prach.c

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/*! \file PHY/LTE_TRANSPORT/prach.c
 * \brief Top-level routines for generating and decoding the PRACH physical channel V8.6 2009-03
 * \author R. Knopp
 * \date 2011
 * \version 0.1
 * \company Eurecom
 * \email: knopp@eurecom.fr
 * \note
 * \warning
 */
#include "PHY/sse_intrin.h"
#include "PHY/defs.h"
#include "PHY/extern.h"
//#include "prach.h"
#include "SCHED/defs.h"
#include "SCHED/extern.h"
#include "UTIL/LOG/vcd_signal_dumper.h"

//#define PRACH_DEBUG 1

uint16_t NCS_unrestricted[16] = {0,13,15,18,22,26,32,38,46,59,76,93,119,167,279,419};
uint16_t NCS_restricted[15]   = {15,18,22,26,32,38,46,55,68,82,100,128,158,202,237}; // high-speed case
uint16_t NCS_4[7]             = {2,4,6,8,10,12,15};

int16_t ru[2*839]; // quantized roots of unity
uint32_t ZC_inv[839]; // multiplicative inverse for roots u
uint16_t du[838];

typedef struct {
  uint8_t f_ra;
  uint8_t t0_ra;
  uint8_t t1_ra;
  uint8_t t2_ra;
} PRACH_TDD_PREAMBLE_MAP_elem;
typedef struct {
  uint8_t num_prach;
  PRACH_TDD_PREAMBLE_MAP_elem map[6];
} PRACH_TDD_PREAMBLE_MAP;

