SDR-DAB_dabradio/dab-processor.cpp

#
/*
 *    Copyright (C) 2014 .. 2017
 *    Jan van Katwijk (J.vanKatwijk@gmail.com)
 *    Lazy Chair Computing
 *
 *    This file is part of the dabradio program
 *    dabradio 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 2 of the License, or
 *    (at your option) any later version.
 *
 *    dabradio 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 dabradio if not, write to the Free Software
 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#include	"dab-processor.h"
#include	"fic-handler.h"
#include	"msc-handler.h"
#include	"radio.h"
#include	"dab-params.h"
#include	"timesyncer.h"
//
/**
  *	\brief dabProcessor
  *	The dabProcessor class is the driver of the processing
  *	of the samplestream.
  *	It is the main interface to the qt-dab program,
  *	local are classes ofdmDecoder, ficHandler and mschandler.
  */

#define	C_LEVEL_SIZE	50
	dabProcessor::dabProcessor	(RadioInterface	*mr,
	                                 deviceHandler	*theDevice,
	                                 uint8_t	dabMode,
	                                 int16_t	threshold,
	                                 int16_t	diff_length,
	                                 QString	picturesPath):
	                                 params (dabMode),
	                                 myReader (mr,
	                                           theDevice,
	                                           nullptr),
	                                 my_ficHandler (mr, dabMode),
	                                 my_mscHandler (mr, dabMode,
	                                                picturesPath),
	                                 phaseSynchronizer (mr,
	                                                    dabMode, 
                                                            threshold,
	                                                    diff_length,
	                                                    nullptr),
	                                 my_ofdmDecoder (mr,
	                                                 dabMode,
	                                                 theDevice -> bitDepth (),
	                                                 nullptr) {
int32_t	i;

	this	-> myRadioInterface	= mr;
	this	-> theDevice		= theDevice;
	this	-> T_null		= params. get_T_null ();
	this	-> T_s			= params. get_T_s ();
	this	-> T_u			= params. get_T_u ();
	this	-> T_F			= params. get_T_F ();
	this	-> nrBlocks		= params. get_L ();
	this	-> carriers		= params. get_carriers ();
	this	-> carrierDiff		= params. get_carrierDiff ();
	this	-> scanMode		= false;

	ofdmBuffer. resize (2 * T_s);
	ofdmBufferIndex			= 0;
	ofdmSymbolCount			= 0;
	tokenCount			= 0;
	fineOffset			= 0;	
	correctionNeeded		= true;
	attempts			= 0;
	myReader. setRunning  (false);
}

	dabProcessor::~dabProcessor	(void) {
	if (isRunning ()) {
	   myReader. setRunning (false);
	                                // exception to be raised
	                        	// through the getSample(s) functions.
	   msleep (100);
	   while (isRunning ()) {
	      usleep (1000);
	   }
	}
}

void	dabProcessor::start (int frequency, bool scanMode) {
	this		-> frequency	= frequency;
	this		-> scanMode	= scanMode;
	startFailures	= 0;
	this -> QThread::start ();
}
	
/***
   *	\brief run
   *	The main thread, reading samples,
   *	time synchronization and frequency synchronization
   *	Identifying blocks in the DAB frame
   *	and sending them to the ofdmDecoder who will transfer the results
   *	Finally, estimating the small freqency error
   */
void	dabProcessor::run	(void) {
int32_t		startIndex;
int32_t		i;
int		attempts;

std::complex<float>	FreqCorr;
timeSyncer	myTimeSyncer (&myReader);

        fineOffset 	  = 0;
        correctionNeeded	= true;
	attempts	= 0;
        theDevice  -> resetBuffer ();
	theDevice	-> restartReader (frequency);
	coarseOffset	= 0;
	fineOffset	= 0;
	myReader. setRunning (true);
	my_mscHandler. start ();
//
//	to get some idea of the signal strength
	try {
	   for (i = 0; i < T_F / 5; i ++) {
	      myReader. getSample (0);
	   }
//Initing:
notSynced:
	   setSynced (false);
	   switch (myTimeSyncer. sync (T_null, T_F)) {
              case TIMESYNC_ESTABLISHED:
                 break;                 // yes, we are ready

              case NO_DIP_FOUND:
                 if (scanMode && (++ attempts >= 5)) {
                    emit (No_Signal_Found ());
                    attempts = 0;
                 }
                 goto notSynced;

              default:                  // does not happen
              case NO_END_OF_DIP_FOUND:
                 goto notSynced;
           }

