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First go at VW mode IMBE FEC.
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@g4klx
g4klx committed Apr 19, 2016
1 parent b560594 commit 38dc134
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Showing 5 changed files with 196 additions and 104 deletions.
162 changes: 127 additions & 35 deletions AMBEFEC.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,7 @@
*/

#include "Golay24128.h"
#include "Hamming.h"
#include "AMBEFEC.h"

#include <cstdio>
Expand Down Expand Up @@ -453,6 +454,15 @@ const unsigned int DSTAR_B_TABLE[] = {2U, 8U, 14U, 20U, 26U, 32U, 38U, 44U, 50U
const unsigned int DSTAR_C_TABLE[] = {4U, 10U, 16U, 22U, 28U, 34U, 40U, 46U, 52U, 58U, 64U, 70U,
5U, 11U, 17U, 23U, 29U, 35U, 41U, 47U, 53U, 59U, 65U, 71U};

const unsigned int IMBE_INTERLEAVE[] = {
0, 7, 12, 19, 24, 31, 36, 43, 48, 55, 60, 67, 72, 79, 84, 91, 96, 103, 108, 115, 120, 127, 132, 139,
1, 6, 13, 18, 25, 30, 37, 42, 49, 54, 61, 66, 73, 78, 85, 90, 97, 102, 109, 114, 121, 126, 133, 138,
2, 9, 14, 21, 26, 33, 38, 45, 50, 57, 62, 69, 74, 81, 86, 93, 98, 105, 110, 117, 122, 129, 134, 141,
3, 8, 15, 20, 27, 32, 39, 44, 51, 56, 63, 68, 75, 80, 87, 92, 99, 104, 111, 116, 123, 128, 135, 140,
4, 11, 16, 23, 28, 35, 40, 47, 52, 59, 64, 71, 76, 83, 88, 95, 100, 107, 112, 119, 124, 131, 136, 143,
5, 10, 17, 22, 29, 34, 41, 46, 53, 58, 65, 70, 77, 82, 89, 94, 101, 106, 113, 118, 125, 130, 137, 142
};

CAMBEFEC::CAMBEFEC()
{
}
Expand Down Expand Up @@ -583,50 +593,132 @@ unsigned int CAMBEFEC::regenerateDStar(unsigned char* bytes) const
return errors;
}

unsigned int CAMBEFEC::regenerateYSF1(unsigned char* bytes) const
unsigned int CAMBEFEC::regenerateYSF3(unsigned char* bytes) const
{
assert(bytes != NULL);

unsigned int errors = 0U;
unsigned int offset = 72U;
for (unsigned int j = 0U; j < 5U; j++, offset += 144U) {
unsigned int a = 0U;
unsigned int b = 0U;
unsigned int c = 0U;

unsigned int MASK = 0x800000U;
for (unsigned int i = 0U; i < 24U; i++) {
unsigned int aPos = DMR_A_TABLE[i] + offset;
unsigned int bPos = DMR_B_TABLE[i] + offset;
unsigned int cPos = DMR_C_TABLE[i] + offset;

if (READ_BIT(bytes, aPos))
a |= MASK;
if (READ_BIT(bytes, bPos))
b |= MASK;
if (READ_BIT(bytes, cPos))
c |= MASK;

MASK >>= 1;
}
bool temp[144U];

errors += regenerate(a, b, c, true);
// De-interleave
for (unsigned int i = 0U; i < 144U; i++) {
unsigned int n = IMBE_INTERLEAVE[i];
temp[i] = READ_BIT(bytes, n);
}

MASK = 0x800000U;
for (unsigned int i = 0U; i < 24U; i++) {
unsigned int aPos = DMR_A_TABLE[i] + offset;
unsigned int bPos = DMR_B_TABLE[i] + offset;
unsigned int cPos = DMR_C_TABLE[i] + offset;
// now ..

// 12 voice bits 0
// 11 golay bits 12
//
// 12 voice bits 23
// 11 golay bits 35
//
// 12 voice bits 46
// 11 golay bits 58
//
// 12 voice bits 69
// 11 golay bits 81
//
// 11 voice bits 92
// 4 hamming bits 103
//
// 11 voice bits 107
// 4 hamming bits 118
//
// 11 voice bits 122
// 4 hamming bits 133
//
// 7 voice bits 137

// De-Whiten some bits
unsigned int prn = 0x00U;
for (int i = 0U; i < 12U; i++)
prn = (prn << 1) | (temp[i] & 1);
prn <<= 4;
for (unsigned int i = 23U; i < 137U; i++) {
prn = (unsigned short)((173 * prn) + 13849);
temp[i] ^= (prn >> 15) & 1;
}

WRITE_BIT(bytes, aPos, a & MASK);
WRITE_BIT(bytes, bPos, b & MASK);
WRITE_BIT(bytes, cPos, c & MASK);
// Check/Fix FEC
bool* bit = temp;