// This is table 5.7.1-4 from 36.211
PRACH_TDD_PREAMBLE_MAP tdd_preamble_map[64][7] = {
  // TDD Configuration Index 0
  { {1,{{0,1,0,2}}},{1,{{0,1,0,1}}}, {1,{{0,1,0,0}}}, {1,{{0,1,0,2}}}, {1,{{0,1,0,1}}}, {1,{{0,1,0,0}}}, {1,{{0,1,0,2}}}},
  // TDD Configuration Index 1
  { {1,{{0,2,0,2}}},{1,{{0,2,0,1}}}, {1,{{0,2,0,0}}}, {1,{{0,2,0,2}}}, {1,{{0,2,0,1}}}, {1,{{0,2,0,0}}}, {1,{{0,2,0,2}}}},
  // TDD Configuration Index 2
  { {1,{{0,1,1,2}}},{1,{{0,1,1,1}}}, {1,{{0,1,1,0}}}, {1,{{0,1,0,1}}}, {1,{{0,1,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,1,1,1}}}},
  // TDD Configuration Index 3
  { {1,{{0,0,0,2}}},{1,{{0,0,0,1}}}, {1,{{0,0,0,0}}}, {1,{{0,0,0,2}}}, {1,{{0,0,0,1}}}, {1,{{0,0,0,0}}}, {1,{{0,0,0,2}}}},
  // TDD Configuration Index 4
  { {1,{{0,0,1,2}}},{1,{{0,0,1,1}}}, {1,{{0,0,1,0}}}, {1,{{0,0,0,1}}}, {1,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,0,1,1}}}},
  // TDD Configuration Index 5
  { {1,{{0,0,0,1}}},{1,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,0,0,1}}}},
  // TDD Configuration Index 6
  { {2,{{0,0,0,2},{0,0,1,2}}}, {2,{{0,0,0,1},{0,0,1,1}}}, {2,{{0,0,0,0},{0,0,1,0}}}, {2,{{0,0,0,1},{0,0,0,2}}}, {2,{{0,0,0,0},{0,0,0,1}}}, {2,{{0,0,0,0},{1,0,0,0}}}, {2,{{0,0,0,2},{0,0,1,1}}}},
  // TDD Configuration Index 7
  { {2,{{0,0,0,1},{0,0,1,1}}}, {2,{{0,0,0,0},{0,0,1,0}}}, {0,{{0,0,0,0},{0,0,0,0}}}, {2,{{0,0,0,0},{0,0,0,2}}}, {0,{{0,0,0,0},{0,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0}}}, {2,{{0,0,0,1},{0,0,1,0}}}},
  // TDD Configuration Index 8
  { {2,{{0,0,0,0},{0,0,1,0}}}, {0,{{0,0,0,0},{0,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0}}}, {2,{{0,0,0,0},{0,0,0,1}}}, {0,{{0,0,0,0},{0,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0}}}, {2,{{0,0,0,0},{0,0,1,1}}}},
  // TDD Configuration Index 9
  { {3,{{0,0,0,1},{0,0,0,2},{0,0,1,2}}}, {3,{{0,0,0,0},{0,0,0,1},{0,0,1,1}}}, {3,{{0,0,0,0},{0,0,1,0},{1,0,0,0}}}, {3,{{0,0,0,0},{0,0,0,1},{0,0,0,2}}}, {3,{{0,0,0,0},{0,0,0,1},{1,0,0,1}}}, {3,{{0,0,0,0},{1,0,0,0},{2,0,0,0}}}, {3,{{0,0,0,1},{0,0,0,2},{0,0,1,1}}}},
  // TDD Configuration Index 10
  { {3,{{0,0,0,0},{0,0,1,0},{0,0,1,1}}}, {3,{{0,0,0,1},{0,0,1,0},{0,0,1,1}}}, {3,{{0,0,0,0},{0,0,1,0},{1,0,1,0}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0}}}, {3,{{0,0,0,0},{0,0,0,1},{1,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0}}}, {3,{{0,0,0,0},{0,0,0,2},{0,0,1,0}}}},
  // TDD Configuration Index 11
  { {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0}}}, {3,{{0,0,0,0},{0,0,0,1},{0,0,1,0}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0}}}, {3,{{0,0,0,1},{0,0,1,0},{0,0,1,1}}}},
  // TDD Configuration Index 12
  { {4,{{0,0,0,1},{0,0,0,2},{0,0,1,1},{0,0,1,2}}}, {4,{{0,0,0,0},{0,0,0,1},{0,0,1,0},{0,0,1,1}}},
    {4,{{0,0,0,0},{0,0,1,0},{1,0,0,0},{1,0,1,0}}},
    {4,{{0,0,0,0},{0,0,0,1},{0,0,0,2},{1,0,0,2}}},
    {4,{{0,0,0,0},{0,0,0,1},{1,0,0,0},{1,0,0,1}}},
    {4,{{0,0,0,0},{1,0,0,0},{2,0,0,0},{3,0,0,0}}},
    {4,{{0,0,0,1},{0,0,0,2},{0,0,1,0},{0,0,1,1}}}
  },
  // TDD Configuration Index 13
  { {4,{{0,0,0,0},{0,0,0,2},{0,0,1,0},{0,0,1,2}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {4,{{0,0,0,0},{0,0,0,1},{0,0,0,2},{1,0,0,1}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {4,{{0,0,0,0},{0,0,0,1},{0,0,0,2},{0,0,1,1}}}
  },
  // TDD Configuration Index 14
  { {4,{{0,0,0,0},{0,0,0,1},{0,0,1,0},{0,0,1,1}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {4,{{0,0,0,0},{0,0,0,1},{0,0,0,2},{1,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {4,{{0,0,0,0},{0,0,0,2},{0,0,1,0},{0,0,1,1}}}
  },
  // TDD Configuration Index 15
  { {5,{{0,0,0,0},{0,0,0,1},{0,0,0,2},{0,0,1,1},{0,0,1,2}}}, {5,{{0,0,0,0},{0,0,0,1},{0,0,1,0},{0,0,1,1},{1,0,0,1}}},
    {5,{{0,0,0,0},{0,0,1,0},{1,0,0,0},{1,0,1,0},{2,0,0,0}}}, {5,{{0,0,0,0},{0,0,0,1},{0,0,0,2},{1,0,0,1},{1,0,0,2}}},
    {5,{{0,0,0,0},{0,0,0,1},{1,0,0,0},{1,0,0,1},{2,0,0,1}}}, {5,{{0,0,0,0},{1,0,0,0},{2,0,0,0},{3,0,0,0},{4,0,0,0}}},
    {5,{{0,0,0,0},{0,0,0,1},{0,0,0,2},{0,0,1,0},{0,0,1,1}}}
  },
  // TDD Configuration Index 16
  { {5,{{0,0,0,1},{0,0,0,2},{0,0,1,0},{0,0,1,1},{0,0,1,2}}}, {5,{{0,0,0,0},{0,0,0,1},{0,0,1,0},{0,0,1,1},{1,0,1,1}}},
    {5,{{0,0,0,0},{0,0,1,0},{1,0,0,0},{1,0,1,0},{2,0,1,0}}}, {5,{{0,0,0,0},{0,0,0,1},{0,0,0,2},{1,0,0,0},{1,0,0,2}}},
    {5,{{0,0,0,0},{0,0,0,1},{1,0,0,0},{1,0,0,1},{2,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}}
  },
  // TDD Configuration Index 17
  { {5,{{0,0,0,0},{0,0,0,1},{0,0,0,2},{0,0,1,0},{0,0,1,2}}}, {5,{{0,0,0,0},{0,0,0,1},{0,0,1,0},{0,0,1,1},{1,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}}, {5,{{0,0,0,0},{0,0,0,1},{0,0,0,2},{1,0,0,0},{1,0,0,1}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}}
  },
  // TDD Configuration Index 18
  { {6,{{0,0,0,0},{0,0,0,1},{0,0,0,2},{0,0,1,0},{0,0,1,1},{0,0,1,2}}},
    {6,{{0,0,0,0},{0,0,0,1},{0,0,1,0},{0,0,1,1},{1,0,0,1},{1,0,1,1}}},
    {6,{{0,0,0,0},{0,0,1,0},{1,0,0,0},{1,0,1,0},{2,0,0,0},{2,0,1,0}}},
    {6,{{0,0,0,0},{0,0,0,1},{0,0,0,2},{1,0,0,0},{1,0,0,1},{1,0,0,2}}},
    {6,{{0,0,0,0},{0,0,0,1},{1,0,0,0},{1,0,0,1},{2,0,0,0},{2,0,0,1}}},
    {6,{{0,0,0,0},{1,0,0,0},{2,0,0,0},{3,0,0,0},{4,0,0,0},{5,0,0,0}}},
    {6,{{0,0,0,0},{0,0,0,1},{0,0,0,2},{0,0,1,0},{0,0,1,1},{1,0,0,2}}}
  },
  // TDD Configuration Index 19
  { {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {6,{{0,0,0,0},{0,0,0,1},{0,0,1,0},{0,0,1,1},{1,0,0,0},{1,0,1,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {6,{{0,0,0,0},{0,0,0,1},{0,0,0,2},{0,0,1,0},{0,0,1,1},{1,0,1,1}}}
  },
  // TDD Configuration Index 20
  { {1,{{0,1,0,1}}},{1,{{0,1,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,1,0,1}}}, {1,{{0,1,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,1,0,1}}}},
  // TDD Configuration Index 21
  { {1,{{0,2,0,1}}},{1,{{0,2,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,2,0,1}}}, {1,{{0,2,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,2,0,1}}}},

  // TDD Configuration Index 22
  { {1,{{0,1,1,1}}},{1,{{0,1,1,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,1,1,0}}}},

  // TDD Configuration Index 23
  { {1,{{0,0,0,1}}},{1,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,0,0,1}}}, {1,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,0,0,1}}}},

  // TDD Configuration Index 24
  { {1,{{0,0,1,1}}},{1,{{0,0,1,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,0,1,0}}}},

  // TDD Configuration Index 25
  { {2,{{0,0,0,1},{0,0,1,1}}}, {2,{{0,0,0,0},{0,0,1,0}}}, {0,{{0,0,0,0},{0,0,0,0}}}, {2,{{0,0,0,1},{1,0,0,1}}}, {2,{{0,0,0,0},{1,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0}}}, {2,{{0,0,0,1},{0,0,1,0}}}},

