// Helper function to keep code base small
void window_push_bench(struct rusage *_start,
struct rusage *_finish,
unsigned long int *_num_iterations,
unsigned int _n)
{
// normalize number of iterations
*_num_iterations *= 8;
if (*_num_iterations < 1) *_num_iterations = 1;
// initialize port
windowcf w = windowcf_create(_n);
unsigned long int i;
// start trials:
// write to port, read from port
getrusage(RUSAGE_SELF, _start);
for (i=0; i<(*_num_iterations); i++) {
windowcf_push(w, 1.0f);
windowcf_push(w, 1.0f);
windowcf_push(w, 1.0f);
windowcf_push(w, 1.0f);
}
getrusage(RUSAGE_SELF, _finish);
*_num_iterations *= 4;
windowcf_destroy(w);
}
// execute framing synchronizer on input buffer
// _q : framing synchronizer object
// _buffer : input buffer [size: _n x 1]
// _n : input buffer size
void wlanframesync_execute(wlanframesync _q,
liquid_float_complex * _buffer,
unsigned int _n)
{
unsigned int i;
float complex x;
for (i=0; i<_n; i++) {
x = _buffer[i];
// correct for carrier frequency offset (only if not in
// initial 'seek PLCP' state)
if (_q->state != WLANFRAMESYNC_STATE_SEEKPLCP) {
nco_crcf_mix_down(_q->nco_rx, x, &x);
nco_crcf_step(_q->nco_rx);
}
// save input sample to buffer
windowcf_push(_q->input_buffer,x);
#if DEBUG_WLANFRAMESYNC
if (_q->debug_enabled) {
// apply agc (estimate initial signal gain)
float complex y;
agc_crcf_execute(_q->agc_rx, x, &y);
windowcf_push(_q->debug_x, x);
windowf_push(_q->debug_rssi, agc_crcf_get_rssi(_q->agc_rx));
}
#endif
switch (_q->state) {
case WLANFRAMESYNC_STATE_SEEKPLCP:
wlanframesync_execute_seekplcp(_q);
break;
case WLANFRAMESYNC_STATE_RXSHORT0:
wlanframesync_execute_rxshort0(_q);
break;
case WLANFRAMESYNC_STATE_RXSHORT1:
wlanframesync_execute_rxshort1(_q);
break;
case WLANFRAMESYNC_STATE_RXLONG0:
wlanframesync_execute_rxlong0(_q);
break;
case WLANFRAMESYNC_STATE_RXLONG1:
wlanframesync_execute_rxlong1(_q);
break;
case WLANFRAMESYNC_STATE_RXSIGNAL:
wlanframesync_execute_rxsignal(_q);
break;
case WLANFRAMESYNC_STATE_RXDATA:
wlanframesync_execute_rxdata(_q);
break;
default:;
// should never get to this point
fprintf(stderr,"error: wlanframesync_execute(), invalid state\n");
exit(1);
}
} // for (i=0; i<_n; i++)
}
int main (int argc, char ** argv) {
w=windowcf_create(SPECTRUM_FFT_LENGTH);
wchA = windowcf_create(TRACK_LENGTH);
wchB = windowcf_create(TRACK_LENGTH);
wchC = windowcf_create(TRACK_LENGTH);
wchA_filtered = windowcf_create(TRACK_LENGTH);
wchB_filtered = windowcf_create(TRACK_LENGTH);
wchC_filtered = windowcf_create(TRACK_LENGTH);
wmag_buffer = windowf_create(TRACK_LENGTH);
nco = nco_crcf_create(LIQUID_NCO);
std::cout << "hydromath daemon is beginning..." << std::endl;
std::cout << "NOTE: if this is symhydromath you must pass in a matfile" << std::endl;
std::cout << argv[1] << std::endl;
shm_init();
shm_getg(hydrophones_results_track, shm_results_track);
shm_getg(hydrophones_results_spectrum, shm_results_spectrum);
//shm_results_track.tracked_ping_count=0;
shm_results_track.tracked_ping_time=0;
if (argc > 1) {
udp_init(argv[1]);
}
else {
udp_init("");
}
//std::thread track_thread(direction_loop);
//
//std::thread spectrum_thread(spectrum_loop);
track_sample_idx = 0;
while (loop(&spt) == 0) {
shm_getg(hydrophones_settings, shm_settings);
for (int i = 0; i < 3*CHANNEL_DEPTH; i+=3) {
windowcf_push(w, std::complex<float>(spt.data[i+1],0)); //This uses channel B
windowcf_push(wchA, std::complex<float>(spt.data[i],0));
windowcf_push(wchB, std::complex<float>(spt.data[i+1],0));
windowcf_push(wchC, std::complex<float>(spt.data[i+2],0));
}
current_sample_count+=CHANNEL_DEPTH;
do_spectrum();
do_track();
}
printf("loop done %li =ci\n",current_sample_count/CHANNEL_DEPTH);
return 0;
}
// execute frame synchronizer
// _q : frame synchronizer object
// _x : input sample array [size: _n x 1]
// _n : number of input samples
void flexframesync_execute(flexframesync _q,
float complex * _x,
unsigned int _n)
{
unsigned int i;
for (i=0; i<_n; i++) {
#if DEBUG_FLEXFRAMESYNC
// write samples to debug buffer
// NOTE: the debug_qdetector_flush prevents samples from being written twice
if (_q->debug_enabled && !_q->debug_qdetector_flush)
windowcf_push(_q->debug_x, _x[i]);
#endif
switch (_q->state) {
case FLEXFRAMESYNC_STATE_DETECTFRAME:
// detect frame (look for p/n sequence)
flexframesync_execute_seekpn(_q, _x[i]);
break;
case FLEXFRAMESYNC_STATE_RXPREAMBLE:
// receive p/n sequence symbols
flexframesync_execute_rxpreamble(_q, _x[i]);
break;
case FLEXFRAMESYNC_STATE_RXHEADER:
// receive header symbols
flexframesync_execute_rxheader(_q, _x[i]);
break;
case FLEXFRAMESYNC_STATE_RXPAYLOAD:
// receive payload symbols
flexframesync_execute_rxpayload(_q, _x[i]);
break;
default:
fprintf(stderr,"error: flexframesync_exeucte(), unknown/unsupported state\n");
exit(1);
}
}
}
// execute frame synchronizer
