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P25 Dibit, Block and PDU Payload Tweaks;

This commit is contained in:
lwvmobile 2023-02-20 12:35:44 -05:00
parent 0217202801
commit 38b962aacf
4 changed files with 126 additions and 27 deletions
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14
src/dsd_dibit.c
View File

@ -283,12 +283,11 @@ static int digitize (dsd_opts* opts, dsd_state* state, int symbol)
valid = 0;
//only run estimate_symbol when we aren't trunking, otherwise noise/gain levels on other rf channels may impact performance severely
//honestly can't say I've seen any improvement when using heuristics, but is detrimental to playing back multiple p25 samples
if (state->synctype == 1 && opts->p25_trunk == 0)
//re-enabling -- heuristics may also work with P2, but cna't see any benefit, need more P2 C4FM samples for testing
if (state->synctype == 1 && opts->p25_trunk == 1) //|| state->synctype == 36
{
// Use the P25 heuristics if available
//valid = estimate_symbol(state->rf_mod, &(state->inv_p25_heuristics), state->last_dibit, symbol, &dibit);
valid = estimate_symbol(state->rf_mod, &(state->inv_p25_heuristics), state->last_dibit, symbol, &dibit);
}
if (valid == 0)
@ -348,12 +347,11 @@ static int digitize (dsd_opts* opts, dsd_state* state, int symbol)
valid = 0;
//only run estimate_symbol when we aren't trunking, otherwise noise/gain levels on other rf channels may impact performance severely
//honestly can't say I've seen any improvement when using heuristics, but is detrimental to playing back multiple p25 samples
if (state->synctype == 0 && opts->p25_trunk == 0)
////re-enabling, but only when trunking (should have uniform volume if not tampered with during setup)
if (state->synctype == 0 && opts->p25_trunk == 1) //|| state->synctype == 35
{
// Use the P25 heuristics if available
//valid = estimate_symbol(state->rf_mod, &(state->p25_heuristics), state->last_dibit, symbol, &dibit);
valid = estimate_symbol(state->rf_mod, &(state->p25_heuristics), state->last_dibit, symbol, &dibit);
}
if (valid == 0)

3
src/p25p1_block.cpp
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@ -40,7 +40,8 @@ static int find_min(uint8_t list[], int len) {
index = i;
unique = 1;
} else if (list[i] == min) {
unique = 0;
//unique = 0;
; //do nothing, still can be correct and pass CRC
}
}
/* return -1 if a minimum can't be found */