  // TDD Configuration Index 26
  { {3,{{0,0,0,1},{0,0,1,1},{1,0,0,1}}}, {3,{{0,0,0,0},{0,0,1,0},{1,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0}}}, {3,{{0,0,0,1},{1,0,0,1},{2,0,0,1}}}, {3,{{0,0,0,0},{1,0,0,0},{2,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0}}}, {3,{{0,0,0,1},{0,0,1,0},{1,0,0,1}}}},

  // TDD Configuration Index 27
  { {4,{{0,0,0,1},{0,0,1,1},{1,0,0,1},{1,0,1,1}}}, {4,{{0,0,0,0},{0,0,1,0},{1,0,0,0},{1,0,1,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {4,{{0,0,0,1},{1,0,0,1},{2,0,0,1},{3,0,0,1}}},
    {4,{{0,0,0,0},{1,0,0,0},{2,0,0,0},{3,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {4,{{0,0,0,1},{0,0,1,0},{1,0,0,1},{1,0,1,0}}}
  },

  // TDD Configuration Index 28
  { {5,{{0,0,0,1},{0,0,1,1},{1,0,0,1},{1,0,1,1},{2,0,0,1}}}, {5,{{0,0,0,0},{0,0,1,0},{1,0,0,0},{1,0,1,0},{2,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}}, {5,{{0,0,0,1},{1,0,0,1},{2,0,0,1},{3,0,0,1},{4,0,0,1}}},
    {5,{{0,0,0,0},{1,0,0,0},{2,0,0,0},{3,0,0,0},{4,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {5,{{0,0,0,1},{0,0,1,0},{1,0,0,1},{1,0,1,0},{2,0,0,1}}}
  },

  // TDD Configuration Index 29
  { {6,{{0,0,0,1},{0,0,1,1},{1,0,0,1},{1,0,1,1},{2,0,0,1},{2,0,1,1}}},
    {6,{{0,0,0,0},{0,0,1,0},{1,0,0,0},{1,0,1,0},{2,0,0,0},{2,0,1,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {6,{{0,0,0,1},{1,0,0,1},{2,0,0,1},{3,0,0,1},{4,0,0,1},{5,0,0,1}}},
    {6,{{0,0,0,0},{1,0,0,0},{2,0,0,0},{3,0,0,0},{4,0,0,0},{5,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {6,{{0,0,0,1},{0,0,1,0},{1,0,0,1},{1,0,1,0},{2,0,0,1},{2,0,1,0}}}
  },


  // TDD Configuration Index 30
  { {1,{{0,1,0,1}}},{1,{{0,1,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,1,0,1}}}, {1,{{0,1,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,1,0,1}}}},

  // TDD Configuration Index 31
  { {1,{{0,2,0,1}}},{1,{{0,2,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,2,0,1}}}, {1,{{0,2,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,2,0,1}}}},

  // TDD Configuration Index 32
  { {1,{{0,1,1,1}}},{1,{{0,1,1,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,1,1,0}}}},

  // TDD Configuration Index 33
  { {1,{{0,0,0,1}}},{1,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,0,0,1}}}, {1,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,0,0,1}}}},

  // TDD Configuration Index 34
  { {1,{{0,0,1,1}}},{1,{{0,0,1,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,0,1,0}}}},

  // TDD Configuration Index 35
  { {2,{{0,0,0,1},{0,0,1,1}}}, {2,{{0,0,0,0},{0,0,1,0}}}, {0,{{0,0,0,0},{0,0,0,0}}}, {2,{{0,0,0,1},{1,0,0,1}}}, {2,{{0,0,0,0},{1,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0}}}, {2,{{0,0,0,1},{0,0,1,0}}}},

  // TDD Configuration Index 36
  { {3,{{0,0,0,1},{0,0,1,1},{1,0,0,1}}}, {3,{{0,0,0,0},{0,0,1,0},{1,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0}}}, {3,{{0,0,0,1},{1,0,0,1},{2,0,0,1}}}, {3,{{0,0,0,0},{1,0,0,0},{2,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0}}}, {3,{{0,0,0,1},{0,0,1,0},{1,0,0,1}}}},

  // TDD Configuration Index 37
  { {4,{{0,0,0,1},{0,0,1,1},{1,0,0,1},{1,0,1,1}}}, {4,{{0,0,0,0},{0,0,1,0},{1,0,0,0},{1,0,1,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {4,{{0,0,0,1},{1,0,0,1},{2,0,0,1},{3,0,0,1}}},
    {4,{{0,0,0,0},{1,0,0,0},{2,0,0,0},{3,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {4,{{0,0,0,1},{0,0,1,0},{1,0,0,1},{1,0,1,0}}}
  },

  // TDD Configuration Index 38
  { {5,{{0,0,0,1},{0,0,1,1},{1,0,0,1},{1,0,1,1},{2,0,0,1}}}, {5,{{0,0,0,0},{0,0,1,0},{1,0,0,0},{1,0,1,0},{2,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}}, {5,{{0,0,0,1},{1,0,0,1},{2,0,0,1},{3,0,0,1},{4,0,0,1}}},
    {5,{{0,0,0,0},{1,0,0,0},{2,0,0,0},{3,0,0,0},{4,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {5,{{0,0,0,1},{0,0,1,0},{1,0,0,1},{1,0,1,0},{2,0,0,1}}}
  },

  // TDD Configuration Index 39
  { {6,{{0,0,0,1},{0,0,1,1},{1,0,0,1},{1,0,1,1},{2,0,0,1},{2,0,1,1}}},
    {6,{{0,0,0,0},{0,0,1,0},{1,0,0,0},{1,0,1,0},{2,0,0,0},{2,0,1,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {6,{{0,0,0,1},{1,0,0,1},{2,0,0,1},{3,0,0,1},{4,0,0,1},{5,0,0,1}}},
    {6,{{0,0,0,0},{1,0,0,0},{2,0,0,0},{3,0,0,0},{4,0,0,0},{5,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {6,{{0,0,0,1},{0,0,1,0},{1,0,0,1},{1,0,1,0},{2,0,0,1},{2,0,1,0}}}
  },

