
    }
    const int nb_periods_per_frame = get_nb_periods_per_frame(tdd->dl_UL_TransmissionPeriodicity);
    const int nb_slots_per_period = ((1<<mu)*10)/nb_periods_per_frame;
    for (int i=0; i<pusch_TimeDomainAllocationList->list.count; i++) {
      startSymbolAndLength = pusch_TimeDomainAllocationList->list.array[i]->startSymbolAndLength;
      SLIV2SL(startSymbolAndLength, &StartSymbolIndex, &NrOfSymbols);
      k2 = *pusch_TimeDomainAllocationList->list.array[i]->k2;
      LOG_D(NR_MAC,"Checking Msg3 TDA %d for Msg3_slot %d Msg3_start %d Msg3_nsymb %d: k2 %d, sliv %d,S %d L %d\n",
            i, msg3_slot, Msg3start, Msg3maxsymb, (int)k2, (int)pusch_TimeDomainAllocationList->list.array[i]->startSymbolAndLength, StartSymbolIndex, NrOfSymbols);
      // we want to transmit in the uplink symbols of mixed slot or the first uplink slot
      abs_slot = (current_slot + k2 + DELTA[mu]);
      int temp_slot = abs_slot % nr_slots_per_frame[mu]; // msg3 slot according to 8.3 in 38.213
      if ((temp_slot % nb_slots_per_period) == msg3_slot &&
          is_xlsch_in_slot(mac->ulsch_slot_bitmap[temp_slot / 64], temp_slot) &&
          StartSymbolIndex == Msg3start &&
          NrOfSymbols <= Msg3maxsymb) {
        ra->Msg3_tda_id = i;
        ra->msg3_startsymb = StartSymbolIndex;
        ra->msg3_nrsymb = NrOfSymbols;
        ra->Msg3_slot = temp_slot;
        break;
      }
    }
    AssertFatal(ra->Msg3_tda_id < 16, "Couldn't find an appropriate TD allocation for Msg3\n");
  }
  else {
    ra->Msg3_tda_id = 0;
    k2 = *pusch_TimeDomainAllocationList->list.array[0]->k2;
    abs_slot = current_slot + k2 + DELTA[mu]; // msg3 slot according to 8.3 in 38.213
    ra->Msg3_slot = abs_slot % nr_slots_per_frame[mu];
  }

  AssertFatal(ra->Msg3_tda_id<16,"Unable to find Msg3 time domain allocation in list\n");

  if (n_slots_frame > abs_slot)
    ra->Msg3_frame = current_frame;
  else
    ra->Msg3_frame = (current_frame + (abs_slot / n_slots_frame)) % 1024;

  // beam association for FR2
  if (*scc->downlinkConfigCommon->frequencyInfoDL->frequencyBandList.list.array[0] >= 257) {
    AssertFatal(tdd,"Dynamic TDD not handled yet\n");
    uint8_t tdd_period_slot = n_slots_frame/get_nb_periods_per_frame(tdd->dl_UL_TransmissionPeriodicity);
    int num_tdd_period = ra->Msg3_slot/tdd_period_slot;
    if((tdd_beam_association[num_tdd_period]!=-1)&&(tdd_beam_association[num_tdd_period]!=ra->beam_id))
      AssertFatal(1==0,"Cannot schedule MSG3\n");
    else
      tdd_beam_association[num_tdd_period] = ra->beam_id;
  }

  LOG_I(NR_MAC, "[RAPROC] Msg3 slot %d: current slot %u Msg3 frame %u k2 %u Msg3_tda_id %u\n", ra->Msg3_slot, current_slot, ra->Msg3_frame, k2,ra->Msg3_tda_id);
  const int buffer_index = ul_buffer_index(ra->Msg3_frame, ra->Msg3_slot, mu, mac->vrb_map_UL_size);
  uint16_t *vrb_map_UL = &mac->common_channels[CC_id].vrb_map_UL[buffer_index * MAX_BWP_SIZE];

  int bwpSize = sc_info->initial_ul_BWPSize;
  int bwpStart = sc_info->initial_ul_BWPStart;
  if (bwpSize != ul_bwp->BWPSize || bwpStart != ul_bwp->BWPStart) {
    int act_bwp_start = ul_bwp->BWPStart;
    int act_bwp_size  = ul_bwp->BWPSize;
    if (!((bwpStart >= act_bwp_start) && ((bwpStart+bwpSize) <= (act_bwp_start+act_bwp_size))))
      bwpStart = act_bwp_start;
  }

  /* search msg3_nb_rb free RBs */
  int rbSize = 0;
  int rbStart = 0;
  while (rbSize < msg3_nb_rb) {
    rbStart += rbSize; /* last iteration rbSize was not enough, skip it */
    rbSize = 0;
    while (rbStart < bwpSize &&
           (vrb_map_UL[rbStart + bwpStart]&SL_to_bitmap(StartSymbolIndex, NrOfSymbols)))
      rbStart++;
    AssertFatal(rbStart < bwpSize - msg3_nb_rb, "no space to allocate Msg 3 for RA!\n");
    while (rbStart + rbSize < bwpSize
           && !(vrb_map_UL[rbStart + bwpStart + rbSize]&SL_to_bitmap(StartSymbolIndex, NrOfSymbols))
           && rbSize < msg3_nb_rb)
      rbSize++;
  }
  ra->msg3_nb_rb = msg3_nb_rb;
  ra->msg3_first_rb = rbStart;
  ra->msg3_bwp_start = bwpStart;
}

static void fill_msg3_pusch_pdu(nfapi_nr_pusch_pdu_t *pusch_pdu,
                                NR_ServingCellConfigCommon_t *scc,
                                int round,
                                int startSymbolAndLength,
                                rnti_t rnti,
                                int scs,
                                int bwp_size,
                                int bwp_start,
                                int mappingtype,
                                int fh,
                                int msg3_first_rb,
                                int msg3_nb_rb)
{
  int start_symbol_index,nr_of_symbols;

  SLIV2SL(startSymbolAndLength, &start_symbol_index, &nr_of_symbols);
  int mcsindex = -1; // init value

  pusch_pdu->pdu_bit_map = PUSCH_PDU_BITMAP_PUSCH_DATA;
  pusch_pdu->rnti = rnti;
  pusch_pdu->handle = 0;
  pusch_pdu->bwp_start = bwp_start;
  pusch_pdu->bwp_size = bwp_size;
  pusch_pdu->subcarrier_spacing = scs;
  pusch_pdu->cyclic_prefix = 0;
  pusch_pdu->mcs_table = 0;
  if (scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->msg3_transformPrecoder == NULL)
    pusch_pdu->transform_precoding = 1; // disabled
  else {
    pusch_pdu->transform_precoding = 0; // enabled
    pusch_pdu->dfts_ofdm.low_papr_group_number = *scc->physCellId % 30;
    pusch_pdu->dfts_ofdm.low_papr_sequence_number = 0;
    if (scc->uplinkConfigCommon->initialUplinkBWP->pusch_ConfigCommon->choice.setup->groupHoppingEnabledTransformPrecoding)
      AssertFatal(1==0,"Hopping mode is not supported in transform precoding\n");
  }
  pusch_pdu->data_scrambling_id = *scc->physCellId;
  pusch_pdu->nrOfLayers = 1;
  pusch_pdu->ul_dmrs_symb_pos = get_l_prime(nr_of_symbols,mappingtype,pusch_dmrs_pos2,pusch_len1,start_symbol_index, scc->dmrs_TypeA_Position);
  LOG_D(NR_MAC, "MSG3 start_sym:%d NR Symb:%d mappingtype:%d, ul_dmrs_symb_pos:%x\n", start_symbol_index, nr_of_symbols, mappingtype, pusch_pdu->ul_dmrs_symb_pos);
  pusch_pdu->dmrs_config_type = 0;
  pusch_pdu->ul_dmrs_scrambling_id = *scc->physCellId; //If provided and the PUSCH is not a msg3 PUSCH, otherwise, L2 should set this to physical cell id.
  pusch_pdu->scid = 0; //DMRS sequence initialization [TS38.211, sec 6.4.1.1.1]. Should match what is sent in DCI 0_1, otherwise set to 0.
  pusch_pdu->dmrs_ports = 1;  // 6.2.2 in 38.214 only port 0 to be used
  pusch_pdu->num_dmrs_cdm_grps_no_data = 2;  // no data in dmrs symbols as in 6.2.2 in 38.214
  pusch_pdu->resource_alloc = 1; //type 1
  pusch_pdu->rb_start = msg3_first_rb;
  if (msg3_nb_rb > pusch_pdu->bwp_size)
    AssertFatal(1==0,"MSG3 allocated number of RBs exceed the BWP size\n");
  else
    pusch_pdu->rb_size = msg3_nb_rb;
  pusch_pdu->vrb_to_prb_mapping = 0;

