93 lines
2.4 KiB
C
93 lines
2.4 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 <stdlib.h>
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#include <srslte/srslte.h>
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#include "srslte/phy/sync/cp.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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int srslte_cp_synch_init(srslte_cp_synch_t *q, uint32_t symbol_sz)
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{
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q->symbol_sz = symbol_sz;
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q->max_symbol_sz = symbol_sz;
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q->corr = srslte_vec_malloc(sizeof(cf_t) * q->symbol_sz);
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if (!q->corr) {
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perror("malloc");
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return SRSLTE_ERROR;
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}
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return SRSLTE_SUCCESS;
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}
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void srslte_cp_synch_free(srslte_cp_synch_t *q)
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{
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if (q->corr) {
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free(q->corr);
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}
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}
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int srslte_cp_synch_resize(srslte_cp_synch_t *q, uint32_t symbol_sz)
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{
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if (symbol_sz > q->max_symbol_sz) {
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fprintf(stderr, "Error in cp_synch_resize(): symbol_sz must be lower than initialized\n");
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return SRSLTE_ERROR;
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}
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q->symbol_sz = symbol_sz;
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return SRSLTE_SUCCESS;
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}
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uint32_t srslte_cp_synch(srslte_cp_synch_t *q, cf_t *input, uint32_t max_offset, uint32_t nof_symbols, uint32_t cp_len)
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{
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if (max_offset > q->symbol_sz) {
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max_offset = q->symbol_sz;
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}
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for (int i=0;i<max_offset;i++) {
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q->corr[i] = 0;
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cf_t *inputPtr = input;
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for (int n=0;n<nof_symbols;n++) {
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uint32_t cplen = (n%7)?cp_len:cp_len+1;
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q->corr[i] += srslte_vec_dot_prod_conj_ccc(&inputPtr[i], &inputPtr[i+q->symbol_sz], cplen)/nof_symbols;
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inputPtr += q->symbol_sz+cplen;
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}
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}
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uint32_t max_idx = srslte_vec_max_abs_ci(q->corr, max_offset);
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return max_idx;
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}
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cf_t srslte_cp_synch_corr_output(srslte_cp_synch_t *q, uint32_t offset)
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{
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if (offset < q->symbol_sz) {
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return q->corr[offset];
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} else {
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return 0;
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}
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}
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