110
src/p25p1_tsbk.c
View File

@ -7,6 +7,73 @@
*-----------------------------------------------------------------------------*/
#include "dsd.h"
int block_convolution (int payload[196], uint8_t decoded[12])
{
int ec = -1; //initialize error value
uint8_t deinterleaved_bits[196];
uint8_t trellis_bytes[12];
uint8_t m_data[14];
uint8_t temp[210]; //temp bit position buffer for convolution
//initialize our deinterleaved bits and bytes with zeroes
for (int i = 0; i < 196; i++) deinterleaved_bits[i] = 0;
for (int i = 0; i < 210; i++) temp[i] = 0;
for (int i = 0; i < 12; i++) trellis_bytes[i] = 0;
for (int i = 0; i < 14; i++) m_data[i] = 0;
//convolution decoder
uint8_t s0;
uint8_t s1;
//initialize our decoded byte buffer with zeroes
for (int i = 0; i < 12; i++) decoded[i] = 0;
static const uint16_t deinterleave_tsbk[] = {
0, 1, 2, 3, 52, 53, 54, 55, 100,101,102,103, 148,149,150,151,
4, 5, 6, 7, 56, 57, 58, 59, 104,105,106,107, 152,153,154,155,
8, 9, 10, 11, 60, 61, 62, 63, 108,109,110,111, 156,157,158,159,
12, 13, 14, 15, 64, 65, 66, 67, 112,113,114,115, 160,161,162,163,
16, 17, 18, 19, 68, 69, 70, 71, 116,117,118,119, 164,165,166,167,
20, 21, 22, 23, 72, 73, 74, 75, 120,121,122,123, 168,169,170,171,
24, 25, 26, 27, 76, 77, 78, 79, 124,125,126,127, 172,173,174,175,
28, 29, 30, 31, 80, 81, 82, 83, 128,129,130,131, 176,177,178,179,
32, 33, 34, 35, 84, 85, 86, 87, 132,133,134,135, 180,181,182,183,
36, 37, 38, 39, 88, 89, 90, 91, 136,137,138,139, 184,185,186,187,
40, 41, 42, 43, 92, 93, 94, 95, 140,141,142,143, 188,189,190,191,
44, 45, 46, 47, 96, 97, 98, 99, 144,145,146,147, 192,193,194,195,
48, 49, 50, 51 };
//get the deinterleaved bits
for (int i = 0; i < 196; i++) deinterleaved_bits[deinterleave_tsbk[i]] = payload[i];
//shift into proper position for the convolutional decoder
for (int i = 0; i < 196; i++) temp[i] = deinterleaved_bits[i] << 1;
CNXDNConvolution_start();
for (int i = 0U; i < 98U; i++) //102U
{
s0 = temp[(2*i)];
s1 = temp[(2*i)+1];
CNXDNConvolution_decode(s0, s1);
}
CNXDNConvolution_chainback(m_data, 96U); //98U
//debug print
fprintf (stderr, "\n Convolution Chainback - ");
for (int i = 0; i < 14; i++) fprintf (stderr, "[%02X]", m_data[i]);
//transfer m_data to decoded bytes -- when sorted out, can probably send decoded straight to chainback, and save the code
// for (int i = 0; i < 12; i++) decoded[i] = m_data[i];
ec = 0; //unknown if a method exists to returns errors from the convolutional decoder, just rely on CRC check for now
return ec;
}
void processTSBK(dsd_opts * opts, dsd_state * state)
{
@ -54,6 +121,9 @@ void processTSBK(dsd_opts * opts, dsd_state * state)
}
//test with the nxdn convolutional decoder
// ec = block_convolution (tsbkbit, tsbk_byte);
//send tsbkbit to block_deinterleave and return tsbk_byte
ec = bd_bridge(tsbkbit, tsbk_byte);
@ -84,7 +154,7 @@ void processTSBK(dsd_opts * opts, dsd_state * state)
tsbk_byte[i] = byte;
}
//convert tsbk_byte to PDU and send to vPDU handler
//convert tsbk_byte to vPDU and send to vPDU handler
//...may or may not be entirely compatible,
MFID = tsbk_byte[1];
PDU[0] = 0x07; //P25p1 TSBK Duid 0x07
@ -106,8 +176,9 @@ void processTSBK(dsd_opts * opts, dsd_state * state)
protectbit = (tsbk_byte[0] >> 6) & 0x1;
//Don't run NET_STS out of this, or will set wrong NAC/CC //&& PDU[1] != 0x49 && PDU[1] != 0x45
//0x49 is telephone grant, 0x46 Unit to Unit Channel Answer Request (seems bogus)
if (MFID < 0x2 && protectbit == 0 && err == 0 && ec == 0 && PDU[1] != 0x7B )
//0x49 is telephone grant, 0x46 Unit to Unit Channel Answer Request (seems bogus) (mfid 90)
// if (MFID < 0x2 && protectbit == 0 && err == 0 && ec == 0 && PDU[1] != 0x7B )
if ( (MFID < 0x2 || MFID == 0xA4 || MFID == 0x90) && protectbit == 0 && err == 0 && ec == 0 && PDU[1] != 0x7B )
{
fprintf (stderr, "%s",KYEL);
process_MAC_VPDU(opts, state, 0, PDU);
@ -115,7 +186,7 @@ void processTSBK(dsd_opts * opts, dsd_state * state)
}
//set our WACN and SYSID here now that we have valid ec and crc/checksum
if (protectbit == 0 && err == 0 && ec == 0 && (tsbk_byte[0] & 0x3F) == 0x3B)
else if (protectbit == 0 && err == 0 && ec == 0 && (tsbk_byte[0] & 0x3F) == 0x3B)
{
long int wacn = (tsbk_byte[3] << 12) | (tsbk_byte[4] << 4) | (tsbk_byte[5] >> 4);;
int sysid = ((tsbk_byte[5] & 0xF) << 8) | tsbk_byte[6];
@ -143,16 +214,43 @@ void processTSBK(dsd_opts * opts, dsd_state * state)
if (opts->payload == 1)
{
fprintf (stderr, "%s",KCYN);
fprintf (stderr, "\n P25 PDU Payload ");
fprintf (stderr, "\n P25 PDU Payload #%d ", j);
for (i = 0; i < 12; i++)
{
fprintf (stderr, "[%02X]", tsbk_byte[i]);
}
}
fprintf (stderr, "%s ", KNRM);
}
else
{
if (opts->payload == 1)
{
fprintf (stderr, "%s",KCYN);
fprintf (stderr, "\n P25 PDU Payload #%d ", j+1);
for (i = 0; i < 12; i++)
{
fprintf (stderr, "[%02X]", tsbk_byte[i]);
}
fprintf (stderr, "\n MFID %02X Protected: %d Last Block: %d", MFID, protectbit, (tsbk_byte[0] >> 7) );
if (ec != 0)
{
fprintf (stderr, "%s",KRED);
fprintf (stderr, " (FEC ERR)");
}
else if (err != 0)
{
fprintf (stderr, "%s",KRED);
fprintf (stderr, " (CRC ERR)");
}
fprintf (stderr, "%s ", KNRM);
}
}
//reset for next rep
ec = -2;
err = -2;
@ -165,5 +263,7 @@ void processTSBK(dsd_opts * opts, dsd_state * state)
j = 4; //set j to break the loop early
}
}
fprintf (stderr, "%s ", KNRM);
fprintf (stderr, "\n");
}