/**
  *	The end of the null period is identified, the actual end
  *	is probably about 40 samples earlier.
  */
SyncOnPhase:
/**
  *	We now have to find the exact first sample of the non-null period.
  *	We use a correlation that will find the first sample after the
  *	cyclic prefix.
  *	When in "sync", i.e. pretty sure that we know were we are,
  *	we skip the "dip" identification and come here right away.
  *
  *	now read in Tu samples. The precise number is not really important
  *	as long as we can be sure that the first sample to be identified
  *	is part of the samples read.
  */
	myReader. getSamples (ofdmBuffer. data (),
	                        T_u, coarseOffset + fineOffset);
//
//	and then, call upon the phase synchronizer to verify/compute
//	the real "first" sample
	   startIndex = phaseSynchronizer. findIndex (ofdmBuffer);
	   if (startIndex < 0) { // no sync, try again
	      if (!correctionNeeded) {
	         setSyncLost ();
	      }
	      startFailures ++;
	      if (scanMode && (startFailures > 3)) {
                 emit (No_Signal_Found ());
	         startFailures = 0;
	      }
	      goto notSynced;
	   }

	   startFailures	= 0;
/**
  *	Once here, we are synchronized, we need to copy the data we
  *	used for synchronization for block 0
  */
	   memmove (ofdmBuffer. data (),
	            &((ofdmBuffer. data ()) [startIndex]),
	                  (T_u - startIndex) * sizeof (std::complex<float>));
	   ofdmBufferIndex	= T_u - startIndex;

Block_0:
/**
  *	Block 0 is special in that it is used for fine time synchronization,
  *	for coarse frequency synchronization
  *	and its content is used as a reference for decoding the
  *	first datablock.
  *	We read the missing samples in the ofdm buffer
  */
	   setSynced (true);
	   myReader. getSamples (&((ofdmBuffer. data ()) [ofdmBufferIndex]),
	                           T_u - ofdmBufferIndex,
	                           coarseOffset + fineOffset);
	   my_ofdmDecoder. processBlock_0 (ofdmBuffer);

//	Here we look only at the block_0 when we need a coarse
//	frequency synchronization.
	   correctionNeeded	= !my_ficHandler. syncReached ();
	   if (correctionNeeded) {
	      int correction	=
	            phaseSynchronizer. estimate_CarrierOffset (ofdmBuffer);
	      if (correction != 100) {
	         coarseOffset	+= correction * carrierDiff;
	         if (abs (coarseOffset) > Khz (35))
	            coarseOffset = 0;
	      }
	   }
/**
  *	after block 0, we will just read in the other (params -> L - 1) blocks
  */
Data_blocks:
/**
  *	The first ones are the FIC blocks. We immediately
  *	start with building up an average of the phase difference
  *	between the samples in the cyclic prefix and the
  *	corresponding samples in the datapart.
  */
	   FreqCorr	= std::complex<float> (0, 0);
	   for (int ofdmSymbolCount = 1;
                ofdmSymbolCount < nrBlocks; ofdmSymbolCount ++) {
              std::vector<int16_t> ibits;
              ibits. resize (2 * params. get_carriers ());
              myReader. getSamples (ofdmBuffer. data (),
                                      T_s, coarseOffset + fineOffset);
              for (i = (int)T_u; i < (int)T_s; i ++)
                 FreqCorr += ofdmBuffer [i] * conj (ofdmBuffer [i - T_u]);

              if (ofdmSymbolCount < 4) {
                 my_ofdmDecoder. decode (ofdmBuffer,
                                        ofdmSymbolCount, ibits. data ());
                 my_ficHandler. process_ficBlock (ibits, ofdmSymbolCount);
              }
              my_mscHandler. process_Msc  (&((ofdmBuffer. data ()) [T_g]),
                                                            ofdmSymbolCount);
           }

