109 lines
3.1 KiB
C
109 lines
3.1 KiB
C
/**
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*
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* \section COPYRIGHT
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*
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* Copyright 2013-2015 Software Radio Systems Limited
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*
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* \section LICENSE
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*
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* This file is part of the srsLTE library.
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*
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* srsLTE is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as
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* published by the Free Software Foundation, either version 3 of
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* the License, or (at your option) any later version.
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*
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* srsLTE is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* A copy of the GNU Affero General Public License can be found in
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* the LICENSE file in the top-level directory of this distribution
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* and at http://www.gnu.org/licenses/.
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*
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*/
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#include <strings.h>
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#include <stdlib.h>
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#include <math.h>
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#include <srslte/srslte.h>
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#include "srslte/phy/utils/cexptab.h"
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#include "srslte/phy/sync/cfo.h"
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#include "srslte/phy/utils/vector.h"
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#include "srslte/phy/utils/debug.h"
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/* Set next macro to 1 for using table generated CFO compensation */
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#define SRSLTE_CFO_USE_EXP_TABLE 0
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int srslte_cfo_init(srslte_cfo_t *h, uint32_t nsamples) {
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#if SRSLTE_CFO_USE_EXP_TABLE
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int ret = SRSLTE_ERROR;
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bzero(h, sizeof(srslte_cfo_t));
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if (srslte_cexptab_init(&h->tab, SRSLTE_CFO_CEXPTAB_SIZE)) {
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goto clean;
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}
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h->cur_cexp = srslte_vec_malloc(sizeof(cf_t) * nsamples);
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if (!h->cur_cexp) {
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goto clean;
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}
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h->tol = 0;
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h->last_freq = 0;
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h->nsamples = nsamples;
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h->max_samples = nsamples;
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srslte_cexptab_gen(&h->tab, h->cur_cexp, h->last_freq, h->nsamples);
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ret = SRSLTE_SUCCESS;
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clean:
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if (ret == SRSLTE_ERROR) {
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srslte_cfo_free(h);
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}
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return ret;
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#else /* SRSLTE_CFO_USE_EXP_TABLE */
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h->nsamples = nsamples;
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return SRSLTE_SUCCESS;
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#endif /* SRSLTE_CFO_USE_EXP_TABLE */
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}
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void srslte_cfo_free(srslte_cfo_t *h) {
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#if SRSLTE_CFO_USE_EXP_TABLE
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srslte_cexptab_free(&h->tab);
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if (h->cur_cexp) {
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free(h->cur_cexp);
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}
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#endif /* SRSLTE_CFO_USE_EXP_TABLE */
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bzero(h, sizeof(srslte_cfo_t));
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}
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void srslte_cfo_set_tol(srslte_cfo_t *h, float tol) {
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h->tol = tol;
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}
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int srslte_cfo_resize(srslte_cfo_t *h, uint32_t samples) {
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#if SRSLTE_CFO_USE_EXP_TABLE
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if (samples <= h->max_samples) {
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srslte_cexptab_gen(&h->tab, h->cur_cexp, h->last_freq, samples);
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h->nsamples = samples;
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} else {
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fprintf(stderr, "Error in cfo_resize(): nof_samples must be lower than initialized\n");
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return SRSLTE_ERROR;
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}
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#endif /* SRSLTE_CFO_USE_EXP_TABLE */
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return SRSLTE_SUCCESS;
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}
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void srslte_cfo_correct(srslte_cfo_t *h, const cf_t *input, cf_t *output, float freq) {
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#if SRSLTE_CFO_USE_EXP_TABLE
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if (fabs(h->last_freq - freq) > h->tol) {
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h->last_freq = freq;
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srslte_cexptab_gen(&h->tab, h->cur_cexp, h->last_freq, h->nsamples);
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DEBUG("CFO generating new table for frequency %.4fe-6\n", freq*1e6);
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}
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srslte_vec_prod_ccc(h->cur_cexp, input, output, h->nsamples);
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#else /* SRSLTE_CFO_USE_EXP_TABLE */
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srslte_vec_apply_cfo(input, freq, output, h->nsamples);
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#endif /* SRSLTE_CFO_USE_EXP_TABLE */
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}
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