  // TDD Configuration Index 40
  { {1,{{0,1,0,0}}},{0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,1,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,1,0,0}}}},
  // TDD Configuration Index 41
  { {1,{{0,2,0,0}}},{0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,2,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,2,0,0}}}},

  // TDD Configuration Index 42
  { {1,{{0,1,1,0}}},{0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}},

  // TDD Configuration Index 43
  { {1,{{0,0,0,0}}},{0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {1,{{0,0,0,0}}}},

  // TDD Configuration Index 44
  { {1,{{0,0,1,0}}},{0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}, {0,{{0,0,0,0}}}},

  // TDD Configuration Index 45
  { {2,{{0,0,0,0},{0,0,1,0}}}, {0,{{0,0,0,0},{0,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0}}}, {2,{{0,0,0,0},{1,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0}}}, {2,{{0,0,0,0},{1,0,0,0}}}},

  // TDD Configuration Index 46
  { {3,{{0,0,0,0},{0,0,1,0},{1,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0}}}, {3,{{0,0,0,0},{1,0,0,0},{2,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0}}}, {3,{{0,0,0,0},{1,0,0,0},{2,0,0,0}}}},

  // TDD Configuration Index 47
  { {4,{{0,0,0,0},{0,0,1,0},{1,0,0,0},{1,0,1,0}}}, {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {4,{{0,0,0,0},{1,0,0,0},{2,0,0,0},{3,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {0,{{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}}},
    {4,{{0,0,0,0},{1,0,0,0},{2,0,0,0},{3,0,0,0}}}
  }
};



uint16_t prach_root_sequence_map0_3[838] = { 129, 710, 140, 699, 120, 719, 210, 629, 168, 671, 84, 755, 105, 734, 93, 746, 70, 769, 60, 779,
                                             2, 837, 1, 838,
                                             56, 783, 112, 727, 148, 691,
                                             80, 759, 42, 797, 40, 799,
                                             35, 804, 73, 766, 146, 693,
                                             31, 808, 28, 811, 30, 809, 27, 812, 29, 810,
                                             24, 815, 48, 791, 68, 771, 74, 765, 178, 661, 136, 703,
                                             86, 753, 78, 761, 43, 796, 39, 800, 20, 819, 21, 818,
                                             95, 744, 202, 637, 190, 649, 181, 658, 137, 702, 125, 714, 151, 688,
                                             217, 622, 128, 711, 142, 697, 122, 717, 203, 636, 118, 721, 110, 729, 89, 750, 103, 736, 61,
                                             778, 55, 784, 15, 824, 14, 825,
                                             12, 827, 23, 816, 34, 805, 37, 802, 46, 793, 207, 632, 179, 660, 145, 694, 130, 709, 223, 616,
                                             228, 611, 227, 612, 132, 707, 133, 706, 143, 696, 135, 704, 161, 678, 201, 638, 173, 666, 106,
                                             733, 83, 756, 91, 748, 66, 773, 53, 786, 10, 829, 9, 830,
                                             7, 832, 8, 831, 16, 823, 47, 792, 64, 775, 57, 782, 104, 735, 101, 738, 108, 731, 208, 631, 184,
                                             655, 197, 642, 191, 648, 121, 718, 141, 698, 149, 690, 216, 623, 218, 621,
                                             152, 687, 144, 695, 134, 705, 138, 701, 199, 640, 162, 677, 176, 663, 119, 720, 158, 681, 164,
                                             675, 174, 665, 171, 668, 170, 669, 87, 752, 169, 670, 88, 751, 107, 732, 81, 758, 82, 757, 100,
                                             739, 98, 741, 71, 768, 59, 780, 65, 774, 50, 789, 49, 790, 26, 813, 17, 822, 13, 826, 6, 833,
                                             5, 834, 33, 806, 51, 788, 75, 764, 99, 740, 96, 743, 97, 742, 166, 673, 172, 667, 175, 664, 187,
                                             652, 163, 676, 185, 654, 200, 639, 114, 725, 189, 650, 115, 724, 194, 645, 195, 644, 192, 647,
                                             182, 657, 157, 682, 156, 683, 211, 628, 154, 685, 123, 716, 139, 700, 212, 627, 153, 686, 213,
                                             626, 215, 624, 150, 689,
                                             225, 614, 224, 615, 221, 618, 220, 619, 127, 712, 147, 692, 124, 715, 193, 646, 205, 634, 206,
                                             633, 116, 723, 160, 679, 186, 653, 167, 672, 79, 760, 85, 754, 77, 762, 92, 747, 58, 781, 62,
                                             777, 69, 770, 54, 785, 36, 803, 32, 807, 25, 814, 18, 821, 11, 828, 4, 835,
                                             3, 836, 19, 820, 22, 817, 41, 798, 38, 801, 44, 795, 52, 787, 45, 794, 63, 776, 67, 772, 72,
                                             767, 76, 763, 94, 745, 102, 737, 90, 749, 109, 730, 165, 674, 111, 728, 209, 630, 204, 635, 117,
                                             722, 188, 651, 159, 680, 198, 641, 113, 726, 183, 656, 180, 659, 177, 662, 196, 643, 155, 684,
                                             214, 625, 126, 713, 131, 708, 219, 620, 222, 617, 226, 613,
                                             230, 609, 232, 607, 262, 577, 252, 587, 418, 421, 416, 423, 413, 426, 411, 428, 376, 463, 395,
                                             444, 283, 556, 285, 554, 379, 460, 390, 449, 363, 476, 384, 455, 388, 451, 386, 453, 361, 478,
                                             387, 452, 360, 479, 310, 529, 354, 485, 328, 511, 315, 524, 337, 502, 349, 490, 335, 504, 324,
                                             515,
                                             323, 516, 320, 519, 334, 505, 359, 480, 295, 544, 385, 454, 292, 547, 291, 548, 381, 458, 399,
                                             440, 380, 459, 397, 442, 369, 470, 377, 462, 410, 429, 407, 432, 281, 558, 414, 425, 247, 592,
                                             277, 562, 271, 568, 272, 567, 264, 575, 259, 580,
                                             237, 602, 239, 600, 244, 595, 243, 596, 275, 564, 278, 561, 250, 589, 246, 593, 417, 422, 248,
                                             591, 394, 445, 393, 446, 370, 469, 365, 474, 300, 539, 299, 540, 364, 475, 362, 477, 298, 541,
                                             312, 527, 313, 526, 314, 525, 353, 486, 352, 487, 343, 496, 327, 512, 350, 489, 326, 513, 319,
                                             520, 332, 507, 333, 506, 348, 491, 347, 492, 322, 517,
                                             330, 509, 338, 501, 341, 498, 340, 499, 342, 497, 301, 538, 366, 473, 401, 438, 371, 468, 408,
                                             431, 375, 464, 249, 590, 269, 570, 238, 601, 234, 605,
                                             257, 582, 273, 566, 255, 584, 254, 585, 245, 594, 251, 588, 412, 427, 372, 467, 282, 557, 403,
                                             436, 396, 443, 392, 447, 391, 448, 382, 457, 389, 450, 294, 545, 297, 542, 311, 528, 344, 495,
                                             345, 494, 318, 521, 331, 508, 325, 514, 321, 518,
                                             346, 493, 339, 500, 351, 488, 306, 533, 289, 550, 400, 439, 378, 461, 374, 465, 415, 424, 270,
                                             569, 241, 598,
                                             231, 608, 260, 579, 268, 571, 276, 563, 409, 430, 398, 441, 290, 549, 304, 535, 308, 531, 358,
                                             481, 316, 523,
                                             293, 546, 288, 551, 284, 555, 368, 471, 253, 586, 256, 583, 263, 576,
                                             242, 597, 274, 565, 402, 437, 383, 456, 357, 482, 329, 510,
                                             317, 522, 307, 532, 286, 553, 287, 552, 266, 573, 261, 578,
                                             236, 603, 303, 536, 356, 483,
                                             355, 484, 405, 434, 404, 435, 406, 433,
                                             235, 604, 267, 572, 302, 537,
                                             309, 530, 265, 574, 233, 606,
                                             367, 472, 296, 543,
                                             336, 503, 305, 534, 373, 466, 280, 559, 279, 560, 419, 420, 240, 599, 258, 581, 229, 610
                                           };

