srsLTE/lte/phy/lib/phch/src/uci.c

/**
 *
 * \section COPYRIGHT
 *
 * Copyright 2013-2014 The libLTE Developers. See the
 * COPYRIGHT file at the top-level directory of this distribution.
 *
 * \section LICENSE
 *
 * This file is part of the libLTE library.
 *
 * libLTE is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * libLTE 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 Lesser General Public License for more details.
 *
 * A copy of the GNU Lesser 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 <stdint.h>
#include <stdio.h>
#include <string.h>
#include <strings.h>
#include <stdlib.h>
#include <stdbool.h>
#include <assert.h>
#include <math.h>

#include "liblte/phy/phch/uci.h"
#include "liblte/phy/phch/harq.h"
#include "liblte/phy/fec/convcoder.h"
#include "liblte/phy/fec/crc.h"
#include "liblte/phy/fec/rm_conv.h"
#include "liblte/phy/common/phy_common.h"
#include "liblte/phy/utils/vector.h"
#include "liblte/phy/utils/debug.h"

/* Table 5.2.2.6.4-1: Basis sequence for (32, O) code */
static uint8_t M_basis_seq[32][11]={
                                    {1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1 },
                                    {1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1 },
                                    {1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1 },
                                    {1, 0, 1, 1, 0, 0, 0, 0, 1, 0, 1 },
                                    {1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1 },
                                    {1, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1 },
                                    {1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1 },
                                    {1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1 },
                                    {1, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1 },
                                    {1, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1 },
                                    {1, 0, 1, 0, 0, 1, 1, 1, 0, 1, 1 },
                                    {1, 1, 1, 0, 0, 1, 1, 0, 1, 0, 1 },
                                    {1, 0, 0, 1, 0, 1, 0, 1, 1, 1, 1 },
                                    {1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1 },
                                    {1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1 },
                                    {1, 1, 0, 0, 1, 1, 1, 1, 0, 1, 1 },
                                    {1, 1, 1, 0, 1, 1, 1, 0, 0, 1, 0 },
                                    {1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0 },
                                    {1, 1, 0, 1, 1, 1, 1, 1, 0, 0, 0 },
                                    {1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0 },
                                    {1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1 },
                                    {1, 1, 0, 1, 0, 0, 0, 0, 0, 1, 1 },
                                    {1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 1 },
                                    {1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 1 },
                                    {1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0 },
                                    {1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1 },
                                    {1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0 },
                                    {1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0 },
                                    {1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0 },
                                    {1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0 },
                                    {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 },
                                    {1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
                                    };

int uci_cqi_init(uci_cqi_t *q) {
  if (crc_init(&q->crc, LTE_CRC8, 8)) {
    return LIBLTE_ERROR;
  }
  return LIBLTE_SUCCESS;
}

void uci_cqi_free(uci_cqi_t *q) {
  
}

static uint32_t Q_prime_cqi(uint32_t O, float beta, uint32_t Q_prime_ri, harq_t *harq_process) {
  uint32_t M_sc = harq_process->prb_alloc.slot[0].nof_prb * RE_X_RB;
  
  uint32_t K = harq_process->cb_segm.C1*harq_process->cb_segm.K1 + 
    harq_process->cb_segm.C2*harq_process->cb_segm.K2;
    
  uint32_t Q_prime = 0;
  if (K > 0) {
    uint32_t M_sc_init = harq_process->nof_prb_pusch_init * RE_X_RB;
    uint32_t L = (O<11)?0:8;
    uint32_t x = (uint32_t) ceilf((float) (O+L)*M_sc_init*harq_process->N_symb_ul*beta/K);

    Q_prime = MIN(x, M_sc * harq_process->N_symb_ul - Q_prime_ri);    
  } else {
    Q_prime = 12*harq_process->prb_alloc.slot[0].nof_prb*RE_X_RB - Q_prime_ri;
  }

  return Q_prime; 
}

/* Encode UCI CQI/PMI for payloads equal or lower to 11 bits (Sec 5.2.2.6.4)
 */
int encode_cqi_short(uci_cqi_t *q, uint8_t *data, uint32_t nof_bits, uint8_t *q_bits, uint32_t Q)
{
  if (nof_bits          < MAX_CQI_LEN &&
      q                 != NULL       &&
      data              != NULL       &&
      q_bits            != NULL) 
  {
    for (int i=0;i<32;i++) {
      q->encoded_cqi[i] = 0;
      for (int n=0;n<nof_bits;n++) {
        q->encoded_cqi[i] += (data[n] * M_basis_seq[i][n]); 
      }
    }
    
    for (int i=0;i<Q;i++) {
      q_bits[i] = q->encoded_cqi[i%32]%2;
    }
    return LIBLTE_SUCCESS;
  } else {
    return LIBLTE_ERROR_INVALID_INPUTS;     
  }
}

