mirror of https://github.com/pvnis/srsRAN_4G.git
Created chest UL
Ismael Gomez
9 years ago
parent
675ba2e568
commit
7f8ee935fc
@ -0,0 +1,54 @@
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/**
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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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#ifndef CHEST_
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#define CHEST_
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#include "srslte/config.h"
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#define SRSLTE_CHEST_MAX_SMOOTH_FIL_LEN 65
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SRSLTE_API void srslte_chest_average_pilots(cf_t *input,
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cf_t *output,
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cf_t *filter,
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uint32_t nof_ref,
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uint32_t nof_symbols,
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uint32_t filter_len);
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SRSLTE_API void srslte_chest_set_smooth_filter3_coeff(float *smooth_filter,
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float w);
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SRSLTE_API float srslte_chest_estimate_noise_pilots(cf_t *noisy,
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cf_t *noiseless,
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cf_t *noise_vec,
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uint32_t nof_pilots);
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SRSLTE_API void srslte_chest_set_triangle_filter(float *fil,
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int filter_len);
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#endif
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@ -0,0 +1,105 @@
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/**
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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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/**********************************************************************************************
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* File: chest_ul.h
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*
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* Description: 3GPP LTE Uplink channel estimator and equalizer.
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* Estimates the channel in the resource elements transmitting references and
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* interpolates for the rest of the resource grid.
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* The equalizer uses the channel estimates to produce an estimation of the
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* transmitted symbol.
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*
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* Reference:
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*********************************************************************************************/
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#ifndef CHEST_UL_
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#define CHEST_UL_
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#include <stdio.h>
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#include "srslte/config.h"
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#include "srslte/ch_estimation/chest_common.h"
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#include "srslte/resampling/interp.h"
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#include "srslte/ch_estimation/refsignal_ul.h"
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#include "srslte/common/phy_common.h"
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typedef struct {
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srslte_cell_t cell;
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srslte_refsignal_ul_t dmrs_signal;
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srslte_refsignal_ul_dmrs_pregen_t dmrs_pregen;
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bool dmrs_signal_configured;
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cf_t *pilot_estimates;
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cf_t *pilot_estimates_average;
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cf_t *pilot_recv_signal;
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cf_t *tmp_noise;
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#ifdef FREQ_SEL_SNR
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float snr_vector[12000];
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float pilot_power[12000];
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#endif
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uint32_t smooth_filter_len;
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float smooth_filter[SRSLTE_CHEST_MAX_SMOOTH_FIL_LEN];
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srslte_interp_linsrslte_vec_t srslte_interp_linvec;
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float pilot_power;
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float noise_estimate;
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} srslte_chest_ul_t;
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SRSLTE_API int srslte_chest_ul_init(srslte_chest_ul_t *q,
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srslte_cell_t cell);
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SRSLTE_API void srslte_chest_ul_free(srslte_chest_ul_t *q);
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SRSLTE_API void srslte_chest_ul_set_cfg(srslte_chest_ul_t *q,
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srslte_refsignal_dmrs_pusch_cfg_t *pusch_cfg,
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srslte_pucch_cfg_t *pucch_cfg,
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srslte_refsignal_srs_cfg_t *srs_cfg);
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SRSLTE_API void srslte_chest_ul_set_smooth_filter(srslte_chest_ul_t *q,
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float *filter,
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uint32_t filter_len);
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SRSLTE_API void srslte_chest_ul_set_smooth_filter3_coeff(srslte_chest_ul_t* q,
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float w);
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SRSLTE_API int srslte_chest_ul_estimate(srslte_chest_ul_t *q,
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cf_t *input,
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cf_t *ce[SRSLTE_MAX_PORTS],
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uint32_t sf_idx);
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SRSLTE_API float srslte_chest_ul_get_noise_estimate(srslte_chest_ul_t *q);
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SRSLTE_API float srslte_chest_ul_get_snr(srslte_chest_ul_t *q);
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#endif
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@ -0,0 +1,82 @@
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/**
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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, cf_t *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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@ -0,0 +1,239 @@
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/**
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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/config.h"
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#include "srslte/ch_estimation/chest_ul.h"
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#include "srslte/utils/vector.h"
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#include "srslte/utils/convolution.h"
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#define NOF_REFS_SYM (q->cell.nof_prb*SRSLTE_NRE)
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#define NOF_REFS_SF (NOF_REFS_SYM*2) // 2 reference symbols per subframe
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/** 3GPP LTE Downlink channel estimator and equalizer.