  pusch_pdu->frequency_hopping = fh;
  //pusch_pdu->tx_direct_current_location;
  //The uplink Tx Direct Current location for the carrier. Only values in the value range of this field between 0 and 3299,
  //which indicate the subcarrier index within the carrier corresponding 1o the numerology of the corresponding uplink BWP and value 3300,
  //which indicates "Outside the carrier" and value 3301, which indicates "Undetermined position within the carrier" are used. [TS38.331, UplinkTxDirectCurrentBWP IE]
  pusch_pdu->uplink_frequency_shift_7p5khz = 0;
  //Resource Allocation in time domain
  pusch_pdu->start_symbol_index = start_symbol_index;
  pusch_pdu->nr_of_symbols = nr_of_symbols;
  //Optional Data only included if indicated in pduBitmap
  pusch_pdu->pusch_data.rv_index = nr_rv_round_map[round%4];
  pusch_pdu->pusch_data.harq_process_id = 0;
  pusch_pdu->pusch_data.new_data_indicator = (round == 0) ? 1 : 0;;
  pusch_pdu->pusch_data.num_cb = 0;
  int num_dmrs_symb = 0;
  for(int i = start_symbol_index; i < start_symbol_index+nr_of_symbols; i++)
    num_dmrs_symb += (pusch_pdu->ul_dmrs_symb_pos >> i) & 1;
  int TBS = 0;
  while(TBS<7) {  // TBS for msg3 is 7 bytes (except for RRCResumeRequest1 currently not implemented)
    mcsindex++;
    AssertFatal(mcsindex<28,"Exceeding MCS limit for Msg3\n");
    int R = nr_get_code_rate_ul(mcsindex,pusch_pdu->mcs_table);
    pusch_pdu->target_code_rate = R;
    pusch_pdu->qam_mod_order = nr_get_Qm_ul(mcsindex,pusch_pdu->mcs_table);
    TBS = nr_compute_tbs(pusch_pdu->qam_mod_order,
                         R,
                         pusch_pdu->rb_size,
                         pusch_pdu->nr_of_symbols,
                         num_dmrs_symb*12, // nb dmrs set for no data in dmrs symbol
                         0, //nb_rb_oh
                         0, // to verify tb scaling
                         pusch_pdu->nrOfLayers)>>3;

    pusch_pdu->mcs_index = mcsindex;
    pusch_pdu->pusch_data.tb_size = TBS;
    pusch_pdu->maintenance_parms_v3.ldpcBaseGraph = get_BG(TBS<<3,R);
  }
}

static void nr_add_msg3(module_id_t module_idP, int CC_id, frame_t frameP, sub_frame_t slotP, NR_RA_t *ra, uint8_t *RAR_pdu)
{
  gNB_MAC_INST *mac = RC.nrmac[module_idP];
  NR_COMMON_channels_t *cc = &mac->common_channels[CC_id];
  NR_ServingCellConfigCommon_t *scc = cc->ServingCellConfigCommon;
  NR_UE_UL_BWP_t *ul_bwp = &ra->UL_BWP;
  NR_UE_ServingCell_Info_t *sc_info = &ra->sc_info;

  if (ra->state == RA_IDLE) {
    LOG_W(NR_MAC,"RA is not active for RA %X. skipping msg3 scheduling\n", ra->rnti);
    return;
  }

  const int scs = ul_bwp->scs;
  const uint16_t mask = SL_to_bitmap(ra->msg3_startsymb, ra->msg3_nrsymb);
  int buffer_index = ul_buffer_index(ra->Msg3_frame, ra->Msg3_slot, scs, mac->vrb_map_UL_size);
  uint16_t *vrb_map_UL = &RC.nrmac[module_idP]->common_channels[CC_id].vrb_map_UL[buffer_index * MAX_BWP_SIZE];
  for (int i = 0; i < ra->msg3_nb_rb; ++i) {
    AssertFatal(!(vrb_map_UL[i + ra->msg3_first_rb + ra->msg3_bwp_start] & mask),
                "RB %d in %4d.%2d is already taken, cannot allocate Msg3!\n",
                i + ra->msg3_first_rb,
                ra->Msg3_frame,
                ra->Msg3_slot);
    vrb_map_UL[i + ra->msg3_first_rb + ra->msg3_bwp_start] |= mask;
  }

  LOG_D(NR_MAC, "[gNB %d][RAPROC] Frame %d, Slot %d : CC_id %d RA is active, Msg3 in (%d,%d)\n", module_idP, frameP, slotP, CC_id, ra->Msg3_frame, ra->Msg3_slot);
  buffer_index = ul_buffer_index(ra->Msg3_frame, ra->Msg3_slot, scs, mac->UL_tti_req_ahead_size);
  nfapi_nr_ul_tti_request_t *future_ul_tti_req = &RC.nrmac[module_idP]->UL_tti_req_ahead[CC_id][buffer_index];
  AssertFatal(future_ul_tti_req->SFN == ra->Msg3_frame
              && future_ul_tti_req->Slot == ra->Msg3_slot,
              "future UL_tti_req's frame.slot %d.%d does not match PUSCH %d.%d\n",
              future_ul_tti_req->SFN,
              future_ul_tti_req->Slot,
              ra->Msg3_frame,
              ra->Msg3_slot);
  future_ul_tti_req->pdus_list[future_ul_tti_req->n_pdus].pdu_type = NFAPI_NR_UL_CONFIG_PUSCH_PDU_TYPE;
  future_ul_tti_req->pdus_list[future_ul_tti_req->n_pdus].pdu_size = sizeof(nfapi_nr_pusch_pdu_t);
  nfapi_nr_pusch_pdu_t *pusch_pdu = &future_ul_tti_req->pdus_list[future_ul_tti_req->n_pdus].pusch_pdu;
  memset(pusch_pdu, 0, sizeof(nfapi_nr_pusch_pdu_t));

  const int ibwp_size = sc_info->initial_ul_BWPSize;
  const int fh = (ul_bwp->pusch_Config && ul_bwp->pusch_Config->frequencyHopping) ? 1 : 0;
  const int startSymbolAndLength = ul_bwp->tdaList_Common->list.array[ra->Msg3_tda_id]->startSymbolAndLength;
  const int mappingtype = ul_bwp->tdaList_Common->list.array[ra->Msg3_tda_id]->mappingType;

  LOG_D(NR_MAC, "Frame %d, Slot %d Adding Msg3 UL Config Request for (%d,%d) : (%d,%d,%d) for rnti: %d\n",
    frameP,
    slotP,
    ra->Msg3_frame,
    ra->Msg3_slot,
    ra->msg3_nb_rb,
    ra->msg3_first_rb,
    ra->msg3_round,
    ra->rnti);

  fill_msg3_pusch_pdu(pusch_pdu,scc,
                      ra->msg3_round,
                      startSymbolAndLength,
                      ra->rnti, scs,
                      ibwp_size, ra->msg3_bwp_start,
                      mappingtype, fh,
                      ra->msg3_first_rb, ra->msg3_nb_rb);
  future_ul_tti_req->n_pdus += 1;

  // calling function to fill rar message
  nr_fill_rar(module_idP, ra, RAR_pdu, pusch_pdu);
}


static void nr_generate_Msg2(module_id_t module_idP,
                             int CC_id,
                             frame_t frameP,
                             sub_frame_t slotP,
                             NR_RA_t *ra,
                             nfapi_nr_dl_tti_request_t *DL_req,
                             nfapi_nr_tx_data_request_t *TX_req)
{
  gNB_MAC_INST *nr_mac = RC.nrmac[module_idP];
  NR_COMMON_channels_t *cc = &nr_mac->common_channels[CC_id];
  NR_UE_DL_BWP_t *dl_bwp = &ra->DL_BWP;
  NR_UE_ServingCell_Info_t *sc_info = &ra->sc_info;

  if ((ra->Msg2_frame == frameP) && (ra->Msg2_slot == slotP)) {

    int mcsIndex = -1;  // initialization value
    int rbStart = 0;
    int rbSize = 8;

    NR_ServingCellConfigCommon_t *scc = cc->ServingCellConfigCommon;
    NR_SearchSpace_t *ss = ra->ra_ss;

    long BWPStart = 0;
    long BWPSize = 0;
    NR_Type0_PDCCH_CSS_config_t *type0_PDCCH_CSS_config = NULL;
    if(*ss->controlResourceSetId != 0) {
      BWPStart = dl_bwp->BWPStart;
      BWPSize = sc_info->initial_dl_BWPSize;
    } else {
      type0_PDCCH_CSS_config = &nr_mac->type0_PDCCH_CSS_config[ra->beam_id];
      BWPStart = type0_PDCCH_CSS_config->cset_start_rb;
      BWPSize = type0_PDCCH_CSS_config->num_rbs;
    }

