srsRAN_4G/srsenb/src/mac/scheduler_ue.cc

/**
 *
 * \section COPYRIGHT
 *
 * Copyright 2013-2017 Software Radio Systems Limited
 *
 * \section LICENSE
 *
 * This file is part of srsLTE.
 *
 * srsUE is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * srsUE is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * A copy of the GNU Affero General Public License can be found in
 * the LICENSE file in the top-level directory of this distribution
 * and at http://www.gnu.org/licenses/.
 *
 */

#include <string.h>

#include "srslte/srslte.h"
#include "srslte/common/pdu.h"
#include "srsenb/hdr/mac/scheduler_ue.h"
#include "srsenb/hdr/mac/scheduler.h"

#define Error(fmt, ...)   log_h->error(fmt, ##__VA_ARGS__)
#define Warning(fmt, ...) log_h->warning(fmt, ##__VA_ARGS__)
#define Info(fmt, ...)    log_h->info(fmt, ##__VA_ARGS__)
#define Debug(fmt, ...)   log_h->debug(fmt, ##__VA_ARGS__)

#define MCS_FIRST_DL 4

/****************************************************** 
 *                  UE class                          *
 ******************************************************/

namespace srsenb {


/*******************************************************
 * 
 * Initialization and configuration functions 
 * 
 *******************************************************/

sched_ue::sched_ue() : dl_next_alloc(NULL), ul_next_alloc(NULL), has_pucch(false), power_headroom(0), rnti(0), max_mcs_dl(0), max_mcs_ul(0),
                       fixed_mcs_ul(0), fixed_mcs_dl(0), phy_config_dedicated_enabled(false)
{
  log_h = NULL;

  bzero(&cell, sizeof(cell));
  bzero(&lch, sizeof(lch));
  bzero(&dci_locations, sizeof(dci_locations));
  bzero(&dl_harq, sizeof(dl_harq));
  bzero(&ul_harq, sizeof(ul_harq));

  pthread_mutex_init(&mutex, NULL);
  reset();
}

sched_ue::~sched_ue() {
  pthread_mutex_lock(&mutex);
  pthread_mutex_unlock(&mutex);
  pthread_mutex_destroy(&mutex);
}

void sched_ue::set_cfg(uint16_t rnti_, sched_interface::ue_cfg_t *cfg_, sched_interface::cell_cfg_t *cell_cfg, 
                            srslte_regs_t *regs, srslte::log *log_h_) 
{
  reset();

  pthread_mutex_lock(&mutex);
  rnti  = rnti_;
  log_h = log_h_; 
  memcpy(&cell, &cell_cfg->cell, sizeof(srslte_cell_t));
  P = srslte_ra_type0_P(cell.nof_prb);

  max_mcs_dl = 28; 
  max_mcs_ul = 28; 

  if (cfg_) {
    memcpy(&cfg, cfg_, sizeof(sched_interface::ue_cfg_t));
  }
  
  Info("SCHED: Added user rnti=0x%x\n", rnti);
  // Config HARQ processes
  for (int i=0;i<SCHED_MAX_HARQ_PROC;i++) {
    dl_harq[i].config(i, cfg.maxharq_tx, log_h); 
    ul_harq[i].config(i, cfg.maxharq_tx, log_h);
  }
  
  // Generate allowed CCE locations   
  for (int cfi=0;cfi<3;cfi++) {
    for (int sf_idx=0;sf_idx<10;sf_idx++) {
      sched::generate_cce_location(regs, &dci_locations[cfi][sf_idx], cfi+1, sf_idx, rnti);
    }
  }

  pthread_mutex_unlock(&mutex);

  for (int i=0;i<sched_interface::MAX_LC;i++) {
    set_bearer_cfg(i, &cfg.ue_bearers[i]);
  }

}

void sched_ue::reset()
{
  pthread_mutex_lock(&mutex);
  bzero(&cfg, sizeof(sched_interface::ue_cfg_t));
  sr = false;
  next_tpc_pusch = 1;
  next_tpc_pucch = 1; 
  buf_mac = 0; 
  buf_ul  = 0;
  phy_config_dedicated_enabled = false;
  dl_cqi = 1;
  ul_cqi = 1;
  dl_cqi_tti = 0;
  ul_cqi_tti = 0;
  dl_ri = 0;
  dl_ri_tti = 0;
  dl_pmi = 0;
  dl_pmi_tti = 0;
  cqi_request_tti = 0;
  for (int i=0;i<SCHED_MAX_HARQ_PROC;i++) {
    for(uint32_t tb = 0; tb < SRSLTE_MAX_TB; tb++) {
      dl_harq[i].reset(tb);
      ul_harq[i].reset(tb);
    }
  }
  pthread_mutex_unlock(&mutex);

  for (int i=0;i<sched_interface::MAX_LC; i++) {
    rem_bearer(i);
  }
}

void sched_ue::set_fixed_mcs(int mcs_ul, int mcs_dl) {
  pthread_mutex_lock(&mutex);
  fixed_mcs_ul = mcs_ul;
  fixed_mcs_dl = mcs_dl;
  pthread_mutex_unlock(&mutex);
}

void sched_ue::set_max_mcs(int mcs_ul, int mcs_dl) {
  pthread_mutex_lock(&mutex);
  if (mcs_ul < 0) {
    max_mcs_ul = 28;     
  } else {
    max_mcs_ul = mcs_ul;     
  }
  if (mcs_dl < 0) {
    max_mcs_dl = 28;     
  } else {
    max_mcs_dl = mcs_dl;     
  }
  pthread_mutex_unlock(&mutex);
}


