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NXDN: Add DCR TCH / PICH Lich 0x48 Payload Only; #299

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Misc Tweaks to Payload Format;
This commit is contained in:
lwvmobile
2025-07-13 10:25:40 -04:00
parent 86b8900b3d
commit ce805a7860
3 changed files with 162 additions and 24 deletions
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6
include/dsd.h
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@@ -1258,13 +1258,15 @@ void nxdn_descramble (uint8_t dibits[], int len);
//nxdn deinterleaving/depuncturing functions
void nxdn_deperm_facch (dsd_opts * opts, dsd_state * state, uint8_t bits[144]);
void nxdn_deperm_sacch (dsd_opts * opts, dsd_state * state, uint8_t bits[60]);
void nxdn_deperm_sacch2(dsd_opts * opts, dsd_state * state, uint8_t bits[60]);
void nxdn_deperm_cac (dsd_opts * opts, dsd_state * state, uint8_t bits[300]);
void nxdn_deperm_facch2_udch (dsd_opts * opts, dsd_state * state, uint8_t bits[348], uint8_t type);
//type-d 'idas' deinterleaving/depuncturing functions
void nxdn_deperm_scch(dsd_opts * opts, dsd_state * state, uint8_t bits[60], uint8_t direction);
void nxdn_deperm_facch3_udch2(dsd_opts * opts, dsd_state * state, uint8_t bits[288], uint8_t type);
//end
//DCR Mode
void nxdn_deperm_sacch2(dsd_opts * opts, dsd_state * state, uint8_t bits[60]);
void nxdn_deperm_pich_tch(dsd_opts * opts, dsd_state * state, uint8_t bits[144]);
//MT and Voice
void nxdn_message_type (dsd_opts * opts, dsd_state * state, uint8_t MessageType);
void nxdn_voice (dsd_opts * opts, dsd_state * state, int voice, uint8_t dbuf[182]);
//Osmocom OP25 12 Rate Trellis Decoder (for NXDN, M17, YSF, etc)

157
src/nxdn_deperm.c
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@@ -516,7 +516,7 @@ void nxdn_deperm_sacch2(dsd_opts * opts, dsd_state * state, uint8_t bits[60])
}
//Configuration of Single Message or Multi Part Message
uint8_t sf_fb = trellis_buf[0];
uint8_t sf_fb = trellis_buf[0];
uint8_t sf_num = (uint8_t) convert_bits_into_output(trellis_buf+1, 2);
uint8_t sf_mes = (uint8_t) convert_bits_into_output(trellis_buf+3, 5);
uint8_t sf_pof = 3-sf_num;
@@ -530,6 +530,8 @@ void nxdn_deperm_sacch2(dsd_opts * opts, dsd_state * state, uint8_t bits[60])
if (sf_mes == 0x01)
fprintf (stderr, "Call; ");
else if (sf_mes == 0x02)
fprintf (stderr, "PDU; ");
else if (sf_mes == 0x1E)
fprintf (stderr, "End; ");
else if (sf_mes == 0x00)
@@ -559,9 +561,6 @@ void nxdn_deperm_sacch2(dsd_opts * opts, dsd_state * state, uint8_t bits[60])
int sf_end = 0; //end of sf
int sf_idx = sf_size*sf_pof; //index position for this frame compared to super frame
int bf_idx = sf_full-sf_size; //index position for buffer to superframe
int sf_bytes = ((sf_size*4)/8);
if ( ((sf_size*4)%8) != 0)
sf_bytes++;
if (sf_fb && sf_pof) //single unit message
memcpy(state->dmr_pdu_sf[0]+0, trellis_buf+bf_idx, sf_size*sizeof(uint8_t));
@@ -621,10 +620,12 @@ void nxdn_deperm_sacch2(dsd_opts * opts, dsd_state * state, uint8_t bits[60])
//multi-part message, continue decoding
if (sf_fb == 0 && sf_num == 0)
{
fprintf (stderr, "\n");
//can't find definitions for these elements, even when MT == 1 and MFID == 0
fprintf (stderr, "Cont(54): ");
for (int i = 0; i < 7; i++)
fprintf (stderr, "%02X", convert_bits_into_output(state->dmr_pdu_sf[0]+(i*8)+18, 8));
