/**
* Update the model of a symbol's Gaussian with new information.
* \param heuristics Pointer to the P25Heuristics module with all the needed state information.
* \param previous_dibit The cleared previous dibit value.
* \param original_dibit The current dibit as it was interpreted initially.
* \param dibit The current dibit. Will be different from original_dibit if the FEC fixed it.
* \param analog_value The actual analog signal value from which the original_dibit was derived.
*/
static void update_p25_heuristics(P25Heuristics* heuristics, int previous_dibit, int original_dibit, int dibit, int analog_value)
{
float mean;
int old_value;
float old_mean;
SymbolHeuristics* sh;
int number_errors;
#ifndef USE_PREVIOUS_DIBIT
previous_dibit = 0;
#endif
// Locate the Gaussian (SymbolHeuristics structure) we are going to update
sh = &(heuristics->symbols[previous_dibit][dibit]);
// Update the circular buffers of values
old_value = sh->values[sh->index];
old_mean = sh->means[sh->index];
// Update the BER statistics
number_errors = 0;
if (original_dibit != dibit) {
if ((original_dibit == 0 && dibit == 3) || (original_dibit == 3 && dibit == 0) ||
(original_dibit == 1 && dibit == 2) || (original_dibit == 2 && dibit == 1)) {
// Interpreting a "00" as "11", "11" as "00", "01" as "10" or "10" as "01" counts as 2 errors
number_errors = 2;
} else {
// The other 8 combinations count (where original_dibit != dibit) as 1 error.
number_errors = 1;
}
}
update_error_stats(heuristics, 2, number_errors);
// Update the running mean and variance. This is to calculate the PDF faster when required
if (sh->count >= HEURISTICS_SIZE) {
sh->sum -= old_value;
sh->var_sum -= (((float)old_value) - old_mean) * (((float)old_value) - old_mean);
}
sh->sum += analog_value;
sh->values[sh->index] = analog_value;
if (sh->count < HEURISTICS_SIZE) {
sh->count++;
}
mean = sh->sum / ((float)sh->count);
sh->means[sh->index] = mean;
if (sh->index >= (HEURISTICS_SIZE-1)) {
sh->index = 0;
} else {
sh->index++;
}
sh->var_sum += (((float)analog_value) - mean) * (((float)analog_value) - mean);
}
void
processLDU1 (dsd_opts* opts, dsd_state* state)
{
// extracts IMBE frames from LDU frame
int i;
char lcformat[9], mfid[9], lcinfo[57];
char lsd1[9], lsd2[9];
int status_count;
char hex_data[12][6]; // Data in hex-words (6 bit words). A total of 12 hex words.
char hex_parity[12][6]; // Parity of the data, again in hex-word format. A total of 12 parity hex words.
int irrecoverable_errors;
AnalogSignal analog_signal_array[12*(3+2)+12*(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[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[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[ 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[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[ 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[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_parity[11][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_parity[10][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_parity[ 9][0]), &status_count, analog_signal_array, &analog_signal_index);
read_and_correct_hex_word (opts, state, &(hex_parity[ 8][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_12_13((char*)hex_data, (char*)hex_parity);
if (irrecoverable_errors == 1)
{
state->debug_header_critical_errors++;
// We can correct (13-1)/2 = 6 errors. If we failed, it means that there were more than 6 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 7 errors of 2 bits.
update_error_stats(&state->p25_heuristics, 12*6+12*6, 7*2);
}
else
{
// Same comments as in processHDU. See there.