/*******************************************************
 * 
 * FAPI-like main scheduler interface. 
 * 
 *******************************************************/

void sched_ue::set_bearer_cfg(uint32_t lc_id, sched_interface::ue_bearer_cfg_t* cfg)
{
  pthread_mutex_lock(&mutex);
  if (lc_id < sched_interface::MAX_LC) {
    memcpy(&lch[lc_id].cfg, cfg, sizeof(sched_interface::ue_bearer_cfg_t));
    lch[lc_id].buf_tx = 0; 
    lch[lc_id].buf_retx = 0; 
    if (lch[lc_id].cfg.direction != sched_interface::ue_bearer_cfg_t::IDLE) {
      Info("SCHED: Set bearer config lc_id=%d, direction=%d\n", lc_id, (int) lch[lc_id].cfg.direction);
    }
  }
  pthread_mutex_unlock(&mutex);
}

void sched_ue::rem_bearer(uint32_t lc_id)
{
  pthread_mutex_lock(&mutex);
  if (lc_id < sched_interface::MAX_LC) {
    bzero(&lch[lc_id], sizeof(ue_bearer_t));
  }
  pthread_mutex_unlock(&mutex);
}

void sched_ue::phy_config_enabled(uint32_t tti, bool enabled)
{
  dl_cqi_tti = tti; 
  phy_config_dedicated_enabled = enabled; 
}

void sched_ue::ul_buffer_state(uint8_t lc_id, uint32_t bsr, bool set_value)
{
  pthread_mutex_lock(&mutex);
  if (lc_id < sched_interface::MAX_LC) {
    if (set_value) {
      lch[lc_id].bsr = bsr;
    } else {
      lch[lc_id].bsr += bsr;
    }
  }
  Debug("SCHED: bsr=%d, lcid=%d, bsr={%d,%d,%d,%d}\n", bsr, lc_id,
       lch[0].bsr, lch[1].bsr, lch[2].bsr, lch[3].bsr);
  pthread_mutex_unlock(&mutex);
}

void sched_ue::ul_phr(int phr)
{ 
  power_headroom = phr;
}

void sched_ue::dl_buffer_state(uint8_t lc_id, uint32_t tx_queue, uint32_t retx_queue)
{
  pthread_mutex_lock(&mutex);
  if (lc_id < sched_interface::MAX_LC) {
    lch[lc_id].buf_retx = retx_queue;
    lch[lc_id].buf_tx   = tx_queue;
    Debug("SCHED: DL lcid=%d buffer_state=%d,%d\n", lc_id, tx_queue, retx_queue);
  }
  pthread_mutex_unlock(&mutex);
}

void sched_ue::mac_buffer_state(uint32_t ce_code)
{
  pthread_mutex_lock(&mutex);
  buf_mac++;
  pthread_mutex_unlock(&mutex);
}

void sched_ue::set_sr()
{
  sr = true; 
}

void sched_ue::unset_sr()
{
  sr = false; 
}

bool sched_ue::pucch_sr_collision(uint32_t current_tti, uint32_t n_cce)
{
  bool ret = false;
  pthread_mutex_lock(&mutex);

  uint32_t n_pucch_sr, n_pucch_nosr;
  srslte_pucch_sched_t pucch_sched;
  bool has_sr;

  if (!phy_config_dedicated_enabled) {
    goto unlock;
  }
  pucch_sched.sps_enabled = false;
  pucch_sched.n_pucch_sr = cfg.sr_N_pucch;
  pucch_sched.n_pucch_2  = cfg.n_pucch_cqi;
  pucch_sched.N_pucch_1  = cfg.pucch_cfg.n1_pucch_an; 

  has_sr = cfg.sr_enabled && srslte_ue_ul_sr_send_tti(cfg.sr_I, current_tti);
  if (!has_sr) {
    goto unlock;
  }
  n_pucch_sr = srslte_pucch_get_npucch(n_cce, SRSLTE_PUCCH_FORMAT_1A, true, &pucch_sched);
  n_pucch_nosr = srslte_pucch_get_npucch(n_cce, SRSLTE_PUCCH_FORMAT_1A, false, &pucch_sched);

  if (srslte_pucch_n_prb(&cfg.pucch_cfg, SRSLTE_PUCCH_FORMAT_1A, n_pucch_sr, cell.nof_prb, cell.cp, 0) == 
      srslte_pucch_n_prb(&cfg.pucch_cfg, SRSLTE_PUCCH_FORMAT_1A, n_pucch_nosr, cell.nof_prb, cell.cp, 0)) 
  {
    ret = true;
  } else {
    ret = false;
  }

unlock:
  pthread_mutex_unlock(&mutex);
  return ret;
}

bool sched_ue::get_pucch_sched(uint32_t current_tti, uint32_t prb_idx[2])
{
  bool ret = false;
  bool has_sr;

  pthread_mutex_lock(&mutex);

  if (!phy_config_dedicated_enabled) {
    goto unlock;
  }

  srslte_pucch_sched_t pucch_sched;
  pucch_sched.sps_enabled = false;
  pucch_sched.n_pucch_sr = cfg.sr_N_pucch;
  pucch_sched.n_pucch_2  = cfg.n_pucch_cqi;
  pucch_sched.N_pucch_1  = cfg.pucch_cfg.n1_pucch_an;
  
  has_sr = cfg.sr_enabled && srslte_ue_ul_sr_send_tti(cfg.sr_I, current_tti);
  