    NR_ControlResourceSet_t *coreset = ra->coreset;
    AssertFatal(coreset != NULL,"Coreset cannot be null for RA-Msg2\n");
    const int coresetid = coreset->controlResourceSetId;
    // Calculate number of symbols
    int time_domain_assignment = get_dl_tda(nr_mac, scc, slotP);
    int mux_pattern = type0_PDCCH_CSS_config ? type0_PDCCH_CSS_config->type0_pdcch_ss_mux_pattern : 1;
    NR_tda_info_t tda_info = get_dl_tda_info(dl_bwp,
                                             ss->searchSpaceType->present,
                                             time_domain_assignment,
                                             scc->dmrs_TypeA_Position,
                                             mux_pattern,
                                             TYPE_RA_RNTI_,
                                             coresetid,
                                             false);

    uint16_t *vrb_map = cc[CC_id].vrb_map;
    for (int i = 0; (i < rbSize) && (rbStart <= (BWPSize - rbSize)); i++) {
      if (vrb_map[BWPStart + rbStart + i]&SL_to_bitmap(tda_info.startSymbolIndex, tda_info.nrOfSymbols)) {
        rbStart += i;
        i = 0;
      }
    }

    if (rbStart > (BWPSize - rbSize)) {
      LOG_E(NR_MAC, "%s(): cannot find free vrb_map for RA RNTI %04x!\n", __func__, ra->RA_rnti);
      return;
    }

    // Checking if the DCI allocation is feasible in current subframe
    nfapi_nr_dl_tti_request_body_t *dl_req = &DL_req->dl_tti_request_body;
    if (dl_req->nPDUs > NFAPI_NR_MAX_DL_TTI_PDUS - 2) {
      LOG_I(NR_MAC, "[RAPROC] Subframe %d: FAPI DL structure is full, skip scheduling UE %d\n", slotP, ra->RA_rnti);
      return;
    }

    uint8_t aggregation_level;
    int CCEIndex = get_cce_index(nr_mac,
                                 CC_id, slotP, 0,
                                 &aggregation_level,
                                 ss,
                                 coreset,
                                 &ra->sched_pdcch,
                                 true);

    if (CCEIndex < 0) {
      LOG_E(NR_MAC, "cannot find free CCE for Msg2 of RA RNTI 0x%04x!\n", ra->rnti);
      nr_clear_ra_proc(module_idP, CC_id, frameP, ra);
      return;
    }

    LOG_D(NR_MAC,"Msg2 startSymbolIndex.nrOfSymbols %d.%d\n",tda_info.startSymbolIndex,tda_info.nrOfSymbols);

    // look up the PDCCH PDU for this CC, BWP, and CORESET. If it does not exist, create it. This is especially
    // important if we have multiple RAs, and the DLSCH has to reuse them, so we need to mark them
    nfapi_nr_dl_tti_pdcch_pdu_rel15_t *pdcch_pdu_rel15 = nr_mac->pdcch_pdu_idx[CC_id][coresetid];
    if (!pdcch_pdu_rel15) {
      nfapi_nr_dl_tti_request_pdu_t *dl_tti_pdcch_pdu = &dl_req->dl_tti_pdu_list[dl_req->nPDUs];
      memset(dl_tti_pdcch_pdu, 0, sizeof(nfapi_nr_dl_tti_request_pdu_t));
      dl_tti_pdcch_pdu->PDUType = NFAPI_NR_DL_TTI_PDCCH_PDU_TYPE;
      dl_tti_pdcch_pdu->PDUSize = (uint8_t)(2 + sizeof(nfapi_nr_dl_tti_pdcch_pdu));
      dl_req->nPDUs += 1;
      pdcch_pdu_rel15 = &dl_tti_pdcch_pdu->pdcch_pdu.pdcch_pdu_rel15;
      nr_configure_pdcch(pdcch_pdu_rel15, coreset, &ra->sched_pdcch);
      nr_mac->pdcch_pdu_idx[CC_id][coresetid] = pdcch_pdu_rel15;
    }

    nfapi_nr_dl_tti_request_pdu_t *dl_tti_pdsch_pdu = &dl_req->dl_tti_pdu_list[dl_req->nPDUs];
    memset((void *)dl_tti_pdsch_pdu,0,sizeof(nfapi_nr_dl_tti_request_pdu_t));
    dl_tti_pdsch_pdu->PDUType = NFAPI_NR_DL_TTI_PDSCH_PDU_TYPE;
    dl_tti_pdsch_pdu->PDUSize = (uint8_t)(2+sizeof(nfapi_nr_dl_tti_pdsch_pdu));
    dl_req->nPDUs+=1;
    nfapi_nr_dl_tti_pdsch_pdu_rel15_t *pdsch_pdu_rel15 = &dl_tti_pdsch_pdu->pdsch_pdu.pdsch_pdu_rel15;

    LOG_A(NR_MAC,"[gNB %d][RAPROC] CC_id %d Frame %d, slotP %d: Generating RA-Msg2 DCI, rnti 0x%x, state %d, CoreSetType %d\n",
          module_idP, CC_id, frameP, slotP, ra->RA_rnti, ra->state,pdcch_pdu_rel15->CoreSetType);

    // SCF222: PDU index incremented for each PDSCH PDU sent in TX control message. This is used to associate control
    // information to data and is reset every slot.
    const int pduindex = nr_mac->pdu_index[CC_id]++;
    uint8_t mcsTableIdx = dl_bwp->mcsTableIdx;

   NR_pdsch_dmrs_t dmrs_parms = get_dl_dmrs_params(scc,
                                                   dl_bwp,
                                                   &tda_info,
                                                   1);

    pdsch_pdu_rel15->pduBitmap = 0;
    pdsch_pdu_rel15->rnti = ra->RA_rnti;
    pdsch_pdu_rel15->pduIndex = pduindex;
    pdsch_pdu_rel15->BWPSize  = BWPSize;
    pdsch_pdu_rel15->BWPStart = BWPStart;
    pdsch_pdu_rel15->SubcarrierSpacing = dl_bwp->scs;
    pdsch_pdu_rel15->CyclicPrefix = 0;
    pdsch_pdu_rel15->NrOfCodewords = 1;
    pdsch_pdu_rel15->mcsTable[0] = mcsTableIdx;
    pdsch_pdu_rel15->rvIndex[0] = 0;
    pdsch_pdu_rel15->dataScramblingId = *scc->physCellId;
    pdsch_pdu_rel15->nrOfLayers = 1;
    pdsch_pdu_rel15->transmissionScheme = 0;
    pdsch_pdu_rel15->refPoint = 0;
    pdsch_pdu_rel15->dmrsConfigType = dmrs_parms.dmrsConfigType;
    pdsch_pdu_rel15->dlDmrsScramblingId = *scc->physCellId;
    pdsch_pdu_rel15->SCID = 0;
    pdsch_pdu_rel15->numDmrsCdmGrpsNoData = dmrs_parms.numDmrsCdmGrpsNoData;
    pdsch_pdu_rel15->dmrsPorts = 1;
    pdsch_pdu_rel15->resourceAlloc = 1;
    pdsch_pdu_rel15->rbStart = rbStart;
    pdsch_pdu_rel15->rbSize = rbSize;
    pdsch_pdu_rel15->VRBtoPRBMapping = 0;
    pdsch_pdu_rel15->StartSymbolIndex = tda_info.startSymbolIndex;
    pdsch_pdu_rel15->NrOfSymbols = tda_info.nrOfSymbols;
    pdsch_pdu_rel15->dlDmrsSymbPos = dmrs_parms.dl_dmrs_symb_pos;

    uint8_t tb_scaling = 0;
    int R, Qm;
    uint32_t TBS=0;

    while(TBS<9) {  // min TBS for RAR is 9 bytes
      mcsIndex++;
      R = nr_get_code_rate_dl(mcsIndex, mcsTableIdx);
      Qm = nr_get_Qm_dl(mcsIndex, mcsTableIdx);
      TBS = nr_compute_tbs(Qm,
                           R,
                           rbSize,
                           tda_info.nrOfSymbols,
                           dmrs_parms.N_PRB_DMRS*dmrs_parms.N_DMRS_SLOT,
                           0, // overhead
                           tb_scaling,  // tb scaling
		           1)>>3;  // layers

      pdsch_pdu_rel15->targetCodeRate[0] = R;
      pdsch_pdu_rel15->qamModOrder[0] = Qm;
      pdsch_pdu_rel15->mcsIndex[0] = mcsIndex;
      pdsch_pdu_rel15->TBSize[0] = TBS;
    }

    pdsch_pdu_rel15->maintenance_parms_v3.tbSizeLbrmBytes = nr_compute_tbslbrm(mcsTableIdx, sc_info->dl_bw_tbslbrm, 1);
    pdsch_pdu_rel15->maintenance_parms_v3.ldpcBaseGraph = get_BG(TBS<<3,R);

    // Fill PDCCH DL DCI PDU
    nfapi_nr_dl_dci_pdu_t *dci_pdu = &pdcch_pdu_rel15->dci_pdu[pdcch_pdu_rel15->numDlDci];
    pdcch_pdu_rel15->numDlDci++;
    dci_pdu->RNTI = ra->RA_rnti;
    dci_pdu->ScramblingId = *scc->physCellId;
    dci_pdu->ScramblingRNTI = 0;
    dci_pdu->AggregationLevel = aggregation_level;
    dci_pdu->CceIndex = CCEIndex;
    dci_pdu->beta_PDCCH_1_0 = 0;
    dci_pdu->powerControlOffsetSS = 1;

    dci_pdu_rel15_t dci_payload;
    dci_payload.frequency_domain_assignment.val = PRBalloc_to_locationandbandwidth0(pdsch_pdu_rel15->rbSize,
                                                                                    pdsch_pdu_rel15->rbStart,
                                                                                    BWPSize);

