flexran_agent_scheduler_dlsch_ue.c

/*
 * 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 1.0  (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 flexran_agent_scheduler_dlsch_ue.c
 * \brief procedures related to eNB for the DLSCH transport channel
 * \author Xenofon Foukas, Navid Nikaein and Raymond Knopp
 * \date 2016
 * \email: x.foukas@sms.ed.ac.uk
 * \version 0.1
 * @ingroup _mac

 */

#include "assertions.h"
#include "PHY/defs.h"
#include "PHY/extern.h"

#include "SCHED/defs.h"
#include "SCHED/extern.h"

#include "LAYER2/MAC/flexran_agent_mac_proto.h"
#include "LAYER2/MAC/defs.h"
#include "LAYER2/MAC/proto.h"
#include "LAYER2/MAC/extern.h"
#include "UTIL/LOG/log.h"
#include "UTIL/LOG/vcd_signal_dumper.h"
#include "UTIL/OPT/opt.h"
#include "OCG.h"
#include "OCG_extern.h"

#include "RRC/LITE/extern.h"
#include "RRC/L2_INTERFACE/openair_rrc_L2_interface.h"

#include "ENB_APP/flexran_agent_defs.h"
#include "flexran_agent_ran_api.h"
#include "pdcp.h"

#include "header.pb-c.h"
#include "flexran.pb-c.h"
#include "flexran_agent_mac.h"
#include <dlfcn.h>

#include "SIMULATION/TOOLS/defs.h" // for taus

#if defined(ENABLE_ITTI)
# include "intertask_interface.h"
#endif

#define ENABLE_MAC_PAYLOAD_DEBUG

/**
 * Local variables to support slicing
 * 
 */


/*!\brief  UE ULSCH scheduling states*/
typedef enum {
  MIN_SLICE_STRATEGY = 0,
  SLICE_MASK,
  UEID_TO_SLICEID,
  MAX_SLICE_STRATEGY
} SLICING_STRATEGY;

// this assumes a max of of 16 UE per eNB/CC
#define SLICE0_MASK 0x000f 
#define SLICE1_MASK 0x00f0
#define SLICE2_MASK 0x0f00
#define SLICE3_MASK 0xf000


// number of active slices for  past and current time
int n_active_slices = 1;
int n_active_slices_current = 1;

// ue to slice mapping
int slicing_strategy = UEID_TO_SLICEID;
int slicing_strategy_current = UEID_TO_SLICEID;

// RB share for each slice for past and current time
float slice_percentage[MAX_NUM_SLICES] = {1.0, 1.0, 0.0, 0.0};
float slice_percentage_current[MAX_NUM_SLICES] = {1.0, 1.0, 0.0, 0.0};
float total_slice_percentage = 0;

// MAX MCS for each slice for past and current time
int slice_maxmcs[MAX_NUM_SLICES] = {28, 28, 28, 28};
int slice_maxmcs_current[MAX_NUM_SLICES] = {28, 28, 28, 28};

int update_dl_scheduler[MAX_NUM_SLICES] = {1, 1, 1, 1};
int update_dl_scheduler_current[MAX_NUM_SLICES] = {1, 1, 1, 1};

// name of available scheduler
char *dl_scheduler_type[MAX_NUM_SLICES] = {"flexran_schedule_ue_spec_embb",
					   "flexran_schedule_ue_spec_urllc",
					   "flexran_schedule_ue_spec_mmtc",
					   "flexran_schedule_ue_spec_be"      // best effort 
};

// pointer to the slice specific scheduler 
slice_scheduler_dl slice_sched_dl[MAX_NUM_SLICES] = {0};


/**
 * preprocessor functions for scheduling
 *
 */


// This function stores the downlink buffer for all the logical channels
void _store_dlsch_buffer (module_id_t Mod_id,
			  int         slice_id,
			  frame_t     frameP,
			  sub_frame_t subframeP)
{

  int                   UE_id,i;
  rnti_t                rnti;
  mac_rlc_status_resp_t rlc_status;
  UE_list_t             *UE_list = &eNB_mac_inst[Mod_id].UE_list;
  UE_TEMPLATE           *UE_template;

  for (UE_id = 0; UE_id < NUMBER_OF_UE_MAX; UE_id++) {
    if (UE_list->active[UE_id] != TRUE) continue;
    
    if (flexran_slice_member(UE_id, slice_id) == 0)
      continue;
    
    UE_template = &UE_list->UE_template[UE_PCCID(Mod_id,UE_id)][UE_id];

    // clear logical channel interface variables
    UE_template->dl_buffer_total = 0;
    UE_template->dl_pdus_total = 0;

    for(i=0; i< MAX_NUM_LCID; i++) {
      UE_template->dl_buffer_info[i]=0;
      UE_template->dl_pdus_in_buffer[i]=0;
      UE_template->dl_buffer_head_sdu_creation_time[i]=0;
      UE_template->dl_buffer_head_sdu_remaining_size_to_send[i]=0;
    }

    rnti = UE_RNTI(Mod_id,UE_id);

    for(i=0; i< MAX_NUM_LCID; i++) { // loop over all the logical channels

      rlc_status = mac_rlc_status_ind(Mod_id,rnti, Mod_id,frameP,subframeP,ENB_FLAG_YES,MBMS_FLAG_NO,i,0 );
      UE_template->dl_buffer_info[i] = rlc_status.bytes_in_buffer; //storing the dlsch buffer for each logical channel
      UE_template->dl_pdus_in_buffer[i] = rlc_status.pdus_in_buffer;
      UE_template->dl_buffer_head_sdu_creation_time[i] = rlc_status.head_sdu_creation_time ;
      UE_template->dl_buffer_head_sdu_creation_time_max = cmax(UE_template->dl_buffer_head_sdu_creation_time_max,
          rlc_status.head_sdu_creation_time );
      UE_template->dl_buffer_head_sdu_remaining_size_to_send[i] = rlc_status.head_sdu_remaining_size_to_send;
      UE_template->dl_buffer_head_sdu_is_segmented[i] = rlc_status.head_sdu_is_segmented;
      UE_template->dl_buffer_total += UE_template->dl_buffer_info[i];//storing the total dlsch buffer
      UE_template->dl_pdus_total   += UE_template->dl_pdus_in_buffer[i];

#ifdef DEBUG_eNB_SCHEDULER

      /* note for dl_buffer_head_sdu_remaining_size_to_send[i] :
       * 0 if head SDU has not been segmented (yet), else remaining size not already segmented and sent
       */
      if (UE_template->dl_buffer_info[i]>0)
        LOG_D(MAC,
              "[eNB %d][SLICE %d] Frame %d Subframe %d : RLC status for UE %d in LCID%d: total of %d pdus and size %d, head sdu queuing time %d, remaining size %d, is segmeneted %d \n",
              Mod_id, slice_id,frameP, subframeP, UE_id,
              i, UE_template->dl_pdus_in_buffer[i],UE_template->dl_buffer_info[i],
              UE_template->dl_buffer_head_sdu_creation_time[i],
              UE_template->dl_buffer_head_sdu_remaining_size_to_send[i],
              UE_template->dl_buffer_head_sdu_is_segmented[i]
             );

