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p25p1_ldu2.c
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p25p1_ldu2.c
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/*
* Copyright (C) 2010 DSD Author
* GPG Key ID: 0x3F1D7FD0 (74EF 430D F7F2 0A48 FCE6 F630 FAA2 635D 3F1D 7FD0)
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
#include "dsd.h"
#include "p25p1_const.h"
#include "p25p1_ldu.h"
#include "p25p1_check_ldu.h"
#include "p25p1_hdu.h"
void
processLDU2 (dsd_opts * opts, dsd_state * state)
{
// extracts IMBE frames from LDU frame
int i;
char mi[73], algid[9], kid[17];
char lsd1[9], lsd2[9];
int algidhex, kidhex;
int status_count;
char hex_data[16][6]; // Data in hex-words (6 bit words). A total of 16 hex words.
char hex_parity[8][6]; // Parity of the data, again in hex-word format. A total of 12 parity hex words.
int irrecoverable_errors;
AnalogSignal analog_signal_array[16*(3+2)+8*(3+2)];
int analog_signal_index;
analog_signal_index = 0;
// we skip the status dibits that occur every 36 symbols
// the first IMBE frame starts 14 symbols before next status
// so we start counter at 36-14-1 = 21
status_count = 21;
if (opts->errorbars == 1)
{
printf ("e:");
}
// IMBE 1
#ifdef TRACE_DSD
state->debug_prefix_2 = '0';
#endif
process_IMBE (opts, state, &status_count);
// IMBE 2
#ifdef TRACE_DSD
state->debug_prefix_2 = '1';
#endif
process_IMBE (opts, state, &status_count);
// Read data after IMBE 2
read_and_correct_hex_word (opts, state, &(hex_data[15][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_data[14][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_data[13][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_data[12][0]), &status_count, analog_signal_array, &analog_signal_index);
analog_signal_array[0*5].sequence_broken = 1;
// IMBE 3
#ifdef TRACE_DSD
state->debug_prefix_2 = '2';
#endif
process_IMBE (opts, state, &status_count);
// Read data after IMBE 3
read_and_correct_hex_word (opts, state, &(hex_data[11][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_data[10][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_data[ 9][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_data[ 8][0]), &status_count, analog_signal_array, &analog_signal_index);
analog_signal_array[4*5].sequence_broken = 1;
// IMBE 4
#ifdef TRACE_DSD
state->debug_prefix_2 = '3';
#endif
process_IMBE (opts, state, &status_count);
// Read data after IMBE 4
read_and_correct_hex_word (opts, state, &(hex_data[ 7][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_data[ 6][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_data[ 5][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_data[ 4][0]), &status_count, analog_signal_array, &analog_signal_index);
analog_signal_array[8*5].sequence_broken = 1;
// IMBE 5
#ifdef TRACE_DSD
state->debug_prefix_2 = '4';
#endif
process_IMBE (opts, state, &status_count);
// Read data after IMBE 5
read_and_correct_hex_word (opts, state, &(hex_data[ 3][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_data[ 2][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_data[ 1][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_data[ 0][0]), &status_count, analog_signal_array, &analog_signal_index);
analog_signal_array[12*5].sequence_broken = 1;
// IMBE 6
#ifdef TRACE_DSD
state->debug_prefix_2 = '5';
#endif
process_IMBE (opts, state, &status_count);
// Read data after IMBE 6
read_and_correct_hex_word (opts, state, &(hex_parity[ 7][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_parity[ 6][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_parity[ 5][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_parity[ 4][0]), &status_count, analog_signal_array, &analog_signal_index);
analog_signal_array[16*5].sequence_broken = 1;
// IMBE 7
#ifdef TRACE_DSD
state->debug_prefix_2 = '6';
#endif
process_IMBE (opts, state, &status_count);
// Read data after IMBE 7
read_and_correct_hex_word (opts, state, &(hex_parity[ 3][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_parity[ 2][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_parity[ 1][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_parity[ 0][0]), &status_count, analog_signal_array, &analog_signal_index);
analog_signal_array[20*5].sequence_broken = 1;
// IMBE 8
#ifdef TRACE_DSD
state->debug_prefix_2 = '7';
#endif
process_IMBE (opts, state, &status_count);
// Read data after IMBE 8: LSD (low speed data)
{
char lsd[8];
char cyclic_parity[8];
for (i=0; i<=6; i+=2)
{
read_dibit(opts, state, lsd+i, &status_count, NULL, NULL);
}
for (i=0; i<=6; i+=2)
{
read_dibit(opts, state, cyclic_parity+i, &status_count, NULL, NULL);
}
for (i=0; i<8; i++)
{
lsd1[i] = lsd[i] + '0';
}
for (i=0; i<=6; i+=2)
{
read_dibit(opts, state, lsd+i, &status_count, NULL, NULL);
}
for (i=0; i<=6; i+=2)
{
read_dibit(opts, state, cyclic_parity+i, &status_count, NULL, NULL);
}
for (i=0; i<8; i++)
{
lsd2[i] = lsd[i] + '0';
}
// TODO: error correction of the LSD bytes...
