mirror of https://github.com/PentHertz/srsLTE.git
83 lines
2.3 KiB
C
83 lines
2.3 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 <stdio.h>
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#include <stdlib.h>
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#include <strings.h>
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#include <string.h>
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#include <complex.h>
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#include <math.h>
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#include "srslte/ch_estimation/chest_common.h"
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#include "srslte/utils/vector.h"
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#include "srslte/utils/convolution.h"
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void srslte_chest_set_triangle_filter(float *fil, int filter_len)
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{
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for (int i=0;i<filter_len/2;i++) {
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fil[i] = i+1;
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fil[i+filter_len/2+1]=filter_len/2-i;
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}
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fil[filter_len/2]=filter_len/2+1;
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float s=0;
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for (int i=0;i<filter_len;i++) {
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s+=fil[i];
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}
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for (int i=0;i<filter_len;i++) {
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fil[i]/=s;
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}
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}
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/* Uses the difference between the averaged and non-averaged pilot estimates */
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float srslte_chest_estimate_noise_pilots(cf_t *noisy, cf_t *noiseless, cf_t *noise_vec, uint32_t nof_pilots)
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{
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/* Substract noisy pilot estimates */
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srslte_vec_sub_ccc(noiseless, noisy, noise_vec, nof_pilots);
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/* Compute average power */
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float power = srslte_vec_avg_power_cf(noise_vec, nof_pilots);
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return power;
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}
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void srslte_chest_set_smooth_filter3_coeff(float *smooth_filter, float w)
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{
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smooth_filter[0] = w;
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smooth_filter[2] = w;
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smooth_filter[1] = 1-2*w;
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}
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void srslte_chest_average_pilots(cf_t *input, cf_t *output, float *filter,
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uint32_t nof_ref, uint32_t nof_symbols, uint32_t filter_len)
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{
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for (int l=0;l<nof_symbols;l++) {
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srslte_conv_same_cf(&input[l*nof_ref], filter, &output[l*nof_ref], nof_ref, filter_len);
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}
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}
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