mirror of https://github.com/PentHertz/srsLTE.git
79 lines
2.7 KiB
C
79 lines
2.7 KiB
C
/**
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*
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* \section COPYRIGHT
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*
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* Copyright 2013-2020 Software Radio Systems Limited
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*
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* By using this file, you agree to the terms and conditions set
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* forth in the LICENSE file which can be found at the top level of
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* the distribution.
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*
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*/
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#ifndef SRSLTE_FADING_H
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#define SRSLTE_FADING_H
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#include "srslte/config.h"
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#include "srslte/phy/common/timestamp.h"
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#include "srslte/phy/dft/dft.h"
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#include <inttypes.h>
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#include <stdint.h>
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#define SRSLTE_CHANNEL_FADING_MAXTAPS 9
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#define SRSLTE_CHANNEL_FADING_NTERMS 16
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typedef enum {
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srslte_channel_fading_model_none = 0,
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srslte_channel_fading_model_epa,
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srslte_channel_fading_model_eva,
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srslte_channel_fading_model_etu,
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} srslte_channel_fading_model_t;
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typedef struct {
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// Configuration parameters
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float srate; // Sampling rate: 1.92e6, 3.84e6, ..., 23.04e6, 30.72e6
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srslte_channel_fading_model_t model; // None, EPA, EVA, ETU
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float doppler; // Maximum doppler: 5, 70, 300
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// Internal tap parametrisation
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uint32_t N; // FFT size
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uint32_t path_delay; // Path delay
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uint32_t state_len; // Length of the impulse response saved in the state
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float coeff_alpha[SRSLTE_CHANNEL_FADING_MAXTAPS][SRSLTE_CHANNEL_FADING_NTERMS]; // Angle of arrival
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float coeff_a[SRSLTE_CHANNEL_FADING_MAXTAPS][SRSLTE_CHANNEL_FADING_NTERMS]; // Random phase
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float coeff_b[SRSLTE_CHANNEL_FADING_MAXTAPS][SRSLTE_CHANNEL_FADING_NTERMS]; // Random phase
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cf_t* h_tap[SRSLTE_CHANNEL_FADING_MAXTAPS]; // Static tap signal in frequency domain
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// Utils
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srslte_dft_plan_t fft; // DFT to frequency domain
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srslte_dft_plan_t ifft; // DFT to time domain
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cf_t* temp; // Temporal buffer, length fft_size
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cf_t* h_freq; // Channel frequency response, length fft_size
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cf_t* y_freq; // Intermediate frequency domain buffer
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float sin_table[1024]; // Table of sinus values
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// State variables
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cf_t* state; // To save impulse response of the filter
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} srslte_channel_fading_t;
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#ifdef __cplusplus
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extern "C" {
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#endif
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SRSLTE_API int srslte_channel_fading_init(srslte_channel_fading_t* q, double srate, const char* model, uint32_t seed);
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SRSLTE_API void srslte_channel_fading_free(srslte_channel_fading_t* q);
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SRSLTE_API double srslte_channel_fading_execute(srslte_channel_fading_t* q,
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const cf_t* in,
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cf_t* out,
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uint32_t nof_samples,
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double init_time);
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#ifdef __cplusplus
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}
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#endif
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#endif // SRSLTE_FADING_H
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