Adding in the missing Transceiver52M directory

git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@2307 19bc5d8c-e614-43d4-8b26-e1612bc8e597

1 files changed, 798 insertions, 0 deletions

diff --git a/Transceiver52M/Transceiver.cpp b/Transceiver52M/Transceiver.cpp
new file mode 100644
index 0000000..7cb2128
--- /dev/null
+++ b/Transceiver52M/Transceiver.cpp
@@ -0,0 +1,798 @@
+/*
+* Copyright 2008, 2009, 2010 Free Software Foundation, Inc.
+*
+* This software is distributed under the terms of the GNU Public License.
+* See the COPYING file in the main directory for details.
+*
+* This use of this software may be subject to additional restrictions.
+* See the LEGAL file in the main directory for details.
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+
+/*
+	Compilation switches
+	TRANSMIT_LOGGING	write every burst on the given slot to a log
+*/
+
+
+#include <stdio.h>
+#include "Transceiver.h"
+#include <Logger.h>
+
+
+
+Transceiver::Transceiver(int wBasePort,
+			 const char *TRXAddress,
+			 int wSamplesPerSymbol,
+			 GSM::Time wTransmitLatency,
+			 RadioInterface *wRadioInterface)
+	:mDataSocket(wBasePort+2,TRXAddress,wBasePort+102),
+	 mControlSocket(wBasePort+1,TRXAddress,wBasePort+101),
+	 mClockSocket(wBasePort,TRXAddress,wBasePort+100)
+{
+  //GSM::Time startTime(0,0);
+  //GSM::Time startTime(gHyperframe/2 - 4*216*60,0);
+  GSM::Time startTime(random() % gHyperframe,0);
+
+  mFIFOServiceLoopThread = new Thread(32768);  ///< thread to push bursts into transmit FIFO
+  mControlServiceLoopThread = new Thread(32768);       ///< thread to process control messages from GSM core
+  mTransmitPriorityQueueServiceLoopThread = new Thread(32768);///< thread to process transmit bursts from GSM core
+
+
+  mSamplesPerSymbol = wSamplesPerSymbol;
+  mRadioInterface = wRadioInterface;
+  mTransmitLatency = wTransmitLatency;
+  mTransmitDeadlineClock = startTime;
+  mLastClockUpdateTime = startTime;
+  mLatencyUpdateTime = startTime;
+  mRadioInterface->getClock()->set(startTime);
+  mMaxExpectedDelay = 0;
+
+  // generate pulse and setup up signal processing library
+  gsmPulse = generateGSMPulse(2,mSamplesPerSymbol);
+  LOG(DEBUG) << "gsmPulse: " << *gsmPulse;
+  sigProcLibSetup(mSamplesPerSymbol);
+
+  txFullScale = mRadioInterface->fullScaleInputValue();
+  rxFullScale = mRadioInterface->fullScaleOutputValue();
+
+  // initialize filler tables with dummy bursts, initialize other per-timeslot variables
+  for (int i = 0; i < 8; i++) {
+    signalVector* modBurst = modulateBurst(gDummyBurst,*gsmPulse,
+					   8 + (i % 4 == 0),
+					   mSamplesPerSymbol);
+    scaleVector(*modBurst,txFullScale);
+    fillerModulus[i]=26;
+    for (int j = 0; j < 102; j++) {
+      fillerTable[j][i] = new signalVector(*modBurst);
+    }
+    delete modBurst;
+    mChanType[i] = NONE;
+    channelResponse[i] = NULL;
+    DFEForward[i] = NULL;
+    DFEFeedback[i] = NULL;
+    channelEstimateTime[i] = startTime;
+  }
+
+  mOn = false;
+  mTxFreq = 0.0;
+  mRxFreq = 0.0;
+  mPower = -10;
+  mEnergyThreshold = 5.0; // based on empirical data
+  prevFalseDetectionTime = startTime;
+}
+
+Transceiver::~Transceiver()
+{
+  delete gsmPulse;
+  sigProcLibDestroy();
+  mTransmitPriorityQueue.clear();
+}
+  
+
+void Transceiver::addRadioVector(BitVector &burst,
+				 int RSSI,
+				 GSM::Time &wTime)
+{
+  // modulate and stick into queue 
+  signalVector* modBurst = modulateBurst(burst,*gsmPulse,
+					 8 + (wTime.TN() % 4 == 0),
+					 mSamplesPerSymbol);
+  scaleVector(*modBurst,txFullScale * pow(10,-RSSI/10));
+  radioVector *newVec = new radioVector(*modBurst,wTime);
+  mTransmitPriorityQueue.write(newVec);
+
+  delete modBurst;
+}
+
+#ifdef TRANSMIT_LOGGING
+void Transceiver::unModulateVector(signalVector wVector) 
+{
+  SoftVector *burst = demodulateBurst(wVector,
+				   *gsmPulse,
+				   mSamplesPerSymbol,
+				   1.0,0.0);
+  LOG(DEBUG) << "LOGGED BURST: " << *burst;
+
+/*
+  unsigned char burstStr[gSlotLen+1];
+  SoftVector::iterator burstItr = burst->begin();
+  for (int i = 0; i < gSlotLen; i++) {
+    // FIXME: Demod bits are inverted!