  // First check if it has pending ACKs 
  for (int i=0;i<SCHED_MAX_HARQ_PROC;i++) {
    if (TTI_TX(dl_harq[i].get_tti()) == current_tti) {
      uint32_t n_pucch = srslte_pucch_get_npucch(dl_harq[i].get_n_cce(), SRSLTE_PUCCH_FORMAT_1A, has_sr, &pucch_sched);
      if (prb_idx) {
        for (int  j=0;j<2;j++) {
          prb_idx[j] = srslte_pucch_n_prb(&cfg.pucch_cfg, SRSLTE_PUCCH_FORMAT_1A, n_pucch, cell.nof_prb, cell.cp, j);
        }
        Debug("SCHED: Reserved Format1A PUCCH for rnti=0x%x, n_prb=%d,%d, n_pucch=%d, ncce=%d, has_sr=%d, n_pucch_1=%d\n",
              rnti, prb_idx[0], prb_idx[1], n_pucch, dl_harq[i].get_n_cce(), has_sr, pucch_sched.N_pucch_1);
      }
      ret = true;
      goto unlock;
    }
  }
  // If there is no Format1A/B, then check if it's expecting Format1
  if (has_sr) {
    if (prb_idx) {        
      for (int i=0;i<2;i++) {
        prb_idx[i] = srslte_pucch_n_prb(&cfg.pucch_cfg, SRSLTE_PUCCH_FORMAT_1, cfg.sr_N_pucch, cell.nof_prb, cell.cp, i); 
      }
    }
    Debug("SCHED: Reserved Format1 PUCCH for rnti=0x%x, n_prb=%d,%d, n_pucch=%d\n", rnti, prb_idx[0], prb_idx[1], cfg.sr_N_pucch);
    ret = true;
    goto unlock;
  }
  // Finally check Format2 (periodic CQI)
  if (cfg.cqi_enabled && srslte_cqi_send(cfg.cqi_idx, current_tti)) {
    if (prb_idx) {
      for (int i=0;i<2;i++) {
        prb_idx[i] = srslte_pucch_n_prb(&cfg.pucch_cfg, SRSLTE_PUCCH_FORMAT_2, cfg.cqi_pucch, cell.nof_prb, cell.cp, i);
      }
      Debug("SCHED: Reserved Format2 PUCCH for rnti=0x%x, n_prb=%d,%d, n_pucch=%d, pmi_idx=%d\n",
            rnti, prb_idx[0], prb_idx[1], cfg.cqi_pucch, cfg.cqi_idx);
    }
    ret = true;
    goto unlock;
  }

  ret = false;
unlock:
  pthread_mutex_unlock(&mutex);
  return ret;
}

int sched_ue::set_ack_info(uint32_t tti, uint32_t tb_idx, bool ack)
{
  pthread_mutex_lock(&mutex);
  int ret = -1;
  for (int i=0;i<SCHED_MAX_HARQ_PROC;i++) {
    if (TTI_TX(dl_harq[i].get_tti()) == tti) {
      Debug("SCHED: Set ACK=%d for rnti=0x%x, pid=%d.%d, tti=%d\n", ack, rnti, i, tb_idx, tti);
      dl_harq[i].set_ack(tb_idx, ack);
      ret = dl_harq[i].get_tbs(tb_idx);
      goto unlock;
    }
  }

  Warning("SCHED: Received ACK info for unknown TTI=%d\n", tti);
  ret = -1;

unlock:
  pthread_mutex_unlock(&mutex);
  return ret;
}

void sched_ue::ul_recv_len(uint32_t lcid, uint32_t len)
{
  pthread_mutex_lock(&mutex);

  // Remove PDCP header??
  if (len > 4) {
    len -= 4; 
  }
  if (lcid < sched_interface::MAX_LC) {
    if (bearer_is_ul(&lch[lcid])) {
      if (lch[lcid].bsr > (int) len) {
        lch[lcid].bsr -= len;
      } else {
        lch[lcid].bsr = 0;
      }
    }
  }
  Debug("SCHED: recv_len=%d, lcid=%d, bsr={%d,%d,%d,%d}\n", len, lcid,
       lch[0].bsr, lch[1].bsr, lch[2].bsr, lch[3].bsr);

  pthread_mutex_unlock(&mutex);
}

void sched_ue::set_ul_crc(uint32_t tti, bool crc_res)
{
  pthread_mutex_lock(&mutex);
  get_ul_harq(tti)->set_ack(0, crc_res);
  pthread_mutex_unlock(&mutex);
}

void sched_ue::set_dl_ri(uint32_t tti, uint32_t ri)
{
  pthread_mutex_lock(&mutex);
  dl_ri     = ri;
  dl_ri_tti = tti;
  pthread_mutex_unlock(&mutex);
}

void sched_ue::set_dl_pmi(uint32_t tti, uint32_t pmi)
{
  pthread_mutex_lock(&mutex);
  dl_pmi     = pmi;
  dl_pmi_tti = tti;
  pthread_mutex_unlock(&mutex);
}

void sched_ue::set_dl_cqi(uint32_t tti, uint32_t cqi)
{
  pthread_mutex_lock(&mutex);
  dl_cqi     = cqi;
  dl_cqi_tti = tti;
  pthread_mutex_unlock(&mutex);
}

void sched_ue::set_dl_ant_info(asn1::rrc::phys_cfg_ded_s::ant_info_c_* d)
{
  pthread_mutex_lock(&mutex);
  dl_ant_info = *d;
  pthread_mutex_unlock(&mutex);
}

void sched_ue::set_ul_cqi(uint32_t tti, uint32_t cqi, uint32_t ul_ch_code)
{
  pthread_mutex_lock(&mutex);
  ul_cqi     = cqi;
  ul_cqi_tti = tti;
  pthread_mutex_unlock(&mutex);
}

void sched_ue::tpc_inc() {
  pthread_mutex_lock(&mutex);
  if (power_headroom > 0) {
    next_tpc_pusch = 3;
    next_tpc_pucch = 3;    
  }
  log_h->info("SCHED: Set TCP=%d for rnti=0x%x\n", next_tpc_pucch, rnti);
  pthread_mutex_unlock(&mutex);
}

void sched_ue::tpc_dec() {
  pthread_mutex_lock(&mutex);
  next_tpc_pusch = 0;
  next_tpc_pucch = 0;
  log_h->info("SCHED: Set TCP=%d for rnti=0x%x\n", next_tpc_pucch, rnti);
  pthread_mutex_unlock(&mutex);
}

/*******************************************************
 * 
 * Functions used to generate DCI grants 
 * 
 *******************************************************/


// Generates a Format1 grant 
int sched_ue::generate_format1(dl_harq_proc *h,
                         sched_interface::dl_sched_data_t *data,
                         uint32_t tti,
                         uint32_t cfi)
{
  pthread_mutex_lock(&mutex);

  srslte_ra_dl_dci_t *dci = &data->dci;
  bzero(dci, sizeof(srslte_ra_dl_dci_t));
  
  uint32_t sf_idx = tti%10; 
  
  int mcs = 0; 
  int tbs = 0; 
  
  dci->alloc_type = SRSLTE_RA_ALLOC_TYPE0; 
  dci->type0_alloc.rbg_bitmask = h->get_rbgmask();
  
