srsRAN_4G/lib/include/srslte/phy/phch/prach.h

/**
 *
 * \section COPYRIGHT
 *
 * Copyright 2013-2015 Software Radio Systems Limited
 *
 * \section LICENSE
 *
 * This file is part of the srsLTE library.
 *
 * 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 PRACH_
#define PRACH_

#include <stdint.h>
#include <stdlib.h>
#include <complex.h>
#include <stdbool.h>
#include "srslte/config.h"
#include "srslte/phy/dft/dft.h"
#include "srslte/phy/common/phy_common.h"


#define SRSLTE_PRACH_MAX_LEN  (2*24576+21024) // Maximum Tcp + Tseq

/** 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 SRSLTE_API {
  // Parameters from higher layers (extracted from SIB2)
  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][839];         // Our set of 64 preamble sequences
  cf_t dft_seqs[64][839];     // DFT-precoded seqs
  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
  
  // 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];
  
} 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 {
  uint32_t config_idx;
  uint32_t root_seq_idx;
  uint32_t zero_corr_zone;
  uint32_t freq_offset;
  bool     hs_flag; 
} srslte_prach_cfg_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 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_cell(srslte_prach_t *p,
                                     uint32_t N_ifft_ul,
                                     uint32_t config_idx,
                                     uint32_t root_seq_index,
                                     bool high_speed_flag,
                                     uint32_t zero_corr_zone_config);

SRSLTE_API int srslte_prach_init_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);

#endif // PRACH_