    LOG_D(NR_MAC,"Msg2 rbSize.rbStart.BWPsize %d.%d.%ld\n",pdsch_pdu_rel15->rbSize,
          pdsch_pdu_rel15->rbStart,
          BWPSize);

    dci_payload.time_domain_assignment.val = time_domain_assignment;
    dci_payload.vrb_to_prb_mapping.val = 0;
    dci_payload.mcs = pdsch_pdu_rel15->mcsIndex[0];
    dci_payload.tb_scaling = tb_scaling;

    LOG_D(NR_MAC,
          "[RAPROC] DCI type 1 payload: freq_alloc %d (%d,%d,%ld), time_alloc %d, vrb to prb %d, mcs %d tb_scaling %d \n",
          dci_payload.frequency_domain_assignment.val,
          pdsch_pdu_rel15->rbStart,
          pdsch_pdu_rel15->rbSize,
          BWPSize,
          dci_payload.time_domain_assignment.val,
          dci_payload.vrb_to_prb_mapping.val,
          dci_payload.mcs,
          dci_payload.tb_scaling);

    LOG_D(NR_MAC,
          "[RAPROC] DCI params: rnti 0x%x, rnti_type %d, dci_format %d coreset params: FreqDomainResource %llx, start_symbol %d  "
          "n_symb %d\n",
          pdcch_pdu_rel15->dci_pdu[0].RNTI,
          TYPE_RA_RNTI_,
          NR_DL_DCI_FORMAT_1_0,
          *(unsigned long long *)pdcch_pdu_rel15->FreqDomainResource,
          pdcch_pdu_rel15->StartSymbolIndex,
          pdcch_pdu_rel15->DurationSymbols);

    fill_dci_pdu_rel15(sc_info,
                       dl_bwp,
                       &ra->UL_BWP,
                       &pdcch_pdu_rel15->dci_pdu[pdcch_pdu_rel15->numDlDci - 1],
                       &dci_payload,
                       NR_DL_DCI_FORMAT_1_0,
                       TYPE_RA_RNTI_,
                       dl_bwp->bwp_id,
                       ss,
                       coreset,
                       0, // parameter not needed for DCI 1_0
                       nr_mac->cset0_bwp_size);

    // DL TX request
    nfapi_nr_pdu_t *tx_req = &TX_req->pdu_list[TX_req->Number_of_PDUs];

    // Program UL processing for Msg3
    nr_get_Msg3alloc(module_idP, CC_id, scc, slotP, frameP, ra, nr_mac->tdd_beam_association);
    nr_add_msg3(module_idP, CC_id, frameP, slotP, ra, (uint8_t *) &tx_req->TLVs[0].value.direct[0]);

    // Start RA contention resolution timer in Msg3 transmission slot (current slot + K2)
    // 3GPP TS 38.321 Section 5.1.5 Contention Resolution
    start_ra_contention_resolution_timer(
        ra,
        scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup->ra_ContentionResolutionTimer,
        *ra->UL_BWP.tdaList_Common->list.array[ra->Msg3_tda_id]->k2,
        ra->UL_BWP.scs);

    if (ra->cfra) {
      NR_UE_info_t *UE = find_nr_UE(&RC.nrmac[module_idP]->UE_info, ra->rnti);
      if (UE) {
        const NR_ServingCellConfig_t *servingCellConfig = UE->CellGroup ? UE->CellGroup->spCellConfig->spCellConfigDedicated : NULL;
        uint32_t delay_ms = servingCellConfig && servingCellConfig->downlinkBWP_ToAddModList ? NR_RRC_SETUP_DELAY_MS + NR_RRC_BWP_SWITCHING_DELAY_MS : NR_RRC_SETUP_DELAY_MS;
        NR_UE_sched_ctrl_t *sched_ctrl = &UE->UE_sched_ctrl;
        sched_ctrl->rrc_processing_timer = (delay_ms << ra->DL_BWP.scs);
      }
      LOG_D(NR_MAC, "Frame %d, Subframe %d: Setting RA-Msg3 reception (CFRA) for SFN.Slot %d.%d\n", frameP, slotP, ra->Msg3_frame, ra->Msg3_slot);
    } else {
      LOG_D(NR_MAC, "Frame %d, Subframe %d: Setting RA-Msg3 reception (CBRA) for SFN.Slot %d.%d\n", frameP, slotP, ra->Msg3_frame, ra->Msg3_slot);
    }

    T(T_GNB_MAC_DL_RAR_PDU_WITH_DATA, T_INT(module_idP), T_INT(CC_id), T_INT(ra->RA_rnti), T_INT(frameP),
      T_INT(slotP), T_INT(0), T_BUFFER(&tx_req->TLVs[0].value.direct[0], tx_req->TLVs[0].length));

    tx_req->PDU_index = pduindex;
    tx_req->num_TLV = 1;
    tx_req->TLVs[0].length = pdsch_pdu_rel15->TBSize[0];
    tx_req->PDU_length = compute_PDU_length(tx_req->num_TLV, pdsch_pdu_rel15->TBSize[0]);
    TX_req->SFN = frameP;
    TX_req->Number_of_PDUs++;
    TX_req->Slot = slotP;

    // Mark the corresponding symbols RBs as used
    fill_pdcch_vrb_map(nr_mac,
                       CC_id,
                       &ra->sched_pdcch,
                       CCEIndex,
                       aggregation_level);
    for (int rb = 0; rb < rbSize; rb++) {
      vrb_map[BWPStart + rb + rbStart] |= SL_to_bitmap(tda_info.startSymbolIndex, tda_info.nrOfSymbols);
    }

    ra->state = WAIT_Msg3;
    LOG_D(NR_MAC,"[gNB %d][RAPROC] Frame %d, Subframe %d: rnti %04x RA state %d\n", module_idP, frameP, slotP, ra->rnti, ra->state);
  }
}

static void prepare_dl_pdus(gNB_MAC_INST *nr_mac,
                            NR_RA_t *ra,
                            NR_UE_DL_BWP_t *dl_bwp,
                            nfapi_nr_dl_tti_request_body_t *dl_req,
                            NR_sched_pucch_t *pucch,
                            NR_pdsch_dmrs_t dmrs_info,
                            NR_tda_info_t tda,
                            int aggregation_level,
                            int CCEIndex,
                            int tb_size,
                            int ndi,
                            int tpc,
                            int delta_PRI,
                            int current_harq_pid,
                            int time_domain_assignment,
                            int CC_id,
                            int rnti,
                            int round,
                            int mcsIndex,
                            int tb_scaling,
                            int pduindex,
                            int rbStart,
                            int rbSize)
{
  // look up the PDCCH PDU for this CC, BWP, and CORESET. If it does not exist, create it. This is especially
  // important if we have multiple RAs, and the DLSCH has to reuse them, so we need to mark them
  NR_ControlResourceSet_t *coreset = ra->coreset;
  const int coresetid = coreset->controlResourceSetId;
  nfapi_nr_dl_tti_pdcch_pdu_rel15_t *pdcch_pdu_rel15 = nr_mac->pdcch_pdu_idx[CC_id][coresetid];
  if (!pdcch_pdu_rel15) {
    nfapi_nr_dl_tti_request_pdu_t *dl_tti_pdcch_pdu = &dl_req->dl_tti_pdu_list[dl_req->nPDUs];
    memset(dl_tti_pdcch_pdu, 0, sizeof(nfapi_nr_dl_tti_request_pdu_t));
    dl_tti_pdcch_pdu->PDUType = NFAPI_NR_DL_TTI_PDCCH_PDU_TYPE;
    dl_tti_pdcch_pdu->PDUSize = (uint8_t)(2 + sizeof(nfapi_nr_dl_tti_pdcch_pdu));
    dl_req->nPDUs += 1;
    pdcch_pdu_rel15 = &dl_tti_pdcch_pdu->pdcch_pdu.pdcch_pdu_rel15;
    nr_configure_pdcch(pdcch_pdu_rel15, coreset, &ra->sched_pdcch);
    nr_mac->pdcch_pdu_idx[CC_id][coresetid] = pdcch_pdu_rel15;
  }

  nfapi_nr_dl_tti_request_pdu_t *dl_tti_pdsch_pdu = &dl_req->dl_tti_pdu_list[dl_req->nPDUs];
  memset((void *)dl_tti_pdsch_pdu,0,sizeof(nfapi_nr_dl_tti_request_pdu_t));
  dl_tti_pdsch_pdu->PDUType = NFAPI_NR_DL_TTI_PDSCH_PDU_TYPE;
  dl_tti_pdsch_pdu->PDUSize = (uint8_t)(2+sizeof(nfapi_nr_dl_tti_pdsch_pdu));
  dl_req->nPDUs+=1;
  nfapi_nr_dl_tti_pdsch_pdu_rel15_t *pdsch_pdu_rel15 = &dl_tti_pdsch_pdu->pdsch_pdu.pdsch_pdu_rel15;