uint16_t prach_root_sequence_map4[138] = {  1,138,2,137,3,136,4,135,5,134,6,133,7,132,8,131,9,130,10,129,
                                            11,128,12,127,13,126,14,125,15,124,16,123,17,122,18,121,19,120,20,119,
                                            21,118,22,117,23,116,24,115,25,114,26,113,27,112,28,111,29,110,30,109,
                                            31,108,32,107,33,106,34,105,35,104,36,103,37,102,38,101,39,100,40,99,
                                            41,98,42,97,43,96,44,95,45,94,46,93,47,92,48,91,49,90,50,89,
                                            51,88,52,87,53,86,54,85,55,84,56,83,57,82,58,81,59,80,60,79,
                                            61,78,62,77,63,76,64,75,65,74,66,73,67,72,68,71,69,70
                                         };

#ifdef USER_MODE
void dump_prach_config(LTE_DL_FRAME_PARMS *frame_parms,uint8_t subframe)
{

  FILE *fd;

  fd = fopen("prach_config.txt","w");
  fprintf(fd,"prach_config: subframe          = %d\n",subframe);
  fprintf(fd,"prach_config: N_RB_UL           = %d\n",frame_parms->N_RB_UL);
  fprintf(fd,"prach_config: frame_type        = %s\n",(frame_parms->frame_type==1) ? "TDD":"FDD");

  if(frame_parms->frame_type==1) fprintf(fd,"prach_config: tdd_config        = %d\n",frame_parms->tdd_config);

  fprintf(fd,"prach_config: rootSequenceIndex = %d\n",frame_parms->prach_config_common.rootSequenceIndex);
  fprintf(fd,"prach_config: prach_ConfigIndex = %d\n",frame_parms->prach_config_common.prach_ConfigInfo.prach_ConfigIndex);
  fprintf(fd,"prach_config: Ncs_config        = %d\n",frame_parms->prach_config_common.prach_ConfigInfo.zeroCorrelationZoneConfig);
  fprintf(fd,"prach_config: highSpeedFlag     = %d\n",frame_parms->prach_config_common.prach_ConfigInfo.highSpeedFlag);
  fprintf(fd,"prach_config: n_ra_prboffset    = %d\n",frame_parms->prach_config_common.prach_ConfigInfo.prach_FreqOffset);
  fclose(fd);

}
#endif

// This function computes the du
void fill_du(uint8_t prach_fmt)
{

  uint16_t iu,u,p;
  uint16_t N_ZC;
  uint16_t *prach_root_sequence_map;

  if (prach_fmt<4) {
    N_ZC = 839;
    prach_root_sequence_map = prach_root_sequence_map0_3;
  } else {
    N_ZC = 139;
    prach_root_sequence_map = prach_root_sequence_map4;
  }

  for (iu=0; iu<(N_ZC-1); iu++) {

    u=prach_root_sequence_map[iu];
    p=1;

    while (((u*p)%N_ZC)!=1)
      p++;

    du[u] = ((p<(N_ZC>>1)) ? p : (N_ZC-p));
  }

}

uint8_t get_num_prach_tdd(LTE_DL_FRAME_PARMS *frame_parms)
{

  return(tdd_preamble_map[frame_parms->prach_config_common.prach_ConfigInfo.prach_ConfigIndex][frame_parms->tdd_config].num_prach);
}