/* Encode UCI CQI/PMI for payloads greater than 11 bits (go through CRC, conv coder and rate match)
 */
int encode_cqi_long(uci_cqi_t *q, uint8_t *data, uint32_t nof_bits, uint8_t *q_bits, uint32_t Q)
{
  convcoder_t encoder;

  if (nof_bits + 8 < MAX_CQI_LEN &&
      q            != NULL       &&
      data         != NULL       &&
      q_bits       != NULL) 
  {

    
    int poly[3] = { 0x6D, 0x4F, 0x57 };
    encoder.K = 7;
    encoder.R = 3;
    encoder.tail_biting = true;
    memcpy(encoder.poly, poly, 3 * sizeof(int));

    memcpy(q->tmp_cqi, data, sizeof(uint8_t) * nof_bits);
    crc_attach(&q->crc, q->tmp_cqi, nof_bits);

    convcoder_encode(&encoder, q->tmp_cqi, q->encoded_cqi, nof_bits + 8);

    DEBUG("CConv output: ", 0);
    
    if (VERBOSE_ISDEBUG()) {
      vec_fprint_b(stdout, q->encoded_cqi, 3 * (nof_bits + 8));
    }

    rm_conv_tx(q->encoded_cqi, 3 * (nof_bits + 8), q_bits, Q);
    
    return LIBLTE_SUCCESS;
  } else {
    return LIBLTE_ERROR_INVALID_INPUTS; 
  }
}

/* Encode UCI CQI/PMI as described in 5.2.2.6 of 36.212 
 */
int uci_encode_cqi(uci_cqi_t *q, uint8_t *cqi_data, uint32_t cqi_len, float beta, uint32_t Q_prime_ri, 
                   harq_t *harq_process, uint8_t *q_bits)
{
  
  uint32_t Q_prime = Q_prime_cqi(cqi_len, beta, Q_prime_ri, harq_process);
  uint32_t Q_m = lte_mod_bits_x_symbol(harq_process->mcs.mod);
  
  int ret = LIBLTE_ERROR;
  if (cqi_len <= 11) {
    ret = encode_cqi_short(q, cqi_data, cqi_len, q_bits, Q_prime*Q_m);
  } else {
    ret = encode_cqi_long(q, cqi_data, cqi_len, q_bits, Q_prime*Q_m);
  }
  if (ret) {
    return ret;
  } else {
    return (int) Q_prime;
  }
}

static uint32_t Q_prime_ri_ack(uint32_t O, uint32_t O_cqi, float beta, harq_t *harq_process) {
  uint32_t M_sc = harq_process->prb_alloc.slot[0].nof_prb * RE_X_RB;
  
  uint32_t K = harq_process->cb_segm.C1*harq_process->cb_segm.K1 + 
    harq_process->cb_segm.C2*harq_process->cb_segm.K2;
  
  // If not carrying UL-SCH, get Q_prime according to 5.2.4.1
  if (K == 0) {
    if (O_cqi <= 11) {
      K = O_cqi; 
    } else {
      K = O_cqi+8;     
    }
  }
    
  uint32_t M_sc_init = harq_process->nof_prb_pusch_init * RE_X_RB;
    
  uint32_t x = (uint32_t) ceilf((float) O*M_sc_init*harq_process->N_symb_ul*beta/K);

  uint32_t Q_prime = MIN(x, 4*M_sc);

  return Q_prime; 
}

/* Encode UCI RI and HARQ bits as described in 5.2.2.6 of 36.212 
 *  Currently only supporting 1-bit RI or 1-bit HARQ
 */
int uci_encode_ri_ack(uint8_t data, uint32_t O_cqi, float beta, harq_t *harq_process, uint8_t *q_bits)
{
  uint32_t Q_m = lte_mod_bits_x_symbol(harq_process->mcs.mod);
  
  q_bits[0] = data;
  q_bits[1] = 2; 
  for (uint32_t i=2;i<Q_m;i++) {
    q_bits[i] = 3;
  }
  
  uint32_t Qprime = Q_prime_ri_ack(1, O_cqi, beta, harq_process);

  for (uint32_t i=1;i<Qprime;i++) {
    memcpy(&q_bits[i*Q_m], q_bits, Q_m*sizeof(uint8_t));  
  }
  
  return (int) Qprime;
}