unsigned long long int mes_hex = (unsigned long long int ) convert_bits_into_output(state->dmr_pdu_sf[0]+18, 54);
fprintf (stderr, " Message: %014llX; ", mes_hex << 0);
}
}
@@ -638,7 +639,7 @@ void nxdn_deperm_sacch2(dsd_opts * opts, dsd_state * state, uint8_t bits[60])
if (sf_num == sf_end)
{
fprintf (stderr, "\n DCR SFULL ");
for (int i = 0; i < sf_bytes; i++)
for (int i = 0; i < 9; i++)
fprintf (stderr, "[%02X]", convert_bits_into_output(state->dmr_pdu_sf[0]+(i*8), 8));
}
@@ -651,12 +652,144 @@ void nxdn_deperm_sacch2(dsd_opts * opts, dsd_state * state, uint8_t bits[60])
memset (state->nxdn_sacch_frame_segment, 1, sizeof(state->nxdn_sacch_frame_segment));
memset (state->nxdn_sacch_frame_segcrc, 1, sizeof(state->nxdn_sacch_frame_segcrc));
}
// else if (crc != check)
}
//PICH or TCH 144 bit (JPN DCR)
//SEE: https://web.archive.org/web/20150417175725/http://arib.or.jp/english/html/overview/doc/1-STD-T98v1_4.pdf
void nxdn_deperm_pich_tch(dsd_opts * opts, dsd_state * state, uint8_t bits[144])
{
uint8_t deperm[144]; //144
uint8_t depunc[192]; //192
uint8_t trellis_buf[96]; //96
uint16_t crc = 1; //crc calculated by function
uint16_t check = 0; //crc from payload for comparison
int out;
memset (deperm, 0, sizeof(deperm));
memset (depunc, 0, sizeof(depunc));
for (int i=0; i<144; i++)
deperm[PERM_16_9[i]] = bits[i];
out = 0;
for (int i=0; i<144; i+=3) {
depunc[out++] = deperm[i+0];
depunc[out++] = 0;
depunc[out++] = deperm[i+1];
depunc[out++] = deperm[i+2];
}
//switch to the convolutional decoder
uint8_t temp[200];
uint8_t s0;
uint8_t s1;
uint8_t m_data[20]; //13
memset (temp, 0, sizeof(temp));
memset (m_data, 0, sizeof(m_data));
memset (trellis_buf, 0, sizeof(trellis_buf));
for (int i = 0; i < 192; i++)
temp[i] = depunc[i] << 1;
CNXDNConvolution_start();
for (int i = 0; i < 96; i++)
{
s0 = temp[(2*i)];
s1 = temp[(2*i)+1];
CNXDNConvolution_decode(s0, s1);
}
CNXDNConvolution_chainback(m_data, 92);
for(int i = 0; i < 12; i++)
{
trellis_buf[(i*8)+0] = (m_data[i] >> 7) & 1;
trellis_buf[(i*8)+1] = (m_data[i] >> 6) & 1;
trellis_buf[(i*8)+2] = (m_data[i] >> 5) & 1;
trellis_buf[(i*8)+3] = (m_data[i] >> 4) & 1;
trellis_buf[(i*8)+4] = (m_data[i] >> 3) & 1;
trellis_buf[(i*8)+5] = (m_data[i] >> 2) & 1;
trellis_buf[(i*8)+6] = (m_data[i] >> 1) & 1;
trellis_buf[(i*8)+7] = (m_data[i] >> 0) & 1;
}
crc = crc12f (trellis_buf, 84); //80
for (int i = 0; i < 12; i++)
{
check = check << 1;
check = check | trellis_buf[84+i]; //80
}
//debug
// if (crc == check)
// fprintf (stderr, " Pass 1 ");
//if the crc fails, attempt again with the other trellis decoder
if (crc != check)
{
//debug
// fprintf (stderr, " Pass 2 ");
crc = 1; check = 0;
memset (trellis_buf, 0, sizeof(trellis_buf));
memset (m_data, 0, sizeof(m_data));
trellis_decode(trellis_buf, depunc, 92);
//fill m_data bytes with trellis_buf
for(int i = 0; i < 12; i++)
m_data[i] = (uint8_t)ConvertBitIntoBytes(&trellis_buf[i*8], 8);
crc = crc12f (trellis_buf, 84);
for (int i = 0; i < 12; i++)
{
check = check << 1;
check = check | trellis_buf[i+84];
}
}
//need more data points, but thinking this is probably similar to facch3
//or udch2 where we need to put two tch (facch1) messages together
// if (crc == check)
// {
// memset (state->dmr_pdu_sf[0], 0, sizeof(state->dmr_pdu_sf[0]));
// memset (state->nxdn_sacch_frame_segment, 1, sizeof(state->nxdn_sacch_frame_segment));