+    burstStr[i] = (unsigned char) ((*burstItr++)*255.0);
+  }
+  burstStr[gSlotLen]='\0';
+  LOG(DEBUG) << "LOGGED BURST: " << burstStr;
+*/
+  delete burst;
+}
+#endif
+
+void Transceiver::pushRadioVector(GSM::Time &nowTime)
+{
+
+  // dump stale bursts, if any
+  while (radioVector* staleBurst = mTransmitPriorityQueue.getStaleBurst(nowTime)) {
+    // Even if the burst is stale, put it in the fillter table.
+    // (It might be an idle pattern.)
+    LOG(NOTICE) << "dumping STALE burst in TRX->USRP interface";
+    const GSM::Time& nextTime = staleBurst->time();
+    int TN = nextTime.TN();
+    int modFN = nextTime.FN() % fillerModulus[TN];
+    delete fillerTable[modFN][TN];
+    fillerTable[modFN][TN] = staleBurst;
+  }
+  
+  int TN = nowTime.TN();
+  int modFN = nowTime.FN() % fillerModulus[nowTime.TN()];
+
+  // if queue contains data at the desired timestamp, stick it into FIFO
+  if (radioVector *next = (radioVector*) mTransmitPriorityQueue.getCurrentBurst(nowTime)) {
+    LOG(DEBUG) << "transmitFIFO: wrote burst " << next << " at time: " << nowTime;
+    delete fillerTable[modFN][TN];
+    fillerTable[modFN][TN] = new signalVector(*(next));
+    mRadioInterface->driveTransmitRadio(*(next),(mChanType[TN]==NONE)); //fillerTable[modFN][TN]));
+    delete next;
+#ifdef TRANSMIT_LOGGING
+    if (nowTime.TN()==TRANSMIT_LOGGING) { 
+      unModulateVector(*(fillerTable[modFN][TN]));
+    }
+#endif
+    return;
+  }
+
+  // otherwise, pull filler data, and push to radio FIFO
+  mRadioInterface->driveTransmitRadio(*(fillerTable[modFN][TN]),(mChanType[TN]==NONE));
+#ifdef TRANSMIT_LOGGING
+  if (nowTime.TN()==TRANSMIT_LOGGING) 
+    unModulateVector(*fillerTable[modFN][TN]);
+#endif
+
+}
+
+void Transceiver::setModulus(int timeslot)
+{
+  switch (mChanType[timeslot]) {
+  case NONE:
+  case I:
+  case II:
+  case III:
+  case FILL:
+    fillerModulus[timeslot] = 26;
+    break;
+  case IV:
+  case VI:
+  case V:
+    fillerModulus[timeslot] = 51;
+    break;
+    //case V: 
+  case VII:
+    fillerModulus[timeslot] = 102;
+    break;
+  default:
+    break;
+  }
+}
+
+
+Transceiver::CorrType Transceiver::expectedCorrType(GSM::Time currTime)
+{
+  
+  unsigned burstTN = currTime.TN();
+  unsigned burstFN = currTime.FN();
+
+  switch (mChanType[burstTN]) {
+  case NONE:
+    return OFF;
+    break;
+  case FILL:
+    return IDLE;
+    break;
+  case I:
+    return TSC;
+    /*if (burstFN % 26 == 25) 
+      return IDLE;
+    else
+      return TSC;*/
+    break;
+  case II:
+    if (burstFN % 2 == 1)
+      return IDLE;
+    else
+      return TSC;
+    break;
+  case III:
+    return TSC;
+    break;
+  case IV:
+  case VI:
+    return RACH;
+    break;
+  case V: {
+    int mod51 = burstFN % 51;
+    if ((mod51 <= 36) && (mod51 >= 14))
+      return RACH;
+    else if ((mod51 == 4) || (mod51 == 5))
+      return RACH;
+    else if ((mod51 == 45) || (mod51 == 46))
+      return RACH;
+    else
+      return TSC;
+    break;
+  }
+  case VII:
+    if ((burstFN % 51 <= 14) && (burstFN % 51 >= 12))
+      return IDLE;
+    else
+      return TSC;
+    break;
+  case LOOPBACK:
+    if ((burstFN % 51 <= 50) && (burstFN % 51 >=48))
+      return IDLE;
+    else
+      return TSC;
+    break;
+  default:
+    return OFF;
+    break;
+  }
+
+}
+    