// _q : frame synchronizer object
// _x : input sample array [size: _n x 1]
// _n : number of input samples
void flexframesync_execute(flexframesync _q,
float complex * _x,
unsigned int _n)
{
unsigned int i;
for (i=0; i<_n; i++) {
#if DEBUG_FLEXFRAMESYNC
if (_q->debug_enabled)
windowcf_push(_q->debug_x, _x[i]);
#endif
switch (_q->state) {
case STATE_DETECTFRAME:
// detect frame (look for p/n sequence)
flexframesync_execute_seekpn(_q, _x[i]);
break;
case STATE_RXPN:
// receive p/n sequence symbols
flexframesync_execute_rxpn(_q, _x[i]);
break;
case STATE_RXHEADER:
// receive header sequence symbols
flexframesync_execute_rxheader(_q, _x[i]);
break;
case STATE_RXPAYLOAD:
// receive payload symbols
flexframesync_execute_rxpayload(_q, _x[i]);
break;
default:
fprintf(stderr,"error: flexframesync_exeucte(), unknown/unsupported state\n");
exit(1);
}
}
}
void ofdmoqamframe64sync_execute(ofdmoqamframe64sync _q,
float complex * _x,
unsigned int _n)
{
unsigned int i;
float complex x;
for (i=0; i<_n; i++) {
x = _x[i];
#if DEBUG_OFDMOQAMFRAME64SYNC
windowcf_push(_q->debug_x,x);
#endif
_q->num_samples++;
// coarse gain correction
//x *= _q->g;
// compensate for CFO
nco_crcf_mix_down(_q->nco_rx, x, &x);
// push sample into analysis filter banks
float complex x_delay0;
float complex x_delay1;
windowcf_index(_q->input_buffer,0, &x_delay0); // full symbol delay
windowcf_index(_q->input_buffer,32,&x_delay1); // half symbol delay
windowcf_push(_q->input_buffer,x);
firpfbch_analyzer_push(_q->ca0, x_delay0); // push input sample
firpfbch_analyzer_push(_q->ca1, x_delay1); // push delayed sample
switch (_q->state) {
case OFDMOQAMFRAME64SYNC_STATE_PLCPSHORT:
ofdmoqamframe64sync_execute_plcpshort(_q,x);
break;
case OFDMOQAMFRAME64SYNC_STATE_PLCPLONG0:
ofdmoqamframe64sync_execute_plcplong0(_q,x);
break;
case OFDMOQAMFRAME64SYNC_STATE_PLCPLONG1:
ofdmoqamframe64sync_execute_plcplong1(_q,x);
break;
case OFDMOQAMFRAME64SYNC_STATE_RXSYMBOLS:
ofdmoqamframe64sync_execute_rxsymbols(_q,x);
break;
default:;
}
} // for (i=0; i<_n; i++)
} // ofdmoqamframe64sync_execute()
void ofdmoqamframe64sync_execute_plcplong1(ofdmoqamframe64sync _q, float complex _x)
{
// cross-correlator
float complex rxy;
firfilt_cccf_push(_q->crosscorr, _x);
firfilt_cccf_execute(_q->crosscorr, &rxy);
rxy *= _q->g;
#if DEBUG_OFDMOQAMFRAME64SYNC
windowcf_push(_q->debug_rxy, rxy);
#endif
_q->timer++;
if (_q->timer < _q->num_subcarriers-8) {
return;
} else if (_q->timer > _q->num_subcarriers+8) {
#if DEBUG_OFDMOQAMFRAME64SYNC_PRINT
printf("warning: ofdmoqamframe64sync could not find second PLCP long sequence; resetting synchronizer\n");
#endif
ofdmoqamframe64sync_reset(_q);
return;
}
if (cabsf(rxy) > 0.7f*(_q->rxy_thresh)*(_q->num_subcarriers)) {
#if DEBUG_OFDMOQAMFRAME64SYNC_PRINT
printf("rxy[1] : %12.8f at input[%3u]\n", cabsf(rxy), _q->num_samples);
#endif
//
float complex * rc;
windowcf_read(_q->input_buffer, &rc);
memmove(_q->S1b, rc, 64*sizeof(float complex));
// estimate frequency offset
float complex rxy_hat=0.0f;
unsigned int j;
for (j=0; j<64; j++) {
rxy_hat += _q->S1a[j] * conjf(_q->S1b[j]) * hamming(j,64);
}
float nu_hat1 = -cargf(rxy_hat);
if (nu_hat1 > M_PI) nu_hat1 -= 2.0f*M_PI;
if (nu_hat1 < -M_PI) nu_hat1 += 2.0f*M_PI;
nu_hat1 /= 64.0f;
#if DEBUG_OFDMOQAMFRAME64SYNC_PRINT
printf("nu_hat[0] = %12.8f\n", _q->nu_hat);
printf("nu_hat[1] = %12.8f\n", nu_hat1);
#endif
nco_crcf_adjust_frequency(_q->nco_rx, nu_hat1);
/*
printf("exiting prematurely\n");
ofdmoqamframe64sync_destroy(_q);
exit(1);
*/
_q->state = OFDMOQAMFRAME64SYNC_STATE_RXSYMBOLS;
}
}
void ofdmframesync_execute(ofdmframesync _q,
float complex * _x,
unsigned int _n)
{
unsigned int i;
float complex x;
for (i=0; i<_n; i++) {
x = _x[i];
// correct for carrier frequency offset
if (_q->state != OFDMFRAMESYNC_STATE_SEEKPLCP) {
nco_crcf_mix_down(_q->nco_rx, x, &x);
nco_crcf_step(_q->nco_rx);
}
// save input sample to buffer
windowcf_push(_q->input_buffer,x);
#if DEBUG_OFDMFRAMESYNC
if (_q->debug_enabled) {
windowcf_push(_q->debug_x, x);
windowf_push(_q->debug_rssi, crealf(x)*crealf(x) + cimagf(x)*cimagf(x));
}
#endif
switch (_q->state) {
case OFDMFRAMESYNC_STATE_SEEKPLCP:
ofdmframesync_execute_seekplcp(_q);
break;
case OFDMFRAMESYNC_STATE_PLCPSHORT0:
ofdmframesync_execute_S0a(_q);
break;
case OFDMFRAMESYNC_STATE_PLCPSHORT1:
ofdmframesync_execute_S0b(_q);
break;
case OFDMFRAMESYNC_STATE_PLCPLONG:
ofdmframesync_execute_S1(_q);
break;
case OFDMFRAMESYNC_STATE_RXSYMBOLS:
ofdmframesync_execute_rxsymbols(_q);
break;
default:;
}
} // for (i=0; i<_n; i++)
} // ofdmframesync_execute()
void ofdmoqamframe64sync_execute_plcpshort(ofdmoqamframe64sync _q, float complex _x)
{
// run AGC, clip output
float complex y;
agc_crcf_execute(_q->sigdet, _x, &y);
//if (agc_crcf_get_signal_level(_q->sigdet) < -15.0f)