// TODO: do something useful with the LSD bytes...
}
// IMBE 9
#ifdef TRACE_DSD
state->debug_prefix_2 = '8';
#endif
process_IMBE (opts, state, &status_count);
if (opts->errorbars == 1)
{
printf ("\n");
}
if (opts->p25status == 1)
{
printf ("lsd1: %s lsd2: %s\n", lsd1, lsd2);
}
// trailing status symbol
{
int status;
status = getDibit (opts, state) + '0';
// TODO: do something useful with the status bits...
}
// Error correct the hex_data using Reed-Solomon hex_parity
irrecoverable_errors = check_and_fix_reedsolomon_24_16_9((char*)hex_data, (char*)hex_parity);
if (irrecoverable_errors == 1)
{
state->debug_header_critical_errors++;
// We can correct (9-1)/2 = 4 errors. If we failed, it means that there were more than 4 errors in
// these 12+12 words. But take into account that each hex word was already error corrected with
// Hamming(10,6,3), which can correct 1 bits on each sequence of (6+4) bits. We could say that there
// were 5 errors of 2 bits.
update_error_stats(&state->p25_heuristics, 12*6+12*6, 5*2);
}
else
{
// Same comments as in processHDU. See there.
char fixed_parity[8*6];
// Correct the dibits that we read according with hex_data values
correct_hamming_dibits((char*)hex_data, 16, analog_signal_array);
// Generate again the Reed-Solomon parity
encode_reedsolomon_24_16_9((char*)hex_data, fixed_parity);
// Correct the dibits that we read according with the fixed parity values
correct_hamming_dibits(fixed_parity, 8, analog_signal_array+16*(3+2));
// Once corrected, contribute this information to the heuristics module
contribute_to_heuristics(state->rf_mod, &(state->p25_heuristics), analog_signal_array, 16*(3+2)+8*(3+2));
}
#ifdef HEURISTICS_DEBUG
printf("(audio errors, header errors, critical header errors) (%i,%i,%i)\n",
state->debug_audio_errors, state->debug_header_errors, state->debug_header_critical_errors);
#endif
// Now put the corrected data into the DSD structures
mi[72] = 0;
algid[8] = 0;
kid[16] = 0;
lsd1[8] = 0;
lsd2[8] = 0;
mi[ 0] = hex_data[15][0] + '0';
mi[ 1] = hex_data[15][1] + '0';
mi[ 2] = hex_data[15][2] + '0';
mi[ 3] = hex_data[15][3] + '0';
mi[ 4] = hex_data[15][4] + '0';
mi[ 5] = hex_data[15][5] + '0';
mi[ 6] = hex_data[14][0] + '0';
mi[ 7] = hex_data[14][1] + '0';
mi[ 8] = hex_data[14][2] + '0';
mi[ 9] = hex_data[14][3] + '0';
mi[10] = hex_data[14][4] + '0';
mi[11] = hex_data[14][5] + '0';
mi[12] = hex_data[13][0] + '0';
mi[13] = hex_data[13][1] + '0';
mi[14] = hex_data[13][2] + '0';
mi[15] = hex_data[13][3] + '0';
mi[16] = hex_data[13][4] + '0';
mi[17] = hex_data[13][5] + '0';
mi[18] = hex_data[12][0] + '0';
mi[19] = hex_data[12][1] + '0';