+SoftVector *Transceiver::pullRadioVector(GSM::Time &wTime,
+				      int &RSSI,
+				      int &timingOffset)
+{
+  bool needDFE = (mMaxExpectedDelay > 1);
+
+  radioVector *rxBurst = (radioVector *) mReceiveFIFO->get();
+
+  if (!rxBurst) return NULL;
+
+  LOG(DEBUG) << "receiveFIFO: read radio vector at time: " << rxBurst->time() << ", new size: " << mReceiveFIFO->size();
+
+  int timeslot = rxBurst->time().TN();
+
+  CorrType corrType = expectedCorrType(rxBurst->time());
+
+  if ((corrType==OFF) || (corrType==IDLE)) {
+    delete rxBurst;
+    return NULL;
+  }
+ 
+  // check to see if received burst has sufficient 
+  signalVector *vectorBurst = rxBurst;
+  complex amplitude = 0.0;
+  float TOA = 0.0;
+  float avgPwr = 0.0;
+  if (!energyDetect(*vectorBurst,20*mSamplesPerSymbol,mEnergyThreshold,&avgPwr)) {
+     LOG(DEBUG) << "Estimated Energy: " << sqrt(avgPwr) << ", at time " << rxBurst->time();
+     double framesElapsed = rxBurst->time()-prevFalseDetectionTime;
+     if (framesElapsed > 50) {  // if we haven't had any false detections for a while, lower threshold
+	mEnergyThreshold -= 10.0/10.0;
+        prevFalseDetectionTime = rxBurst->time();
+     }
+     delete rxBurst;
+     return NULL;
+  }
+  LOG(DEBUG) << "Estimated Energy: " << sqrt(avgPwr) << ", at time " << rxBurst->time();
+
+  // run the proper correlator
+  bool success = false;
+  if (corrType==TSC) {
+    LOG(DEBUG) << "looking for TSC at time: " << rxBurst->time();
+    signalVector *channelResp;
+    double framesElapsed = rxBurst->time()-channelEstimateTime[timeslot];
+    bool estimateChannel = false;
+    if ((framesElapsed > 50) || (channelResponse[timeslot]==NULL)) {
+	if (channelResponse[timeslot]) delete channelResponse[timeslot];
+        if (DFEForward[timeslot]) delete DFEForward[timeslot];
+        if (DFEFeedback[timeslot]) delete DFEFeedback[timeslot];
+        channelResponse[timeslot] = NULL;
+        DFEForward[timeslot] = NULL;
+        DFEFeedback[timeslot] = NULL;
+	estimateChannel = true;
+    }
+    if (!needDFE) estimateChannel = false;
+    float chanOffset;
+    success = analyzeTrafficBurst(*vectorBurst,
+				  mTSC,
+				  3.0,
+				  mSamplesPerSymbol,
+				  &amplitude,
+				  &TOA,
+				  mMaxExpectedDelay, 
+				  estimateChannel,
+				  &channelResp,
+				  &chanOffset);
+    if (success) {
+      LOG(DEBUG) << "FOUND TSC!!!!!! " << amplitude << " " << TOA;
+      mEnergyThreshold -= 1.0F/10.0F;
+      if (mEnergyThreshold < 0.0) mEnergyThreshold = 0.0;
+      SNRestimate[timeslot] = amplitude.norm2()/(mEnergyThreshold*mEnergyThreshold+1.0); // this is not highly accurate
+      if (estimateChannel) {
+         LOG(DEBUG) << "estimating channel...";
+         channelResponse[timeslot] = channelResp;
+       	 chanRespOffset[timeslot] = chanOffset;
+         chanRespAmplitude[timeslot] = amplitude;
+	 scaleVector(*channelResp, complex(1.0,0.0)/amplitude);
+         designDFE(*channelResp, SNRestimate[timeslot], 7, &DFEForward[timeslot], &DFEFeedback[timeslot]);
+         channelEstimateTime[timeslot] = rxBurst->time();  
+         LOG(DEBUG) << "SNR: " << SNRestimate[timeslot] << ", DFE forward: " << *DFEForward[timeslot] << ", DFE backward: " << *DFEFeedback[timeslot];
+      }
+    }
+    else {
+      double framesElapsed = rxBurst->time()-prevFalseDetectionTime; 