// return;
if (cabsf(y) > 2.0f)
y = 2.0f*liquid_cexpjf(cargf(y));
// auto-correlators
//autocorr_cccf_push(_q->autocorr, _x);
autocorr_cccf_push(_q->autocorr, y);
autocorr_cccf_execute(_q->autocorr, &_q->rxx);
#if DEBUG_OFDMOQAMFRAME64SYNC
windowcf_push(_q->debug_rxx, _q->rxx);
windowf_push(_q->debug_rssi, agc_crcf_get_signal_level(_q->sigdet));
#endif
float rxx_mag = cabsf(_q->rxx);
float threshold = (_q->rxx_thresh)*(_q->autocorr_length);
if (rxx_mag > threshold) {
// wait for auto-correlation to peak before changing state
if (rxx_mag > _q->rxx_mag_max) {
_q->rxx_mag_max = rxx_mag;
return;
}
// estimate CFO
_q->nu_hat = cargf(_q->rxx);
if (_q->nu_hat > M_PI/2.0f) _q->nu_hat -= M_PI;
if (_q->nu_hat < -M_PI/2.0f) _q->nu_hat += M_PI;
_q->nu_hat *= 4.0f / (float)(_q->num_subcarriers);
#if DEBUG_OFDMOQAMFRAME64SYNC_PRINT
printf("rxx = |%12.8f| arg{%12.8f}\n", cabsf(_q->rxx),cargf(_q->rxx));
printf("nu_hat = %12.8f\n", _q->nu_hat);
#endif
nco_crcf_set_frequency(_q->nco_rx, _q->nu_hat);
_q->state = OFDMOQAMFRAME64SYNC_STATE_PLCPLONG0;
_q->g = agc_crcf_get_gain(_q->sigdet);
#if DEBUG_OFDMOQAMFRAME64SYNC_PRINT
printf("gain : %f\n", _q->g);
#endif
_q->timer=0;
}
}
void ampmodem_demodulate(ampmodem _q,
float complex _y,
float *_x)
{
#if DEBUG_AMPMODEM
windowcf_push(_q->debug_x, _y);
#endif
if (_q->suppressed_carrier) {
// single side-band suppressed carrier
if (_q->type != LIQUID_AMPMODEM_DSB) {
*_x = crealf(_y);
return;
}
// coherent demodulation
// mix signal down
float complex y_hat;
nco_crcf_mix_down(_q->oscillator, _y, &y_hat);
// compute phase error
float phase_error = tanhf( crealf(y_hat) * cimagf(y_hat) );
#if DEBUG_AMPMODEM
// compute frequency error
float nco_freq = nco_crcf_get_frequency(_q->oscillator);
float freq_error = nco_freq/(2*M_PI) - _q->fc/(2*M_PI);
// retain phase and frequency errors
windowf_push(_q->debug_phase_error, phase_error);
windowf_push(_q->debug_freq_error, freq_error);
#endif
// adjust nco, pll objects
nco_crcf_pll_step(_q->oscillator, phase_error);
// step NCO
nco_crcf_step(_q->oscillator);
// set output
*_x = crealf(y_hat);
} else {
// non-coherent demodulation (peak detector)
float t = cabsf(_y);
// remove DC bias
_q->ssb_q_hat = ( _q->ssb_alpha)*t +
(1 - _q->ssb_alpha)*_q->ssb_q_hat;
*_x = 2.0f*(t - _q->ssb_q_hat);
}
}
void ofdmoqamframe64sync_execute_plcplong0(ofdmoqamframe64sync _q, float complex _x)
{
// cross-correlator
float complex rxy;
firfilt_cccf_push(_q->crosscorr, _x);
firfilt_cccf_execute(_q->crosscorr, &rxy);
rxy *= _q->g;
#if DEBUG_OFDMOQAMFRAME64SYNC
windowcf_push(_q->debug_rxy, rxy);
#endif
_q->timer++;
if (_q->timer > 10*(_q->num_subcarriers)) {
#if DEBUG_OFDMOQAMFRAME64SYNC_PRINT
printf("warning: ofdmoqamframe64sync could not find first PLCP long sequence; resetting synchronizer\n");
#endif
ofdmoqamframe64sync_reset(_q);
return;
}
if (cabsf(rxy) > (_q->rxy_thresh)*(_q->num_subcarriers)) {
#if DEBUG_OFDMOQAMFRAME64SYNC_PRINT
printf("rxy[0] : %12.8f at input[%3u]\n", cabsf(rxy), _q->num_samples);
#endif
// run analyzers
//firpfbch_analyzer_run(_q->ca0, _q->S1a);
//firpfbch_analyzer_run(_q->ca1, _q->S1b);
_q->sample_phase = (_q->num_samples + (_q->num_subcarriers)/2) % _q->num_subcarriers;
//_q->sample_phase = (_q->num_samples) % _q->num_subcarriers;
#if DEBUG_OFDMOQAMFRAME64SYNC_PRINT
printf("sample phase : %u\n",_q->sample_phase);
#endif
//
float complex * rc;
windowcf_read(_q->input_buffer, &rc);
memmove(_q->S1a, rc, 64*sizeof(float complex));
_q->state = OFDMOQAMFRAME64SYNC_STATE_PLCPLONG1;
_q->timer = 0;
}
}
// execute frame synchronizer
// _q : frame synchronizer object
// _x : input sample array [size: _n x 1]
// _n : number of input samples
void gmskframesync_execute(gmskframesync _q,
float complex * _x,
unsigned int _n)
{
// push through synchronizer
unsigned int i;
for (i=0; i<_n; i++) {
float complex xf; // input sample
#if GMSKFRAMESYNC_PREFILTER
iirfilt_crcf_execute(_q->prefilter, _x[i], &xf);
#else
xf = _x[i];
#endif
#if DEBUG_GMSKFRAMESYNC
if (_q->debug_enabled)
windowcf_push(_q->debug_x, xf);
#endif
switch (_q->state) {
case STATE_DETECTFRAME:
// look for p/n sequence
gmskframesync_execute_detectframe(_q, xf);
break;
case STATE_RXPREAMBLE:
// receive p/n sequence symbols
gmskframesync_execute_rxpreamble(_q, xf);
break;
case STATE_RXHEADER:
// receive header
gmskframesync_execute_rxheader(_q, xf);
break;
case STATE_RXPAYLOAD:
// receive payload
gmskframesync_execute_rxpayload(_q, xf);
break;
}
}
}
void ofdmframesync_execute_rxsymbols(ofdmframesync _q)
{
// wait for timeout
_q->timer--;
if (_q->timer == 0) {
// run fft
float complex * rc;
windowcf_read(_q->input_buffer, &rc);
memmove(_q->x, &rc[_q->cp_len-_q->backoff], (_q->M)*sizeof(float complex));
FFT_EXECUTE(_q->fft);
// recover symbol in internal _q->X buffer
ofdmframesync_rxsymbol(_q);