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* Estimates the channel in the resource elements transmitting references and interpolates for the rest
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* of the resource grid.
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*
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* The equalizer uses the channel estimates to produce an estimation of the transmitted symbol.
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*
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* This object depends on the srslte_refsignal_t object for creating the LTE CSR signal.
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*/
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int srslte_chest_ul_init(srslte_chest_ul_t *q, srslte_cell_t cell)
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{
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int ret = SRSLTE_ERROR_INVALID_INPUTS;
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if (q != NULL &&
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srslte_cell_isvalid(&cell))
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{
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bzero(q, sizeof(srslte_chest_ul_t));
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ret = srslte_refsignal_ul_init(&q->dmrs_signal, cell);
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if (ret != SRSLTE_SUCCESS) {
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fprintf(stderr, "Error initializing CSR signal (%d)\n",ret);
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goto clean_exit;
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}
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q->tmp_noise = srslte_vec_malloc(sizeof(cf_t) * NOF_REFS_SF);
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if (!q->tmp_noise) {
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perror("malloc");
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goto clean_exit;
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}
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q->pilot_estimates = srslte_vec_malloc(sizeof(cf_t) * NOF_REFS_SF);
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if (!q->pilot_estimates) {
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perror("malloc");
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goto clean_exit;
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}
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q->pilot_estimates_average = srslte_vec_malloc(sizeof(cf_t) * NOF_REFS_SF);
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if (!q->pilot_estimates_average) {
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perror("malloc");
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goto clean_exit;
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}
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q->pilot_recv_signal = srslte_vec_malloc(sizeof(cf_t) * NOF_REFS_SF);
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if (!q->pilot_recv_signal) {
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perror("malloc");
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goto clean_exit;
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}
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if (srslte_interp_linear_vector_init(&q->srslte_interp_linvec, NOF_REFS_SYM)) {
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fprintf(stderr, "Error initializing vector interpolator\n");
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goto clean_exit;
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}
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q->smooth_filter_len = 3;
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srslte_chest_ul_set_smooth_filter3_coeff(q, 0.1);
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q->cell = cell;
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}
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q->dmrs_signal_configured = false;
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ret = SRSLTE_SUCCESS;
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clean_exit:
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if (ret != SRSLTE_SUCCESS) {
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srslte_chest_ul_free(q);
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}
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return ret;
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}
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void srslte_chest_ul_free(srslte_chest_ul_t *q)
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{
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srslte_refsignal_ul_free(&q->dmrs_signal);
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if (q->tmp_noise) {
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free(q->tmp_noise);
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}
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srslte_interp_linear_vector_free(&q->srslte_interp_linvec);
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if (q->pilot_estimates) {
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free(q->pilot_estimates);
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}
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if (q->pilot_estimates_average) {
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free(q->pilot_estimates_average);
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}
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if (q->pilot_recv_signal) {
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free(q->pilot_recv_signal);
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}
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bzero(q, sizeof(srslte_chest_ul_t));
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}
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void srslte_chest_ul_set_cfg(srslte_chest_ul_t *q,
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srslte_refsignal_dmrs_pusch_cfg_t *pusch_cfg,
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srslte_pucch_cfg_t *pucch_cfg,
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srslte_refsignal_srs_cfg_t *srs_cfg)
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{
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srslte_chest_ul_set_cfg(&q->dmrs_signal, pusch_cfg, pucch_cfg, srs_cfg);
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srslte_refsignal_dmrs_pusch_pregen(&q->dmrs_signal, &q->dmrs_pregen);
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q->dmrs_signal_configured = true;
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}
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/* Uses the difference between the averaged and non-averaged pilot estimates */
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static float estimate_noise_pilots(srslte_chest_ul_t *q)
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{
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float power = srslte_chest_estimate_noise_pilots(q->pilot_estimates,
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q->pilot_estimates_average,
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q->tmp_noise,
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NOF_REFS_SF);
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return (1/q->smooth_filter[0])*power;
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}
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#define cesymb(i) ce[SRSLTE_RE_IDX(q->cell.nof_prb,i,0)]
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static void interpolate_pilots(srslte_chest_ul_t *q, cf_t *pilot_estimates, cf_t *ce)
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{
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/* interpolate the symbols with references in the freq domain */
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uint32_t L1 = SRSLTE_REFSIGNAL_UL_L(0, q->cell.cp);
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uint32_t L2 = SRSLTE_REFSIGNAL_UL_L(1, q->cell.cp);
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uint32_t NL = SRSLTE_CP_NSYMB(q->cell.cp);
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/* Interpolate in the time domain between symbols */
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srslte_interp_linear_vector3(&q->srslte_interp_linvec, &cesymb(L2), &cesymb(L1), &cesymb(L1), &cesymb(L1-1), (L2-L1)-1);
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srslte_interp_linear_vector( &q->srslte_interp_linvec, &cesymb(L1), &cesymb(L2), &cesymb(L1+1), (L2-L1)-1);
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srslte_interp_linear_vector2(&q->srslte_interp_linvec, &cesymb(L1), &cesymb(L2), &cesymb(L2), &cesymb(L2+1), (NL-L2)-1);
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// TODO: Maybe here need to do some averaging with previous symbols?
