/* Initialize resampling signal vectors */
void init_resampler(signalVector **lpf,
signalVector **buf,
signalVector **hist,
int tx)
{
int P, Q, taps, hist_len;
float cutoff_freq;
if (tx) {
LOG(INFO) << "Initializing Tx resampler";
P = OUTRATE;
Q = INRATE;
taps = 651;
hist_len = INHISTORY;
} else {
LOG(INFO) << "Initializing Rx resampler";
P = INRATE;
Q = OUTRATE;
taps = 961;
hist_len = OUTHISTORY;
}
if (!*lpf) {
cutoff_freq = (P < Q) ? (1.0/(float) Q) : (1.0/(float) P);
*lpf = createLPF(cutoff_freq, taps, P);
}
if (!*buf) {
*buf = new signalVector();
}
if (!*hist);
*hist = new signalVector(hist_len);
}
// assumes filter group delay is 0.5*(length of filter)
signalVector *polyphaseResampleVector(signalVector &wVector,
int P, int Q,
signalVector *LPF)
{
bool deleteLPF = false;
if (LPF==NULL) {
float cutoffFreq = (P < Q) ? (1.0/(float) Q) : (1.0/(float) P);
LPF = createLPF(cutoffFreq/3.0,100*POLYPHASESPAN+1,Q);
deleteLPF = true;
}
signalVector *resampledVector = new signalVector((int) ceil(wVector.size()*(float) P / (float) Q));
resampledVector->fill(0);
resampledVector->isRealOnly(wVector.isRealOnly());
signalVector::iterator newItr = resampledVector->begin();
//FIXME: need to update for real-only vectors
int outputIx = (LPF->size()-1)/2/Q; //((P > Q) ? P : Q);
while (newItr < resampledVector->end()) {
int outputBranch = (outputIx*Q) % P;
int inputOffset = (outputIx*Q - outputBranch)/P;
signalVector::const_iterator inputItr = wVector.begin() + inputOffset;
signalVector::const_iterator filtItr = LPF->begin() + outputBranch;
while (inputItr >= wVector.end()) {
inputItr--;
filtItr+=P;
}
complex sum = 0.0;
if (!LPF->isRealOnly()) {
while ( (inputItr >= wVector.begin()) && (filtItr < LPF->end()) ) {
sum += (*inputItr)*(*filtItr);
inputItr--;
filtItr += P;
}
}
else {
while ( (inputItr >= wVector.begin()) && (filtItr < LPF->end()) ) {
sum += (*inputItr)*(filtItr->real());
inputItr--;
filtItr += P;
}
}
*newItr = sum;
newItr++;
outputIx++;
}
if (deleteLPF) delete LPF;
return resampledVector;
}
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;
}
void RadioInterface::pushBuffer(void) {
if (sendBuffer->size() < INCHUNK) {
return;
}
int numChunks = sendBuffer->size()/INCHUNK;
signalVector* truncatedBuffer = new signalVector(numChunks*INCHUNK);
sendBuffer->segmentCopyTo(*truncatedBuffer,0,numChunks*INCHUNK);
if (!sendLPF) {
int P = OUTRATE; int Q = INRATE;
float cutoffFreq = (P < Q) ? (1.0/(float) Q) : (1.0/(float) P);
sendLPF = createLPF(cutoffFreq,651,P);
}
// resample data to USRP sample rate
signalVector *inputVector = new signalVector(*sendHistory,*truncatedBuffer);
signalVector *resampledVector = polyphaseResampleVector(*inputVector,
OUTRATE,
INRATE,sendLPF);
delete inputVector;
// Set transmit gain and power here.
scaleVector(*resampledVector, usrp->fullScaleInputValue());
short *resampledVectorShort = USRPifyVector(*resampledVector);
// start the USRP when we actually have data to send to the USRP.
if (!started) {
started = true;
LOG(INFO) << "Starting USRP";
usrp->start();
LOG(DEBUG) << "USRP started";
usrp->updateAlignment(10000);
usrp->updateAlignment(10000);
}
// send resampleVector
writingRadioLock.lock();
int samplesWritten = usrp->writeSamples(resampledVectorShort+OUTHISTORY*2,
(resampledVector->size()-OUTHISTORY),
&underrun,
writeTimestamp);
//LOG(DEEPDEBUG) << "writeTimestamp: " << writeTimestamp << ", samplesWritten: " << samplesWritten;
writeTimestamp += (TIMESTAMP) samplesWritten;
wroteRadioSignal.signal();
writingRadioLock.unlock();
LOG(DEEPDEBUG) << "converted " << truncatedBuffer->size()
<< " transceiver samples into " << samplesWritten
<< " radio samples ";
delete resampledVector;
delete []resampledVectorShort;
// update the history of sent data
truncatedBuffer->segmentCopyTo(*sendHistory,truncatedBuffer->size()-INHISTORY,
INHISTORY);
// update the buffer, i.e. keep the samples we didn't send
signalVector *tmp = sendBuffer;
sendBuffer = new signalVector(sendBuffer->size()-truncatedBuffer->size());
tmp->segmentCopyTo(*sendBuffer,truncatedBuffer->size(),
sendBuffer->size());
delete tmp;
delete truncatedBuffer;
}