  NR_COMMON_channels_t *cc = &nr_mac->common_channels[CC_id];
  NR_ServingCellConfigCommon_t *scc = cc->ServingCellConfigCommon;

  long BWPStart = 0;
  long BWPSize = 0;
  NR_Type0_PDCCH_CSS_config_t *type0_PDCCH_CSS_config = NULL;
  NR_SearchSpace_t *ss = ra->ra_ss;
  if(*ss->controlResourceSetId!=0) {
    BWPStart = dl_bwp->BWPStart;
    BWPSize  = dl_bwp->BWPSize;
  } else {
    type0_PDCCH_CSS_config = &nr_mac->type0_PDCCH_CSS_config[ra->beam_id];
    BWPStart = type0_PDCCH_CSS_config->cset_start_rb;
    BWPSize = type0_PDCCH_CSS_config->num_rbs;
  }

  int mcsTableIdx = dl_bwp->mcsTableIdx;

  pdsch_pdu_rel15->pduBitmap = 0;
  pdsch_pdu_rel15->rnti = rnti;
  pdsch_pdu_rel15->pduIndex = pduindex;
  pdsch_pdu_rel15->BWPSize  = BWPSize;
  pdsch_pdu_rel15->BWPStart = BWPStart;
  pdsch_pdu_rel15->SubcarrierSpacing = dl_bwp->scs;
  pdsch_pdu_rel15->CyclicPrefix = 0;
  pdsch_pdu_rel15->NrOfCodewords = 1;
  int R = nr_get_code_rate_dl(mcsIndex,mcsTableIdx);
  pdsch_pdu_rel15->targetCodeRate[0] = R;
  int Qm = nr_get_Qm_dl(mcsIndex, mcsTableIdx);
  pdsch_pdu_rel15->qamModOrder[0] = Qm;
  pdsch_pdu_rel15->mcsIndex[0] = mcsIndex;
  pdsch_pdu_rel15->mcsTable[0] = mcsTableIdx;
  pdsch_pdu_rel15->rvIndex[0] = nr_rv_round_map[round % 4];
  pdsch_pdu_rel15->dataScramblingId = *scc->physCellId;
  pdsch_pdu_rel15->nrOfLayers = 1;
  pdsch_pdu_rel15->transmissionScheme = 0;
  pdsch_pdu_rel15->refPoint = 0;
  pdsch_pdu_rel15->dmrsConfigType = dmrs_info.dmrsConfigType;
  pdsch_pdu_rel15->dlDmrsScramblingId = *scc->physCellId;
  pdsch_pdu_rel15->SCID = 0;
  pdsch_pdu_rel15->numDmrsCdmGrpsNoData = dmrs_info.numDmrsCdmGrpsNoData;
  pdsch_pdu_rel15->dmrsPorts = 1;
  pdsch_pdu_rel15->resourceAlloc = 1;
  pdsch_pdu_rel15->rbStart = rbStart;
  pdsch_pdu_rel15->rbSize = rbSize;
  pdsch_pdu_rel15->VRBtoPRBMapping = 0;
  pdsch_pdu_rel15->StartSymbolIndex = tda.startSymbolIndex;
  pdsch_pdu_rel15->NrOfSymbols = tda.nrOfSymbols;
  pdsch_pdu_rel15->dlDmrsSymbPos = dmrs_info.dl_dmrs_symb_pos;

  int x_Overhead = 0;
  nr_get_tbs_dl(&dl_tti_pdsch_pdu->pdsch_pdu, x_Overhead, pdsch_pdu_rel15->numDmrsCdmGrpsNoData, tb_scaling);

  pdsch_pdu_rel15->maintenance_parms_v3.tbSizeLbrmBytes = nr_compute_tbslbrm(mcsTableIdx, ra->sc_info.dl_bw_tbslbrm, 1);
  pdsch_pdu_rel15->maintenance_parms_v3.ldpcBaseGraph = get_BG(tb_size<<3,R);

  pdsch_pdu_rel15->precodingAndBeamforming.num_prgs=1;
  pdsch_pdu_rel15->precodingAndBeamforming.prg_size=275;
  pdsch_pdu_rel15->precodingAndBeamforming.dig_bf_interfaces=1;
  pdsch_pdu_rel15->precodingAndBeamforming.prgs_list[0].pm_idx = 0;
  pdsch_pdu_rel15->precodingAndBeamforming.prgs_list[0].dig_bf_interface_list[0].beam_idx = ra->beam_id;

  /* Fill PDCCH DL DCI PDU */
  nfapi_nr_dl_dci_pdu_t *dci_pdu = &pdcch_pdu_rel15->dci_pdu[pdcch_pdu_rel15->numDlDci];
  pdcch_pdu_rel15->numDlDci++;
  dci_pdu->RNTI = rnti;
  dci_pdu->ScramblingId = *scc->physCellId;
  dci_pdu->ScramblingRNTI = 0;
  dci_pdu->AggregationLevel = aggregation_level;
  dci_pdu->CceIndex = CCEIndex;
  dci_pdu->beta_PDCCH_1_0 = 0;
  dci_pdu->powerControlOffsetSS = 1;

  dci_pdu_rel15_t dci_payload;
  dci_payload.frequency_domain_assignment.val = PRBalloc_to_locationandbandwidth0(pdsch_pdu_rel15->rbSize,
                                                                                  pdsch_pdu_rel15->rbStart,
                                                                                  BWPSize);

  dci_payload.format_indicator = 1;
  dci_payload.time_domain_assignment.val = time_domain_assignment;
  dci_payload.vrb_to_prb_mapping.val = 0;
  dci_payload.mcs = pdsch_pdu_rel15->mcsIndex[0];
  dci_payload.tb_scaling = tb_scaling;
  dci_payload.rv = pdsch_pdu_rel15->rvIndex[0];
  dci_payload.harq_pid = current_harq_pid;
  dci_payload.ndi = ndi;
  dci_payload.dai[0].val = pucch ? (pucch->dai_c-1) & 3 : 0;
  dci_payload.tpc = tpc; // TPC for PUCCH: table 7.2.1-1 in 38.213
  dci_payload.pucch_resource_indicator = delta_PRI; // This is delta_PRI from 9.2.1 in 38.213
  dci_payload.pdsch_to_harq_feedback_timing_indicator.val = pucch ? pucch->timing_indicator : 0;

  LOG_D(NR_MAC,
        "[RAPROC] DCI 1_0 payload: freq_alloc %d (%d,%d,%d), time_alloc %d, vrb to prb %d, mcs %d tb_scaling %d pucchres %d harqtiming %d\n",
        dci_payload.frequency_domain_assignment.val,
        pdsch_pdu_rel15->rbStart,
        pdsch_pdu_rel15->rbSize,
        pdsch_pdu_rel15->BWPSize,
        dci_payload.time_domain_assignment.val,
        dci_payload.vrb_to_prb_mapping.val,
        dci_payload.mcs,
        dci_payload.tb_scaling,
        dci_payload.pucch_resource_indicator,
        dci_payload.pdsch_to_harq_feedback_timing_indicator.val);

  LOG_D(NR_MAC,
        "[RAPROC] DCI params: rnti 0x%x, rnti_type %d, dci_format %d coreset params: FreqDomainResource %llx, start_symbol %d  "
        "n_symb %d, BWPsize %d\n",
        pdcch_pdu_rel15->dci_pdu[0].RNTI,
        TYPE_TC_RNTI_,
        NR_DL_DCI_FORMAT_1_0,
        (unsigned long long)pdcch_pdu_rel15->FreqDomainResource,
        pdcch_pdu_rel15->StartSymbolIndex,
        pdcch_pdu_rel15->DurationSymbols,
        pdsch_pdu_rel15->BWPSize);

  fill_dci_pdu_rel15(&ra->sc_info,
                     dl_bwp,
                     &ra->UL_BWP,
                     &pdcch_pdu_rel15->dci_pdu[pdcch_pdu_rel15->numDlDci - 1],
                     &dci_payload,
                     NR_DL_DCI_FORMAT_1_0,
                     TYPE_TC_RNTI_,
                     dl_bwp->bwp_id,
                     ss,
                     coreset,
                     0, // parameter not needed for DCI 1_0
                     nr_mac->cset0_bwp_size);