#if DEBUG_OFDMFRAMESYNC
if (_q->debug_enabled) {
unsigned int i;
for (i=0; i<_q->M; i++) {
if (_q->p[i] == OFDMFRAME_SCTYPE_DATA)
windowcf_push(_q->debug_framesyms, _q->X[i]);
}
}
#endif
// invoke callback
if (_q->callback != NULL) {
int retval = _q->callback(_q->X, _q->p, _q->M, _q->userdata);
if (retval != 0)
ofdmframesync_reset(_q);
}
// reset timer
_q->timer = _q->M + _q->cp_len;
}
}
void gmskframesync_execute_detectframe(gmskframesync _q,
float complex _x)
{
// push sample into pre-demod p/n sequence buffer
windowcf_push(_q->buffer, _x);
// push through pre-demod synchronizer
int detected = detector_cccf_correlate(_q->frame_detector,
_x,
&_q->tau_hat,
&_q->dphi_hat,
&_q->gamma_hat);
// check if frame has been detected
if (detected) {
//printf("***** frame detected! tau-hat:%8.4f, dphi-hat:%8.4f, gamma:%8.2f dB\n",
// _q->tau_hat, _q->dphi_hat, 20*log10f(_q->gamma_hat));
// push buffered samples through synchronizer
// NOTE: state will be updated to STATE_RXPREAMBLE internally
gmskframesync_pushpn(_q);
}
}
// execute synchronizer, seeking p/n sequence
// _q : frame synchronizer object
// _x : input sample
// _sym : demodulated symbol
void flexframesync_execute_seekpn(flexframesync _q,
float complex _x)
{
// push sample into pre-demod p/n sequence buffer
windowcf_push(_q->buffer, _x);
// push through pre-demod synchronizer
int detected = detector_cccf_correlate(_q->frame_detector,
_x,
&_q->tau_hat,
&_q->dphi_hat,
&_q->gamma_hat);
// check if frame has been detected
if (detected) {
//printf("***** frame detected! tau-hat:%8.4f, dphi-hat:%8.4f, gamma:%8.2f dB\n",
// _q->tau_hat, _q->dphi_hat, 20*log10f(_q->gamma_hat));
// push buffered samples through synchronizer
// NOTE: this will set internal state appropriately
// to STATE_DETECTFRAME
flexframesync_pushpn(_q);
}
}
int main(int argc, char*argv[])
{
// options
unsigned int num_channels=6; // number of channels (must be even)
unsigned int m=4; // filter delay
unsigned int num_symbols=4*m; // number of symbols
// validate input
if (num_channels%2) {
fprintf(stderr,"error: %s, number of channels must be even\n", argv[0]);
exit(1);
}
// derived values
unsigned int num_samples = num_channels * num_symbols;
unsigned int i;
unsigned int j;
// generate filter
// NOTE : these coefficients can be random; the purpose of this
// exercise is to demonstrate mathematical equivalence
#if 0
unsigned int h_len = 2*m*num_channels;
float h[h_len];
for (i=0; i<h_len; i++) h[i] = randnf();
#else
unsigned int h_len = 2*m*num_channels+1;
float h[h_len];
// NOTE: 81.29528 dB > beta = 8.00000 (6 channels, m=4)
liquid_firdes_kaiser(h_len, 1.0f/(float)num_channels, 81.29528f, 0.0f, h);
#endif
// normalize
float hsum = 0.0f;
for (i=0; i<h_len; i++) hsum += h[i];
for (i=0; i<h_len; i++) h[i] = h[i] * num_channels / hsum;
// sub-sampled filters for M=6 channels, m=4, beta=8.0
// -3.2069e-19 -6.7542e-04 -1.3201e-03 2.2878e-18 3.7613e-03 5.8033e-03
// -7.2899e-18 -1.2305e-02 -1.7147e-02 1.6510e-17 3.1187e-02 4.0974e-02
// -3.0032e-17 -6.8026e-02 -8.6399e-02 4.6273e-17 1.3732e-01 1.7307e-01
// -6.2097e-17 -2.8265e-01 -3.7403e-01 7.3699e-17 8.0663e-01 1.6438e+00
// 2.0001e+00 1.6438e+00 8.0663e-01 7.3699e-17 -3.7403e-01 -2.8265e-01
// -6.2097e-17 1.7307e-01 1.3732e-01 4.6273e-17 -8.6399e-02 -6.8026e-02
// -3.0032e-17 4.0974e-02 3.1187e-02 1.6510e-17 -1.7147e-02 -1.2305e-02
// -7.2899e-18 5.8033e-03 3.7613e-03 2.2878e-18 -1.3201e-03 -6.7542e-04
// create filterbank manually
dotprod_crcf dp[num_channels]; // vector dot products
windowcf w[num_channels]; // window buffers
#if DEBUG
// print coefficients
printf("h_prototype:\n");
for (i=0; i<h_len; i++)
printf(" h[%3u] = %12.8f\n", i, h[i]);
#endif
// create objects
unsigned int h_sub_len = 2*m;
float h_sub[h_sub_len];
for (i=0; i<num_channels; i++) {
// sub-sample prototype filter
#if 0
for (j=0; j<h_sub_len; j++)
h_sub[j] = h[j*num_channels+i];
#else
// load coefficients in reverse order
for (j=0; j<h_sub_len; j++)
h_sub[h_sub_len-j-1] = h[j*num_channels+i];
#endif
// create window buffer and dotprod objects
dp[i] = dotprod_crcf_create(h_sub, h_sub_len);
w[i] = windowcf_create(h_sub_len);
#if DEBUG
printf("h_sub[%u] : \n", i);
for (j=0; j<h_sub_len; j++)
printf(" h[%3u] = %12.8f\n", j, h_sub[j]);
#endif
}
// generate DFT object
float complex x[num_channels]; // time-domain buffer
float complex X[num_channels]; // freq-domain buffer
#if 1
fftplan fft = fft_create_plan(num_channels, X, x, LIQUID_FFT_BACKWARD, 0);
#else
fftplan fft = fft_create_plan(num_channels, X, x, LIQUID_FFT_FORWARD, 0);
#endif
float complex y[num_samples]; // time-domain input
float complex Y0[2*num_symbols][num_channels]; // channelizer output
float complex Y1[2*num_symbols][num_channels]; // conventional output
// generate input sequence
for (i=0; i<num_samples; i++) {