NewOffset:
//	we integrate the newly found frequency error with the
//	existing frequency error.
	   fineOffset += 0.1 * arg (FreqCorr) / (2 * M_PI) * carrierDiff;
//
/**
  *	OK,  here we are at the end of the frame
  *	Assume everything went well and skip T_null samples
  */
	   myReader. getSamples (ofdmBuffer. data (),
	                         T_null, coarseOffset);

	   float sum    = 0;
           for (i = 0; i < T_null; i ++)
              sum += abs (ofdmBuffer [i]);
           sum /= T_null;

           static       float snr       = 0;
           snr = 0.9 * snr +
                 0.1 * 20 * log10 ((myReader. get_sLevel () + 0.005) / sum);
           static int ccc       = 0;
           if (++ccc > 10) {
              ccc = 0;
              show_snr ((int)snr);
           }

/**
  *	The first sample to be found for the next frame should be T_g
  *	samples ahead. Before going for the next frame, we
  *	we just check the fineCorrector
  */
	   if (fineOffset > carrierDiff / 2) {
	      coarseOffset	+= carrierDiff;
	      fineOffset	-= carrierDiff;
	   }
	   else
	   if (fineOffset < -carrierDiff / 2) {
	      coarseOffset -= carrierDiff;
	      fineOffset += carrierDiff;
	   }
ReadyForNewFrame:
///	and off we go, up to the next frame
	   goto SyncOnPhase;
	}
	catch (int e) {
//	   fprintf (stderr, "dabProcessor is stopping\n");
	   ;
	}
	my_mscHandler.  stop ();
	my_ficHandler.  stop ();
}

void	dabProcessor:: reset	(void) {
	myReader. setRunning (false);
	while (isRunning ())
	   usleep (1000);
	usleep (10000);
	my_ficHandler.  reset ();
	QThread::start ();
}

void	dabProcessor::stop	(void) {
	myReader. setRunning (false);
	while (isRunning ())
	   usleep (1000);
	theDevice	-> stopReader ();
	usleep (10000);
	my_ficHandler.  reset ();
}

void	dabProcessor::coarseCorrectorOn (void) {
	correctionNeeded 	= true;
	coarseOffset	= 0;
}

void	dabProcessor::coarseCorrectorOff (void) {
	correctionNeeded	= false;
}

//	we could have derived the dab processor from fic and msc handlers,
//	however, from a logical point of view they are more delegates than
//	parents.
uint8_t dabProcessor::kindofService           (QString &s) {
	return my_ficHandler. kindofService (s);
}

void	dabProcessor::dataforAudioService     (int16_t c, audiodata *dd) {
	my_ficHandler. dataforAudioService (c, dd);
}

void	dabProcessor::dataforAudioService     (QString &s,audiodata *dd) {
	my_ficHandler. dataforAudioService (s, dd, 0);
}

void	dabProcessor::dataforAudioService     (QString &s,
	                                          audiodata *d, int16_t c) {
	my_ficHandler. dataforAudioService (s, d, c);
}

void	dabProcessor::dataforDataService	(int16_t c, packetdata *dd) {
	my_ficHandler. dataforDataService (c, dd);
}

void	dabProcessor::dataforDataService	(QString &s, packetdata *dd) {
	my_ficHandler. dataforDataService (s, dd, 0);
}

void	dabProcessor::dataforDataService	(QString &s,
	                                            packetdata *d, int16_t c) {
	my_ficHandler. dataforDataService (s, d, c);
}


void	dabProcessor::reset_msc (void) {
	my_mscHandler. reset ();
}

void	dabProcessor::set_audioChannel (audiodata *d,
	                                RingBuffer<int16_t> *b,
	                                RingBuffer<uint8_t> *db) {
	my_mscHandler. set_Channel (d, b, (RingBuffer<uint8_t> *)nullptr);
	for (int i = 1; i < 10; i ++) {
           packetdata pd;
           dataforDataService (d -> serviceName, &pd, i);
           if (pd. defined) {
              set_dataChannel (&pd, db);
              break;
           }
        }
}

void	dabProcessor::set_dataChannel (packetdata *d,
	                                      RingBuffer<uint8_t> *b) {
	my_mscHandler. set_Channel (d, (RingBuffer<int16_t> *)nullptr, b);
}

QString dabProcessor::get_ensembleName	(void) {
	return my_ficHandler. get_ensembleName ();
}

void	dabProcessor::clearEnsemble	(void) {
	my_ficHandler. clearEnsemble ();
}