  
  // If this is the first transmission for this UE, make room for MAC Contention Resolution ID
  bool need_conres_ce = false; 
  if (is_first_dl_tx()) {
    need_conres_ce = true; 
  }
  if (h->is_empty(0)) {

    uint32_t req_bytes = get_pending_dl_new_data_unlocked(tti);
    
    uint32_t nof_prb = format1_count_prb(h->get_rbgmask(), cell.nof_prb);  
    srslte_ra_dl_grant_t grant; 
    srslte_ra_dl_dci_to_grant_prb_allocation(dci, &grant, cell.nof_prb);
    uint32_t nof_ctrl_symbols = cfi+(cell.nof_prb<10?1:0);
    uint32_t nof_re = srslte_ra_dl_grant_nof_re(&grant, cell, sf_idx, nof_ctrl_symbols);
    if (need_conres_ce and cell.nof_prb < 10) { // SRB0 Tx. Use a higher MCS for the PRACH to fit in 6 PRBs
      tbs = srslte_ra_tbs_from_idx(srslte_ra_dl_tbs_idx_from_mcs(MCS_FIRST_DL), nof_prb) / 8;
      mcs = MCS_FIRST_DL;
    } else if (fixed_mcs_dl < 0) {
      tbs = alloc_tbs_dl(nof_prb, nof_re, req_bytes, &mcs);
    } else {
      tbs = srslte_ra_tbs_from_idx(srslte_ra_dl_tbs_idx_from_mcs(fixed_mcs_dl), nof_prb) / 8;
      mcs = fixed_mcs_dl; 
    }

    h->new_tx(0, tti, mcs, tbs, data->dci_location.ncce);

    // Allocate MAC ConRes CE
    if (need_conres_ce) {
      data->pdu[0][0].lcid = srslte::sch_subh::CON_RES_ID;
      data->nof_pdu_elems[0]++;
      Info("SCHED: Added MAC Contention Resolution CE for rnti=0x%x\n", rnti);
    }

    int rem_tbs = tbs;
    int x = 0;
    do {
      x = alloc_pdu(rem_tbs, &data->pdu[0][data->nof_pdu_elems[0]]);
      rem_tbs -= x;
      if (x) {
        data->nof_pdu_elems[0]++;
      }
    } while(rem_tbs > 0 && x > 0);

    Debug("SCHED: Alloc format1 new mcs=%d, tbs=%d, nof_prb=%d, req_bytes=%d\n", mcs, tbs, nof_prb, req_bytes);
  } else {
    h->new_retx(0, tti, &mcs, &tbs);
    Debug("SCHED: Alloc format1 previous mcs=%d, tbs=%d\n", mcs, tbs);
  }

  data->rnti    = rnti;

  if (tbs > 0) {
    dci->harq_process = h->get_id(); 
    dci->mcs_idx      = (uint32_t) mcs;
    dci->rv_idx       = sched::get_rvidx(h->nof_retx(0));
    dci->ndi          = h->get_ndi(0);
    dci->tpc_pucch    = (uint8_t) next_tpc_pucch;
    next_tpc_pucch    = 1; 
    data->tbs[0]      = (uint32_t) tbs;
    data->tbs[1]      = 0;
    dci->tb_en[0]     = true;
    dci->tb_en[1]     = false; 
  }
  pthread_mutex_unlock(&mutex);
  return tbs;
}

// Generates a Format2a grant
int sched_ue::generate_format2a(dl_harq_proc *h,
                         sched_interface::dl_sched_data_t *data,
                         uint32_t tti,
                         uint32_t cfi)
{
  pthread_mutex_lock(&mutex);
  int ret = generate_format2a_unlocked(h, data, tti, cfi);
  pthread_mutex_unlock(&mutex);
  return ret;
}

// Generates a Format2a grant
int sched_ue::generate_format2a_unlocked(dl_harq_proc *h,
                                       sched_interface::dl_sched_data_t *data,
                                       uint32_t tti,
                                       uint32_t cfi)
{
  bool tb_en[SRSLTE_MAX_TB] = {false};

  srslte_ra_dl_dci_t *dci = &data->dci;
  bzero(dci, sizeof(srslte_ra_dl_dci_t));

  uint32_t sf_idx = tti%10;

  dci->alloc_type = SRSLTE_RA_ALLOC_TYPE0;
  dci->type0_alloc.rbg_bitmask = h->get_rbgmask();

  uint32_t nof_prb = format1_count_prb(h->get_rbgmask(), cell.nof_prb);
  uint32_t nof_ctrl_symbols = cfi + (cell.nof_prb < 10 ? 1 : 0);
  srslte_ra_dl_grant_t grant;
  srslte_ra_dl_dci_to_grant_prb_allocation(dci, &grant, cell.nof_prb);
  uint32_t nof_re = srslte_ra_dl_grant_nof_re(&grant, cell, sf_idx, nof_ctrl_symbols);
  bool no_retx = true;

  if (dl_ri == 0) {
    if (h->is_empty(1)) {
      /* One layer, tb1 buffer is empty, send tb0 only */
      tb_en[0] = true;
    } else {
      /* One layer, tb1 buffer is not empty, send tb1 only */
      tb_en[1] = true;
    }
  } else {
    /* Two layers, retransmit what TBs that have not been Acknowledged */
    for (uint32_t tb = 0; tb < SRSLTE_MAX_TB; tb++) {
      if (!h->is_empty(tb)) {
        tb_en[tb] = true;
        no_retx = false;
      }
    }
    /* Two layers, no retransmissions...  */
    if (no_retx) {
      tb_en[0] = true;
      tb_en[1] = true;
    }
  }

  for (uint32_t tb = 0; tb < SRSLTE_MAX_TB; tb++) {
    uint32_t req_bytes = get_pending_dl_new_data_unlocked(tti);
    int mcs = 0;
    int tbs = 0;

    if (!h->is_empty(tb)) {
      h->new_retx(tb, tti, &mcs, &tbs);
      Debug("SCHED: Alloc format2/2a previous mcs=%d, tbs=%d\n", mcs, tbs);
    } else if (tb_en[tb] && req_bytes && no_retx) {
      if (fixed_mcs_dl < 0) {
        tbs = alloc_tbs_dl(nof_prb, nof_re, req_bytes, &mcs);
      } else {
        tbs = srslte_ra_tbs_from_idx((uint32_t)srslte_ra_dl_tbs_idx_from_mcs((uint32_t)fixed_mcs_dl), nof_prb) / 8;
        mcs = fixed_mcs_dl;
      }
      h->new_tx(tb, tti, mcs, tbs, data->dci_location.ncce);

      int rem_tbs = tbs;
      int x = 0;
      do {
        x = alloc_pdu(rem_tbs, &data->pdu[tb][data->nof_pdu_elems[tb]]);
        rem_tbs -= x;
        if (x) {
          data->nof_pdu_elems[tb]++;
        }
      } while (rem_tbs > 0 && x > 0);