#endif

    }

    //#ifdef DEBUG_eNB_SCHEDULER
    if ( UE_template->dl_buffer_total>0)
      LOG_D(MAC,"[eNB %d] Frame %d Subframe %d : RLC status for UE %d : total DL buffer size %d and total number of pdu %d \n",
            Mod_id, frameP, subframeP, UE_id,
            UE_template->dl_buffer_total,
            UE_template->dl_pdus_total
           );

    //#endif
  }
}


// This function returns the estimated number of RBs required by each UE for downlink scheduling
void _assign_rbs_required (module_id_t Mod_id,
			   int         slice_id,
			   frame_t     frameP,
			   sub_frame_t subframe,
			   uint16_t    nb_rbs_required[MAX_NUM_CCs][NUMBER_OF_UE_MAX],
			   uint16_t    nb_rbs_allowed_slice[MAX_NUM_CCs][MAX_NUM_SLICES],
			   int         min_rb_unit[MAX_NUM_CCs])
{


  rnti_t           rnti;
  uint16_t         TBS = 0;
  LTE_eNB_UE_stats *eNB_UE_stats[MAX_NUM_CCs];
  int              UE_id,n,i,j,CC_id,pCCid,tmp;
  UE_list_t        *UE_list = &eNB_mac_inst[Mod_id].UE_list;
  //  UE_TEMPLATE           *UE_template;

  // clear rb allocations across all CC_ids
  for (UE_id = 0; UE_id < NUMBER_OF_UE_MAX; UE_id++) {
    if (UE_list->active[UE_id] != TRUE) continue;
    
    if (flexran_slice_member(UE_id, slice_id) == 0)
      continue;
    
    pCCid = UE_PCCID(Mod_id,UE_id);
    rnti = UE_list->UE_template[pCCid][UE_id].rnti;

    /* skip UE not present in PHY (for any of its active CCs) */
    if (!phy_stats_exist(Mod_id, rnti))
      continue;

    //update CQI information across component carriers
    for (n=0; n<UE_list->numactiveCCs[UE_id]; n++) {
      CC_id = UE_list->ordered_CCids[n][UE_id];
      eNB_UE_stats[CC_id] = mac_xface->get_eNB_UE_stats(Mod_id,CC_id,rnti);
      eNB_UE_stats[CC_id]->dlsch_mcs1 = cqi_to_mcs[flexran_get_ue_wcqi(Mod_id, UE_id)];
    }

    // provide the list of CCs sorted according to MCS
    for (i=0; i<UE_list->numactiveCCs[UE_id]; i++) {
      for (j=i+1; j<UE_list->numactiveCCs[UE_id]; j++) {
        DevAssert( j < MAX_NUM_CCs );

        if (eNB_UE_stats[UE_list->ordered_CCids[i][UE_id]]->dlsch_mcs1 >
            eNB_UE_stats[UE_list->ordered_CCids[j][UE_id]]->dlsch_mcs1) {
          tmp = UE_list->ordered_CCids[i][UE_id];
          UE_list->ordered_CCids[i][UE_id] = UE_list->ordered_CCids[j][UE_id];
          UE_list->ordered_CCids[j][UE_id] = tmp;
        }
      }
    }

    /* NN --> RK
     * check the index of UE_template"
     */
    if (UE_list->UE_template[pCCid][UE_id].dl_buffer_total> 0) {
      LOG_D(MAC,"[preprocessor] assign RB for UE %d\n",UE_id);

      for (i=0; i<UE_list->numactiveCCs[UE_id]; i++) {
        CC_id = UE_list->ordered_CCids[i][UE_id];
	eNB_UE_stats[CC_id] = mac_xface->get_eNB_UE_stats(Mod_id,CC_id,rnti);

        if (cqi_to_mcs[flexran_get_ue_wcqi(Mod_id, UE_id)] == 0) {//eNB_UE_stats[CC_id]->dlsch_mcs1==0) {
          nb_rbs_required[CC_id][UE_id] = 4;  // don't let the TBS get too small
        } else {
          nb_rbs_required[CC_id][UE_id] = min_rb_unit[CC_id];
        }

        TBS = mac_xface->get_TBS_DL(cqi_to_mcs[flexran_get_ue_wcqi(Mod_id, UE_id)], nb_rbs_required[CC_id][UE_id]);
	nb_rbs_allowed_slice[CC_id][slice_id] = flexran_nb_rbs_allowed_slice(slice_percentage[slice_id],
									     flexran_get_N_RB_DL(Mod_id, CC_id));
        LOG_D(MAC,"[preprocessor] start RB assignement for UE %d CC_id %d dl buffer %d (RB unit %d, MCS %d, TBS %d) \n",
              UE_id, CC_id, UE_list->UE_template[pCCid][UE_id].dl_buffer_total,
              nb_rbs_required[CC_id][UE_id], flexran_get_ue_wcqi(Mod_id, UE_id), TBS);

        /* calculating required number of RBs for each UE */
        while (TBS < UE_list->UE_template[pCCid][UE_id].dl_buffer_total)  {
          nb_rbs_required[CC_id][UE_id] += min_rb_unit[CC_id];

          if (nb_rbs_required[CC_id][UE_id] > nb_rbs_allowed_slice[CC_id][slice_id]) {
            TBS = mac_xface->get_TBS_DL(cqi_to_mcs[flexran_get_ue_wcqi(Mod_id, UE_id)], nb_rbs_allowed_slice[CC_id][slice_id]);
            nb_rbs_required[CC_id][UE_id] = nb_rbs_allowed_slice[CC_id][slice_id];
            break;
          }

          TBS = mac_xface->get_TBS_DL(cqi_to_mcs[flexran_get_ue_wcqi(Mod_id, UE_id)], nb_rbs_required[CC_id][UE_id]);
        } // end of while

        LOG_D(MAC,"[eNB %d][SLICE %d] Frame %d: UE %d on CC %d: RB unit %d,  nb_required RB %d (TBS %d, mcs %d)\n",
              Mod_id, slice_id,frameP,UE_id, CC_id,  min_rb_unit[CC_id], nb_rbs_required[CC_id][UE_id], TBS, cqi_to_mcs[flexran_get_ue_wcqi(Mod_id, UE_id)]);
      }
    }
  }
}

void _dlsch_scheduler_pre_processor_allocate (module_id_t   Mod_id,
					      int           UE_id,
					      uint8_t       CC_id,
					      int           N_RBG,
					      int           transmission_mode,
					      int           min_rb_unit,
					      uint8_t       N_RB_DL,
					      uint16_t      nb_rbs_required[MAX_NUM_CCs][NUMBER_OF_UE_MAX],
					      uint16_t      nb_rbs_required_remaining[MAX_NUM_CCs][NUMBER_OF_UE_MAX],
					      unsigned char rballoc_sub[MAX_NUM_CCs][N_RBG_MAX],
					      unsigned char MIMO_mode_indicator[MAX_NUM_CCs][N_RBG_MAX]) {
  int i;
  UE_list_t *UE_list=&eNB_mac_inst[Mod_id].UE_list;
  UE_sched_ctrl *ue_sched_ctl = &UE_list->UE_sched_ctrl[UE_id];

  for(i=0; i<N_RBG; i++) {

    if((rballoc_sub[CC_id][i] == 0)           &&
        (ue_sched_ctl->rballoc_sub_UE[CC_id][i] == 0) &&
        (nb_rbs_required_remaining[CC_id][UE_id]>0)   &&
        (ue_sched_ctl->pre_nb_available_rbs[CC_id] < nb_rbs_required[CC_id][UE_id])) {

