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/**
* Copyright 2013-2021 Software Radio Systems Limited
*
* This file is part of srsLTE.
*
* srsLTE 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.
*
* srsLTE 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: prach.h
*
* Description: Physical random access channel.
*
* Reference: 3GPP TS 36.211 version 10.0.0 Release 10 Sec. 5.7
*****************************************************************************/
#ifndef SRSLTE_PRACH_H
#define SRSLTE_PRACH_H
#include "srslte/config.h"
#include "srslte/phy/common/phy_common.h"
#include "srslte/phy/dft/dft.h"
#include <complex.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#define SRSLTE_PRACH_MAX_LEN (2 * 24576 + 21024) // Maximum Tcp + Tseq
// Long PRACH ZC sequence sequence length
#define SRSLTE_PRACH_N_ZC_LONG 839
// Short PRACH ZC sequence sequence length
#define SRSLTE_PRACH_N_ZC_SHORT 139
/** Generation and detection of RACH signals for uplink.
* Currently only supports preamble formats 0-3.
* Does not currently support high speed flag.
* Based on 3GPP TS 36.211 version 10.7.0 Release 10.
*/
typedef struct {
int idx;
float factor;
cf_t phase_array[2 * SRSLTE_PRACH_N_ZC_LONG];
} srslte_prach_cancellation_t;
typedef struct SRSLTE_API {
// Parameters from higher layers (extracted from SIB2)
bool is_nr;
uint32_t config_idx;
uint32_t f; // preamble format
uint32_t rsi; // rootSequenceIndex
bool hs; // highSpeedFlag
uint32_t zczc; // zeroCorrelationZoneConfig
uint32_t N_ifft_ul; // IFFT size for uplink
uint32_t N_ifft_prach; // IFFT size for PRACH generation
uint32_t max_N_ifft_ul;
// Working parameters
uint32_t N_zc; // PRACH sequence length
uint32_t N_cs; // Cyclic shift size
uint32_t N_seq; // Preamble length
float T_seq; // Preamble length in seconds
float T_tot; // Total sequence length in seconds
uint32_t N_cp; // Cyclic prefix length
// Generated tables
cf_t seqs[64][SRSLTE_PRACH_N_ZC_LONG]; // Our set of 64 preamble sequences
cf_t dft_seqs[64][SRSLTE_PRACH_N_ZC_LONG]; // DFT-precoded seqs
uint64_t dft_gen_bitmap; // Bitmap where each bit Indicates if the dft has been generated for sequence i.
uint32_t root_seqs_idx[64]; // Indices of root seqs in seqs table
uint32_t N_roots; // Number of root sequences used in this configuration
cf_t* td_signals[64];
// Containers
cf_t* ifft_in;
cf_t* ifft_out;
cf_t* prach_bins;
cf_t* corr_spec;
float* corr;
// PRACH IFFT
srslte_dft_plan_t fft;
srslte_dft_plan_t ifft;
// ZC-sequence FFT and IFFT
srslte_dft_plan_t zc_fft;
srslte_dft_plan_t zc_ifft;
cf_t* signal_fft;
float detect_factor;
uint32_t deadzone;
float peak_values[65];
uint32_t peak_offsets[65];
uint32_t num_ra_preambles;
bool successive_cancellation;
bool freq_domain_offset_calc;
srslte_tdd_config_t tdd_config;
uint32_t current_prach_idx;
cf_t* cross;
cf_t* corr_freq;
srslte_prach_cancellation_t prach_cancel;
cf_t sub[839 * 2];
float phase[839];
} srslte_prach_t;
typedef struct SRSLTE_API {
int nof_sf;
uint32_t sf[5];
} srslte_prach_sf_config_t;
typedef enum SRSLTE_API {
SRSLTE_PRACH_SFN_EVEN = 0,
SRSLTE_PRACH_SFN_ANY,
} srslte_prach_sfn_t;
typedef struct {
bool is_nr; // Set to true if NR
uint32_t config_idx;
uint32_t root_seq_idx;
uint32_t zero_corr_zone;
uint32_t freq_offset;
uint32_t num_ra_preambles;
bool hs_flag;
srslte_tdd_config_t tdd_config;
bool enable_successive_cancellation;
bool enable_freq_domain_offset_calc;
} srslte_prach_cfg_t;
typedef struct SRSLTE_API {
uint32_t f;
uint32_t t0;
uint32_t t1;
uint32_t t2;
} srslte_prach_tdd_loc_t;
typedef struct SRSLTE_API {
uint32_t nof_elems;
srslte_prach_tdd_loc_t elems[6];
} srslte_prach_tdd_loc_table_t;
SRSLTE_API uint32_t srslte_prach_get_preamble_format(uint32_t config_idx);
SRSLTE_API srslte_prach_sfn_t srslte_prach_get_sfn(uint32_t config_idx);
SRSLTE_API bool srslte_prach_tti_opportunity(srslte_prach_t* p, uint32_t current_tti, int allowed_subframe);
SRSLTE_API bool
srslte_prach_tti_opportunity_config_fdd(uint32_t config_idx, uint32_t current_tti, int allowed_subframe);
SRSLTE_API bool srslte_prach_tti_opportunity_config_tdd(uint32_t config_idx,
uint32_t tdd_ul_dl_config,
uint32_t current_tti,
uint32_t* prach_idx);
SRSLTE_API uint32_t srslte_prach_f_ra_tdd(uint32_t config_idx,
uint32_t tdd_ul_dl_config,
uint32_t current_tti,
uint32_t prach_idx,
uint32_t prach_offset,
uint32_t n_rb_ul);
SRSLTE_API uint32_t srslte_prach_f_id_tdd(uint32_t config_idx, uint32_t tdd_ul_dl_config, uint32_t prach_idx);
SRSLTE_API uint32_t srslte_prach_nof_f_idx_tdd(uint32_t config_idx, uint32_t tdd_ul_dl_config);
SRSLTE_API void srslte_prach_sf_config(uint32_t config_idx, srslte_prach_sf_config_t* sf_config);
SRSLTE_API int srslte_prach_init(srslte_prach_t* p, uint32_t max_N_ifft_ul);
SRSLTE_API int srslte_prach_set_cfg(srslte_prach_t* p, srslte_prach_cfg_t* cfg, uint32_t nof_prb);
SRSLTE_API int srslte_prach_gen(srslte_prach_t* p, uint32_t seq_index, uint32_t freq_offset, cf_t* signal);
SRSLTE_API int srslte_prach_detect(srslte_prach_t* p,
uint32_t freq_offset,
cf_t* signal,
uint32_t sig_len,
uint32_t* indices,
uint32_t* ind_len);
SRSLTE_API int srslte_prach_detect_offset(srslte_prach_t* p,
uint32_t freq_offset,
cf_t* signal,
uint32_t sig_len,
uint32_t* indices,
float* t_offsets,
float* peak_to_avg,
uint32_t* ind_len);
SRSLTE_API void srslte_prach_set_detect_factor(srslte_prach_t* p, float factor);
SRSLTE_API int srslte_prach_free(srslte_prach_t* p);
SRSLTE_API int srslte_prach_print_seqs(srslte_prach_t* p);
SRSLTE_API int srslte_prach_process(srslte_prach_t* p,
cf_t* signal,
uint32_t* indices,
float* t_offsets,
float* peak_to_avg,
uint32_t* n_indices,
int cancellation_idx,
uint32_t begin,
uint32_t sig_len);
#endif // SRSLTE_PRACH_H