public void decode(RadioLog.Common.SafeBitArray message, int start, int end)
{
/* load each of the nodes with deinterleaved constellations */
for (int index = 0; index < 49; index++)
{
Constellation c = getConstellation(message, index * 4);
mConstellationNodes[index].setConstellation(c);
}
/* test to see if constellations are correct - otherwise correct them */
ConstellationNode firstNode = mConstellationNodes[0];
if (!firstNode.startsWith(Dibit.D0) || !firstNode.isCorrect())
{
firstNode.correctTo(Dibit.D0);
}
/* clear constellations from original message */
message.ClearRange(start, end - start);
/* replace with decoded values from the nodes */
for (int index = 0; index < 49; index++)
{
ConstellationNode node = mConstellationNodes[index];
if (node.firstBit())
{
message.SetBit(start + (index * 2));
}
if (node.secondBit())
{
message.SetBit(start + (index * 2) + 1);
}
}
}
public static RadioLog.Common.SafeBitArray interleave(RadioLog.Common.SafeBitArray message, int start, int end)
{
RadioLog.Common.SafeBitArray original = message.CloneFromIndexToIndex(start, end);
/* Clear block bits in source message */
message.ClearRange(start, end);
/* Iterate only the set bits in the original message and apply
* the deinterleave -- we don't have to evaluate the 0 bits */
for (int i = original.nextSetBit(0);
i >= 0 && i < INTERLEAVE.Length;
i = original.nextSetBit(i + 1))
{
message.SetBit(start + INTERLEAVE[i]);
}
return(message);
}
public void Receive(bool softBit)
{
if (mSampleCounter >= 0)
{
if (softBit)
{
mBitSet.SetBit(mSampleCounter);
}
else
{
mBitSet.ClearBit(mSampleCounter);
}
}
mSampleCounter++;
if (mSampleCounter >= mSymbolLength)
{
bool decision = mBitSet.Cardinality() >= mDecisionThreshold;
send(decision);
/* Shift timing left if the left bit in the bitset is opposite
* the decision and the right bit is the same */
if ((mBitSet[0] ^ decision) &&
(!(mBitSet[mSymbolLength - 1] ^ decision)))
{
sendTapEvent(mBitSet, Shift.LEFT, decision);
reset();
mSampleCounter--;
}
/* Shift timing right if the left bit is the same as the
* decision and the right bit is opposite */
else if ((!(mBitSet[0] ^ decision)) && (mBitSet[mSymbolLength - 1] ^ decision))
{
sendTapEvent(mBitSet, Shift.RIGHT, decision);
/* Last bit from previous symbol to pre-fill next symbol */
bool previousSoftBit = mBitSet[mSymbolLength - 1];
reset();
if (previousSoftBit)
{
mBitSet.SetBit(0);
}
mSampleCounter++;
}
/* No shift */
else
{
sendTapEvent(mBitSet, Shift.NONE, decision);
reset();
}
}
}