//y[i] = randnf() * cexpf(_Complex_I*randf()*2*M_PI);
y[i] = (i==0) ? 1.0f : 0.0f;
y[i] = cexpf(_Complex_I*sqrtf(2.0f)*i*i);
printf("y[%3u] = %12.8f + %12.8fj\n", i, crealf(y[i]), cimagf(y[i]));
}
//
// run analysis filter bank
//
#if 0
unsigned int filter_index = 0;
#else
unsigned int filter_index = num_channels/2-1;
#endif
float complex y_hat; // input sample
float complex * r; // buffer read pointer
int toggle = 0; // flag indicating buffer/filter alignment
//
for (i=0; i<2*num_symbols; i++) {
// load buffers in blocks of num_channels/2
for (j=0; j<num_channels/2; j++) {
// grab sample
y_hat = y[i*num_channels/2 + j];
// push sample into buffer at filter index
windowcf_push(w[filter_index], y_hat);
// decrement filter index
filter_index = (filter_index + num_channels - 1) % num_channels;
//filter_index = (filter_index + 1) % num_channels;
}
// execute filter outputs
// reversing order of output (not sure why this is necessary)
unsigned int offset = toggle ? num_channels/2 : 0;
toggle = 1-toggle;
for (j=0; j<num_channels; j++) {
unsigned int buffer_index = (offset+j)%num_channels;
unsigned int dotprod_index = j;
windowcf_read(w[buffer_index], &r);
//dotprod_crcf_execute(dp[dotprod_index], r, &X[num_channels-j-1]);
dotprod_crcf_execute(dp[dotprod_index], r, &X[buffer_index]);
}
printf("***** i = %u\n", i);
for (j=0; j<num_channels; j++)
printf(" v2[%4u] = %12.8f + %12.8fj\n", j, crealf(X[j]), cimagf(X[j]));
// execute DFT, store result in buffer 'x'
fft_execute(fft);
// scale fft output
for (j=0; j<num_channels; j++)
x[j] *= 1.0f / (num_channels);
// move to output array
for (j=0; j<num_channels; j++)
Y0[i][j] = x[j];
}
// destroy objects
for (i=0; i<num_channels; i++) {
dotprod_crcf_destroy(dp[i]);
windowcf_destroy(w[i]);
}
fft_destroy_plan(fft);
//
// run traditional down-converter (inefficient)
//
// generate filter object
firfilt_crcf f = firfilt_crcf_create(h, h_len);
float dphi; // carrier frequency
unsigned int n=0;
for (i=0; i<num_channels; i++) {
// reset filter
firfilt_crcf_clear(f);
// set center frequency
dphi = 2.0f * M_PI * (float)i / (float)num_channels;
// reset symbol counter
n=0;
for (j=0; j<num_samples; j++) {
// push down-converted sample into filter
firfilt_crcf_push(f, y[j]*cexpf(-_Complex_I*j*dphi));
// compute output at the appropriate sample time
assert(n<2*num_symbols);
if ( ((j+1)%(num_channels/2))==0 ) {
firfilt_crcf_execute(f, &Y1[n][i]);
n++;
}
}
assert(n==2*num_symbols);
}
firfilt_crcf_destroy(f);
// print filterbank channelizer
printf("\n");
printf("filterbank channelizer:\n");
for (i=0; i<2*num_symbols; i++) {
printf("%2u:", i);
for (j=0; j<num_channels; j++) {
printf("%6.3f+%6.3fj, ", crealf(Y0[i][j]), cimagf(Y0[i][j]));
}
printf("\n");
}
#if 0
// print traditional channelizer
printf("\n");
printf("traditional channelizer:\n");
for (i=0; i<2*num_symbols; i++) {
printf("%2u:", i);
for (j=0; j<num_channels; j++) {
printf("%6.3f+%6.3fj, ", crealf(Y1[i][j]), cimagf(Y1[i][j]));
}
printf("\n");
}
//
// compare results
//
float mse[num_channels];
float complex d;
for (i=0; i<num_channels; i++) {
mse[i] = 0.0f;
for (j=0; j<2*num_symbols; j++) {
d = Y0[j][i] - Y1[j][i];
mse[i] += crealf(d*conjf(d));
}
mse[i] /= num_symbols;
}
printf("\n");
printf(" e:");
for (i=0; i<num_channels; i++)
printf("%12.4e ", sqrt(mse[i]));
printf("\n");
#endif
printf("done.\n");
return 0;
}
void ofdmoqamframe64sync_rxpayload(ofdmoqamframe64sync _q,
float complex * _Y0,
float complex * _Y1)
{
unsigned int j=0;
unsigned int t=0;
int sctype;
unsigned int pilot_phase = msequence_advance(_q->ms_pilot);
// gain correction (equalizer)
unsigned int i;
for (i=0; i<_q->num_subcarriers; i++) {
_Y0[i] *= _q->G[i];// * _q->zeta;
_Y1[i] *= _q->G[i];// * _q->zeta;
}
// TODO : extract pilots
for (i=0; i<_q->num_subcarriers; i++) {
sctype = ofdmoqamframe64_getsctype(i);
if (sctype==OFDMOQAMFRAME64_SCTYPE_PILOT) {
// pilot subcarrier : use p/n sequence for pilot phase
float complex y0 = ((i%2)==0 ? _Y0[i] : _Y1[i]) / _q->zeta;
float complex y1 = ((i%2)==0 ? _Y1[i] : _Y0[i]) / _q->zeta;
float complex p = (pilot_phase ? 1.0f : -1.0f);
float phi_hat =
ofdmoqamframe64sync_estimate_pilot_phase(y0,y1,p);
_q->y_phase[t] = phi_hat;
t++;
#if DEBUG_OFDMOQAMFRAME64SYNC_PRINT
printf("i = %u\n", i);
printf("y0 = %12.8f + j*%12.8f;\n", crealf(y0),cimagf(y0));
printf("y1 = %12.8f + j*%12.8f;\n", crealf(y1),cimagf(y1));
printf("phi_hat = %12.8f\n", phi_hat);
#endif
/*
printf("exiting prematurely\n");
ofdmoqamframe64sync_destroy(_q);
exit(1);
*/
}
}
assert(t==4);
// pilot phase correction
/*
_q->y_phase[0] = cargf(_q->X[11]); // -21
_q->y_phase[1] = cargf(_q->X[25]); // -7
_q->y_phase[2] = cargf(_q->X[39]); // 7
_q->y_phase[3] = cargf(_q->X[53]); // 21
*/
// try to unwrap phase
for (i=1; i<4; i++) {
while ((_q->y_phase[i] - _q->y_phase[i-1]) > M_PI)