      Debug("SCHED: Alloc format2/2a new mcs=%d, tbs=%d, nof_prb=%d, req_bytes=%d\n", mcs, tbs, nof_prb, req_bytes);
    }

    /* Fill DCI TB dedicated fields */
    if (tbs > 0) {
      if (tb == 0) {
        dci->mcs_idx = (uint32_t) mcs;
        dci->rv_idx = sched::get_rvidx(h->nof_retx(tb));
        dci->ndi = h->get_ndi(tb);
      } else {
        dci->mcs_idx_1 = (uint32_t) mcs;
        dci->rv_idx_1 = sched::get_rvidx(h->nof_retx(tb));
        dci->ndi_1 = h->get_ndi(tb);
      }
      data->tbs[tb] = (uint32_t) tbs;
      dci->tb_en[tb] = true;
    } else {
      data->tbs[tb] = 0;
      dci->tb_en[tb] = false;
    }
  }

  /* Fill common fields */
  data->rnti = rnti;
  dci->harq_process = h->get_id();
  dci->tpc_pucch = (uint8_t) next_tpc_pucch;
  next_tpc_pucch = 1;

  int ret = data->tbs[0] + data->tbs[1];
  return ret;
}


// Generates a Format2 grant
int sched_ue::generate_format2(dl_harq_proc *h,
                         sched_interface::dl_sched_data_t *data,
                         uint32_t tti,
                         uint32_t cfi)
{

  pthread_mutex_lock(&mutex);

  /* Call Format 2a (common) */
  int ret = generate_format2a_unlocked(h, data, tti, cfi);

  /* Compute precoding information */
  if (SRSLTE_RA_DL_GRANT_NOF_TB(&data->dci) == 1) {
    data->dci.pinfo = (uint8_t) (dl_pmi + 1) % (uint8_t) 5;
  } else {
    data->dci.pinfo = (uint8_t) (dl_pmi & 1);
  }

  pthread_mutex_unlock(&mutex);

  return ret;
}


int sched_ue::generate_format0(ul_harq_proc *h,
                         sched_interface::ul_sched_data_t *data, 
                         uint32_t tti,
                         bool cqi_request) 
{
  pthread_mutex_lock(&mutex);

  srslte_ra_ul_dci_t *dci = &data->dci;
  bzero(dci, sizeof(srslte_ra_ul_dci_t));
  
  int mcs = 0;   
  int tbs = 0; 
  
  ul_harq_proc::ul_alloc_t allocation = h->get_alloc();
  
  bool is_newtx = true;
  if (h->get_rar_mcs(&mcs)) {
    tbs = srslte_ra_tbs_from_idx(srslte_ra_ul_tbs_idx_from_mcs(mcs), allocation.L) / 8;
    h->new_tx(tti, mcs, tbs); 
  } else if (h->is_empty(0)) {
    
    uint32_t req_bytes = get_pending_ul_new_data_unlocked(tti);
    
    uint32_t N_srs = 0; 
    uint32_t nof_re = (2*(SRSLTE_CP_NSYMB(cell.cp)-1) - N_srs)*allocation.L*SRSLTE_NRE;
    if (fixed_mcs_ul < 0) {
      tbs = alloc_tbs_ul(allocation.L, nof_re, req_bytes, &mcs);
    } else {
      tbs = srslte_ra_tbs_from_idx(srslte_ra_ul_tbs_idx_from_mcs(fixed_mcs_ul), allocation.L) / 8;
      mcs = fixed_mcs_ul;
    }
    
    h->new_tx(tti, mcs, tbs);  

  } else {    
    h->new_retx(0, tti, &mcs, NULL);
    is_newtx = false;
    tbs      = srslte_ra_tbs_from_idx(srslte_ra_ul_tbs_idx_from_mcs(mcs), allocation.L) / 8;
  }
  
  data->rnti = rnti; 
  data->tbs  = tbs; 
  
  if (tbs > 0) {
    dci->type2_alloc.L_crb = allocation.L;
    dci->type2_alloc.RB_start = allocation.RB_start;
    dci->rv_idx      = sched::get_rvidx(h->nof_retx(0));
    if (!is_newtx && h->is_adaptive_retx()) {
      dci->mcs_idx     = 28+dci->rv_idx;
    } else {
      dci->mcs_idx     = mcs;
    }
    dci->ndi         = h->get_ndi(0);
    dci->cqi_request = cqi_request; 
    dci->freq_hop_fl = srslte_ra_ul_dci_t::SRSLTE_RA_PUSCH_HOP_DISABLED; 
    dci->tpc_pusch   = next_tpc_pusch; 
    next_tpc_pusch   = 1; 
  }

  pthread_mutex_unlock(&mutex);

  return tbs;
}

/*******************************************************
 * 
 * Functions used by scheduler or scheduler metric objects
 * 
 *******************************************************/

bool sched_ue::bearer_is_ul(ue_bearer_t *lch) {
  return lch->cfg.direction == sched_interface::ue_bearer_cfg_t::UL || lch->cfg.direction == sched_interface::ue_bearer_cfg_t::BOTH;
}

bool sched_ue::bearer_is_dl(ue_bearer_t *lch) {
  return lch->cfg.direction == sched_interface::ue_bearer_cfg_t::DL || lch->cfg.direction == sched_interface::ue_bearer_cfg_t::BOTH;
}

uint32_t sched_ue::get_max_retx() {
  return cfg.maxharq_tx; 
}

bool sched_ue::is_first_dl_tx()
{
  for (int i=0;i<SCHED_MAX_HARQ_PROC;i++) {
    if (dl_harq[i].nof_tx(0) > 0) {
      return false; 
    }
  }
  return true; 
}

bool sched_ue::needs_cqi(uint32_t tti, bool will_be_sent)
{
  pthread_mutex_lock(&mutex);
  bool ret = needs_cqi_unlocked(tti, will_be_sent);
  pthread_mutex_unlock(&mutex);
  return ret;
}