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}
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void srslte_chest_ul_set_smooth_filter(srslte_chest_ul_t *q, float *filter, uint32_t filter_len) {
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if (filter_len < SRSLTE_CHEST_MAX_SMOOTH_FIL_LEN) {
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if (filter) {
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memcpy(q->smooth_filter, filter, filter_len*sizeof(float));
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q->smooth_filter_len = filter_len;
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} else {
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q->smooth_filter_len = 0;
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}
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} else {
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fprintf(stderr, "Error setting smoothing filter: filter len exceeds maximum (%d>%d)\n",
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filter_len, SRSLTE_CHEST_MAX_SMOOTH_FIL_LEN);
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}
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}
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void srslte_chest_ul_set_smooth_filter3_coeff(srslte_chest_ul_t* q, float w)
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{
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srslte_chest_set_smooth_filter3_coeff(q->smooth_filter, w);
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q->smooth_filter_len = 3;
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}
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static void average_pilots(srslte_chest_ul_t *q, cf_t *input, cf_t *output) {
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uint32_t nsymbols = 2;
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uint32_t nref = NOF_REFS_SYM;
|
||||
srslte_chest_average_pilots(input, output, q->smooth_filter, nref, nsymbols, q->smooth_filter_len);
|
||||
}
|
||||
|
||||
int srslte_chest_ul_estimate(srslte_chest_ul_t *q, cf_t *input, cf_t *ce,
|
||||
uint32_t nof_prb, uint32_t sf_idx, uint32_t cyclic_shift_for_dmrs, uint32_t n_prb[2])
|
||||
{
|
||||
if (!q->dmrs_signal_configured) {
|
||||
fprintf(stderr, "Error must call srslte_chest_ul_set_cfg() before using the UL estimator\n");
|
||||
return SRSLTE_ERROR;
|
||||
}
|
||||
|
||||
/* Get references from the input signal */
|
||||
srslte_refsignal_dmrs_pusch_get(&q->dmrs_signal, input, nof_prb, n_prb, q->pilot_recv_signal);
|
||||
|
||||
/* Use the known DMRS signal to compute Least-squares estimates */
|
||||
srslte_vec_prod_conj_ccc(q->pilot_recv_signal, q->dmrs_pregen.r[cyclic_shift_for_dmrs][sf_idx][nof_prb],
|
||||
q->pilot_estimates, NOF_REFS_SF);
|
||||
|
||||
if (ce != NULL) {
|
||||
if (q->smooth_filter_len > 0) {
|
||||
average_pilots(q, q->pilot_estimates, q->pilot_estimates_average);
|
||||
interpolate_pilots(q, q->pilot_estimates_average, ce);
|
||||
|
||||
/* If averaging, compute noise from difference between received and averaged estimates */
|
||||
if (sf_idx == 0 || sf_idx == 5) {
|
||||
q->noise_estimate = estimate_noise_pilots(q);
|
||||
}
|
||||
} else {
|
||||
interpolate_pilots(q, q->pilot_estimates, ce);
|
||||
q->noise_estimate = 0;
|
||||
}
|
||||
}
|
||||
|
||||
// Estimate received pilot power
|
||||
q->pilot_power = srslte_vec_avg_power_cf(q->pilot_recv_signal, NOF_REFS_SF);
|
||||
return 0;
|
||||
}
|
||||
|
||||
float srslte_chest_ul_get_noise_estimate(srslte_chest_ul_t *q) {
|
||||
return q->noise_estimate;
|
||||
}
|
||||
|
||||
float srslte_chest_ul_get_snr(srslte_chest_ul_t *q) {
|
||||
return q->pilot_power/srslte_chest_ul_get_noise_estimate(q);
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue