void RadioInterface::driveReceiveRadio() {
if (!mOn) return;
if (mReceiveFIFO.size() > 8) return;
pullBuffer();
GSM::Time rcvClock = mClock.get();
rcvClock.decTN(receiveOffset);
unsigned tN = rcvClock.TN();
int rcvSz = rcvCursor/2;
int readSz = 0;
const int symbolsPerSlot = gSlotLen + 8;
// while there's enough data in receive buffer, form received
// GSM bursts and pass up to Transceiver
// Using the 157-156-156-156 symbols per timeslot format.
while (rcvSz > (symbolsPerSlot + (tN % 4 == 0))*samplesPerSymbol) {
signalVector rxVector((symbolsPerSlot + (tN % 4 == 0)*samplesPerSymbol));
unUSRPifyVector(rcvBuffer+readSz*2,rxVector);
GSM::Time tmpTime = rcvClock;
if (rcvClock.FN() >= 0) {
LOG(DEEPDEBUG) << "FN: " << rcvClock.FN();
radioVector* rxBurst = new radioVector(rxVector,tmpTime);
mReceiveFIFO.put(rxBurst);
}
mClock.incTN();
rcvClock.incTN();
//if (mReceiveFIFO.size() >= 16) mReceiveFIFO.wait(8);
LOG(DEBUG) << "receiveFIFO: wrote radio vector at time: " << mClock.get() << ", new size: " << mReceiveFIFO.size() ;
readSz += (symbolsPerSlot+(tN % 4 == 0))*samplesPerSymbol;
rcvSz -= (symbolsPerSlot+(tN % 4 == 0))*samplesPerSymbol;
tN = rcvClock.TN();
}
if (readSz > 0) {
memcpy(rcvBuffer,rcvBuffer+2*readSz,sizeof(short)*2*(rcvCursor-readSz));
rcvCursor = rcvCursor-2*readSz;
}
}
void RadioInterface::pullBuffer(void)
{
writingRadioLock.lock();
// These timestamps are in samples @ 400 kHz.
while (readTimestamp > writeTimestamp - (TIMESTAMP) 2*OUTCHUNK) {
LOG(DEEPDEBUG) << "waiting..." << readTimestamp << " " << writeTimestamp;
wroteRadioSignal.wait(writingRadioLock);
//wroteRadioSignal.wait(writingRadioLock,1);
}
writingRadioLock.unlock();
bool localUnderrun;
// receive receiveVector
short* shortVector = new short[OUTCHUNK*2];
int samplesRead = usrp->readSamples(shortVector,OUTCHUNK,&overrun,readTimestamp,&localUnderrun);
underrun |= localUnderrun;
readTimestamp += (TIMESTAMP) samplesRead;
while (samplesRead < OUTCHUNK) {
int oldSamplesRead = samplesRead;
samplesRead += usrp->readSamples(shortVector+2*samplesRead,
OUTCHUNK-samplesRead,
&overrun,
readTimestamp,
&localUnderrun);
underrun |= localUnderrun;
readTimestamp += (TIMESTAMP) (samplesRead - oldSamplesRead);
}
signalVector *receiveVector = unUSRPifyVector(shortVector,samplesRead);
delete []shortVector;
if (!rcvLPF) {
int P = INRATE; int Q = OUTRATE;
float cutoffFreq = (P < Q) ? (1.0/(float) Q) : (1.0/(float) P);
rcvLPF = createLPF(cutoffFreq,961,P);
}
signalVector *retVector = NULL;
if (!rcvHistory) {
rcvHistory = new signalVector(OUTHISTORY);
rcvHistory->fill(0);
}
// resample received data to multiple of GSM symbol rate
signalVector inputVector(*rcvHistory,*receiveVector);
retVector = polyphaseResampleVector(inputVector,
INRATE,OUTRATE,rcvLPF);
// push sampled data to back of receive buffer
signalVector *tmp = retVector;
retVector = new signalVector(retVector->size()-INHISTORY);
tmp->segmentCopyTo(*retVector,INHISTORY,tmp->size()-INHISTORY);
delete tmp;
LOG(DEEPDEBUG) << "converted " << receiveVector->size()
<< " radio samples into " << retVector->size()
<< " transceiver samples ";
// update history of received data
receiveVector->segmentCopyTo(*rcvHistory,receiveVector->size()-OUTHISTORY,OUTHISTORY);
delete receiveVector;
if (rcvBuffer) {
signalVector *tmp = rcvBuffer;
rcvBuffer = new signalVector(*tmp,*retVector);
delete tmp;
delete retVector;
}
else
rcvBuffer = retVector;
}