uint8_t get_fid_prach_tdd(LTE_DL_FRAME_PARMS *frame_parms,uint8_t tdd_map_index)
{

  return(tdd_preamble_map[frame_parms->prach_config_common.prach_ConfigInfo.prach_ConfigIndex][frame_parms->tdd_config].map[tdd_map_index].f_ra);
}

uint8_t get_prach_fmt(uint8_t prach_ConfigIndex,lte_frame_type_t frame_type)
{

  if (frame_type == FDD) // FDD
    return(prach_ConfigIndex>>4);

  else {
    if (prach_ConfigIndex < 20)
      return (0);

    if (prach_ConfigIndex < 30)
      return (1);

    if (prach_ConfigIndex < 40)
      return (2);

    if (prach_ConfigIndex < 48)
      return (3);
    else
      return (4);
  }
}


int is_prach_subframe(LTE_DL_FRAME_PARMS *frame_parms,uint32_t frame, uint8_t subframe)
{

  uint8_t prach_ConfigIndex  = frame_parms->prach_config_common.prach_ConfigInfo.prach_ConfigIndex;
  uint8_t tdd_config         = frame_parms->tdd_config;
  uint8_t t0_ra;
  uint8_t t1_ra;
  uint8_t t2_ra;


  if (frame_parms->frame_type == FDD) { //FDD
    //implement Table 5.7.1-2 from 36.211 (Rel-10, p.41)
    if ((((frame&1) == 1) && (subframe < 9)) ||
        (((frame&1) == 0) && (subframe == 9)))  // This is an odd frame, ignore even-only PRACH frames
      if (((prach_ConfigIndex&0xf)<3) || // 0,1,2,16,17,18,32,33,34,48,49,50
          ((prach_ConfigIndex&0x1f)==18) || // 18,50
          ((prach_ConfigIndex&0xf)==15))   // 15,47
        return(0);

    switch (prach_ConfigIndex&0x1f) {
    case 0:
    case 3:
      return(subframe==1);
      break;

    case 1:
    case 4:
      return(subframe==4);
      break;

    case 2:
    case 5:
      return(subframe==7);
      break;

    case 6:
      return((subframe==1) || (subframe==6));
      break;

    case 7:
      return((subframe==2) || (subframe==7));
      break;

    case 8:
      return((subframe==3) || (subframe==8));
      break;

    case 9:
      return((subframe==1) || (subframe==4) || (subframe==7));
      break;

    case 10:
      return((subframe==2) || (subframe==5) || (subframe==8));
      break;

    case 11:
      return((subframe==3) || (subframe==6) || (subframe==9));
      break;

    case 12:
      return((subframe&1)==0);
      break;

    case 13:
      return((subframe&1)==1);
      break;

    case 14:
      return(1==1);
      break;

    case 15:
      return(subframe==9);
      break;
    }
  } else { // TDD

    if (prach_ConfigIndex>=64) {
      LOG_E(PHY,"[PHY] Illegal prach_ConfigIndex %d for ",prach_ConfigIndex);
      return(0);
    }

    if (tdd_preamble_map[prach_ConfigIndex][tdd_config].num_prach==0) {
      LOG_E(PHY,"[PHY] Illegal prach_ConfigIndex %d for ",prach_ConfigIndex);
      return(0);
    }

    t0_ra = tdd_preamble_map[prach_ConfigIndex][tdd_config].map[0].t0_ra;
    t1_ra = tdd_preamble_map[prach_ConfigIndex][tdd_config].map[0].t1_ra;
    t2_ra = tdd_preamble_map[prach_ConfigIndex][tdd_config].map[0].t2_ra;
#ifdef PRACH_DEBUG
    LOG_D(PHY,"[PRACH] Checking for PRACH format (ConfigIndex %d) in TDD subframe %d (%d,%d,%d)\n",
          prach_ConfigIndex,
          subframe,
          t0_ra,t1_ra,t2_ra);
#endif

    if ((((t0_ra == 1) && ((frame &1)==0))||  // frame is even and PRACH is in even frames
         ((t0_ra == 2) && ((frame &1)==1))||  // frame is odd and PRACH is in odd frames
         (t0_ra == 0)) &&                                // PRACH is in all frames
        (((subframe<5)&&(t1_ra==0)) ||                   // PRACH is in 1st half-frame
         (((subframe>4)&&(t1_ra==1))))) {                // PRACH is in 2nd half-frame
      if (prach_ConfigIndex<48)                          // PRACH only in normal UL subframe
        return((((subframe%5)-2)==t2_ra));
      else                                               // PRACH can be in UpPTS
        return((((subframe%5)-1)==t2_ra));
    } else
      return(1==2);
  }

  // shouldn't get here!
  return(2==1);
}

static short prach_tmp[45600*2] __attribute__((aligned(16)));

int32_t generate_prach(PHY_VARS_UE *phy_vars_ue,uint8_t eNB_id,uint8_t subframe, uint16_t Nf)
{

  lte_frame_type_t frame_type         = phy_vars_ue->lte_frame_parms.frame_type;
  uint8_t tdd_config         = phy_vars_ue->lte_frame_parms.tdd_config;
  uint16_t rootSequenceIndex = phy_vars_ue->lte_frame_parms.prach_config_common.rootSequenceIndex;
  uint8_t prach_ConfigIndex  = phy_vars_ue->lte_frame_parms.prach_config_common.prach_ConfigInfo.prach_ConfigIndex;
  uint8_t Ncs_config         = phy_vars_ue->lte_frame_parms.prach_config_common.prach_ConfigInfo.zeroCorrelationZoneConfig;
  uint8_t restricted_set     = phy_vars_ue->lte_frame_parms.prach_config_common.prach_ConfigInfo.highSpeedFlag;
  uint8_t n_ra_prboffset     = phy_vars_ue->lte_frame_parms.prach_config_common.prach_ConfigInfo.prach_FreqOffset;
  uint8_t preamble_index     = phy_vars_ue->prach_resources[eNB_id]->ra_PreambleIndex;
  uint8_t tdd_mapindex       = phy_vars_ue->prach_resources[eNB_id]->ra_TDD_map_index;
  int16_t *prachF           = phy_vars_ue->lte_ue_prach_vars[eNB_id]->prachF;
  int16_t *prach            = (int16_t*)prach_tmp;
  int16_t *prach2;
  int16_t amp               = phy_vars_ue->lte_ue_prach_vars[eNB_id]->amp;
  int16_t Ncp;
  uint8_t n_ra_prb;
  uint16_t NCS;
  uint16_t *prach_root_sequence_map;
  uint16_t preamble_offset,preamble_shift;
  uint16_t preamble_index0,n_shift_ra,n_shift_ra_bar;
  uint16_t d_start,n_group_ra,numshift;