      // if this UE is not scheduled for TM5
      if (ue_sched_ctl->dl_pow_off[CC_id] != 0 )  {

	if ((i == N_RBG-1) && ((N_RB_DL == 25) || (N_RB_DL == 50))) {
	  rballoc_sub[CC_id][i] = 1;
	  ue_sched_ctl->rballoc_sub_UE[CC_id][i] = 1;
	  MIMO_mode_indicator[CC_id][i] = 1;
	  if (transmission_mode == 5 ) {
	    ue_sched_ctl->dl_pow_off[CC_id] = 1;
	  }   
	  nb_rbs_required_remaining[CC_id][UE_id] = nb_rbs_required_remaining[CC_id][UE_id] - min_rb_unit+1;
          ue_sched_ctl->pre_nb_available_rbs[CC_id] = ue_sched_ctl->pre_nb_available_rbs[CC_id] + min_rb_unit - 1;
        } else {
	  if (nb_rbs_required_remaining[CC_id][UE_id] >=  min_rb_unit){
	    rballoc_sub[CC_id][i] = 1;
	    ue_sched_ctl->rballoc_sub_UE[CC_id][i] = 1;
	    MIMO_mode_indicator[CC_id][i] = 1;
	    if (transmission_mode == 5 ) {
	      ue_sched_ctl->dl_pow_off[CC_id] = 1;
	    }
	    nb_rbs_required_remaining[CC_id][UE_id] = nb_rbs_required_remaining[CC_id][UE_id] - min_rb_unit;
	    ue_sched_ctl->pre_nb_available_rbs[CC_id] = ue_sched_ctl->pre_nb_available_rbs[CC_id] + min_rb_unit;
	  }
	}
      } // dl_pow_off[CC_id][UE_id] ! = 0
    }
  }
}

void _dlsch_scheduler_pre_processor_reset (int module_idP,
					   int UE_id,
					   uint8_t  CC_id,
					   int frameP,
					   int subframeP,					  
					   int N_RBG,
					   uint16_t nb_rbs_required[MAX_NUM_CCs][NUMBER_OF_UE_MAX],
					   uint16_t nb_rbs_required_remaining[MAX_NUM_CCs][NUMBER_OF_UE_MAX],
					   uint16_t nb_rbs_allowed_slice[MAX_NUM_CCs][MAX_NUM_SLICES],
					   unsigned char rballoc_sub[MAX_NUM_CCs][N_RBG_MAX],
					   unsigned char MIMO_mode_indicator[MAX_NUM_CCs][N_RBG_MAX]) {
  int i,j;
  UE_list_t *UE_list=&eNB_mac_inst[module_idP].UE_list;
  UE_sched_ctrl *ue_sched_ctl = &UE_list->UE_sched_ctrl[UE_id];
  uint8_t *vrb_map = eNB_mac_inst[module_idP].common_channels[CC_id].vrb_map;
  int RBGsize = PHY_vars_eNB_g[module_idP][CC_id]->frame_parms.N_RB_DL/N_RBG;
#ifdef SF05_LIMIT
  //int subframe05_limit=0;
  int sf05_upper=-1,sf05_lower=-1;
#endif
  //  LTE_eNB_UE_stats *eNB_UE_stats = mac_xface->get_eNB_UE_stats(module_idP,CC_id,rnti);
  
  flexran_update_TA(module_idP, UE_id, CC_id);

  if (UE_id==0) {
    VCD_SIGNAL_DUMPER_DUMP_VARIABLE_BY_NAME(VCD_SIGNAL_DUMPER_VARIABLES_UE0_TIMING_ADVANCE,ue_sched_ctl->ta_update);
  }
  nb_rbs_required[CC_id][UE_id]=0;
  ue_sched_ctl->pre_nb_available_rbs[CC_id] = 0;
  ue_sched_ctl->dl_pow_off[CC_id] = 2;
  nb_rbs_required_remaining[CC_id][UE_id] = 0;
  for (i=0; i<n_active_slices;i++)
    nb_rbs_allowed_slice[CC_id][i] = 0;
#ifdef SF05_LIMIT  
  switch (N_RBG) {
  case 6:
    sf05_lower=0;
    sf05_upper=5;
    break;
  case 8:
    sf05_lower=2;
    sf05_upper=5;
    break;
  case 13:
    sf05_lower=4;
    sf05_upper=7;
    break;
  case 17:
    sf05_lower=7;
    sf05_upper=9;
    break;
  case 25:
    sf05_lower=11;
    sf05_upper=13;
    break;
  }
#endif
  // Initialize Subbands according to VRB map
  for (i=0; i<N_RBG; i++) {
    ue_sched_ctl->rballoc_sub_UE[CC_id][i] = 0;
    rballoc_sub[CC_id][i] = 0;
#ifdef SF05_LIMIT
    // for avoiding 6+ PRBs around DC in subframe 0-5 (avoid excessive errors)

    if ((subframeP==0 || subframeP==5) && 
	(i>=sf05_lower && i<=sf05_upper))
      rballoc_sub[CC_id][i]=1;
#endif
    // for SI-RNTI,RA-RNTI and P-RNTI allocations
    for (j=0;j<RBGsize;j++) {
      if (vrb_map[j+(i*RBGsize)]!=0)  {
	rballoc_sub[CC_id][i] = 1;
	LOG_D(MAC,"Frame %d, subframe %d : vrb %d allocated\n",frameP,subframeP,j+(i*RBGsize));
	break;
      }
    }
    LOG_D(MAC,"Frame %d Subframe %d CC_id %d RBG %i : rb_alloc %d\n",frameP,subframeP,CC_id,i,rballoc_sub[CC_id][i]);
    MIMO_mode_indicator[CC_id][i] = 2;
  }
}