_q->y_phase[i] -= 2*M_PI;
while ((_q->y_phase[i] - _q->y_phase[i-1]) < -M_PI)
_q->y_phase[i] += 2*M_PI;
}
// fit phase to 1st-order polynomial (2 coefficients)
polyf_fit(_q->x_phase, _q->y_phase, 4, _q->p_phase, 2);
//nco_crcf_step(_q->nco_pilot);
float theta_hat = nco_crcf_get_phase(_q->nco_pilot);
float phase_error = _q->p_phase[0] - theta_hat;
while (phase_error > M_PI) phase_error -= 2.0f*M_PI;
while (phase_error < -M_PI) phase_error += 2.0f*M_PI;
pll_step(_q->pll_pilot, _q->nco_pilot, 0.1f*phase_error);
#if DEBUG_OFDMOQAMFRAME64SYNC_PRINT
// print phase results
for (i=0; i<4; i++) {
printf("x(%3u) = %12.8f; y(%3u) = %12.8f;\n", i+1, _q->x_phase[i], i+1, _q->y_phase[i]);
}
printf("p(1) = %12.8f\n", _q->p_phase[0]);
printf("p(2) = %12.8f\n", _q->p_phase[1]);
#endif
#if DEBUG_OFDMOQAMFRAME64SYNC
windowf_push(_q->debug_pilotphase, _q->p_phase[0]);
windowf_push(_q->debug_pilotphase_hat, theta_hat);
#endif
// compensate for phase shift due to timing offset
float theta;
_q->p_phase[0] = theta_hat;
_q->p_phase[1] = 0.0f;
for (i=0; i<_q->num_subcarriers; i++) {
// TODO : compute phase for delayed symbol (different from non-delayed symbol)
theta = polyf_val(_q->p_phase, 2, (float)(i)-32.0f);
_Y0[i] *= liquid_cexpjf(-theta);
_Y1[i] *= liquid_cexpjf(-theta);
}
nco_crcf_step(_q->nco_pilot);
// strip data subcarriers
for (i=0; i<_q->num_subcarriers; i++) {
sctype = ofdmoqamframe64_getsctype(i);
if (sctype==OFDMOQAMFRAME64_SCTYPE_NULL) {
// disabled subcarrier
} else if (sctype==OFDMOQAMFRAME64_SCTYPE_PILOT) {
// pilot subcarrier
} else {
// data subcarrier
if ((i%2)==0) {
// even subcarrier
_q->data[j] = crealf(_Y0[i]) +
cimagf(_Y1[i]) * _Complex_I;
} else {
// odd subcarrier
_q->data[j] = cimagf(_Y0[i]) * _Complex_I +
crealf(_Y1[i]);
}
// scaling factor
_q->data[j] /= _q->zeta;
j++;
}
}
assert(j==48);
#if DEBUG_OFDMOQAMFRAME64SYNC
for (i=0; i<48; i++)
windowcf_push(_q->debug_framesyms,_q->data[i]);
#endif
if (_q->callback != NULL) {
int retval = _q->callback(_q->data, _q->userdata);
if (retval == -1) {
printf("exiting prematurely\n");
ofdmoqamframe64sync_destroy(_q);
exit(0);
} else if (retval == 1) {
#if DEBUG_OFDMOQAMFRAME64SYNC_PRINT
printf("resetting synchronizer\n");
#endif
ofdmoqamframe64sync_reset(_q);
} else {
// do nothing
}
}
}
// receive data symbols
void wlanframesync_execute_rxdata(wlanframesync _q)
{
_q->timer++;
if (_q->timer < 80)
return;
//printf(" receiving symbol %u...\n", _q->num_symbols);
// reset timer
_q->timer = 0;
// run fft
float complex * rc;
windowcf_read(_q->input_buffer, &rc);
memmove(_q->x, &rc[16-2], 64*sizeof(float complex));
// compute fft, storing result into _q->X
FFT_EXECUTE(_q->fft);
// recover symbol, correcting for gain, pilot phase, etc.
wlanframesync_rxsymbol(_q);
// demodulate and pack
unsigned int i;
unsigned int n=0;
unsigned int sym;
for (i=0; i<64; i++) {
unsigned int k = (i + 32) % 64;
if ( k==0 || (k > 26 && k < 38) ) {
// NULL subcarrier
} else if (k==43 || k==57 || k==7 || k==21) {
// PILOT subcarrier
} else {
// DATA subcarrier
assert(n<48);
sym = wlan_demodulate(_q->mod_scheme, _q->X[k]);
_q->modem_syms[n] = sym;
n++;
#if DEBUG_WLANFRAMESYNC
// TODO : move this outside loop
if (_q->debug_enabled)
windowcf_push(_q->debug_framesyms, _q->X[k]);
#endif
}
}
assert(n==48);
// pack modem symbols
//printf(" %3u = %3u * %3u\n", _q->enc_msg_len, _q->nsym, _q->bytes_per_symbol);
unsigned int num_written;
liquid_wlan_repack_bytes(_q->modem_syms, _q->nbpsc, 48,
&_q->msg_enc[_q->num_symbols * _q->bytes_per_symbol], 8, _q->bytes_per_symbol,
&num_written);
assert(num_written == _q->bytes_per_symbol);
// increment number of received symbols
_q->num_symbols++;
// check number of symbols
if (_q->num_symbols == _q->nsym) {
// decode message
wlan_packet_decode(_q->rate, _q->seed, _q->length, _q->msg_enc, _q->msg_dec);
// assemble RX vector
struct wlan_rxvector_s rxvector;
rxvector.LENGTH = _q->length;
rxvector.RSSI = 200 + (unsigned int) (10*log10f(_q->g0));
rxvector.DATARATE = _q->rate;
rxvector.SERVICE = 0;
// invoke callback
if (_q->callback != NULL) {
//int retval =
_q->callback(_q->msg_dec, rxvector, _q->userdata);
}
// reset and return
wlanframesync_reset(_q);
}
}
void do_track(){
if (local_track_freq != shm_settings.track_frequency_target) {
if (ff.sosMap.count(shm_settings.track_frequency_target)) { //frequency key exists
if (track_filterA != NULL)
iirfilt_crcf_destroy(track_filterA);
if (track_filterB != NULL)
iirfilt_crcf_destroy(track_filterB);
if (track_filterC != NULL)
iirfilt_crcf_destroy(track_filterC);
float *b = &((ff.sosMap[shm_settings.track_frequency_target]->b)[0]);
float *a = &((ff.sosMap[shm_settings.track_frequency_target]->a)[0]);
track_filterA = iirfilt_crcf_create_sos(b,a,NUMBER_OF_SECTIONS);
track_filterB = iirfilt_crcf_create_sos(b,a,NUMBER_OF_SECTIONS);