  uint8_t prach_fmt = get_prach_fmt(prach_ConfigIndex,frame_type);
  uint8_t Nsp=2;
  uint8_t f_ra,t1_ra;
  uint16_t N_ZC = (prach_fmt<4)?839:139;
  uint8_t not_found;
  int k;
  int16_t *Xu;
  uint16_t u;
  int32_t Xu_re,Xu_im;
  uint16_t offset,offset2;
  int prach_start;
#ifdef EXMIMO
  int overflow,j;
#endif
  int i, prach_len;
  uint16_t first_nonzero_root_idx=0;

  //LOG_I(PHY,"[PRACH] prach_start=%d\n",prach_start);

#ifdef BIT8_TX
  prach_start = ((subframe*phy_vars_ue->lte_frame_parms.samples_per_tti)<<1)-phy_vars_ue->N_TA_offset;
#else
#ifdef EXMIMO
  prach_start =  (phy_vars_ue->rx_offset+subframe*phy_vars_ue->lte_frame_parms.samples_per_tti-openair_daq_vars.timing_advance-phy_vars_ue->N_TA_offset);

  if (prach_start<0)
    prach_start+=(phy_vars_ue->lte_frame_parms.samples_per_tti*LTE_NUMBER_OF_SUBFRAMES_PER_FRAME);

  if (prach_start>=(phy_vars_ue->lte_frame_parms.samples_per_tti*LTE_NUMBER_OF_SUBFRAMES_PER_FRAME))
    prach_start-=(phy_vars_ue->lte_frame_parms.samples_per_tti*LTE_NUMBER_OF_SUBFRAMES_PER_FRAME);

#else //normal case (simulation)
  prach_start = subframe*phy_vars_ue->lte_frame_parms.samples_per_tti-phy_vars_ue->N_TA_offset;
#endif
#endif

  // First compute physical root sequence
  if (restricted_set == 0) {
    if (Ncs_config>15) {
      LOG_E(PHY,"[PHY] FATAL, Illegal Ncs_config for unrestricted format %d\n",Ncs_config);
      mac_xface->macphy_exit("PRACH: Illegal Ncs_config for unrestricted format");
      return 0; // not reached
    }

    NCS = NCS_unrestricted[Ncs_config];
  } else {
    if (Ncs_config>14) {
      LOG_E(PHY,"[PHY] FATAL, Illegal Ncs_config for restricted format %d\n",Ncs_config);
      mac_xface->macphy_exit("PRACH: Illegal Ncs_config for restricted format");
      return 0; // not reached
    }

    NCS = NCS_restricted[Ncs_config];
  }

  n_ra_prb = n_ra_prboffset;
  prach_root_sequence_map = (prach_fmt<4) ? prach_root_sequence_map0_3 : prach_root_sequence_map4;

  if (frame_type == TDD) { // TDD

    if (tdd_preamble_map[prach_ConfigIndex][tdd_config].num_prach==0) {
      LOG_E(PHY,"[PHY][UE %d] Illegal prach_ConfigIndex %d for ",phy_vars_ue->Mod_id,prach_ConfigIndex);
    }

    // adjust n_ra_prboffset for frequency multiplexing (p.36 36.211)
    f_ra = tdd_preamble_map[prach_ConfigIndex][tdd_config].map[tdd_mapindex].f_ra;

    if (prach_fmt < 4) {
      if ((f_ra&1) == 0) {
        n_ra_prb = n_ra_prboffset + 6*(f_ra>>1);
      } else {
        n_ra_prb = phy_vars_ue->lte_frame_parms.N_RB_UL - 6 - n_ra_prboffset + 6*(f_ra>>1);
      }
    } else {
      if ((tdd_config >2) && (tdd_config<6))
        Nsp = 2;

      t1_ra = tdd_preamble_map[prach_ConfigIndex][tdd_config].map[0].t1_ra;

      if ((((Nf&1)*(2-Nsp)+t1_ra)&1) == 0) {
        n_ra_prb = 6*f_ra;
      } else {
        n_ra_prb = phy_vars_ue->lte_frame_parms.N_RB_UL - 6*(f_ra+1);
      }
    }
  }

  // This is the relative offset (for unrestricted case) in the root sequence table (5.7.2-4 from 36.211) for the given preamble index
  preamble_offset = ((NCS==0)? preamble_index : (preamble_index/(N_ZC/NCS)));

  if (restricted_set == 0) {
    // This is the \nu corresponding to the preamble index
    preamble_shift  = (NCS==0)? 0 : (preamble_index % (N_ZC/NCS));
    preamble_shift *= NCS;
  } else { // This is the high-speed case