char fixed_parity[12*6];
// Correct the dibits that we read according with hex_data values
correct_hamming_dibits((char*)hex_data, 12, analog_signal_array);
// Generate again the Reed-Solomon parity
encode_reedsolomon_24_12_13((char*)hex_data, fixed_parity);
// Correct the dibits that we read according with the fixed parity values
correct_hamming_dibits(fixed_parity, 12, analog_signal_array+12*(3+2));
// Once corrected, contribute this information to the heuristics module
contribute_to_heuristics(state->rf_mod, &(state->p25_heuristics), analog_signal_array, 12*(3+2)+12*(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
lcformat[8] = 0;
mfid[8] = 0;
lcinfo[56] = 0;
lsd1[8] = 0;
lsd2[8] = 0;
lcformat[0] = hex_data[11][0] + '0';
lcformat[1] = hex_data[11][1] + '0';
lcformat[2] = hex_data[11][2] + '0';
lcformat[3] = hex_data[11][3] + '0';
lcformat[4] = hex_data[11][4] + '0';
lcformat[5] = hex_data[11][5] + '0';
lcformat[6] = hex_data[10][0] + '0';
lcformat[7] = hex_data[10][1] + '0';
mfid[0] = hex_data[10][2] + '0';
mfid[1] = hex_data[10][3] + '0';
mfid[2] = hex_data[10][4] + '0';
mfid[3] = hex_data[10][5] + '0';
mfid[4] = hex_data[ 9][0] + '0';
mfid[5] = hex_data[ 9][1] + '0';
mfid[6] = hex_data[ 9][2] + '0';
mfid[7] = hex_data[ 9][3] + '0';
lcinfo[0] = hex_data[ 9][4] + '0';
lcinfo[1] = hex_data[ 9][5] + '0';
lcinfo[2] = hex_data[ 8][0] + '0';
lcinfo[3] = hex_data[ 8][1] + '0';
lcinfo[4] = hex_data[ 8][2] + '0';
lcinfo[5] = hex_data[ 8][3] + '0';
lcinfo[6] = hex_data[ 8][4] + '0';
lcinfo[7] = hex_data[ 8][5] + '0';
lcinfo[8] = hex_data[ 7][0] + '0';
lcinfo[9] = hex_data[ 7][1] + '0';
lcinfo[10] = hex_data[ 7][2] + '0';
lcinfo[11] = hex_data[ 7][3] + '0';
lcinfo[12] = hex_data[ 7][4] + '0';
lcinfo[13] = hex_data[ 7][5] + '0';
lcinfo[14] = hex_data[ 6][0] + '0';
lcinfo[15] = hex_data[ 6][1] + '0';
lcinfo[16] = hex_data[ 6][2] + '0';
lcinfo[17] = hex_data[ 6][3] + '0';
lcinfo[18] = hex_data[ 6][4] + '0';
lcinfo[19] = hex_data[ 6][5] + '0';
lcinfo[20] = hex_data[ 5][0] + '0';
lcinfo[21] = hex_data[ 5][1] + '0';
lcinfo[22] = hex_data[ 5][2] + '0';
lcinfo[23] = hex_data[ 5][3] + '0';
lcinfo[24] = hex_data[ 5][4] + '0';
lcinfo[25] = hex_data[ 5][5] + '0';
lcinfo[26] = hex_data[ 4][0] + '0';
lcinfo[27] = hex_data[ 4][1] + '0';
lcinfo[28] = hex_data[ 4][2] + '0';
lcinfo[29] = hex_data[ 4][3] + '0';
lcinfo[30] = hex_data[ 4][4] + '0';
lcinfo[31] = hex_data[ 4][5] + '0';
lcinfo[32] = hex_data[ 3][0] + '0';
lcinfo[33] = hex_data[ 3][1] + '0';
lcinfo[34] = hex_data[ 3][2] + '0';
lcinfo[35] = hex_data[ 3][3] + '0';
lcinfo[36] = hex_data[ 3][4] + '0';
lcinfo[37] = hex_data[ 3][5] + '0';
lcinfo[38] = hex_data[ 2][0] + '0';
lcinfo[39] = hex_data[ 2][1] + '0';
lcinfo[40] = hex_data[ 2][2] + '0';
lcinfo[41] = hex_data[ 2][3] + '0';
lcinfo[42] = hex_data[ 2][4] + '0';
lcinfo[43] = hex_data[ 2][5] + '0';
lcinfo[44] = hex_data[ 1][0] + '0';
lcinfo[45] = hex_data[ 1][1] + '0';
lcinfo[46] = hex_data[ 1][2] + '0';
lcinfo[47] = hex_data[ 1][3] + '0';
lcinfo[48] = hex_data[ 1][4] + '0';
lcinfo[49] = hex_data[ 1][5] + '0';
lcinfo[50] = hex_data[ 0][0] + '0';
lcinfo[51] = hex_data[ 0][1] + '0';
lcinfo[52] = hex_data[ 0][2] + '0';
lcinfo[53] = hex_data[ 0][3] + '0';
lcinfo[54] = hex_data[ 0][4] + '0';
lcinfo[55] = hex_data[ 0][5] + '0';
processP25lcw (opts, state, lcformat, mfid, lcinfo, irrecoverable_errors);
}
void
processTDULC (dsd_opts* opts, dsd_state* state)
{
int i;
char lcinfo[57], lcformat[9], mfid[9];
int status_count;
char dodeca_data[6][12]; // Data in 12-bit words. A total of 6 words.