// Private lock-free implemenentation
bool sched_ue::needs_cqi_unlocked(uint32_t tti, bool will_be_sent)
{
  bool ret = false;
  if (phy_config_dedicated_enabled &&
      cfg.aperiodic_cqi_period     &&
      get_pending_dl_new_data_unlocked(tti) > 0)
  {
    uint32_t interval = srslte_tti_interval(tti, dl_cqi_tti);
    bool needscqi = interval >= cfg.aperiodic_cqi_period;
    if (needscqi) {
      uint32_t interval_sent = srslte_tti_interval(tti, cqi_request_tti);
      if (interval_sent >= 16) {
        if (will_be_sent) {
          cqi_request_tti = tti;
        }
        Debug("SCHED: Needs_cqi, last_sent=%d, will_be_sent=%d\n", cqi_request_tti, will_be_sent);
        ret = true;
      }
    }
  }
  return ret;
}

uint32_t sched_ue::get_pending_dl_new_data(uint32_t tti)
{
  pthread_mutex_lock(&mutex);
  uint32_t pending_data = get_pending_dl_new_data_unlocked(tti);
  pthread_mutex_unlock(&mutex);
  return pending_data;
}

/// Use this function in the dl-metric to get the bytes to be scheduled. It accounts for the UE data,
/// the RAR resources, and headers
/// \param tti
/// \return number of bytes to be allocated
uint32_t sched_ue::get_pending_dl_new_data_total(uint32_t tti)
{
  pthread_mutex_lock(&mutex);
  uint32_t req_bytes = get_pending_dl_new_data_unlocked(tti);
  if(req_bytes>0) {
    req_bytes += (req_bytes < 128) ? 2 : 3; // consider the header
    if(is_first_dl_tx()) {
      req_bytes += 6; // count for RAR
    }
  }
  pthread_mutex_unlock(&mutex);
  return req_bytes;
}

// Private lock-free implementation
uint32_t sched_ue::get_pending_dl_new_data_unlocked(uint32_t tti)
{
  uint32_t pending_data = 0;
  for (int i=0;i<sched_interface::MAX_LC;i++) {
    if (bearer_is_dl(&lch[i])) {
      pending_data += lch[i].buf_retx + lch[i].buf_tx;
    }
  }
  return pending_data;
}

uint32_t sched_ue::get_pending_ul_new_data(uint32_t tti)
{
  pthread_mutex_lock(&mutex);
  uint32_t pending_data = get_pending_ul_new_data_unlocked(tti);
  pthread_mutex_unlock(&mutex);
  return pending_data;
}

uint32_t sched_ue::get_pending_ul_old_data()
{
  pthread_mutex_lock(&mutex);
  uint32_t pending_data = get_pending_ul_old_data_unlocked();
  pthread_mutex_unlock(&mutex);
  return pending_data;
}

// Private lock-free implementation
uint32_t sched_ue::get_pending_ul_new_data_unlocked(uint32_t tti)
{
  uint32_t pending_data = 0;
  for (int i=0;i<sched_interface::MAX_LC;i++) {
    if (bearer_is_ul(&lch[i])) {
      pending_data += lch[i].bsr;
    }
  }
  if (!pending_data && is_sr_triggered()) {
    return 512;
  }
  if (!pending_data && needs_cqi_unlocked(tti)) {
    return 128;
  }
  uint32_t pending_ul_data = get_pending_ul_old_data_unlocked();
  if (pending_data > pending_ul_data) {
    pending_data -= pending_ul_data;
  } else {
    pending_data = 0;
  }
  if (pending_data) {
    Debug("SCHED: pending_data=%d, pending_ul_data=%d, bsr={%d,%d,%d,%d}\n", pending_data,pending_ul_data,
          lch[0].bsr, lch[1].bsr, lch[2].bsr, lch[3].bsr);
  }
  return pending_data;
}

// Private lock-free implementation
uint32_t sched_ue::get_pending_ul_old_data_unlocked()
{
  uint32_t pending_data = 0;
  for (int i=0;i<SCHED_MAX_HARQ_PROC;i++) {
    pending_data += ul_harq[i].get_pending_data();
  }
  return pending_data;
}

uint32_t sched_ue::prb_to_rbg(uint32_t nof_prb)
{
  return (uint32_t) ceil((float) nof_prb / P);
}

uint32_t sched_ue::rgb_to_prb(uint32_t nof_rbg)
{
  return P*nof_rbg;
}

uint32_t sched_ue::get_required_prb_dl(uint32_t req_bytes, uint32_t nof_ctrl_symbols)
{
  pthread_mutex_lock(&mutex);

  int mcs = 0;
  uint32_t nof_re = 0;
  int tbs = 0;

  uint32_t nbytes = 0;
  uint32_t n;
  for (n=0; n < cell.nof_prb && nbytes < req_bytes; ++n) {
    nof_re = srslte_ra_dl_approx_nof_re(cell, n+1, nof_ctrl_symbols);
    if (is_first_dl_tx() && cell.nof_prb < 10) {
      tbs = srslte_ra_tbs_from_idx(srslte_ra_dl_tbs_idx_from_mcs(MCS_FIRST_DL), n + 1) / 8;
      Info("get_required_prb: req_bytes=%d, tbs=%d, nof_prb=%d\n", req_bytes, tbs, n);
    } else if (fixed_mcs_dl < 0) {
      tbs = alloc_tbs_dl(n+1, nof_re, 0, &mcs);
    } else {
      tbs = srslte_ra_tbs_from_idx(srslte_ra_dl_tbs_idx_from_mcs(fixed_mcs_dl), n + 1) / 8;
    }
    if (tbs > 0) {
      nbytes = tbs;
    } else if (tbs < 0) {
      pthread_mutex_unlock(&mutex);
      return 0;
    }
  }