// This function assigns pre-available RBS to each UE in specified sub-bands before scheduling is done
void _dlsch_scheduler_pre_processor (module_id_t   Mod_id,
				     int      slice_id,
				     frame_t       frameP,
				     sub_frame_t   subframeP,
				     int           N_RBG[MAX_NUM_CCs],
				     int           *mbsfn_flag)
{

  unsigned char rballoc_sub[MAX_NUM_CCs][N_RBG_MAX], total_ue_count;
  unsigned char MIMO_mode_indicator[MAX_NUM_CCs][N_RBG_MAX];
  int                     UE_id, i;
  uint8_t round = 0;
  uint8_t harq_pid = 0;
  uint16_t                ii,j;
  uint16_t                nb_rbs_required[MAX_NUM_CCs][NUMBER_OF_UE_MAX];
  uint16_t                nb_rbs_allowed_slice[MAX_NUM_CCs][MAX_NUM_SLICES];
  uint16_t                nb_rbs_required_remaining[MAX_NUM_CCs][NUMBER_OF_UE_MAX];
  uint16_t                nb_rbs_required_remaining_1[MAX_NUM_CCs][NUMBER_OF_UE_MAX];
  uint16_t                average_rbs_per_user[MAX_NUM_CCs] = {0};
  rnti_t             rnti;
  int                min_rb_unit[MAX_NUM_CCs];
  uint16_t r1=0;
  uint8_t CC_id;
  UE_list_t *UE_list = &eNB_mac_inst[Mod_id].UE_list;
  LTE_DL_FRAME_PARMS   *frame_parms[MAX_NUM_CCs] = {0};

  int transmission_mode = 0;
  UE_sched_ctrl *ue_sched_ctl;
  
  
  for (CC_id=0; CC_id<MAX_NUM_CCs; CC_id++) {
    
    if (mbsfn_flag[CC_id]>0)  // If this CC is allocated for MBSFN skip it here
      continue;
    
    frame_parms[CC_id] = mac_xface->get_lte_frame_parms(Mod_id,CC_id);
    
    
    min_rb_unit[CC_id]=get_min_rb_unit(Mod_id,CC_id);
    
    for (i = 0; i < NUMBER_OF_UE_MAX; i++) {
      if (UE_list->active[i] != TRUE) continue;

      UE_id = i;
      // Initialize scheduling information for all active UEs
      
      //if (flexran_slice_member(UE_id, slice_id) == 0)
      //continue;
      _dlsch_scheduler_pre_processor_reset(Mod_id,
					   UE_id,
					   CC_id,
					   frameP,
					   subframeP,
					   N_RBG[CC_id],
					   nb_rbs_required,
					   nb_rbs_required_remaining,
					   nb_rbs_allowed_slice, 
					   rballoc_sub,
					   MIMO_mode_indicator);

    }
  }
  
  /* Store the DLSCH buffer for each logical channel for each UE */
  _store_dlsch_buffer (Mod_id,slice_id,frameP,subframeP);

  // Calculate the number of RBs required by each UE on the basis of logical channel's buffer
  _assign_rbs_required (Mod_id,slice_id, frameP,subframeP,nb_rbs_required,nb_rbs_allowed_slice,min_rb_unit);

  // Sorts the user on the basis of dlsch logical channel buffer and CQI
  sort_UEs (Mod_id,frameP,subframeP);

  total_ue_count = 0;

  // loop over all active UEs
  for (i=UE_list->head; i>=0; i=UE_list->next[i]) { 
    rnti = flexran_get_ue_crnti(Mod_id, i);
    if(rnti == NOT_A_RNTI)
      continue;
    if (UE_list->UE_sched_ctrl[i].ul_out_of_sync == 1)
      continue;

    UE_id = i;
    
    if (flexran_slice_member(UE_id, slice_id) == 0)
      continue;
    
    if (!phy_stats_exist(Mod_id, rnti))
      continue;

    for (ii=0; ii < UE_num_active_CC(UE_list,UE_id); ii++) {
      CC_id = UE_list->ordered_CCids[ii][UE_id];
      ue_sched_ctl = &UE_list->UE_sched_ctrl[UE_id];
      ue_sched_ctl->max_allowed_rbs[CC_id]=nb_rbs_allowed_slice[CC_id][slice_id];
      flexran_get_harq(Mod_id, CC_id, UE_id, frameP, subframeP, &harq_pid, &round, openair_harq_DL);

      // if there is no available harq_process, skip the UE
      if (UE_list->UE_sched_ctrl[UE_id].harq_pid[CC_id]<0)
        continue;

      average_rbs_per_user[CC_id]=0;

      frame_parms[CC_id] = mac_xface->get_lte_frame_parms(Mod_id,CC_id);

      //      mac_xface->get_ue_active_harq_pid(Mod_id,CC_id,rnti,frameP,subframeP,&harq_pid,&round,0);

      if(round>0) {
        nb_rbs_required[CC_id][UE_id] = UE_list->UE_template[CC_id][UE_id].nb_rb[harq_pid];
      }

      //nb_rbs_required_remaining[UE_id] = nb_rbs_required[UE_id];
      if (nb_rbs_required[CC_id][UE_id] > 0) {
        total_ue_count = total_ue_count + 1;
      }


      // hypotetical assignement
      /*
       * If schedule is enabled and if the priority of the UEs is modified
       * The average rbs per logical channel per user will depend on the level of
       * priority. Concerning the hypothetical assignement, we should assign more
       * rbs to prioritized users. Maybe, we can do a mapping between the
       * average rbs per user and the level of priority or multiply the average rbs
       * per user by a coefficient which represents the degree of priority.
       */

      if (total_ue_count == 0) {
        average_rbs_per_user[CC_id] = 0;
      } else if( (min_rb_unit[CC_id] * total_ue_count) <= nb_rbs_allowed_slice[CC_id][slice_id] ) {
        average_rbs_per_user[CC_id] = (uint16_t) floor(nb_rbs_allowed_slice[CC_id][slice_id]/total_ue_count);
      } else {
        average_rbs_per_user[CC_id] = min_rb_unit[CC_id]; // consider the total number of use that can be scheduled UE
      }
    }
  }

  // note: nb_rbs_required is assigned according to total_buffer_dl
  // extend nb_rbs_required to capture per LCID RB required
  for(i=UE_list->head; i>=0; i=UE_list->next[i]) {
    rnti = UE_RNTI(Mod_id,i);
   
    if(rnti == NOT_A_RNTI)
      continue;

    if (UE_list->UE_sched_ctrl[i].ul_out_of_sync == 1)
      continue;

    if (!phy_stats_exist(Mod_id, rnti))
      continue;

    if (flexran_slice_member(i, slice_id) == 0)
      continue;
    
    for (ii=0; ii<UE_num_active_CC(UE_list,i); ii++) {
      CC_id = UE_list->ordered_CCids[ii][i];

      // control channel
      if (mac_eNB_get_rrc_status(Mod_id,rnti) < RRC_RECONFIGURED) {
        nb_rbs_required_remaining_1[CC_id][i] = nb_rbs_required[CC_id][i];
      } else {
        nb_rbs_required_remaining_1[CC_id][i] = cmin(average_rbs_per_user[CC_id],nb_rbs_required[CC_id][i]);

