Improve the FEC reconstruction a little.
This commit is contained in:
parent
c63ce4897e
commit
578085134c
|
@ -58,39 +58,27 @@ bool CDMRTrellis::decode(const unsigned char* data, unsigned char* payload)
|
|||
unsigned char points[49U];
|
||||
dibitsToPoints(dibits, points);
|
||||
|
||||
unsigned char tribits[49U];
|
||||
|
||||
// Check the original code
|
||||
unsigned char tribits[49U];
|
||||
unsigned int failPos = checkCode(points, tribits);
|
||||
if (failPos == 999U) {
|
||||
tribitsToBits(tribits, payload);
|
||||
return true;
|
||||
}
|
||||
|
||||
for (unsigned j = 0U; j < 20U; j++) {
|
||||
unsigned int bestPos = 0U;
|
||||
unsigned int bestVal = 0U;
|
||||
unsigned char savePoints[49U];
|
||||
for (unsigned int i = 0U; i < 49U; i++)
|
||||
savePoints[i] = points[i];
|
||||
|
||||
for (unsigned int i = 0U; i < 16U; i++) {
|
||||
points[failPos] = i;
|
||||
bool ret = fixCode(points, failPos, payload);
|
||||
if (ret)
|
||||
return true;
|
||||
|
||||
unsigned int pos = checkCode(points, tribits);
|
||||
if (pos == 999U) {
|
||||
tribitsToBits(tribits, payload);
|
||||
return true;
|
||||
}
|
||||
if (failPos == 0U)
|
||||
return false;
|
||||
|
||||
if (pos > bestPos) {
|
||||
bestPos = pos;
|
||||
bestVal = i;
|
||||
}
|
||||
}
|
||||
|
||||
points[failPos] = bestVal;
|
||||
failPos = bestPos;
|
||||
}
|
||||
|
||||
return false;
|
||||
// Backtrack one place for a last go
|
||||
return fixCode(savePoints, failPos - 1U, payload);
|
||||
}
|
||||
|
||||
void CDMRTrellis::encode(const unsigned char* payload, unsigned char* data)
|
||||
|
@ -330,6 +318,35 @@ void CDMRTrellis::tribitsToBits(const unsigned char* tribits, unsigned char* pay
|
|||
}
|
||||
}
|
||||
|
||||
bool CDMRTrellis::fixCode(unsigned char* points, unsigned int failPos, unsigned char* payload) const
|
||||
{
|
||||
for (unsigned j = 0U; j < 20U; j++) {
|
||||
unsigned int bestPos = 0U;
|
||||
unsigned int bestVal = 0U;
|
||||
|
||||
for (unsigned int i = 0U; i < 16U; i++) {
|
||||
points[failPos] = i;
|
||||
|
||||
unsigned char tribits[49U];
|
||||
unsigned int pos = checkCode(points, tribits);
|
||||
if (pos == 999U) {
|
||||
tribitsToBits(tribits, payload);
|
||||
return true;
|
||||
}
|
||||
|
||||
if (pos > bestPos) {
|
||||
bestPos = pos;
|
||||
bestVal = i;
|
||||
}
|
||||
}
|
||||
|
||||
points[failPos] = bestVal;
|
||||
failPos = bestPos;
|
||||
}
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
unsigned int CDMRTrellis::checkCode(const unsigned char* points, unsigned char* tribits) const
|
||||
{
|
||||
unsigned char state = 0U;
|
||||
|
|
|
@ -29,6 +29,7 @@ private:
|
|||
void pointsToDibits(const unsigned char* points, signed char* dibits) const;
|
||||
void bitsToTribits(const unsigned char* payload, unsigned char* tribits) const;
|
||||
void tribitsToBits(const unsigned char* tribits, unsigned char* payload) const;
|
||||
bool fixCode(unsigned char* points, unsigned int failPos, unsigned char* payload) const;
|
||||
unsigned int checkCode(const unsigned char* points, unsigned char* tribits) const;
|
||||
};
|
||||
|
||||
|
|
Loading…
Reference in New Issue