#ifdef PRACH_DEBUG
    LOG_D(PHY,"[UE %d] High-speed mode, NCS_config %d\n",phy_vars_ue->Mod_id,Ncs_config);
#endif

    not_found = 1;
    preamble_index0 = preamble_index;
    // set preamble_offset to initial rootSequenceIndex and look if we need more root sequences for this
    // preamble index and find the corresponding cyclic shift
    preamble_offset = 0; // relative rootSequenceIndex;

    while (not_found == 1) {
      // current root depending on rootSequenceIndex and preamble_offset
      int index = (rootSequenceIndex + preamble_offset) % N_ZC;

      if (prach_fmt<4) {
        // prach_root_sequence_map points to prach_root_sequence_map0_3
        DevAssert( index < sizeof(prach_root_sequence_map0_3) / sizeof(prach_root_sequence_map0_3[0]) );
      } else {
        // prach_root_sequence_map points to prach_root_sequence_map4
        DevAssert( index < sizeof(prach_root_sequence_map4) / sizeof(prach_root_sequence_map4[0]) );
      }

      u = prach_root_sequence_map[index];

      if ( (du[u]<(N_ZC/3)) && (du[u]>=NCS) ) {
        n_shift_ra     = du[u]/NCS;
        d_start        = (du[u]<<1) + (n_shift_ra * NCS);
        n_group_ra     = N_ZC/d_start;
        n_shift_ra_bar = max(0,(N_ZC-(du[u]<<1)-(n_group_ra*d_start))/N_ZC);
      } else if  ( (du[u]>=(N_ZC/3)) && (du[u]<=((N_ZC - NCS)>>1)) ) {
        n_shift_ra     = (N_ZC - (du[u]<<1))/NCS;
        d_start        = N_ZC - (du[u]<<1) + (n_shift_ra * NCS);
        n_group_ra     = du[u]/d_start;
        n_shift_ra_bar = min(n_shift_ra,max(0,(du[u]- (n_group_ra*d_start))/NCS));
      } else {
        n_shift_ra     = 0;
        n_shift_ra_bar = 0;
      }

      // This is the number of cyclic shifts for the current root u
      numshift = (n_shift_ra*n_group_ra) + n_shift_ra_bar;

      if (numshift>0 && preamble_index0==preamble_index)
        first_nonzero_root_idx = preamble_offset;

      if (preamble_index0 < numshift) {
        not_found      = 0;
        preamble_shift = (d_start * (preamble_index0/n_shift_ra)) + ((preamble_index0%n_shift_ra)*NCS);

      } else { // skip to next rootSequenceIndex and recompute parameters
        preamble_offset++;
        preamble_index0 -= numshift;
      }
    }
  }

  // now generate PRACH signal
#ifdef PRACH_DEBUG

  if (NCS>0)
    LOG_D(PHY,"Generate PRACH for RootSeqIndex %d, Preamble Index %d, NCS %d (NCS_config %d, N_ZC/NCS %d) n_ra_prb %d: Preamble_offset %d, Preamble_shift %d\n",
          rootSequenceIndex,preamble_index,NCS,Ncs_config,N_ZC/NCS,n_ra_prb,
          preamble_offset,preamble_shift);

#endif

  //  nsymb = (frame_parms->Ncp==0) ? 14:12;
  //  subframe_offset = (unsigned int)frame_parms->ofdm_symbol_size*subframe*nsymb;

  k = (12*n_ra_prb) - 6*phy_vars_ue->lte_frame_parms.N_RB_UL;

  if (k<0)
    k+=phy_vars_ue->lte_frame_parms.ofdm_symbol_size;

  k*=12;
  k+=13;

  Xu = (int16_t*)phy_vars_ue->X_u[preamble_offset-first_nonzero_root_idx];

  /*
    k+=(12*phy_vars_ue->lte_frame_parms.first_carrier_offset);
    if (k>(12*phy_vars_ue->lte_frame_parms.ofdm_symbol_size))
    k-=(12*phy_vars_ue->lte_frame_parms.ofdm_symbol_size);
  */
  k*=2;

  switch (phy_vars_ue->lte_frame_parms.N_RB_UL) {
  case 6:
    memset((void*)prachF,0,4*1536);
    break;

  case 15:
    memset((void*)prachF,0,4*3072);
    break;

  case 25:
    memset((void*)prachF,0,4*6144);
    break;

  case 50:
    memset((void*)prachF,0,4*12288);
    break;

  case 75:
    memset((void*)prachF,0,4*19432);
    break;

  case 100:
    memset((void*)prachF,0,4*24576);
    break;
  }

  for (offset=0,offset2=0; offset<N_ZC; offset++,offset2+=preamble_shift) {

    if (offset2 >= N_ZC)
      offset2 -= N_ZC;

    Xu_re = (((int32_t)Xu[offset<<1]*amp)>>15);
    Xu_im = (((int32_t)Xu[1+(offset<<1)]*amp)>>15);
    prachF[k++]= ((Xu_re*ru[offset2<<1]) - (Xu_im*ru[1+(offset2<<1)]))>>15;
    prachF[k++]= ((Xu_im*ru[offset2<<1]) + (Xu_re*ru[1+(offset2<<1)]))>>15;

    if (k==(12*2*phy_vars_ue->lte_frame_parms.ofdm_symbol_size))
      k=0;
  }

  switch (prach_fmt) {
  case 0:
    Ncp = 3168;
    break;

  case 1:
  case 3:
    Ncp = 21024;
    break;

  case 2:
    Ncp = 6240;
    break;

  case 4:
    Ncp = 448;
    break;

  default:
    Ncp = 3168;
    break;
  }

  switch (phy_vars_ue->lte_frame_parms.N_RB_UL) {
  case 6:
    Ncp>>=4;
    prach+=4; // makes prach2 aligned to 128-bit
    break;

  case 15:
    Ncp>>=3;
    break;

  case 25:
    Ncp>>=2;
    break;

  case 50:
    Ncp>>=1;
    break;

  case 75:
    Ncp=(Ncp*3)>>2;
    break;
  }


  prach2 = prach+(Ncp<<1);

  // do IDFT
  switch (phy_vars_ue->lte_frame_parms.N_RB_UL) {
  case 6:
    if (prach_fmt == 4) {
      fft(prachF,prach2,twiddle_ifft256,rev256,8,4,0);
      //TODO: account for repeated format in fft output
      memcpy((void*)prach<