mi[20] = hex_data[12][2] + '0';
mi[21] = hex_data[12][3] + '0';
mi[22] = hex_data[12][4] + '0';
mi[23] = hex_data[12][5] + '0';
mi[24] = hex_data[11][0] + '0';
mi[25] = hex_data[11][1] + '0';
mi[26] = hex_data[11][2] + '0';
mi[27] = hex_data[11][3] + '0';
mi[28] = hex_data[11][4] + '0';
mi[29] = hex_data[11][5] + '0';
mi[30] = hex_data[10][0] + '0';
mi[31] = hex_data[10][1] + '0';
mi[32] = hex_data[10][2] + '0';
mi[33] = hex_data[10][3] + '0';
mi[34] = hex_data[10][4] + '0';
mi[35] = hex_data[10][5] + '0';
mi[36] = hex_data[ 9][0] + '0';
mi[37] = hex_data[ 9][1] + '0';
mi[38] = hex_data[ 9][2] + '0';
mi[39] = hex_data[ 9][3] + '0';
mi[40] = hex_data[ 9][4] + '0';
mi[41] = hex_data[ 9][5] + '0';
mi[42] = hex_data[ 8][0] + '0';
mi[43] = hex_data[ 8][1] + '0';
mi[44] = hex_data[ 8][2] + '0';
mi[45] = hex_data[ 8][3] + '0';
mi[46] = hex_data[ 8][4] + '0';
mi[47] = hex_data[ 8][5] + '0';
mi[48] = hex_data[ 7][0] + '0';
mi[49] = hex_data[ 7][1] + '0';
mi[50] = hex_data[ 7][2] + '0';
mi[51] = hex_data[ 7][3] + '0';
mi[52] = hex_data[ 7][4] + '0';
mi[53] = hex_data[ 7][5] + '0';
mi[54] = hex_data[ 6][0] + '0';
mi[55] = hex_data[ 6][1] + '0';
mi[56] = hex_data[ 6][2] + '0';
mi[57] = hex_data[ 6][3] + '0';
mi[58] = hex_data[ 6][4] + '0';
mi[59] = hex_data[ 6][5] + '0';
mi[60] = hex_data[ 5][0] + '0';
mi[61] = hex_data[ 5][1] + '0';
mi[62] = hex_data[ 5][2] + '0';
mi[63] = hex_data[ 5][3] + '0';
mi[64] = hex_data[ 5][4] + '0';
mi[65] = hex_data[ 5][5] + '0';
mi[66] = hex_data[ 4][0] + '0';
mi[67] = hex_data[ 4][1] + '0';
mi[68] = hex_data[ 4][2] + '0';
mi[69] = hex_data[ 4][3] + '0';
mi[70] = hex_data[ 4][4] + '0';
mi[71] = hex_data[ 4][5] + '0';
algid[0] = hex_data[ 3][0] + '0';
algid[1] = hex_data[ 3][1] + '0';
algid[2] = hex_data[ 3][2] + '0';
algid[3] = hex_data[ 3][3] + '0';
algid[4] = hex_data[ 3][4] + '0';
algid[5] = hex_data[ 3][5] + '0';
algid[6] = hex_data[ 2][0] + '0';
algid[7] = hex_data[ 2][1] + '0';
kid[0] = hex_data[ 2][2] + '0';
kid[1] = hex_data[ 2][3] + '0';
kid[2] = hex_data[ 2][4] + '0';
kid[3] = hex_data[ 2][5] + '0';
kid[4] = hex_data[ 1][0] + '0';
kid[5] = hex_data[ 1][1] + '0';
kid[6] = hex_data[ 1][2] + '0';
kid[7] = hex_data[ 1][3] + '0';
kid[8] = hex_data[ 1][4] + '0';
kid[9] = hex_data[ 1][5] + '0';
kid[10] = hex_data[ 0][0] + '0';
kid[11] = hex_data[ 0][1] + '0';
kid[12] = hex_data[ 0][2] + '0';
kid[13] = hex_data[ 0][3] + '0';
kid[14] = hex_data[ 0][4] + '0';
kid[15] = hex_data[ 0][5] + '0';
if (opts->p25enc == 1)
{
algidhex = strtol (algid, NULL, 2);
kidhex = strtol (kid, NULL, 2);
printf ("mi: %s algid: $%x kid: $%x\n", mi, algidhex, kidhex);
}
}