      }
    }
  }

  //Allocation to UEs is done in 2 rounds,
  // 1st stage: average number of RBs allocated to each UE
  // 2nd stage: remaining RBs are allocated to high priority UEs
  for(r1=0; r1<2; r1++) {

    for(i=UE_list->head; i>=0; i=UE_list->next[i]) {
      
      if (flexran_slice_member(i, slice_id) == 0)
	continue;
      
      for (ii=0; ii<UE_num_active_CC(UE_list,i); ii++) {
        CC_id = UE_list->ordered_CCids[ii][i];

        if(r1 == 0) {
          nb_rbs_required_remaining[CC_id][i] = nb_rbs_required_remaining_1[CC_id][i];
        } else { // rb required based only on the buffer - rb allloctaed in the 1st round + extra reaming rb form the 1st round
          nb_rbs_required_remaining[CC_id][i] = nb_rbs_required[CC_id][i]-nb_rbs_required_remaining_1[CC_id][i]+nb_rbs_required_remaining[CC_id][i];
        }

        if (nb_rbs_required[CC_id][i]> 0 )
          LOG_D(MAC,"round %d : nb_rbs_required_remaining[%d][%d]= %d (remaining_1 %d, required %d,  pre_nb_available_rbs %d, N_RBG %d, rb_unit %d)\n",
                r1, CC_id, i,
                nb_rbs_required_remaining[CC_id][i],
                nb_rbs_required_remaining_1[CC_id][i],
                nb_rbs_required[CC_id][i],
                UE_list->UE_sched_ctrl[i].pre_nb_available_rbs[CC_id],
                N_RBG[CC_id],
                min_rb_unit[CC_id]);

      }
    }

    if (total_ue_count > 0 ) {
      for(i=UE_list->head; i>=0; i=UE_list->next[i]) {
        UE_id = i;
	
	if (flexran_slice_member(UE_id, slice_id) == 0)
	  continue;
        
	for (ii=0; ii<UE_num_active_CC(UE_list,UE_id); ii++) {
          CC_id = UE_list->ordered_CCids[ii][UE_id];
	  ue_sched_ctl = &UE_list->UE_sched_ctrl[UE_id];
	  flexran_get_harq(Mod_id, CC_id, UE_id, frameP, subframeP, &harq_pid, &round, openair_harq_DL);	  
          rnti = UE_RNTI(Mod_id,UE_id);

          // LOG_D(MAC,"UE %d rnti 0x\n", UE_id, rnti );
          if(rnti == NOT_A_RNTI)
            continue;

	  if (UE_list->UE_sched_ctrl[UE_id].ul_out_of_sync == 1)
	    continue;

	  if (!phy_stats_exist(Mod_id, rnti))
            continue;

          transmission_mode = mac_xface->get_transmission_mode(Mod_id,CC_id,rnti);
          //rrc_status = mac_eNB_get_rrc_status(Mod_id,rnti);
          /* 1st allocate for the retx */

          // retransmission in data channels
          // control channel in the 1st transmission
          // data channel for all TM
          LOG_T(MAC,"calling dlsch_scheduler_pre_processor_allocate .. \n ");
          _dlsch_scheduler_pre_processor_allocate (Mod_id,
						   UE_id,
						   CC_id,
						   N_RBG[CC_id],
						   transmission_mode,
						   min_rb_unit[CC_id],
						   frame_parms[CC_id]->N_RB_DL,
						   nb_rbs_required,
						   nb_rbs_required_remaining,
						   rballoc_sub,
						   MIMO_mode_indicator);
        }
      }
    } // total_ue_count
  } // end of for for r1 and r2

  for(i=UE_list->head; i>=0; i=UE_list->next[i]) {
    UE_id = i;
    ue_sched_ctl = &UE_list->UE_sched_ctrl[UE_id];
 
    if (flexran_slice_member(UE_id, slice_id) == 0)
      continue;

    for (ii=0; ii<UE_num_active_CC(UE_list,UE_id); ii++) {
      CC_id = UE_list->ordered_CCids[ii][UE_id];
      //PHY_vars_eNB_g[Mod_id]->mu_mimo_mode[UE_id].dl_pow_off = dl_pow_off[UE_id];

      if (ue_sched_ctl->pre_nb_available_rbs[CC_id] > 0 ) {
        LOG_D(MAC,"******************DL Scheduling Information for UE%d ************************\n",UE_id);
        LOG_D(MAC,"dl power offset UE%d = %d \n",UE_id,ue_sched_ctl->dl_pow_off[CC_id]);
        LOG_D(MAC,"***********RB Alloc for every subband for UE%d ***********\n",UE_id);

        for(j=0; j<N_RBG[CC_id]; j++) {
          //PHY_vars_eNB_g[Mod_id]->mu_mimo_mode[UE_id].rballoc_sub[i] = rballoc_sub_UE[CC_id][UE_id][i];
          LOG_D(MAC,"RB Alloc for UE%d and Subband%d = %d\n",UE_id,j,ue_sched_ctl->rballoc_sub_UE[CC_id][j]);
        }

        //PHY_vars_eNB_g[Mod_id]->mu_mimo_mode[UE_id].pre_nb_available_rbs = pre_nb_available_rbs[CC_id][UE_id];
        LOG_D(MAC,"[eNB %d][SLICE %d] Total RBs allocated for UE%d = %d\n",
	      Mod_id, slice_id, UE_id,ue_sched_ctl->pre_nb_available_rbs[CC_id]);
      }
    }
  }
}

#define SF05_LIMIT 1

/*
 * Main Downlink Slicing
 *
 */

void
flexran_schedule_ue_dl_spec_default(mid_t   mod_id,
				 uint32_t      frame,
				 uint32_t      subframe,
				 int           *mbsfn_flag,
				 Protocol__FlexranMessage **dl_info)
//------------------------------------------------------------------------------
{
  int i=0;
  
  flexran_agent_mac_create_empty_dl_config(mod_id, dl_info);
   
  for (i = 0; i < n_active_slices; i++) {
    
    // Load any updated functions
    if (update_dl_scheduler[i] > 0 ) {
      slice_sched_dl[i] = dlsym(NULL, dl_scheduler_type[i]); 
      update_dl_scheduler[i] = 0;
      update_dl_scheduler_current[i] = 0;
      slice_percentage_current[i]= slice_percentage[i];
      total_slice_percentage+=slice_percentage[i];
      LOG_N(MAC,"update dl scheduler slice %d\n", i);
    }
 
    // check if the number of slices has changed, and log 
    if (n_active_slices_current != n_active_slices ){
      if ((n_active_slices > 0) && (n_active_slices <= MAX_NUM_SLICES)) {
	LOG_N(MAC,"[eNB %d]frame %d subframe %d: number of active slices has changed: %d-->%d\n",
	      mod_id, frame, subframe, n_active_slices_current, n_active_slices);

	n_active_slices_current = n_active_slices;

      } else {
	LOG_W(MAC,"invalid number of slices %d, revert to the previous value %d\n",n_active_slices, n_active_slices_current);
	n_active_slices = n_active_slices_current;
      }
    }
    