  pthread_mutex_unlock(&mutex);
  return n;
}

uint32_t sched_ue::get_required_prb_ul(uint32_t req_bytes) 
{
  int mcs = 0; 
  int tbs = 0; 
  uint32_t nbytes = 0; 
  uint32_t N_srs = 0;

  uint32_t n = 0;
  if (req_bytes == 0) {
    return 0; 
  }

  pthread_mutex_lock(&mutex);

  for (n=1;n<cell.nof_prb && nbytes < req_bytes + 4;n++) {
    uint32_t nof_re = (2*(SRSLTE_CP_NSYMB(cell.cp)-1) - N_srs)*n*SRSLTE_NRE;
    int tbs = 0; 
    if (fixed_mcs_ul < 0) {
      tbs = alloc_tbs_ul(n, nof_re, 0, &mcs);
    } else {
      tbs = srslte_ra_tbs_from_idx(srslte_ra_ul_tbs_idx_from_mcs(fixed_mcs_ul), n) / 8;
    }
    if (tbs > 0) {
      nbytes = tbs; 
    }
  }

  while (!srslte_dft_precoding_valid_prb(n) && n<=cell.nof_prb) {
    n++;
  }

  pthread_mutex_unlock(&mutex);

  return n; 
}

bool sched_ue::is_sr_triggered()
{
  return sr; 
}

void sched_ue::reset_timeout_dl_harq(uint32_t tti) {
  for (int i=0;i<SCHED_MAX_HARQ_PROC;i++) {
    if (!(dl_harq[i].is_empty(0) && dl_harq[i].is_empty(1))) {
      if (srslte_tti_interval(tti, dl_harq[i].get_tti()) > 50) {
        log_h->info("SCHED: pid=%d is old. tti_pid=%d, now is %d, resetting\n", i, dl_harq[i].get_tti(), tti);
        dl_harq[i].reset(0);
        dl_harq[i].reset(1);
      }
    }
  }
}

/* Gets HARQ process with oldest pending retx */
dl_harq_proc* sched_ue::get_pending_dl_harq(uint32_t tti)
{
#if ASYNC_DL_SCHED

  pthread_mutex_lock(&mutex);

  int oldest_idx=-1;
  uint32_t oldest_tti = 0; 
  for (int i=0;i<SCHED_MAX_HARQ_PROC;i++) {
    if (dl_harq[i].has_pending_retx(0, tti) || dl_harq[i].has_pending_retx(1, tti)) {
      uint32_t x = srslte_tti_interval(tti, dl_harq[i].get_tti()); 
      if (x > oldest_tti) {
        oldest_idx = i; 
        oldest_tti = x; 
      }
    }
  }
  dl_harq_proc *h = NULL;
  if (oldest_idx >= 0) {
    h = &dl_harq[oldest_idx];
  }

  pthread_mutex_unlock(&mutex);

  return h;

#else
  return &dl_harq[tti%SCHED_MAX_HARQ_PROC];
#endif
}

dl_harq_proc* sched_ue::get_empty_dl_harq()
{
  pthread_mutex_lock(&mutex);

  dl_harq_proc *h = NULL;
  for (int i=0;i<SCHED_MAX_HARQ_PROC && !h;i++) {
    if (dl_harq[i].is_empty(0) && dl_harq[i].is_empty(1)) {
      h = &dl_harq[i];
    }
  }
  pthread_mutex_unlock(&mutex);
  return h;
}

ul_harq_proc* sched_ue::get_ul_harq(uint32_t tti)
{
  return &ul_harq[tti%SCHED_MAX_HARQ_PROC];
}

srslte_dci_format_t sched_ue::get_dci_format() {
  srslte_dci_format_t ret = SRSLTE_DCI_FORMAT1;

  if (phy_config_dedicated_enabled) {
    /* FIXME: Assumes UE-Specific Search Space (Not common) */
    switch (dl_ant_info.explicit_value().tx_mode) {
      case asn1::rrc::ant_info_ded_s::tx_mode_e_::tm1:
      case asn1::rrc::ant_info_ded_s::tx_mode_e_::tm2:
        ret = SRSLTE_DCI_FORMAT1;
        break;
      case asn1::rrc::ant_info_ded_s::tx_mode_e_::tm3:
        ret = SRSLTE_DCI_FORMAT2A;
        break;
      case asn1::rrc::ant_info_ded_s::tx_mode_e_::tm4:
        ret = SRSLTE_DCI_FORMAT2;
        break;
      case asn1::rrc::ant_info_ded_s::tx_mode_e_::tm5:
      case asn1::rrc::ant_info_ded_s::tx_mode_e_::tm6:
      case asn1::rrc::ant_info_ded_s::tx_mode_e_::tm7:
      case asn1::rrc::ant_info_ded_s::tx_mode_e_::tm8_v920:
      default:
        Warning("Incorrect transmission mode (rnti=%04x)\n", rnti);
    }
  }

  return ret;
}


/* Find lowest DCI aggregation level supported by the UE spectral efficiency */
uint32_t sched_ue::get_aggr_level(uint32_t nof_bits)
{
  pthread_mutex_lock(&mutex);
  uint32_t l=0;
  float max_coderate = srslte_cqi_to_coderate(dl_cqi);
  float coderate = 99;
  float factor=1.5;
  uint32_t l_max = 3;
  if (cell.nof_prb == 6) {
    factor = 1.0;
    l_max  = 2;
  }
  do {
    coderate = srslte_pdcch_coderate(nof_bits, l);
    l++;
  } while(l<l_max && factor*coderate > max_coderate);
  Debug("SCHED: CQI=%d, l=%d, nof_bits=%d, coderate=%.2f, max_coderate=%.2f\n", dl_cqi, l, nof_bits, coderate, max_coderate);
  pthread_mutex_unlock(&mutex);
  return l;
}

sched_ue::sched_dci_cce_t* sched_ue::get_locations(uint32_t cfi, uint32_t sf_idx)
{
  if (cfi > 0 && cfi <= 3) {
    return &dci_locations[cfi-1][sf_idx];
  } else {
    Error("SCHED: Invalid CFI=%d\n", cfi);
    return &dci_locations[0][sf_idx]; 
  }    
}