// memset (state->nxdn_sacch_frame_segcrc, 1, sizeof(state->nxdn_sacch_frame_segcrc));
// uint8_t opcode = (uint8_t)ConvertBitIntoBytes(&trellis_buf[0], 8);
// uint8_t gi = trellis_buf[16];
// uint16_t source = (uint16_t)ConvertBitIntoBytes(&trellis_buf[24], 16);
// uint16_t target = (uint16_t)ConvertBitIntoBytes(&trellis_buf[40], 16);
// if (opcode != 0)
// {
// fprintf (stderr, "\n ");
// fprintf (stderr, "OP: %02X; ", opcode);
// fprintf (stderr, "Source: %d; Target: %d; ", source, target);
// if (gi)
// fprintf (stderr, "Private; ");
// else fprintf (stderr, "Group; ");
// }
// }
// else
// {
// fprintf (stderr, "\n ");
// fprintf (stderr, "%s", KRED);
// fprintf (stderr, " (CRC ERR)");
// fprintf (stderr, "%s", KNRM);
// }
if (opts->payload == 1)
{
fprintf (stderr, "\n");
fprintf (stderr, " TCH Payload ");
for (int i = 0; i < 12; i++)
{
fprintf (stderr, "[%02X]", m_data[i]);
}
if (crc != check && opts->payload == 1)
{
fprintf (stderr, "%s", KRED);
fprintf (stderr, " (CRC ERR)");
fprintf (stderr, "%s", KNRM);
}
}
UNUSED(state);
}

23
src/nxdn_frame.c
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@@ -51,6 +51,7 @@ void nxdn_frame (dsd_opts * opts, dsd_state * state)
//DCR Mode Specific Things
int sacch2 = 0;
int pich_tch = 0;
//new breakdown of lich codes
uint8_t lich_rf = 0; //RF Channel Type
@@ -125,7 +126,7 @@ void nxdn_frame (dsd_opts * opts, dsd_state * state)
break;
case 0x28: //facch2 types
case 0x29:
case 0x48:
// case 0x48: //removing from here, moving to DCR as pich_tch
case 0x49:
facch2 = 1;
break;
@@ -176,13 +177,15 @@ void nxdn_frame (dsd_opts * opts, dsd_state * state)
sacch = 1;
break;
//DCR Mode
//DCR Voice
case 0x46:
voice = 3;
sacch2 = 1;
break;
//DCR Data or End Frame (bad parity)
//DCR Data or End Frame
case 0x48:
pich_tch = 3;
case 0x4A:
sacch2 = 1;
break;
@@ -194,8 +197,8 @@ void nxdn_frame (dsd_opts * opts, dsd_state * state)
scch = 1;
voice = 3;
break;
case 0x74: //vch in 1, facch1 in 2 (facch 2 steal)
case 0x75:
// case 0x74: //False Positive on DCR, keep disabled, or revert this line
case 0x75: //vch in 1, facch1 in 2 (facch 2 steal)
idas = 1;
scch = 1;
voice = 1;
@@ -342,7 +345,7 @@ void nxdn_frame (dsd_opts * opts, dsd_state * state)
else direction = 1;
// RF Channel Type
if (lich != 0x46 && lich != 0x4A)
if (sacch2 == 0)
{
if (lich_rf == 0) fprintf (stderr, "RCCH ");
@@ -501,16 +504,16 @@ void nxdn_frame (dsd_opts * opts, dsd_state * state)
if (facch3) nxdn_deperm_facch3_udch2(opts, state, facch3_bits, 1);
if (sacch) nxdn_deperm_sacch(opts, state, sacch_bits);
if (sacch2) nxdn_deperm_sacch2(opts, state, sacch_bits);
if (cac) nxdn_deperm_cac(opts, state, cac_bits);
//Seperated UDCH user data from facch2 data
if (udch) nxdn_deperm_facch2_udch(opts, state, facch2_bits, 0);
if (facch2) nxdn_deperm_facch2_udch(opts, state, facch2_bits, 1);
//SHOULD be okay to run facch1's again on steal frames, will need testing
// if (facch & 1) nxdn_deperm_facch(opts, state, facch_bits_a);
// if (facch & 2) nxdn_deperm_facch(opts, state, facch_bits_b);
//DCR
if (sacch2) nxdn_deperm_sacch2(opts, state, sacch_bits);
if (pich_tch & 1) nxdn_deperm_pich_tch(opts, state, facch_bits_a);
if (pich_tch & 2) nxdn_deperm_pich_tch(opts, state, facch_bits_b);
//only run facch in second slot if its not equal to the first one
//ideally, this would work better AFTER decoding/FEC