    // check if the slice rb share has changed, and log the console
    if (slice_percentage_current[i] != slice_percentage[i]){
 //      if ((slice_percentage[i] >= 0.0) && (slice_percentage[i] <= 1.0)){
	// if ((total_slice_percentage - slice_percentage_current[i]  + slice_percentage[i]) <= 1.0) {
	//   total_slice_percentage=total_slice_percentage - slice_percentage_current[i]  + slice_percentage[i];
	  LOG_N(MAC,"[eNB %d][SLICE %d] frame %d subframe %d: total percentage %f, slice RB percentage has changed: %f-->%f\n",
		mod_id, i, frame, subframe, total_slice_percentage, slice_percentage_current[i], slice_percentage[i]);

	  slice_percentage_current[i] = slice_percentage[i];

	// } else {
	//   LOG_W(MAC,"[eNB %d][SLICE %d] invalid total RB share (%f->%f), revert the previous value (%f->%f)\n",
	// 	mod_id,i,  
	// 	total_slice_percentage,
	// 	total_slice_percentage - slice_percentage_current[i]  + slice_percentage[i],
	// 	slice_percentage[i],slice_percentage_current[i]);

	//   slice_percentage[i]= slice_percentage_current[i];

	// }
 //      } else {
	// LOG_W(MAC,"[eNB %d][SLICE %d] invalid slice RB share, revert the previous value (%f->%f)\n",mod_id, i,  slice_percentage[i],slice_percentage_current[i]);

	// slice_percentage[i]= slice_percentage_current[i];

      // }
    }
  
    // check if the slice max MCS, and log the console
    if (slice_maxmcs_current[i] != slice_maxmcs[i]){
      if ((slice_maxmcs[i] >= 0) && (slice_maxmcs[i] < 29)){
	LOG_N(MAC,"[eNB %d][SLICE %d] frame %d subframe %d: slice MAX MCS has changed: %d-->%d\n",
	      mod_id, i, frame, subframe, slice_maxmcs_current[i], slice_maxmcs[i]);

	slice_maxmcs_current[i] = slice_maxmcs[i];

      } else {
	LOG_W(MAC,"[eNB %d][SLICE %d] invalid slice max mcs %d, revert the previous value %d\n",mod_id, i,  slice_percentage[i],slice_percentage[i]);

	slice_maxmcs[i]= slice_maxmcs_current[i];

      }
    }
    
    // check if a new scheduler, and log the console
    if (update_dl_scheduler_current[i] != update_dl_scheduler[i]){
      LOG_N(MAC,"[eNB %d][SLICE %d] frame %d subframe %d: DL scheduler for this slice is updated: %s \n",
	    mod_id, i, frame, subframe, dl_scheduler_type[i]);

      update_dl_scheduler_current[i] = update_dl_scheduler[i];
      
    }

    // Run each enabled slice-specific schedulers one by one
    //LOG_N(MAC,"[eNB %d]frame %d subframe %d slice %d: calling the scheduler\n", mod_id, frame, subframe,i);
    slice_sched_dl[i](mod_id, i, frame, subframe, mbsfn_flag,dl_info);

  }
  
}

uint16_t flexran_nb_rbs_allowed_slice(float rb_percentage, int total_rbs){
  return  (uint16_t) floor(rb_percentage * total_rbs); 
}

int flexran_slice_maxmcs(int slice_id) {
  return slice_maxmcs[slice_id];
}

int flexran_slice_member(int UE_id, int slice_id){
  // group membership definition
  int slice_member = 0 ;
  
  if ((slice_id < 0) || (slice_id > n_active_slices))
    LOG_W(MAC,"out of range slice id %d\n",slice_id);

  switch (slicing_strategy) {
  case SLICE_MASK:
    switch (slice_id){
    case 0:
      if (SLICE0_MASK&UE_id){
	slice_member=1;
      }
      break;
    case 1:
      if (SLICE1_MASK&UE_id){
	slice_member=1;
      }
      break;
    case 2:
      if (SLICE2_MASK&UE_id){
	slice_member=1;
      }
       break;
    case 3:
      if (SLICE3_MASK&UE_id){
	slice_member=1;
      }
      break;
    default :
      LOG_W(MAC,"unknown slice_id %d\n", slice_id);
      break;
      
    }
    break;
  case UEID_TO_SLICEID:
  default:
    if ((UE_id % n_active_slices) == slice_id){
      slice_member= 1; // this ue is a member of this slice
    }
    break;
  }
  
  return slice_member;
}
/* more aggressive rb and mcs allocation with medium priority and the traffic qci */
void
flexran_schedule_ue_spec_embb(mid_t         mod_id,
			      int           slice_id, 
			      uint32_t      frame,
			      uint32_t      subframe,
			      int           *mbsfn_flag,
			      Protocol__FlexranMessage **dl_info)

{
  flexran_schedule_ue_dl_spec_common(mod_id,
				  slice_id,
				  frame,
				  subframe,
				  mbsfn_flag,
				  dl_info);
  
}
/* more conservative mcs allocation with high priority and the traffic qci */
void
flexran_schedule_ue_spec_urllc(mid_t         mod_id,
			       int           slice_id, 
			       uint32_t      frame,
			       uint32_t      subframe,
			       int           *mbsfn_flag,
			       Protocol__FlexranMessage **dl_info)

{
  flexran_schedule_ue_dl_spec_common(mod_id,
				  slice_id,
				  frame,
				  subframe,
				  mbsfn_flag,
				  dl_info);
  
}
/* constant rb allocation with low mcs with low priority and given the UE capabilities */
void
flexran_schedule_ue_spec_mmtc(mid_t         mod_id,
			      int           slice_id, 
			      uint32_t      frame,
			      uint32_t      subframe,
			      int           *mbsfn_flag,
			      Protocol__FlexranMessage **dl_info)
  
{
  
  flexran_schedule_ue_dl_spec_common(mod_id,
				  slice_id,
				  frame,
				  subframe,
				  mbsfn_flag,
				  dl_info);
  
}
/* regular rb and mcs allocation with low priority */
void
flexran_schedule_ue_spec_be(mid_t         mod_id,
			    int           slice_id, 
			    uint32_t      frame,
			    uint32_t      subframe,
			    int           *mbsfn_flag,
			    Protocol__FlexranMessage **dl_info)
  
{
  
  flexran_schedule_ue_dl_spec_common(mod_id,
				  slice_id,
				  frame,
				  subframe,
				  mbsfn_flag,
				  dl_info);
  