char dodeca_parity[6][12]; // Reed-Solomon parity of the data. A total of 6 parity 12-bit words.
int irrecoverable_errors;
AnalogSignal analog_signal_array[6*(6+6)+6*(6+6)+10];
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;
for(i=5; i>=0; i--) {
read_and_correct_dodeca_word (opts, state, &(dodeca_data[i][0]), &status_count, analog_signal_array, &analog_signal_index);
}
for(i=5; i>=0; i--) {
read_and_correct_dodeca_word (opts, state, &(dodeca_parity[i][0]), &status_count, analog_signal_array, &analog_signal_index);
}
// Swap the two 6-bit words to accommodate for the expected word order of the Reed-Solomon decoding
swap_hex_words((char*)dodeca_data, (char*)dodeca_parity);
// Error correct the hex_data using Reed-Solomon hex_parity
irrecoverable_errors = check_and_fix_reedsolomon_24_12_13((char*)dodeca_data, (char*)dodeca_parity);
// Recover the original order
swap_hex_words((char*)dodeca_data, (char*)dodeca_parity);
if (irrecoverable_errors == 1)
{
state->debug_header_critical_errors++;
// We can correct (13-1)/2 = 6 errors. If we failed, it means that there were more than 6 errors in
// these 12+12 words. But take into account that each hex word was already error corrected with
// Golay 24, which can correct 3 bits on each sequence of (12+12) bits. We could say that there were
// 7 errors of 4 bits.
update_error_stats(&state->p25_heuristics, 12*6+12*6, 7*4);
}
else
{
// Same comments as in processHDU. See there.
char fixed_parity[6*12];
// Correct the dibits that we read according with hex_data values
correct_golay_dibits_12((char*)dodeca_data, 6, analog_signal_array);
// Generate again the Reed-Solomon parity
// Now, swap again for Reed-Solomon
swap_hex_words((char*)dodeca_data, (char*)dodeca_parity);
encode_reedsolomon_24_12_13((char*)dodeca_data, fixed_parity);
// Swap again to recover the original order
swap_hex_words((char*)dodeca_data, fixed_parity);
// Correct the dibits that we read according with the fixed parity values
correct_golay_dibits_12(fixed_parity, 6, analog_signal_array+6*(6+6));
// Once corrected, contribute this information to the heuristics module
analog_signal_array[0].sequence_broken = 1;
contribute_to_heuristics(state->rf_mod, &(state->p25_heuristics), analog_signal_array, 6*(6+6)+6*(6+6));
}
// Next 10 dibits should be zeros
// If an irrecoverable error happens, you should start a new sequence since the previous dibit was not set
read_zeros(opts, state, analog_signal_array + 6*(6+6)+6*(6+6), 20, &status_count, irrecoverable_errors);
// Next we should find an status dibit
if (status_count != 35) {
printf("*** SYNC ERROR\n");
}
// trailing status symbol
{
int status;
status = getDibit (opts, state) + '0';
// TODO: do something useful with the status bits...