// c0
unsigned int g1 = 0U;
for (unsigned int i = 0U; i < 23U; i++)
g1 = (g1 << 1) | (bit[i] & 1);
unsigned int g3 = CGolay24128::decode23127(g1);
unsigned int g2 = CGolay24128::encode23127(g3);
for (int i = 23; i >= 0; i--) {
bit[i] = g2 & 1;
g2 >>= 1;
}
bit += 23U;

// c1
g1 = 0U;
for (unsigned int i = 0U; i < 23U; i++)
g1 = (g1 << 1) | (bit[i] & 1);
g3 = CGolay24128::decode23127(g1);
g2 = CGolay24128::encode23127(g3);
for (int i = 23; i >= 0; i--) {
bit[i] = g2 & 1;
g2 >>= 1;
}
bit += 23U;

// c2
g1 = 0;
for (int i = 0; i < 23; i++)
g1 = (g1 << 1) | (bit[i] & 1);
g3 = CGolay24128::decode23127(g1);
g2 = CGolay24128::encode23127(g3);
for (int i = 23; i >= 0; i--) {
bit[i] = g2 & 1;
g2 >>= 1;
}
bit += 23U;

// c3
g1 = 0U;
for (int i = 0U; i < 23U; i++)
g1 = (g1 << 1) | (bit[i] & 1);
g3 = CGolay24128::decode23127(g1);
g2 = CGolay24128::encode23127(g3);
for (int i = 23; i >= 0; i--) {
bit[i] = g2 & 1;
g2 >>= 1;
}
bit += 23U;

// c4
CHamming::decode15113_1(bit);
bit += 15U;

// c5
CHamming::decode15113_1(bit);
bit += 15U;

// c6
CHamming::decode15113_1(bit);

// Whiten some bits
prn = 0x00U;
for (unsigned int i = 0U; i < 12U; i++)
prn = (prn << 1) | (temp[i] & 1);
prn <<= 4;
for (unsigned int i = 23U; i < 137U; i++) {
prn = (unsigned short)((173 * prn) + 13849);
temp[i] ^= (prn >> 15) & 1;
}

MASK >>= 1;
}
// Interleave
for (unsigned int i = 0U; i < 144U; i++) {
unsigned int n = IMBE_INTERLEAVE[i];
WRITE_BIT(bytes, n, temp[i]);
}

return errors;
return 0U;
}

unsigned int CAMBEFEC::regenerate(unsigned int& a, unsigned int& b, unsigned int& c, bool b23) const
Expand Down
2 changes: 1 addition & 1 deletion AMBEFEC.h
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Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,7 @@ class CAMBEFEC {

unsigned int regenerateDStar(unsigned char* bytes) const;

unsigned int regenerateYSF1(unsigned char* bytes) const;
unsigned int regenerateYSF3(unsigned char* bytes) const;

private:
unsigned int regenerate(unsigned int& a, unsigned int& b, unsigned int& c, bool b23) const;
Expand Down
26 changes: 12 additions & 14 deletions YSFControl.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -108,8 +108,7 @@ bool CYSFControl::writeModem(unsigned char *data)

LogMessage("YSF, EOT, FI=%X FN=%u FT=%u DT=%X", fi, fn, ft, dt);

m_payload.decode(data + 2U, fi, fn, ft, dt);
// m_payload.encode(data + 2U); XXX
m_payload.process(data + 2U, fi, fn, ft, dt);

m_frames++;

Expand Down Expand Up @@ -150,14 +149,19 @@ bool CYSFControl::writeModem(unsigned char *data)

LogMessage("YSF, Valid FICH, FI=%X FN=%u FT=%u DT=%X", fi, fn, ft, dt);

m_payload.decode(data + 2U, fi, fn, ft, dt);
// payload.encode(data + 2U); XXX
m_payload.process(data + 2U, fi, fn, ft, dt);

bool change = false;

if (cm == 0x00U && m_dest == NULL) {
m_dest = (unsigned char*)"CQCQCQ ";
change = true;
if (m_dest == NULL) {
if (cm == YSF_CM_GROUP) {
m_dest = (unsigned char*)"CQCQCQ ";
change = true;
} else {
m_dest = m_payload.getDest();
if (m_dest != NULL)
change = true;
}
}

if (m_source == NULL) {
Expand All @@ -166,12 +170,6 @@ bool CYSFControl::writeModem(unsigned char *data)
change = true;
}

if (m_dest == NULL) {
m_dest = m_payload.getDest();
if (m_dest != NULL)
change = true;
}

if (change) {
if (m_source != NULL && m_dest != NULL) {
m_display->writeFusion((char*)m_source, (char*)m_dest);
Expand All @@ -188,7 +186,7 @@ bool CYSFControl::writeModem(unsigned char *data)
}
} else {
// Reconstruct FICH based on the last valid frame
m_fich.setFI(0x01U); // Communication channel
m_fich.setFI(YSF_FI_COMMUNICATIONS); // Communication channel
}

m_frames++;
Expand Down
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