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C

/**
* Copyright 2013-2021 Software Radio Systems Limited
*
* This file is part of srsRAN.
*
* srsRAN is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version.
*
* srsRAN 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 Affero General Public License for more details.
*
* A copy of the GNU Affero 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/.
*
*/
/**
* \file ch_awgn.h
* \brief Additive white Gaussian noise channel object
*
*/
#include "srsran/config.h"
#include <stdint.h>
#ifndef SRSRAN_CH_AWGN_H
#define SRSRAN_CH_AWGN_H
#ifdef __cplusplus
extern "C" {
#endif
/**
* \brief srsRAN channel AWGN implements an efficient Box-Muller Method accelerated with SIMD.
*/
typedef struct {
float* table_cos;
float* table_log;
uint32_t rand_state;
float std_dev;
} srsran_channel_awgn_t;
/**
* \brief function of the channel AWGN object
*
* @param q AWGN channel object
* @param seed random generator seed
*/
SRSRAN_API int srsran_channel_awgn_init(srsran_channel_awgn_t* q, uint32_t seed);
/**
* \brief the noise level N0 in decibels full scale (dBfs)
*
* @param q AWGN channel object
* @param n0_dBfs noise level
*/
SRSRAN_API int srsran_channel_awgn_set_n0(srsran_channel_awgn_t* q, float n0_dBfs);
/**
* \brief the complex AWGN channel
*
* @param q AWGN channel object
* @param in complex input array
* @param out complex output array
* @param length number of samples
*/
SRSRAN_API void srsran_channel_awgn_run_c(srsran_channel_awgn_t* q, const cf_t* in, cf_t* out, uint32_t length);
/**
* \brief the real AWGN channel
*
* @param q AWGN channel object
* @param in real input array
* @param out real output array
* @param length number of samples
*/
SRSRAN_API void srsran_channel_awgn_run_f(srsran_channel_awgn_t* q, const float* in, float* out, uint32_t length);
/**
* \brief AWGN channel generator data
*
* @param q AWGN channel object
*/
SRSRAN_API void srsran_channel_awgn_free(srsran_channel_awgn_t* q);
/**
* \brief signal \p input with AWGN to obtain signal \p output (complex case).
*
* @param[in] input Input signal
* @param[out] output Output signal
* @param[in] variance Noise variance
* @param[in] len Number of samples
*/
SRSRAN_API void srsran_ch_awgn_c(const cf_t* input, cf_t* output, float variance, uint32_t len);
/**
* \brief Perturb signal \p input with AWGN to obtain signal \p output (real case).
*
* @param[in] input Input signal
* @param[out] output Output signal
* @param[in] variance Noise variance
* @param[in] len Number of samples
*/
SRSRAN_API void srsran_ch_awgn_f(const float* input, float* output, float variance, uint32_t len);
SRSRAN_API float srsran_ch_awgn_get_variance(float ebno_db, float rate);
#ifdef __cplusplus
}
#endif
#endif // SRSRAN_CH_AWGN_H