  LOG_D(NR_MAC, "BWPSize: %i\n", pdcch_pdu_rel15->BWPSize);
  LOG_D(NR_MAC, "BWPStart: %i\n", pdcch_pdu_rel15->BWPStart);
  LOG_D(NR_MAC, "SubcarrierSpacing: %i\n", pdcch_pdu_rel15->SubcarrierSpacing);
  LOG_D(NR_MAC, "CyclicPrefix: %i\n", pdcch_pdu_rel15->CyclicPrefix);
  LOG_D(NR_MAC, "StartSymbolIndex: %i\n", pdcch_pdu_rel15->StartSymbolIndex);
  LOG_D(NR_MAC, "DurationSymbols: %i\n", pdcch_pdu_rel15->DurationSymbols);
  for (int n = 0; n < 6; n++)
    LOG_D(NR_MAC, "FreqDomainResource[%i]: %x\n", n, pdcch_pdu_rel15->FreqDomainResource[n]);
  LOG_D(NR_MAC, "CceRegMappingType: %i\n", pdcch_pdu_rel15->CceRegMappingType);
  LOG_D(NR_MAC, "RegBundleSize: %i\n", pdcch_pdu_rel15->RegBundleSize);
  LOG_D(NR_MAC, "InterleaverSize: %i\n", pdcch_pdu_rel15->InterleaverSize);
  LOG_D(NR_MAC, "CoreSetType: %i\n", pdcch_pdu_rel15->CoreSetType);
  LOG_D(NR_MAC, "ShiftIndex: %i\n", pdcch_pdu_rel15->ShiftIndex);
  LOG_D(NR_MAC, "precoderGranularity: %i\n", pdcch_pdu_rel15->precoderGranularity);
  LOG_D(NR_MAC, "numDlDci: %i\n", pdcch_pdu_rel15->numDlDci);
}

static void nr_generate_Msg4(module_id_t module_idP,
                             int CC_id,
                             frame_t frameP,
                             sub_frame_t slotP,
                             NR_RA_t *ra,
                             nfapi_nr_dl_tti_request_t *DL_req,
                             nfapi_nr_tx_data_request_t *TX_req)
{
  gNB_MAC_INST *nr_mac = RC.nrmac[module_idP];
  NR_COMMON_channels_t *cc = &nr_mac->common_channels[CC_id];
  NR_UE_DL_BWP_t *dl_bwp = &ra->DL_BWP;

  // if it is a DL slot, if the RA is in MSG4 state
  if (is_xlsch_in_slot(nr_mac->dlsch_slot_bitmap[slotP / 64], slotP)) {

    NR_ServingCellConfigCommon_t *scc = cc->ServingCellConfigCommon;
    NR_SearchSpace_t *ss = ra->ra_ss;

    NR_ControlResourceSet_t *coreset = ra->coreset;
    AssertFatal(coreset!=NULL,"Coreset cannot be null for RA-Msg4\n");

    uint16_t mac_sdu_length = 0;

    NR_UE_info_t *UE = find_nr_UE(&nr_mac->UE_info, ra->rnti);
    if (!UE) {
      LOG_E(NR_MAC, "want to generate Msg4, but rnti %04x not in the table\n", ra->rnti);
      return;
    }

    NR_UE_sched_ctrl_t *sched_ctrl = &UE->UE_sched_ctrl;
    /* get the PID of a HARQ process awaiting retrnasmission, or -1 otherwise */
    int current_harq_pid = sched_ctrl->retrans_dl_harq.head;

    logical_chan_id_t lcid = DL_SCH_LCID_CCCH;
    if (current_harq_pid < 0) {
      // Check for data on SRB0 (RRCSetup)
      mac_rlc_status_resp_t srb_status = mac_rlc_status_ind(module_idP, ra->rnti, module_idP, frameP, slotP, ENB_FLAG_YES, MBMS_FLAG_NO, lcid, 0, 0);

      if (srb_status.bytes_in_buffer == 0) {
        lcid = DL_SCH_LCID_DCCH;
        // Check for data on SRB1 (RRCReestablishment, RRCReconfiguration)
        srb_status = mac_rlc_status_ind(module_idP, ra->rnti, module_idP, frameP, slotP, ENB_FLAG_YES, MBMS_FLAG_NO, lcid, 0, 0);
      }

      // Need to wait until data for Msg4 is ready
      if (srb_status.bytes_in_buffer == 0)
        return;
      mac_sdu_length = srb_status.bytes_in_buffer;
    }

    long BWPStart = 0;
    long BWPSize = 0;
    NR_Type0_PDCCH_CSS_config_t *type0_PDCCH_CSS_config = NULL;
    if(*ss->controlResourceSetId!=0) {
      BWPStart = dl_bwp->BWPStart;
      BWPSize  = dl_bwp->BWPSize;
    } else {
      type0_PDCCH_CSS_config = &nr_mac->type0_PDCCH_CSS_config[ra->beam_id];
      BWPStart = type0_PDCCH_CSS_config->cset_start_rb;
      BWPSize = type0_PDCCH_CSS_config->num_rbs;
    }

    // get CCEindex, needed also for PUCCH and then later for PDCCH
    uint8_t aggregation_level;
    int CCEIndex = get_cce_index(nr_mac,
                                 CC_id, slotP, 0,
                                 &aggregation_level,
                                 ss,
                                 coreset,
                                 &ra->sched_pdcch,
                                 true);

    if (CCEIndex < 0) {
      LOG_E(NR_MAC, "%s(): cannot find free CCE for RA RNTI 0x%04x!\n", __func__, ra->rnti);
      return;
    }

    // Checking if the DCI allocation is feasible in current subframe
    nfapi_nr_dl_tti_request_body_t *dl_req = &DL_req->dl_tti_request_body;
    if (dl_req->nPDUs > NFAPI_NR_MAX_DL_TTI_PDUS - 2) {
      LOG_I(NR_MAC, "[RAPROC] Subframe %d: FAPI DL structure is full, skip scheduling UE %d\n", slotP, ra->rnti);
      return;
    }

    uint8_t time_domain_assignment = get_dl_tda(nr_mac, scc, slotP);
    int mux_pattern = type0_PDCCH_CSS_config ? type0_PDCCH_CSS_config->type0_pdcch_ss_mux_pattern : 1;
    NR_tda_info_t msg4_tda = get_dl_tda_info(dl_bwp,
                                             ss->searchSpaceType->present,
                                             time_domain_assignment,
                                             scc->dmrs_TypeA_Position,
                                             mux_pattern,
                                             TYPE_TC_RNTI_,
                                             coreset->controlResourceSetId,
                                             false);

    NR_pdsch_dmrs_t dmrs_info = get_dl_dmrs_params(scc,
                                                   dl_bwp,
                                                   &msg4_tda,
                                                   1);

    uint8_t mcsTableIdx = dl_bwp->mcsTableIdx;
    uint8_t mcsIndex = 0;
    int rbStart = 0;
    int rbSize = 0;
    uint8_t tb_scaling = 0;
    uint32_t tb_size = 0;
    uint16_t pdu_length;
    if(current_harq_pid >= 0) { // in case of retransmission
      NR_UE_harq_t *harq = &sched_ctrl->harq_processes[current_harq_pid];
      DevAssert(!harq->is_waiting);
      pdu_length = harq->tb_size;
    }
    else {
      uint8_t subheader_len = (mac_sdu_length < 256) ? sizeof(NR_MAC_SUBHEADER_SHORT) : sizeof(NR_MAC_SUBHEADER_LONG);
      pdu_length = mac_sdu_length + subheader_len + 7; //7 is contetion resolution length
    }

    // increase PRBs until we get to BWPSize or TBS is bigger than MAC PDU size
    do {
      if(rbSize < BWPSize)
        rbSize++;
      else
        mcsIndex++;
      LOG_D(NR_MAC,"Calling nr_compute_tbs with N_PRB_DMRS %d, N_DMRS_SLOT %d\n",dmrs_info.N_PRB_DMRS,dmrs_info.N_DMRS_SLOT);
      tb_size = nr_compute_tbs(nr_get_Qm_dl(mcsIndex, mcsTableIdx),
                                     nr_get_code_rate_dl(mcsIndex, mcsTableIdx),
                                     rbSize, msg4_tda.nrOfSymbols, dmrs_info.N_PRB_DMRS * dmrs_info.N_DMRS_SLOT, 0, tb_scaling,1) >> 3;
    } while (tb_size < pdu_length && mcsIndex<=28);

    AssertFatal(tb_size >= pdu_length,"Cannot allocate Msg4\n");

    int i = 0;
    uint16_t *vrb_map = cc[CC_id].vrb_map;
    while ((i < rbSize) && (rbStart + rbSize <= BWPSize)) {
      if (vrb_map[BWPStart + rbStart + i]&SL_to_bitmap(msg4_tda.startSymbolIndex, msg4_tda.nrOfSymbols)) {
        rbStart += i+1;
        i = 0;
      } else {
        i++;
      }
    }

    if (rbStart > (BWPSize - rbSize)) {
      LOG_E(NR_MAC, "%s(): cannot find free vrb_map for RNTI %04x!\n", __func__, ra->rnti);
      return;
    }

    const int delta_PRI = 0;
    int r_pucch = nr_get_pucch_resource(coreset, ra->UL_BWP.pucch_Config, CCEIndex);