26
src/p25p2_vpdu.c
View File

@ -940,7 +940,7 @@ void process_MAC_VPDU(dsd_opts * opts, dsd_state * state, int type, unsigned lon
}
//Unit-to-Unit Answer Request (UU_ANS_REQ)
if (MAC[1+len_a] == 0x45)
if (MAC[1+len_a] == 0x45 && MAC[2+len_a] != 0x90)
{
int svc = MAC[2+len_a];
int answer = MAC[3+len_a];
@ -952,17 +952,17 @@ void process_MAC_VPDU(dsd_opts * opts, dsd_state * state, int type, unsigned lon
}
//Telephone Interconnect Voice Channel Grant (TELE_INT_CH_GRANT)
if (MAC[1+len_a] == 0x48)
{
fprintf (stderr, "\n Telephone Interconnect Voice Channel Grant ");
}
//Telephone Interconnect Voice Channel Grant (TELE_INT_CH_GRANT) //look at PDU for this, see if this is tunable
// if (MAC[1+len_a] == 0x48 && MAC[2+len_a] != 0x90)
// {
// fprintf (stderr, "\n Telephone Interconnect Voice Channel Grant ");
// }
//Telephone Interconnect Voice Channel Grant Update (TELE_INT_CH_GRANT_UPDT)
if (MAC[1+len_a] == 0x49)
{
fprintf (stderr, "\n Telephone Interconnect Voice Channel Grant Update ");
}
// //Telephone Interconnect Voice Channel Grant Update (TELE_INT_CH_GRANT_UPDT)
// if (MAC[1+len_a] == 0x49 && MAC[2+len_a] != 0x90)
// {
// fprintf (stderr, "\n Telephone Interconnect Voice Channel Grant Update ");
// }
//Synchronization Broadcast (SYNC_BCST)
if (MAC[1+len_a] == 0x70)
@ -986,12 +986,12 @@ void process_MAC_VPDU(dsd_opts * opts, dsd_state * state, int type, unsigned lon
else offhour = ( (ltoff & 0b11111 ) / 2);
int seconds = slots / 135; //very rough estimation, but may be close enough for grins
if (seconds > 60) seconds = 60; //sanity check for rounding error
if (seconds > 59) seconds = 59; //sanity check for rounding error
fprintf (stderr, " Date: 20%02d.%02d.%02d Time: %02d:%02d:%02d UTC\n",
year, month, day, hour, min, seconds);
fprintf (stderr, " Local Time Offset: %.01f Hours;", offhour);
//if ist bit is set, then time on system may be considered invalid (i.e., no external time sync)
if (ist % 1)
if (ist == 1)
{
fprintf (stderr, " Invalid System Time ");
}