track_filterC = iirfilt_crcf_create_sos(b,a,NUMBER_OF_SECTIONS);
shm_results_track.track_state = 0;
local_track_freq = shm_settings.track_frequency_target;
float normalized_frequency = (float) shm_settings.track_frequency_target / (float) SAMPLING_FREQUENCY;
nco_crcf_set_frequency(nco,2*M_PI*normalized_frequency);
}
else { //frequency key does not exist. Trigger error state
shm_results_track.track_state = -1;
std::cerr << shm_settings.track_frequency_target << " WARN TRACK FREQ NOT IN SOS TABLE" << std::endl;
}
shm_setg(hydrophones_results_track, shm_results_track);
}
std::complex<float> *chA_ptr, *chA_filtered_ptr;
std::complex<float> *chB_ptr, *chB_filtered_ptr;
std::complex<float> *chC_ptr, *chC_filtered_ptr;
float *mag_ptr;
windowcf_read(wchA,&chA_ptr);
windowcf_read(wchB,&chB_ptr);
windowcf_read(wchC,&chC_ptr);
std::complex<float> filtOutA, filtOutB, filtOutC;
for (int i = 0; i < SAMPLING_DEPTH; i++) {
iirfilt_crcf_execute(track_filterA,chA_ptr[i],&filtOutA);
iirfilt_crcf_execute(track_filterB,chB_ptr[i],&filtOutB);
iirfilt_crcf_execute(track_filterC,chC_ptr[i],&filtOutC);
windowcf_read(wchA_filtered,&chA_filtered_ptr);
windowcf_read(wchB_filtered,&chB_filtered_ptr);
windowcf_read(wchC_filtered,&chC_filtered_ptr);
windowcf_push(wchA_filtered,filtOutA);
windowcf_push(wchB_filtered,filtOutB);
windowcf_push(wchC_filtered,filtOutC);
float b_sqrd = std::pow(std::real(filtOutB),2);
pwr_sum += b_sqrd;
windowf_read(wmag_buffer,&mag_ptr);
pwr_sum -= mag_ptr[0];
windowf_push(wmag_buffer,b_sqrd);
double normalized_pwr = pwr_sum / (double)TRACK_LENGTH;
if (normalized_pwr > shm_settings.track_magnitude_threshold &&
(track_sample_idx - shm_results_track.tracked_ping_time) >= shm_settings.track_cooldown_samples) {
std::complex<float> dtft_coeff_A = goertzelNonInteger(chA_filtered_ptr,TRACK_LENGTH,shm_settings.track_frequency_target,SAMPLING_FREQUENCY);
std::complex<float> dtft_coeff_B = goertzelNonInteger(chB_filtered_ptr,TRACK_LENGTH,shm_settings.track_frequency_target,SAMPLING_FREQUENCY);
std::complex<float> dtft_coeff_C = goertzelNonInteger(chC_filtered_ptr,TRACK_LENGTH,shm_settings.track_frequency_target,SAMPLING_FREQUENCY);
float phaseA = std::arg(dtft_coeff_A);
float phaseB = std::arg(dtft_coeff_B);
float phaseC = std::arg(dtft_coeff_C);
shm_results_track.diff_phase_y = phase_difference(phaseC,phaseB);
shm_results_track.diff_phase_x = phase_difference(phaseA,phaseB);
float kx = SOUND_SPEED * shm_results_track.diff_phase_x / (NIPPLE_DISTANCE * 2 * M_PI * shm_settings.track_frequency_target);
float ky = SOUND_SPEED * shm_results_track.diff_phase_y / (NIPPLE_DISTANCE * 2 * M_PI * shm_settings.track_frequency_target);
float kz_2 = 1 - kx * kx - ky * ky;
if (kz_2 < 0) {
std::cerr << "WARNING: z mag is negative! " << kz_2 << std::endl;
kz_2 = 0;
}
shm_results_track.tracked_ping_heading_radians = std::atan2(ky, kx);
shm_results_track.tracked_ping_elevation_radians = std::acos(std::sqrt(kz_2));
shm_results_track.tracked_ping_count++;
shm_results_track.tracked_ping_frequency = shm_results_spectrum.most_recent_ping_frequency;
shm_results_track.tracked_ping_time = track_sample_idx;
std::cout << "PING DETECTED @ n=" << track_sample_idx << " w/ pwr="<< normalized_pwr<< std::endl;
std::cout << "@ HEADING=" << shm_results_track.tracked_ping_heading_radians*(180.0f/M_PI) << std::endl;
shm_setg(hydrophones_results_track, shm_results_track);
}
track_sample_idx++;
}
}
int main() {
// options
unsigned int num_channels=4; // number of channels
unsigned int m=5; // filter delay
unsigned int num_symbols=12; // number of symbols
// derived values
unsigned int num_samples = num_channels * num_symbols;
unsigned int i;
unsigned int j;
// generate filter
// NOTE : these coefficients can be random; the purpose of this
// exercise is to demonstrate mathematical equivalence
unsigned int h_len = 2*m*num_channels;
float h[h_len];
for (i=0; i<h_len; i++) h[i] = randnf();
//for (i=0; i<h_len; i++) h[i] = 0.1f*i;
//for (i=0; i<h_len; i++) h[i] = (i<=m) ? 1.0f : 0.0f;
//for (i=0; i<h_len; i++) h[i] = 1.0f;
// create filterbank manually
dotprod_crcf dp[num_channels]; // vector dot products
windowcf w[num_channels]; // window buffers
#if DEBUG
// print coefficients
printf("h_prototype:\n");
for (i=0; i<h_len; i++)
printf(" h[%3u] = %12.8f\n", i, h[i]);
#endif
// create objects
unsigned int h_sub_len = 2*m;
float h_sub[h_sub_len];
for (i=0; i<num_channels; i++) {
// sub-sample prototype filter, loading coefficients in
// reverse order
#if 0
for (j=0; j<h_sub_len; j++)
h_sub[j] = h[j*num_channels+i];
#else
for (j=0; j<h_sub_len; j++)
h_sub[h_sub_len-j-1] = h[j*num_channels+i];
#endif
// create window buffer and dotprod objects
dp[i] = dotprod_crcf_create(h_sub, h_sub_len);
w[i] = windowcf_create(h_sub_len);
#if DEBUG