    LOG_D(NR_MAC,"[RAPROC] Msg4 r_pucch %d (CCEIndex %d, delta_PRI %d)\n", r_pucch, CCEIndex, delta_PRI);

    int alloc = nr_acknack_scheduling(nr_mac, UE, frameP, slotP, r_pucch, 1);
    if (alloc < 0) {
      LOG_D(NR_MAC,"Couldn't find a pucch allocation for ack nack (msg4) in frame %d slot %d\n",frameP,slotP);
      return;
    }

    // HARQ management
    if (current_harq_pid < 0) {
      AssertFatal(sched_ctrl->available_dl_harq.head >= 0,
                  "UE context not initialized: no HARQ processes found\n");
      current_harq_pid = sched_ctrl->available_dl_harq.head;
      remove_front_nr_list(&sched_ctrl->available_dl_harq);
    }
    NR_UE_harq_t *harq = &sched_ctrl->harq_processes[current_harq_pid];
    DevAssert(!harq->is_waiting);
    add_tail_nr_list(&sched_ctrl->feedback_dl_harq, current_harq_pid);
    harq->is_waiting = true;
    ra->harq_pid = current_harq_pid;
    UE->mac_stats.dl.rounds[harq->round]++;

    NR_sched_pucch_t *pucch = &sched_ctrl->sched_pucch[alloc];
    harq->feedback_slot = pucch->ul_slot;
    harq->feedback_frame = pucch->frame;
    harq->tb_size = tb_size;

    uint8_t *buf = (uint8_t *) harq->transportBlock;
    // Bytes to be transmitted
    if (harq->round == 0) {
      // UE Contention Resolution Identity MAC CE
      uint16_t mac_pdu_length = nr_write_ce_dlsch_pdu(module_idP, nr_mac->sched_ctrlCommon, buf, 255, ra->cont_res_id);
      LOG_D(NR_MAC,"Encoded contention resolution mac_pdu_length %d\n",mac_pdu_length);
      uint8_t buffer[CCCH_SDU_SIZE];
      uint8_t mac_subheader_len = sizeof(NR_MAC_SUBHEADER_SHORT);
      // Get RLC data on the SRB (RRCSetup, RRCReestablishment)
      mac_sdu_length = mac_rlc_data_req(module_idP,
                                        ra->rnti,
                                        module_idP,
                                        frameP,
                                        ENB_FLAG_YES,
                                        MBMS_FLAG_NO,
                                        lcid,
                                        CCCH_SDU_SIZE,
                                        (char *)buffer,
                                        0,
                                        0);

      if (mac_sdu_length < 256) {
        ((NR_MAC_SUBHEADER_SHORT *)&buf[mac_pdu_length])->R = 0;
        ((NR_MAC_SUBHEADER_SHORT *)&buf[mac_pdu_length])->F = 0;
        ((NR_MAC_SUBHEADER_SHORT *)&buf[mac_pdu_length])->LCID = lcid;
        ((NR_MAC_SUBHEADER_SHORT *)&buf[mac_pdu_length])->L = mac_sdu_length;
        ra->mac_pdu_length = mac_pdu_length + mac_sdu_length + sizeof(NR_MAC_SUBHEADER_SHORT);
      } else {
        mac_subheader_len = sizeof(NR_MAC_SUBHEADER_LONG);
        ((NR_MAC_SUBHEADER_LONG *)&buf[mac_pdu_length])->R = 0;
        ((NR_MAC_SUBHEADER_LONG *)&buf[mac_pdu_length])->F = 1;
        ((NR_MAC_SUBHEADER_LONG *)&buf[mac_pdu_length])->LCID = lcid;
        ((NR_MAC_SUBHEADER_LONG *)&buf[mac_pdu_length])->L = htons(mac_sdu_length);
        ra->mac_pdu_length = mac_pdu_length + mac_sdu_length + sizeof(NR_MAC_SUBHEADER_LONG);
      }
      memcpy(&buf[mac_pdu_length + mac_subheader_len], buffer, mac_sdu_length);
    }

    const int pduindex = nr_mac->pdu_index[CC_id]++;
    prepare_dl_pdus(nr_mac, ra, dl_bwp, dl_req, pucch, dmrs_info, msg4_tda, aggregation_level, CCEIndex, tb_size, harq->ndi, sched_ctrl->tpc1, delta_PRI,
                    current_harq_pid, time_domain_assignment, CC_id, ra->rnti, harq->round, mcsIndex, tb_scaling, pduindex, rbStart, rbSize);

    // Add padding header and zero rest out if there is space left
    if (ra->mac_pdu_length < harq->tb_size) {
      NR_MAC_SUBHEADER_FIXED *padding = (NR_MAC_SUBHEADER_FIXED *) &buf[ra->mac_pdu_length];
      padding->R = 0;
      padding->LCID = DL_SCH_LCID_PADDING;
      for(int k = ra->mac_pdu_length+1; k<harq->tb_size; k++) {
        buf[k] = 0;
      }
    }

    T(T_GNB_MAC_DL_PDU_WITH_DATA, T_INT(module_idP), T_INT(CC_id), T_INT(ra->rnti),
      T_INT(frameP), T_INT(slotP), T_INT(current_harq_pid), T_BUFFER(harq->transportBlock, harq->tb_size));

    // DL TX request
    nfapi_nr_pdu_t *tx_req = &TX_req->pdu_list[TX_req->Number_of_PDUs];
    memcpy(tx_req->TLVs[0].value.direct, harq->transportBlock, sizeof(uint8_t) * harq->tb_size);
    tx_req->PDU_index = pduindex;
    tx_req->num_TLV = 1;
    tx_req->TLVs[0].length =  harq->tb_size;
    tx_req->PDU_length = compute_PDU_length(tx_req->num_TLV, tx_req->TLVs[0].length);
    TX_req->SFN = frameP;
    TX_req->Number_of_PDUs++;
    TX_req->Slot = slotP;

    // Mark the corresponding symbols and RBs as used
    fill_pdcch_vrb_map(nr_mac,
                       CC_id,
                       &ra->sched_pdcch,
                       CCEIndex,
                       aggregation_level);
    for (int rb = 0; rb < rbSize; rb++) {
      vrb_map[BWPStart + rb + rbStart] |= SL_to_bitmap(msg4_tda.startSymbolIndex, msg4_tda.nrOfSymbols);
    }

    ra->state = WAIT_Msg4_ACK;
    LOG_I(NR_MAC,"UE %04x Generate msg4: feedback at %4d.%2d, payload %d bytes, next state WAIT_Msg4_ACK\n", ra->rnti, pucch->frame, pucch->ul_slot, harq->tb_size);
  }
}

static void nr_check_Msg4_Ack(module_id_t module_id, int CC_id, frame_t frame, sub_frame_t slot, NR_RA_t *ra)
{
  NR_UE_info_t *UE = find_nr_UE(&RC.nrmac[module_id]->UE_info, ra->rnti);
  if (!UE) {
    LOG_E(NR_MAC, "Cannot check Msg4 ACK/NACK, rnti %04x not in the table\n", ra->rnti);
    return;
  }
  const int current_harq_pid = ra->harq_pid;

  NR_UE_sched_ctrl_t *sched_ctrl = &UE->UE_sched_ctrl;
  NR_UE_harq_t *harq = &sched_ctrl->harq_processes[current_harq_pid];

  LOG_D(NR_MAC, "ue rnti 0x%04x, harq is waiting %d, round %d, frame %d %d, harq id %d\n", ra->rnti, harq->is_waiting, harq->round, frame, slot, current_harq_pid);

  if (harq->is_waiting == 0) {
    if (harq->round == 0) {
      if (UE->Msg4_ACKed) {
        LOG_A(NR_MAC, "(UE RNTI 0x%04x) Received Ack of RA-Msg4. CBRA procedure succeeded!\n", ra->rnti);
      } else {
        LOG_I(NR_MAC, "%4d.%2d UE %04x: RA Procedure failed at Msg4!\n", frame, slot, ra->rnti);
        nr_mac_trigger_ul_failure(sched_ctrl, UE->current_DL_BWP.scs);
      }

      // Pause scheduling according to:
      // 3GPP TS 38.331 Section 12 Table 12.1-1: UE performance requirements for RRC procedures for UEs
      nr_mac_enable_ue_rrc_processing_timer(RC.nrmac[module_id], UE, false);

      nr_clear_ra_proc(module_id, CC_id, frame, ra);
      if (sched_ctrl->retrans_dl_harq.head >= 0) {
        remove_nr_list(&sched_ctrl->retrans_dl_harq, current_harq_pid);
      }
    } else {
      LOG_I(NR_MAC, "(UE %04x) Received Nack of RA-Msg4. Preparing retransmission!\n", ra->rnti);
      ra->state = Msg4;
    }
  }
}

void nr_clear_ra_proc(module_id_t module_idP, int CC_id, frame_t frameP, NR_RA_t *ra)
{
  /* we assume that this function is mutex-protected from outside */
  NR_SCHED_ENSURE_LOCKED(&RC.nrmac[module_idP]->sched_lock);
  LOG_D(NR_MAC,"[gNB %d][RAPROC] CC_id %d Frame %d Clear Random access information rnti %x\n", module_idP, CC_id, frameP, ra->rnti);
  ra->state = RA_IDLE;
  ra->timing_offset = 0;
  ra->RRC_timer = 20;
  ra->msg3_round = 0;
  if(ra->cfra == false) {
    ra->rnti = 0;
  }
}