+      LOG(DEBUG) << "wTime: " << rxBurst->time() << ", pTime: " << prevFalseDetectionTime << ", fElapsed: " << framesElapsed;
+      mEnergyThreshold += 10.0F/10.0F*exp(-framesElapsed);
+      prevFalseDetectionTime = rxBurst->time();
+      channelResponse[timeslot] = NULL;
+    }
+  }
+  else {
+    // RACH burst
+    success = detectRACHBurst(*vectorBurst,
+			      5.0,  // detection threshold
+			      mSamplesPerSymbol,
+			      &amplitude,
+			      &TOA);
+    if (success) {
+      LOG(DEBUG) << "FOUND RACH!!!!!! " << amplitude << " " << TOA;
+      mEnergyThreshold -= (1.0F/10.0F);
+      if (mEnergyThreshold < 0.0) mEnergyThreshold = 0.0;
+      channelResponse[timeslot] = NULL; 
+    }
+    else {
+      double framesElapsed = rxBurst->time()-prevFalseDetectionTime;
+      mEnergyThreshold += (1.0F/10.0F)*exp(-framesElapsed);
+      prevFalseDetectionTime = rxBurst->time();
+    }
+  }
+  LOG(DEBUG) << "energy Threshold = " << mEnergyThreshold; 
+
+  // demodulate burst
+  SoftVector *burst = NULL;
+  if ((rxBurst) && (success)) {
+    if ((corrType==RACH) || (!needDFE)) {
+      burst = demodulateBurst(*vectorBurst,
+			      *gsmPulse,
+			      mSamplesPerSymbol,
+			      amplitude,TOA);
+    }
+    else { // TSC
+      scaleVector(*vectorBurst,complex(1.0,0.0)/amplitude);
+      burst = equalizeBurst(*vectorBurst,
+			    TOA-chanRespOffset[timeslot],
+			    mSamplesPerSymbol,
+			    *DFEForward[timeslot],
+			    *DFEFeedback[timeslot]);
+    }
+    wTime = rxBurst->time();
+    // FIXME:  what is full scale for the USRP?  we get more that 12 bits of resolution...
+    RSSI = (int) floor(20.0*log10(rxFullScale/amplitude.abs()));
+    LOG(DEBUG) << "RSSI: " << RSSI;
+    timingOffset = (int) round(TOA*256.0/mSamplesPerSymbol);
+  }
+
+  //if (burst) LOG(DEBUG) << "burst: " << *burst << '\n';
+
+  delete rxBurst;
+
+  return burst;
+}
+
+void Transceiver::start()
+{
+  mControlServiceLoopThread->start((void * (*)(void*))ControlServiceLoopAdapter,(void*) this);
+}
+
+void Transceiver::reset()
+{
+  mTransmitPriorityQueue.clear();
+  //mTransmitFIFO->clear();
+  //mReceiveFIFO->clear();
+}
+
+  
+void Transceiver::driveControl()
+{
+
+  int MAX_PACKET_LENGTH = 100;
+
+  // check control socket
+  char buffer[MAX_PACKET_LENGTH];
+  int msgLen = -1;
+  buffer[0] = '\0';
+ 
+  msgLen = mControlSocket.read(buffer);
+
+  if (msgLen < 1) {
+    return;
+  }
+
+  char cmdcheck[4];
+  char command[MAX_PACKET_LENGTH];
+  char response[MAX_PACKET_LENGTH];
+
+  sscanf(buffer,"%3s %s",cmdcheck,command);
+ 
+  writeClockInterface();
+
+  if (strcmp(cmdcheck,"CMD")!=0) {
+    LOG(WARNING) << "bogus message on control interface";
+    return;
+  }
+  LOG(INFO) << "command is " << buffer;
+
+  if (strcmp(command,"POWEROFF")==0) {
+    // turn off transmitter/demod
+    sprintf(response,"RSP POWEROFF 0"); 
+  }
+  else if (strcmp(command,"POWERON")==0) {
+    // turn on transmitter/demod
+    if (!mTxFreq || !mRxFreq) 
+      sprintf(response,"RSP POWERON 1");
+    else {
+      sprintf(response,"RSP POWERON 0");
+      if (!mOn) {
+        // Prepare for thread start
+        mPower = -20;
+        mRadioInterface->start();
+        generateRACHSequence(*gsmPulse,mSamplesPerSymbol);
+
+        // Start radio interface threads.
