srsLTE/lte/phy/lib/filter/src/dft_precoding.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/common/phy_common.h"
#include "liblte/phy/utils/debug.h"
#include "liblte/phy/utils/vector.h"
#include "liblte/phy/utils/dft.h"
#include "liblte/phy/filter/dft_precoding.h"

/* Create DFT plans for transform precoding */
int dft_precoding_init(dft_precoding_t *q, uint32_t max_prb) 
{
  int ret = LIBLTE_ERROR_INVALID_INPUTS; 
  bzero(q, sizeof(dft_precoding_t));
  
  if (max_prb >= MAX_PRB) {
    ret = LIBLTE_ERROR; 
    for (uint32_t i=0;i<max_prb;i++) {
      if((i % 2) == 0 || (i % 3) == 0 || (i % 5) == 0) {        
        if (dft_plan_c(&q->dft_plan[i], i*RE_X_RB, FORWARD)) {
          fprintf(stderr, "Error: Creating DFT plan %d\n",i);
          goto clean_exit;
        }
        if (dft_plan_c(&q->idft_plan[i], i*RE_X_RB, BACKWARD)) {
          fprintf(stderr, "Error: Creating DFT plan %d\n",i);
          goto clean_exit;
        }        
      }
    }
    q->max_prb = max_prb;
    ret = LIBLTE_SUCCESS;
  } 

clean_exit:
  if (ret == LIBLTE_ERROR) {
    dft_precoding_free(q);
  }
  return ret; 
}

/* Free DFT plans for transform precoding */
void dft_precoding_free(dft_precoding_t *q) 
{
  for (uint32_t i=0;i<q->max_prb;i++) {
    if((i % 2) == 0 || (i % 3) == 0 || (i % 5) == 0) {      
      dft_plan_free(&q->dft_plan[i]);
      dft_plan_free(&q->idft_plan[i]);        
    }
  }  
  bzero(q, sizeof(dft_precoding_t));
}

int dft_precoding(dft_precoding_t *q, cf_t *input, cf_t *output, 
                  uint32_t nof_prb, uint32_t nof_symbols) 
{
  
  if ((nof_prb%2) || (nof_prb%3) || (nof_prb%5)) {
    fprintf(stderr, "Error invalid number of PRB (%d)\n", nof_prb);
    return LIBLTE_ERROR; 
  }

  for (uint32_t i=0;i<nof_symbols;i++) {
    dft_run_c(&q->dft_plan[nof_prb], &input[i*RE_X_RB*nof_prb], &output[i*RE_X_RB*nof_prb]);
  }
  
  return LIBLTE_SUCCESS;
}

int dft_predecoding(dft_precoding_t *q, cf_t *input, cf_t *output, 
                    uint32_t nof_prb, uint32_t nof_symbols)
{
  if ((nof_prb%2) || (nof_prb%3) || (nof_prb%5)) {
    fprintf(stderr, "Error invalid number of PRB (%d)\n", nof_prb);
    return LIBLTE_ERROR; 
  }

  for (uint32_t i=0;i<nof_symbols;i++) {
    dft_run_c(&q->dft_plan[nof_prb], &input[i*RE_X_RB*nof_prb], &output[i*RE_X_RB*nof_prb]);
  }
  
  return LIBLTE_SUCCESS;
  
}