/////////////////////////////////////
//    Random Access Response PDU   //
//         TS 38.213 ch 8.2        //
//        TS 38.321 ch 6.2.3       //
/////////////////////////////////////
//| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |// bit-wise
//| E | T |       R A P I D       |//
//| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |//
//| R |           T A             |//
//|       T A         |  UL grant |//
//|            UL grant           |//
//|            UL grant           |//
//|            UL grant           |//
//|         T C - R N T I         |//
//|         T C - R N T I         |//
/////////////////////////////////////
//       UL grant  (27 bits)       //
/////////////////////////////////////
//| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |// bit-wise
//|-------------------|FHF|F_alloc|//
//|        Freq allocation        |//
//|    F_alloc    |Time allocation|//
//|      MCS      |     TPC   |CSI|//
/////////////////////////////////////
// WIP
// todo:
// - handle MAC RAR BI subheader
// - sending only 1 RAR subPDU
// - UL Grant: hardcoded CSI, TPC, time alloc
// - padding
static void nr_fill_rar(uint8_t Mod_idP, NR_RA_t *ra, uint8_t *dlsch_buffer, nfapi_nr_pusch_pdu_t *pusch_pdu)
{
  LOG_D(NR_MAC, "[gNB] Generate RAR MAC PDU frame %d slot %d preamble index %u TA command %d \n", ra->Msg2_frame, ra-> Msg2_slot, ra->preamble_index, ra->timing_offset);
  NR_RA_HEADER_BI *rarbi = (NR_RA_HEADER_BI *) dlsch_buffer;
  NR_RA_HEADER_RAPID *rarh = (NR_RA_HEADER_RAPID *) (dlsch_buffer + 1);
  NR_MAC_RAR *rar = (NR_MAC_RAR *) (dlsch_buffer + 2);
  unsigned char csi_req = 0, tpc_command;

  tpc_command = 3; // this is 0 dB

  /// E/T/R/R/BI subheader ///
  // E = 1, MAC PDU includes another MAC sub-PDU (RAPID)
  // T = 0, Back-off indicator subheader
  // R = 2, Reserved
  // BI = 0, 5ms
  rarbi->E = 1;
  rarbi->T = 0;
  rarbi->R = 0;
  rarbi->BI = 0;

  /// E/T/RAPID subheader ///
  // E = 0, one only RAR, first and last
  // T = 1, RAPID
  rarh->E = 0;
  rarh->T = 1;
  rarh->RAPID = ra->preamble_index;

  /// RAR MAC payload ///
  rar->R = 0;

  // TA command
  rar->TA1 = (uint8_t) (ra->timing_offset >> 5);    // 7 MSBs of timing advance
  rar->TA2 = (uint8_t) (ra->timing_offset & 0x1f);  // 5 LSBs of timing advance

  // TC-RNTI
  rar->TCRNTI_1 = (uint8_t) (ra->rnti >> 8);        // 8 MSBs of rnti
  rar->TCRNTI_2 = (uint8_t) (ra->rnti & 0xff);      // 8 LSBs of rnti

  // UL grant

  ra->msg3_TPC = tpc_command;

  if (pusch_pdu->frequency_hopping)
    AssertFatal(1==0,"PUSCH with frequency hopping currently not supported");

  int bwp_size = pusch_pdu->bwp_size;
  int prb_alloc = PRBalloc_to_locationandbandwidth0(ra->msg3_nb_rb, ra->msg3_first_rb, bwp_size);
  int valid_bits = 14;
  int f_alloc = prb_alloc & ((1 << valid_bits) - 1);

  uint32_t ul_grant = csi_req | (tpc_command << 1) | (pusch_pdu->mcs_index << 4) | (ra->Msg3_tda_id << 8) | (f_alloc << 12) | (pusch_pdu->frequency_hopping << 26);

  rar->UL_GRANT_1 = (uint8_t) (ul_grant >> 24) & 0x07;
  rar->UL_GRANT_2 = (uint8_t) (ul_grant >> 16) & 0xff;
  rar->UL_GRANT_3 = (uint8_t) (ul_grant >> 8) & 0xff;
  rar->UL_GRANT_4 = (uint8_t) ul_grant & 0xff;

#ifdef DEBUG_RAR
  LOG_I(NR_MAC, "rarh->E = 0x%x\n", rarh->E);
  LOG_I(NR_MAC, "rarh->T = 0x%x\n", rarh->T);
  LOG_I(NR_MAC, "rarh->RAPID = 0x%x (%i)\n", rarh->RAPID, rarh->RAPID);
  LOG_I(NR_MAC, "rar->R = 0x%x\n", rar->R);
  LOG_I(NR_MAC, "rar->TA1 = 0x%x\n", rar->TA1);
  LOG_I(NR_MAC, "rar->TA2 = 0x%x\n", rar->TA2);
  LOG_I(NR_MAC, "rar->UL_GRANT_1 = 0x%x\n", rar->UL_GRANT_1);
  LOG_I(NR_MAC, "rar->UL_GRANT_2 = 0x%x\n", rar->UL_GRANT_2);
  LOG_I(NR_MAC, "rar->UL_GRANT_3 = 0x%x\n", rar->UL_GRANT_3);
  LOG_I(NR_MAC, "rar->UL_GRANT_4 = 0x%x\n", rar->UL_GRANT_4);
  LOG_I(NR_MAC, "rar->TCRNTI_1 = 0x%x\n", rar->TCRNTI_1);
  LOG_I(NR_MAC, "rar->TCRNTI_2 = 0x%x\n", rar->TCRNTI_2);
#endif
  LOG_D(NR_MAC,
        "In %s: Transmitted RAR with t_alloc %d f_alloc %d ta_command %d mcs %d freq_hopping %d tpc_command %d csi_req %d t_crnti "
        "%x \n",
        __FUNCTION__,
        rar->UL_GRANT_3 & 0x0f,
        (rar->UL_GRANT_3 >> 4) | (rar->UL_GRANT_2 << 4) | ((rar->UL_GRANT_1 & 0x03) << 12),
        rar->TA2 + (rar->TA1 << 5),
        rar->UL_GRANT_4 >> 4,
        rar->UL_GRANT_1 >> 2,
        tpc_command,
        csi_req,
        rar->TCRNTI_2 + (rar->TCRNTI_1 << 8));
}

void nr_schedule_RA(module_id_t module_idP,
                    frame_t frameP,
                    sub_frame_t slotP,
                    nfapi_nr_ul_dci_request_t *ul_dci_req,
                    nfapi_nr_dl_tti_request_t *DL_req,
                    nfapi_nr_tx_data_request_t *TX_req)
{
  gNB_MAC_INST *mac = RC.nrmac[module_idP];
  /* already mutex protected: held in gNB_dlsch_ulsch_scheduler() */
  NR_SCHED_ENSURE_LOCKED(&mac->sched_lock);

  start_meas(&mac->schedule_ra);
  for (int CC_id = 0; CC_id < MAX_NUM_CCs; CC_id++) {
    NR_COMMON_channels_t *cc = &mac->common_channels[CC_id];
    for (int i = 0; i < NR_NB_RA_PROC_MAX; i++) {
      NR_RA_t *ra = &cc->ra[i];
      LOG_D(NR_MAC, "RA[state:%d]\n", ra->state);

      // Check RA Contention Resolution timer
      if (ra->state >= WAIT_Msg3) {
        ra->contention_resolution_timer--;
        if (ra->contention_resolution_timer < 0) {
          LOG_W(NR_MAC, "(%d.%d) RA Contention Resolution timer expired for UE 0x%04x, RA procedure failed...\n", frameP, slotP, ra->rnti);
          nr_mac_release_ue(mac, ra->rnti);
          nr_clear_ra_proc(module_idP, CC_id, frameP, ra);
          continue;
        }
      }

      switch (ra->state) {
        case Msg2:
          nr_generate_Msg2(module_idP, CC_id, frameP, slotP, ra, DL_req, TX_req);
          break;
        case Msg3_retransmission:
          nr_generate_Msg3_retransmission(module_idP, CC_id, frameP, slotP, ra, ul_dci_req);
          break;
        case Msg3_dcch_dtch:
          /* fallthrough */
        case Msg4:
          nr_generate_Msg4(module_idP, CC_id, frameP, slotP, ra, DL_req, TX_req);
          break;
        case WAIT_Msg4_ACK:
          nr_check_Msg4_Ack(module_idP, CC_id, frameP, slotP, ra);
          break;
        default:
          break;
      }
    }
  }
  stop_meas(&mac->schedule_ra);
}