}

//------------------------------------------------------------------------------
void
flexran_schedule_ue_dl_spec_common(mid_t   mod_id,
				int           slice_id, 
				uint32_t      frame,
				uint32_t      subframe,
				int           *mbsfn_flag,
				Protocol__FlexranMessage **dl_info)
//------------------------------------------------------------------------------
{
  uint8_t               CC_id;
  int                   UE_id;
  int                   N_RBG[MAX_NUM_CCs];
  unsigned char         aggregation;
  mac_rlc_status_resp_t rlc_status;
  unsigned char         header_len = 0, header_len_last = 0, ta_len = 0;
  uint16_t              nb_rb, nb_rb_temp, total_nb_available_rb[MAX_NUM_CCs], nb_available_rb;
  uint16_t              TBS, j, rnti;
  uint8_t         round            = 0;
  uint8_t         harq_pid         = 0;
  uint16_t              sdu_length_total = 0;
  int                   mcs, mcs_tmp;
  uint16_t              min_rb_unit[MAX_NUM_CCs];
  eNB_MAC_INST         *eNB      = &eNB_mac_inst[mod_id];
  /* TODO: Must move the helper structs to scheduler implementation */
  UE_list_t            *UE_list  = &eNB->UE_list;
  int32_t                 normalized_rx_power, target_rx_power;
  int32_t                 tpc = 1;
  static int32_t          tpc_accumulated=0;
  UE_sched_ctrl           *ue_sched_ctl;
  LTE_eNB_UE_stats     *eNB_UE_stats     = NULL;
  Protocol__FlexDlData *dl_data[NUM_MAX_UE];
  int num_ues_added = 0;
  int channels_added = 0;

  Protocol__FlexDlDci *dl_dci;
  Protocol__FlexRlcPdu *rlc_pdus[11];
  uint32_t ce_flags = 0;

  uint8_t            rballoc_sub[25];
  int i;
  uint32_t data_to_request;
  uint32_t dci_tbs;
  uint8_t ue_has_transmission = 0;
  uint32_t ndi;
  
#if 0
  
  if (UE_list->head==-1) {
    return;
  }
  
#endif

  start_meas(&eNB->schedule_dlsch);
  VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME(VCD_SIGNAL_DUMPER_FUNCTIONS_SCHEDULE_DLSCH,VCD_FUNCTION_IN);

  //weight = get_ue_weight(module_idP,UE_id);
  aggregation = 1; // set to the maximum aggregation level

  for (CC_id=0; CC_id<MAX_NUM_CCs; CC_id++) {
    min_rb_unit[CC_id] = get_min_rb_unit(mod_id, CC_id);
    // get number of PRBs less those used by common channels
    total_nb_available_rb[CC_id] = flexran_get_N_RB_DL(mod_id, CC_id);
    for (i=0;i < flexran_get_N_RB_DL(mod_id, CC_id); i++)
      if (eNB->common_channels[CC_id].vrb_map[i] != 0)
	total_nb_available_rb[CC_id]--;
    
    N_RBG[CC_id] = flexran_get_N_RBG(mod_id, CC_id);

    // store the global enb stats:
    eNB->eNB_stats[CC_id].num_dlactive_UEs =  UE_list->num_UEs;
    eNB->eNB_stats[CC_id].available_prbs =  total_nb_available_rb[CC_id];
    eNB->eNB_stats[CC_id].total_available_prbs +=  total_nb_available_rb[CC_id];
    eNB->eNB_stats[CC_id].dlsch_bytes_tx=0;
    eNB->eNB_stats[CC_id].dlsch_pdus_tx=0;
  }

   VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME(VCD_SIGNAL_DUMPER_FUNCTIONS_DLSCH_PREPROCESSOR,VCD_FUNCTION_IN);

   start_meas(&eNB->schedule_dlsch_preprocessor);
   _dlsch_scheduler_pre_processor(mod_id,
				  slice_id,
				  frame,
				  subframe,
				  N_RBG,
				  mbsfn_flag);
   stop_meas(&eNB->schedule_dlsch_preprocessor);
   VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME(VCD_SIGNAL_DUMPER_FUNCTIONS_DLSCH_PREPROCESSOR,VCD_FUNCTION_OUT);

   for (CC_id=0; CC_id<MAX_NUM_CCs; CC_id++) {
    LOG_D(MAC, "doing schedule_ue_spec for CC_id %d\n",CC_id);

    if (mbsfn_flag[CC_id]>0)
      continue;
    
    for (UE_id=UE_list->head; UE_id>=0; UE_id=UE_list->next[UE_id]) {
  
      rnti = flexran_get_ue_crnti(mod_id, UE_id);
      eNB_UE_stats = mac_xface->get_eNB_UE_stats(mod_id,CC_id,rnti);
      ue_sched_ctl = &UE_list->UE_sched_ctrl[UE_id];
      
      if (eNB_UE_stats==NULL) {

        	LOG_D(MAC,"[eNB] Cannot find eNB_UE_stats\n");
                //  mac_xface->macphy_exit("[MAC][eNB] Cannot find eNB_UE_stats\n");
        	continue;
      }
      
      if (flexran_slice_member(UE_id, slice_id) == 0)
      	continue;
      
      if (rnti==NOT_A_RNTI) {
        LOG_D(MAC,"Cannot find rnti for UE_id %d (num_UEs %d)\n", UE_id,UE_list->num_UEs);
        // mac_xface->macphy_exit("Cannot find rnti for UE_id");
        continue;
      }

      switch(mac_xface->get_transmission_mode(mod_id,CC_id,rnti)){
      case 1:
      case 2:
      case 7:
        	aggregation = get_aggregation(get_bw_index(mod_id,CC_id), 
				      eNB_UE_stats->DL_cqi[0],
				      format1);
      	break;
      case 3:
        	aggregation = get_aggregation(get_bw_index(mod_id,CC_id), 
				      eNB_UE_stats->DL_cqi[0],
				      format2A);
      	break;
      default:
        	LOG_W(MAC,"Unsupported transmission mode %d\n", mac_xface->get_transmission_mode(mod_id,CC_id,rnti));
        	aggregation = 2;
      }
     
      if ((ue_sched_ctl->pre_nb_available_rbs[CC_id] == 0) ||  // no RBs allocated 
	  CCE_allocation_infeasible(mod_id, CC_id, 0, subframe, aggregation, rnti)) {

            LOG_D(MAC,"[eNB %d] Frame %d : no RB allocated for UE %d on CC_id %d: continue \n",
                  mod_id, frame, UE_id, CC_id);
            //if(mac_xface->get_transmission_mode(module_idP,rnti)==5)
            continue; //to next user (there might be rbs availiable for other UEs in TM5
            // else
            //  break;
      }

      if (flexran_get_duplex_mode(mod_id, CC_id) == PROTOCOL__FLEX_DUPLEX_MODE__FLDM_TDD)  {
        set_ue_dai (subframe,
                    flexran_get_subframe_assignment(mod_id, CC_id),
                    UE_id,
                    CC_id,
                    UE_list);
        //TODO: update UL DAI after DLSCH scheduling
        //set_ul_DAI(mod_id, UE_id, CC_id, frame, subframe,frame_parms);
      }

      channels_added = 0;