/* Allocates first available RLC PDU */
int sched_ue::alloc_pdu(int tbs_bytes, sched_interface::dl_sched_pdu_t* pdu)
{
  // TODO: Implement lcid priority (now lowest index is lowest priority)
  int x = 0; 
  int i = 0; 
  for (i=0;i<sched_interface::MAX_LC && !x;i++) {
    if (lch[i].buf_retx) {
      x = SRSLTE_MIN(lch[i].buf_retx, tbs_bytes);
      lch[i].buf_retx -= x; 
    } else if (lch[i].buf_tx) {
      x = SRSLTE_MIN(lch[i].buf_tx, tbs_bytes);
      lch[i].buf_tx -= x; 
    }
  }
  if (x) {
    pdu->lcid   = i-1; 
    pdu->nbytes = x;  
    Debug("SCHED: Allocated lcid=%d, nbytes=%d, tbs_bytes=%d\n", pdu->lcid, pdu->nbytes, tbs_bytes);
  }
  return x;
}

uint32_t sched_ue::format1_count_prb(uint32_t bitmask, uint32_t cell_nof_prb) {
  uint32_t P = srslte_ra_type0_P(cell_nof_prb);
  uint32_t nb = (int) ceilf((float) cell_nof_prb / P);
  
  uint32_t nof_prb = 0;   
  for (uint32_t i = 0; i < nb; i++) {
    if (bitmask & (1 << (nb - i - 1))) {
      for (uint32_t j = 0; j < P; j++) {
        if (i*P+j < cell_nof_prb) {
          nof_prb++;
        }
      }
    }
  }
  return nof_prb; 
}

int sched_ue::cqi_to_tbs(uint32_t cqi, uint32_t nof_prb, uint32_t nof_re, uint32_t max_mcs, uint32_t max_Qm, bool is_ul,
                         uint32_t* mcs)
{
  float max_coderate = srslte_cqi_to_coderate(cqi);
  int sel_mcs = max_mcs+1; 
  float coderate = 99;
  float eff_coderate = 99;
  uint32_t Qm = 1;
  int tbs = 0; 

  do {
    sel_mcs--;
    uint32_t tbs_idx = (is_ul) ? srslte_ra_ul_tbs_idx_from_mcs(sel_mcs) : srslte_ra_dl_tbs_idx_from_mcs(sel_mcs);
    tbs = srslte_ra_tbs_from_idx(tbs_idx, nof_prb);
    coderate = srslte_coderate(tbs, nof_re);
    srslte_mod_t mod = (is_ul) ? srslte_ra_ul_mod_from_mcs(sel_mcs) : srslte_ra_dl_mod_from_mcs(sel_mcs);
    Qm               = SRSLTE_MIN(max_Qm, srslte_mod_bits_x_symbol(mod));
    eff_coderate = coderate/Qm;
  } while((sel_mcs > 0 && coderate > max_coderate) || eff_coderate > 0.930);
  if (mcs) {
    *mcs = (uint32_t) sel_mcs; 
  }
  return tbs; 
}

int sched_ue::alloc_tbs_dl(uint32_t nof_prb,
                        uint32_t nof_re,
                        uint32_t req_bytes,
                        int *mcs)
{
  return alloc_tbs(nof_prb, nof_re, req_bytes, false, mcs);
}

int sched_ue::alloc_tbs_ul(uint32_t nof_prb,
                           uint32_t nof_re,
                           uint32_t req_bytes,
                           int *mcs)
{
  return alloc_tbs(nof_prb, nof_re, req_bytes, true, mcs);
}

  /* In this scheduler we tend to use all the available bandwidth and select the MCS
 * that approximates the minimum between the capacity and the requested rate 
 */
int sched_ue::alloc_tbs(uint32_t nof_prb,
                        uint32_t nof_re,
                        uint32_t req_bytes,
                        bool is_ul,
                        int *mcs)
{
  uint32_t sel_mcs = 0;

  uint32_t cqi     = is_ul?ul_cqi:dl_cqi;
  uint32_t max_mcs = is_ul?max_mcs_ul:max_mcs_dl;
  uint32_t max_Qm  = is_ul?4:6; // Allow 16-QAM in PUSCH Only

  // TODO: Compute real spectral efficiency based on PUSCH-UCI configuration
  int tbs = cqi_to_tbs(cqi, nof_prb, nof_re, max_mcs, max_Qm, is_ul, &sel_mcs) / 8;

  /* If less bytes are requested, lower the MCS */
  if (tbs > (int) req_bytes && req_bytes > 0) {
    int req_tbs_idx = srslte_ra_tbs_to_table_idx(req_bytes * 8, nof_prb);
    int req_mcs     = (is_ul) ? srslte_ra_ul_mcs_from_tbs_idx(req_tbs_idx) : srslte_ra_dl_mcs_from_tbs_idx(req_tbs_idx);

    if (req_mcs < sel_mcs) {
      sel_mcs = req_mcs;
      tbs = srslte_ra_tbs_from_idx(req_tbs_idx, nof_prb)/8;
    }
  }
  // Avoid the unusual case n_prb=1, mcs=6 tbs=328 (used in voip)
  if (nof_prb == 1 && sel_mcs == 6) {
    sel_mcs--;
    uint32_t tbs_idx = (is_ul) ? srslte_ra_ul_tbs_idx_from_mcs(sel_mcs) : srslte_ra_dl_tbs_idx_from_mcs(sel_mcs);
    tbs              = srslte_ra_tbs_from_idx(tbs_idx, nof_prb) / 8;
  }

  if (mcs && tbs >= 0) {
    *mcs = (int) sel_mcs; 
  }
       
  return tbs; 
}


}