+        mFIFOServiceLoopThread->start((void * (*)(void*))FIFOServiceLoopAdapter,(void*) this);
+        mTransmitPriorityQueueServiceLoopThread->start((void * (*)(void*))TransmitPriorityQueueServiceLoopAdapter,(void*) this);
+        writeClockInterface();
+
+        mOn = true;
+      }
+    }
+  }
+  else if (strcmp(command,"SETMAXDLY")==0) {
+    //set expected maximum time-of-arrival
+    int maxDelay;
+    sscanf(buffer,"%3s %s %d",cmdcheck,command,&maxDelay);
+    mMaxExpectedDelay = maxDelay; // 1 GSM symbol is approx. 1 km
+    sprintf(response,"RSP SETMAXDLY 0 %d",maxDelay);
+  }
+  else if (strcmp(command,"SETRXGAIN")==0) {
+    //set expected maximum time-of-arrival
+    int newGain;
+    sscanf(buffer,"%3s %s %d",cmdcheck,command,&newGain);
+    newGain = mRadioInterface->setRxGain(newGain);
+    sprintf(response,"RSP SETRXGAIN 0 %d",newGain);
+  }
+  else if (strcmp(command,"NOISELEV")==0) {
+    if (mOn) {
+      sprintf(response,"RSP NOISELEV 0 %d",
+              (int) round(20.0*log10(rxFullScale/mEnergyThreshold)));
+    }
+    else {
+      sprintf(response,"RSP NOISELEV 1  0");
+    }
+  }   
+  else if (strcmp(command,"SETPOWER")==0) {
+    // set output power in dB
+    int dbPwr;
+    sscanf(buffer,"%3s %s %d",cmdcheck,command,&dbPwr);
+    if (!mOn) 
+      sprintf(response,"RSP SETPOWER 1 %d",dbPwr);
+    else {
+      mPower = dbPwr;
+      mRadioInterface->setPowerAttenuation(pow(10.0,dbPwr/10.0));
+      sprintf(response,"RSP SETPOWER 0 %d",dbPwr);
+    }
+  }
+  else if (strcmp(command,"ADJPOWER")==0) {
+    // adjust power in dB steps
+    int dbStep;
+    sscanf(buffer,"%3s %s %d",cmdcheck,command,&dbStep);
+    if (!mOn) 
+      sprintf(response,"RSP ADJPOWER 1 %d",mPower);
+    else {
+      mPower += dbStep;
+      sprintf(response,"RSP ADJPOWER 0 %d",mPower);
+    }
+  }
+#define FREQOFFSET 0//11.2e3
+  else if (strcmp(command,"RXTUNE")==0) {
+    // tune receiver
+    int freqKhz;
+    sscanf(buffer,"%3s %s %d",cmdcheck,command,&freqKhz);
+    mRxFreq = freqKhz*1.0e3+FREQOFFSET;
+    if (!mRadioInterface->tuneRx(mRxFreq)) {
+       LOG(ALERT) << "RX failed to tune";
+       sprintf(response,"RSP RXTUNE 1 %d",freqKhz);
+    }
+    else
+       sprintf(response,"RSP RXTUNE 0 %d",freqKhz);
+  }
+  else if (strcmp(command,"TXTUNE")==0) {
+    // tune txmtr
+    int freqKhz;
+    sscanf(buffer,"%3s %s %d",cmdcheck,command,&freqKhz);
+    //freqKhz = 890e3;
+    mTxFreq = freqKhz*1.0e3+FREQOFFSET;
+    if (!mRadioInterface->tuneTx(mTxFreq)) {
+       LOG(ALERT) << "TX failed to tune";
+       sprintf(response,"RSP TXTUNE 1 %d",freqKhz);
+    }
+    else
+       sprintf(response,"RSP TXTUNE 0 %d",freqKhz);
+  }
+  else if (strcmp(command,"SETTSC")==0) {
+    // set TSC
+    int TSC;
+    sscanf(buffer,"%3s %s %d",cmdcheck,command,&TSC);
+    if (mOn)
+      sprintf(response,"RSP SETTSC 1 %d",TSC);
+    else {
+      mTSC = TSC;
+      generateMidamble(*gsmPulse,mSamplesPerSymbol,TSC);
+      sprintf(response,"RSP SETTSC 0 %d",TSC);
+    }
+  }
+  else if (strcmp(command,"SETSLOT")==0) {
+    // set TSC 
+    int  corrCode;
+    int  timeslot;
+    sscanf(buffer,"%3s %s %d %d",cmdcheck,command,&timeslot,&corrCode);
+    if ((timeslot < 0) || (timeslot > 7)) {
+      LOG(WARNING) << "bogus message on control interface";