}
// Put the corrected data into the DSD structures
lcformat[8] = 0;
mfid[8] = 0;
lcinfo[56] = 0;
lcformat[0] = dodeca_data[5][ 0] + '0';
lcformat[1] = dodeca_data[5][ 1] + '0';
lcformat[2] = dodeca_data[5][ 2] + '0';
lcformat[3] = dodeca_data[5][ 3] + '0';
lcformat[4] = dodeca_data[5][ 4] + '0';
lcformat[5] = dodeca_data[5][ 5] + '0';
lcformat[6] = dodeca_data[5][ 6] + '0';
lcformat[7] = dodeca_data[5][ 7] + '0';
mfid[0] = dodeca_data[5][ 8] + '0';
mfid[1] = dodeca_data[5][ 9] + '0';
mfid[2] = dodeca_data[5][10] + '0';
mfid[3] = dodeca_data[5][11] + '0';
mfid[4] = dodeca_data[4][ 0] + '0';
mfid[5] = dodeca_data[4][ 1] + '0';
mfid[6] = dodeca_data[4][ 2] + '0';
mfid[7] = dodeca_data[4][ 3] + '0';
lcinfo[0] = dodeca_data[4][ 4] + '0';
lcinfo[1] = dodeca_data[4][ 5] + '0';
lcinfo[2] = dodeca_data[4][ 6] + '0';
lcinfo[3] = dodeca_data[4][ 7] + '0';
lcinfo[4] = dodeca_data[4][ 8] + '0';
lcinfo[5] = dodeca_data[4][ 9] + '0';
lcinfo[6] = dodeca_data[4][10] + '0';
lcinfo[7] = dodeca_data[4][11] + '0';
lcinfo[8] = dodeca_data[3][ 0] + '0';
lcinfo[9] = dodeca_data[3][ 1] + '0';
lcinfo[10] = dodeca_data[3][ 2] + '0';
lcinfo[11] = dodeca_data[3][ 3] + '0';
lcinfo[12] = dodeca_data[3][ 4] + '0';
lcinfo[13] = dodeca_data[3][ 5] + '0';
lcinfo[14] = dodeca_data[3][ 6] + '0';
lcinfo[15] = dodeca_data[3][ 7] + '0';
lcinfo[16] = dodeca_data[3][ 8] + '0';
lcinfo[17] = dodeca_data[3][ 9] + '0';
lcinfo[18] = dodeca_data[3][10] + '0';
lcinfo[19] = dodeca_data[3][11] + '0';
lcinfo[20] = dodeca_data[2][ 0] + '0';
lcinfo[21] = dodeca_data[2][ 1] + '0';
lcinfo[22] = dodeca_data[2][ 2] + '0';
lcinfo[23] = dodeca_data[2][ 3] + '0';
lcinfo[24] = dodeca_data[2][ 4] + '0';
lcinfo[25] = dodeca_data[2][ 5] + '0';
lcinfo[26] = dodeca_data[2][ 6] + '0';
lcinfo[27] = dodeca_data[2][ 7] + '0';
lcinfo[28] = dodeca_data[2][ 8] + '0';
lcinfo[29] = dodeca_data[2][ 9] + '0';
lcinfo[30] = dodeca_data[2][10] + '0';
lcinfo[31] = dodeca_data[2][11] + '0';
lcinfo[32] = dodeca_data[1][ 0] + '0';
lcinfo[33] = dodeca_data[1][ 1] + '0';
lcinfo[34] = dodeca_data[1][ 2] + '0';
lcinfo[35] = dodeca_data[1][ 3] + '0';
lcinfo[36] = dodeca_data[1][ 4] + '0';
lcinfo[37] = dodeca_data[1][ 5] + '0';
lcinfo[38] = dodeca_data[1][ 6] + '0';
lcinfo[39] = dodeca_data[1][ 7] + '0';
lcinfo[40] = dodeca_data[1][ 8] + '0';
lcinfo[41] = dodeca_data[1][ 9] + '0';
lcinfo[42] = dodeca_data[1][10] + '0';
lcinfo[43] = dodeca_data[1][11] + '0';
lcinfo[44] = dodeca_data[0][ 0] + '0';
lcinfo[45] = dodeca_data[0][ 1] + '0';
lcinfo[46] = dodeca_data[0][ 2] + '0';
lcinfo[47] = dodeca_data[0][ 3] + '0';
lcinfo[48] = dodeca_data[0][ 4] + '0';
lcinfo[49] = dodeca_data[0][ 5] + '0';
lcinfo[50] = dodeca_data[0][ 6] + '0';
lcinfo[51] = dodeca_data[0][ 7] + '0';
lcinfo[52] = dodeca_data[0][ 8] + '0';
lcinfo[53] = dodeca_data[0][ 9] + '0';
lcinfo[54] = dodeca_data[0][10] + '0';
lcinfo[55] = dodeca_data[0][11] + '0';
processP25lcw (opts, state, lcformat, mfid, lcinfo);
}