      // After this point all the UEs will be scheduled
      dl_data[num_ues_added] = (Protocol__FlexDlData *) malloc(sizeof(Protocol__FlexDlData));
      protocol__flex_dl_data__init(dl_data[num_ues_added]);
      dl_data[num_ues_added]->has_rnti = 1;
      dl_data[num_ues_added]->rnti = rnti;
      dl_data[num_ues_added]->n_rlc_pdu = 0;
      dl_data[num_ues_added]->has_serv_cell_index = 1;
      dl_data[num_ues_added]->serv_cell_index = CC_id;
            
      flexran_get_harq(mod_id, CC_id, UE_id, frame, subframe, &harq_pid, &round, openair_harq_DL);
      sdu_length_total=0;
      mcs = cqi_to_mcs[flexran_get_ue_wcqi(mod_id, UE_id)];
      //      LOG_I(FLEXRAN_AGENT, "The MCS is %d\n", mcs);
      mcs = cmin(mcs,flexran_slice_maxmcs(slice_id));
// #ifdef EXMIMO

//        if (mac_xface->get_transmission_mode(mod_id, CC_id, rnti) == 5) {
// 	  mcs = cqi_to_mcs[flexran_get_ue_wcqi(mod_id, UE_id)];
// 	  mcs =  cmin(mcs,16);
//        }

// #endif

      /*Get pre available resource blocks based on buffers*/ 
      nb_available_rb = ue_sched_ctl->pre_nb_available_rbs[CC_id];
      // initializing the rb allocation indicator for each UE
       for(j = 0; j < flexran_get_N_RBG(mod_id, CC_id); j++) {

          UE_list->UE_template[CC_id][UE_id].rballoc_subband[harq_pid][j] = 0;
        	rballoc_sub[j] = 0;
      }

      /* LOG_D(MAC,"[eNB %d] Frame %d: Scheduling UE %d on CC_id %d (rnti %x, harq_pid %d, round %d, rb %d, cqi %d, mcs %d, rrc %d)\n", */
      /*       mod_id, frame, UE_id, CC_id, rnti, harq_pid, round, nb_available_rb, */
      /*       eNB_UE_stats->DL_cqi[0], mcs, */
      /*       UE_list->eNB_UE_stats[CC_id][UE_id].rrc_status); */

      dl_dci = (Protocol__FlexDlDci*) malloc(sizeof(Protocol__FlexDlDci));
      protocol__flex_dl_dci__init(dl_dci);
      dl_data[num_ues_added]->dl_dci = dl_dci;

      
      dl_dci->has_rnti = 1;
      dl_dci->rnti = rnti;
      dl_dci->has_harq_process = 1;
      dl_dci->harq_process = harq_pid;
      
      /* process retransmission  */
      if (round > 0) {

      	LOG_D(FLEXRAN_AGENT, "There was a retransmission just now and the round was %d\n", round);

      	if (flexran_get_duplex_mode(mod_id, CC_id) == PROTOCOL__FLEX_DUPLEX_MODE__FLDM_TDD) {
      	  UE_list->UE_template[CC_id][UE_id].DAI++;
      	  update_ul_dci(mod_id, CC_id, rnti, UE_list->UE_template[CC_id][UE_id].DAI);
      	  LOG_D(MAC,"DAI update: CC_id %d subframeP %d: UE %d, DAI %d\n",
      		CC_id, subframe,UE_id,UE_list->UE_template[CC_id][UE_id].DAI);
      	}

      	mcs = UE_list->UE_template[CC_id][UE_id].mcs[harq_pid];

      	  // get freq_allocation
      	nb_rb = UE_list->UE_template[CC_id][UE_id].nb_rb[harq_pid];
      	  
      	/*TODO: Must add this to FlexRAN agent API */
      	dci_tbs = mac_xface->get_TBS_DL(mcs, nb_rb);

      	if (nb_rb <= nb_available_rb) {
      	  
      	  if(nb_rb == ue_sched_ctl->pre_nb_available_rbs[CC_id]) {
      	    for(j = 0; j < flexran_get_N_RBG(mod_id, CC_id); j++) { // for indicating the rballoc for each sub-band
      	      UE_list->UE_template[CC_id][UE_id].rballoc_subband[harq_pid][j] = ue_sched_ctl->rballoc_sub_UE[CC_id][j];
                  }
      	  } else {
      	    nb_rb_temp = nb_rb;
      	    j = 0;

      	    while((nb_rb_temp > 0) && (j < flexran_get_N_RBG(mod_id, CC_id))) {
      	      if(ue_sched_ctl->rballoc_sub_UE[CC_id][j] == 1) {
      		UE_list->UE_template[CC_id][UE_id].rballoc_subband[harq_pid][j] = ue_sched_ctl->rballoc_sub_UE[CC_id][j];
      		
      		if((j == flexran_get_N_RBG(mod_id, CC_id) - 1) &&
      		   ((flexran_get_N_RB_DL(mod_id, CC_id) == 25)||
      		    (flexran_get_N_RB_DL(mod_id, CC_id) == 50))) {
      		  nb_rb_temp = nb_rb_temp - min_rb_unit[CC_id]+1;
      		} else {
      		  nb_rb_temp = nb_rb_temp - min_rb_unit[CC_id];
      		}
      	      }
      	      j = j + 1;
      	    }
      	  }

      	  nb_available_rb -= nb_rb;
      	  PHY_vars_eNB_g[mod_id][CC_id]->mu_mimo_mode[UE_id].pre_nb_available_rbs = nb_rb;
      	  PHY_vars_eNB_g[mod_id][CC_id]->mu_mimo_mode[UE_id].dl_pow_off = ue_sched_ctl->dl_pow_off[CC_id];
      	  
      	  for(j=0; j < flexran_get_N_RBG(mod_id, CC_id); j++) {
      	    PHY_vars_eNB_g[mod_id][CC_id]->mu_mimo_mode[UE_id].rballoc_sub[j] = UE_list->UE_template[CC_id][UE_id].rballoc_subband[harq_pid][j];
      	    rballoc_sub[j] = UE_list->UE_template[CC_id][UE_id].rballoc_subband[harq_pid][j];
      	  }

      	  // Keep the old NDI, do not toggle
      	  ndi = UE_list->UE_template[CC_id][UE_id].oldNDI[harq_pid];
      	  tpc = UE_list->UE_template[CC_id][UE_id].oldTPC[harq_pid];
      	  UE_list->UE_template[CC_id][UE_id].mcs[harq_pid] = mcs;

      	  ue_has_transmission = 1;
      	  num_ues_added++;
      	} else {
      	  LOG_D(MAC,"[eNB %d] Frame %d CC_id %d : don't schedule UE %d, its retransmission takes more resources than we have\n",
                      mod_id, frame, CC_id, UE_id);
      	  ue_has_transmission = 0;
      	}
      	//End of retransmission
      }

       else { /* This is a potentially new SDU opportunity */
	rlc_status.bytes_in_buffer = 0;
        // Now check RLC information to compute number of required RBs
        // get maximum TBS size for RLC request
        //TBS = mac_xface->get_TBS(eNB_UE_stats->DL_cqi[0]<<1,nb_available_rb);
        TBS = mac_xface->