+      sprintf(response,"RSP SETSLOT 1 %d %d",timeslot,corrCode);
+      return;
+    }     
+    mChanType[timeslot] = (ChannelCombination) corrCode;
+    setModulus(timeslot);
+    sprintf(response,"RSP SETSLOT 0 %d %d",timeslot,corrCode);
+
+  }
+  else {
+    LOG(WARNING) << "bogus command " << command << " on control interface.";
+  }
+
+  mControlSocket.write(response,strlen(response)+1);
+
+}
+
+bool Transceiver::driveTransmitPriorityQueue() 
+{
+
+  char buffer[gSlotLen+50];
+
+  // check data socket
+  size_t msgLen = mDataSocket.read(buffer);
+
+  if (msgLen!=gSlotLen+1+4+1) {
+    LOG(ERR) << "badly formatted packet on GSM->TRX interface";
+    return false;
+  }
+
+  int timeSlot = (int) buffer[0];
+  uint64_t frameNum = 0;
+  for (int i = 0; i < 4; i++)
+    frameNum = (frameNum << 8) | (0x0ff & buffer[i+1]);
+  
+  /*
+  if (GSM::Time(frameNum,timeSlot) >  mTransmitDeadlineClock + GSM::Time(51,0)) {
+    // stale burst
+    //LOG(DEBUG) << "FAST! "<< GSM::Time(frameNum,timeSlot);
+    //writeClockInterface();
+    }*/
+
+/*
+  DAB -- Just let these go through the demod.
+  if (GSM::Time(frameNum,timeSlot) < mTransmitDeadlineClock) {
+    // stale burst from GSM core
+    LOG(NOTICE) << "STALE packet on GSM->TRX interface at time "<< GSM::Time(frameNum,timeSlot);
+    return false;
+  }
+*/
+  
+  // periodically update GSM core clock
+  LOG(DEBUG) << "mTransmitDeadlineClock " << mTransmitDeadlineClock
+		<< " mLastClockUpdateTime " << mLastClockUpdateTime;
+  if (mTransmitDeadlineClock > mLastClockUpdateTime + GSM::Time(216,0))
+    writeClockInterface();
+
+
+  LOG(DEBUG) << "rcvd. burst at: " << GSM::Time(frameNum,timeSlot);
+  
+  int RSSI = (int) buffer[5];
+  static BitVector newBurst(gSlotLen);
+  BitVector::iterator itr = newBurst.begin();
+  char *bufferItr = buffer+6;
+  while (itr < newBurst.end()) 
+    *itr++ = *bufferItr++;
+  
+  GSM::Time currTime = GSM::Time(frameNum,timeSlot);
+  
+  addRadioVector(newBurst,RSSI,currTime);
+  
+  LOG(DEBUG) "added burst - time: " << currTime << ", RSSI: " << RSSI; // << ", data: " << newBurst; 
+
+  return true;
+
+
+}
+ 
+void Transceiver::driveReceiveFIFO() 
+{
+
+  SoftVector *rxBurst = NULL;
+  int RSSI;
+  int TOA;  // in 1/256 of a symbol
+  GSM::Time burstTime;
+
+  mRadioInterface->driveReceiveRadio();
+
+  rxBurst = pullRadioVector(burstTime,RSSI,TOA);
+
+  if (rxBurst) { 
+
+    LOG(DEBUG) << "burst parameters: "
+	  << " time: " << burstTime
+	  << " RSSI: " << RSSI
+	  << " TOA: "  << TOA
+	  << " bits: " << *rxBurst;
+    
+    char burstString[gSlotLen+10];
+    burstString[0] = burstTime.TN();
+    for (int i = 0; i < 4; i++)
+      burstString[1+i] = (burstTime.FN() >> ((3-i)*8)) & 0x0ff;
+    burstString[5] = RSSI;
+    burstString[6] = (TOA >> 8) & 0x0ff;
+    burstString[7] = TOA & 0x0ff;
+    SoftVector::iterator burstItr = rxBurst->begin();
+
+    for (unsigned int i = 0; i < gSlotLen; i++) {
+      burstString[8+i] =(char) round((*burstItr++)*255.0);
+    }
+    burstString[gSlotLen+9] = '\0';
+    delete rxBurst;
+
+    mDataSocket.write(burstString,gSlotLen+10);
+  }
+
+}
+
+void Transceiver::driveTransmitFIFO() 
+{
+
+  /**
+      Features a carefully controlled latency mechanism, to 
+      assure that transmit packets arrive at the radio/USRP
+      before they need to be transmitted.
+
+      Deadline clock indicates the burst that needs to be
+      pushed into the FIFO right NOW.  If transmit queue does
+      not have a burst, stick in filler data.
+  */
+
+
+  RadioClock *radioClock = (mRadioInterface->getClock());
+  
+  if (mOn) {
+    //radioClock->wait(); // wait until clock updates
+    LOG(DEBUG) << "radio clock " << radioClock->get();
+    while (radioClock->get() + mTransmitLatency > mTransmitDeadlineClock) {
+      // if underrun, then we're not providing bursts to radio/USRP fast
+      //   enough.  Need to increase latency by one GSM frame.
+      if (mRadioInterface->isUnderrun()) {
+        // only do latency update every 10 frames, so we don't over update
+	if (radioClock->get() > mLatencyUpdateTime + GSM::Time(10,0)) {
+	  mTransmitLatency = mTransmitLatency + GSM::Time(1,0);
+	  LOG(INFO) << "new latency: " << mTransmitLatency;
+	  mLatencyUpdateTime = radioClock->get();
+	}
+      }
+      else {
+        // if underrun hasn't occurred in the last sec (216 frames) drop
+        //    transmit latency by a timeslot
+	if (mTransmitLatency > GSM::Time(1,1)) {
+            if (radioClock->get() > mLatencyUpdateTime + GSM::Time(216,0)) {
+	    mTransmitLatency.decTN();
+	    LOG(INFO) << "reduced latency: " << mTransmitLatency;
+	    mLatencyUpdateTime = radioClock->get();
+	  }
+	}
+      }
+      // time to push burst to transmit FIFO
+      pushRadioVector(mTransmitDeadlineClock);
+      mTransmitDeadlineClock.incTN();
+    }
+    
+  }
+  // FIXME -- This should not be a hard spin.
+  // But any delay here causes us to throw omni_thread_fatal.
+  //else radioClock->wait();
+}
+
+
+
+void Transceiver::writeClockInterface()
+{
+  char command[50];
+  // FIXME -- This should be adaptive.
+  sprintf(command,"IND CLOCK %llu",(unsigned long long) (mTransmitDeadlineClock.FN()+2));
+
+  LOG(INFO) << "ClockInterface: sending " << command;
+
+  mClockSocket.write(command,strlen(command)+1);
+
+  mLastClockUpdateTime = mTransmitDeadlineClock;
+
+}   
+  
+
+
+
+void *FIFOServiceLoopAdapter(Transceiver *transceiver)
+{
+  while (1) {
+    transceiver->driveReceiveFIFO();
+    transceiver->driveTransmitFIFO();
+    pthread_testcancel();
+  }
+  return NULL;
+}
+
+void *ControlServiceLoopAdapter(Transceiver *transceiver)
+{
+  while (1) {
+    transceiver->driveControl();
+    pthread_testcancel();
+  }
+  return NULL;
+}
+
+void *TransmitPriorityQueueServiceLoopAdapter(Transceiver *transceiver)
+{
+  while (1) {
+    bool stale = false;
+    // Flush the UDP packets until a successful transfer.
+    while (!transceiver->driveTransmitPriorityQueue()) {
+      stale = true; 
+    }
+    if (stale) {
+      // If a packet was stale, remind the GSM stack of the clock.
+      transceiver->writeClockInterface();
+    }
+    pthread_testcancel();
+  }
+  return NULL;
+}