printf("h_sub[%u] : \n", i);
for (j=0; j<h_sub_len; j++)
printf(" h[%3u] = %12.8f\n", j, h_sub[j]);
#endif
}
// generate DFT object
float complex x[num_channels]; // time-domain buffer
float complex X[num_channels]; // freq-domain buffer
#if 0
fftplan fft = fft_create_plan(num_channels, X, x, LIQUID_FFT_BACKWARD, 0);
#else
fftplan fft = fft_create_plan(num_channels, X, x, LIQUID_FFT_FORWARD, 0);
#endif
// generate filter object
firfilt_crcf f = firfilt_crcf_create(h, h_len);
float complex y[num_samples]; // time-domain input
float complex Y0[num_symbols][num_channels]; // channelized output
float complex Y1[num_symbols][num_channels]; // channelized output
// generate input sequence (complex noise)
for (i=0; i<num_samples; i++)
y[i] = randnf() * cexpf(_Complex_I*randf()*2*M_PI);
//
// run analysis filter bank
//
#if 0
unsigned int filter_index = 0;
#else
unsigned int filter_index = num_channels-1;
#endif
float complex y_hat; // input sample
float complex * r; // read pointer
for (i=0; i<num_symbols; i++) {
// load buffers
for (j=0; j<num_channels; j++) {
// grab sample
y_hat = y[i*num_channels + j];
// push sample into buffer at filter index
windowcf_push(w[filter_index], y_hat);
// decrement filter index
filter_index = (filter_index + num_channels - 1) % num_channels;
//filter_index = (filter_index + 1) % num_channels;
}
// execute filter outputs, reversing order of output (not
// sure why this is necessary)
for (j=0; j<num_channels; j++) {
windowcf_read(w[j], &r);
dotprod_crcf_execute(dp[j], r, &X[num_channels-j-1]);
}
// execute DFT, store result in buffer 'x'
fft_execute(fft);
// move to output array
for (j=0; j<num_channels; j++)
Y0[i][j] = x[j];
}
//
// run traditional down-converter (inefficient)
//
float dphi; // carrier frequency
unsigned int n=0;
for (i=0; i<num_channels; i++) {
// reset filter
firfilt_crcf_reset(f);
// set center frequency
dphi = 2.0f * M_PI * (float)i / (float)num_channels;
// reset symbol counter
n=0;
for (j=0; j<num_samples; j++) {
// push down-converted sample into filter
firfilt_crcf_push(f, y[j]*cexpf(-_Complex_I*j*dphi));
// compute output at the appropriate sample time
assert(n<num_symbols);
if ( ((j+1)%num_channels)==0 ) {
firfilt_crcf_execute(f, &Y1[n][i]);
n++;
}
}
assert(n==num_symbols);
}
// destroy objects
for (i=0; i<num_channels; i++) {
dotprod_crcf_destroy(dp[i]);
windowcf_destroy(w[i]);
}
fft_destroy_plan(fft);
firfilt_crcf_destroy(f);
// print filterbank channelizer
printf("\n");
printf("filterbank channelizer:\n");
for (i=0; i<num_symbols; i++) {
printf("%3u: ", i);
for (j=0; j<num_channels; j++) {
printf(" %8.5f+j%8.5f, ", crealf(Y0[i][j]), cimagf(Y0[i][j]));
}
printf("\n");
}
// print traditional channelizer
printf("\n");
printf("traditional channelizer:\n");
for (i=0; i<num_symbols; i++) {
printf("%3u: ", i);
for (j=0; j<num_channels; j++) {
printf(" %8.5f+j%8.5f, ", crealf(Y1[i][j]), cimagf(Y1[i][j]));
}
printf("\n");
}
//
// compare results
//
float mse[num_channels];
float complex d;
for (i=0; i<num_channels; i++) {
mse[i] = 0.0f;
for (j=0; j<num_symbols; j++) {
d = Y0[j][i] - Y1[j][i];
mse[i] += crealf(d*conjf(d));
}
mse[i] /= num_symbols;
}
printf("\n");
printf("rmse: ");
for (i=0; i<num_channels; i++)
printf("%12.4e ", sqrt(mse[i]));
printf("\n");
printf("done.\n");
return 0;
}
int main() {
// options
unsigned int num_channels=64; // must be even number
unsigned int num_symbols=16; // number of symbols
unsigned int m=3; // filter delay (symbols)
float beta = 0.9f; // filter excess bandwidth factor
float phi = 0.0f; // carrier phase offset;
float dphi = 0.04f; // carrier frequency offset
// number of frames (compensate for filter delay)
unsigned int num_frames = num_symbols + 2*m;
unsigned int num_samples = num_channels * num_frames;
unsigned int i;
unsigned int j;
// create filter prototype
unsigned int h_len = 2*num_channels*m + 1;
float h[h_len];
float complex hc[h_len];
float complex gc[h_len];
liquid_firdes_rkaiser(num_channels, m, beta, 0.0f, h);
unsigned int g_len = 2*num_channels*m;
for (i=0; i<g_len; i++) {
hc[i] = h[i];
gc[i] = h[g_len-i-1] * cexpf(_Complex_I*dphi*i);
}
// data arrays
float complex s[num_channels]; // input symbols
float complex y[num_samples]; // time-domain samples
float complex Y0[num_frames][num_channels]; // channelized output
float complex Y1[num_frames][num_channels]; // channelized output
// create ofdm/oqam generator object and generate data
ofdmoqam qs = ofdmoqam_create(num_channels, m, beta, 0.0f, LIQUID_SYNTHESIZER, 0);
for (i=0; i<num_frames; i++) {
for (j=0; j<num_channels; j++) {
if (i<num_symbols) {
#if 0
// QPSK on all subcarriers
s[j] = (rand() % 2 ? 1.0f : -1.0f) +
(rand() % 2 ? 1.0f : -1.0f) * _Complex_I;
s[j] *= 1.0f / sqrtf(2.0f);
#else
// BPSK on even subcarriers
s[j] = rand() % 2 ? 1.0f : -1.0f;
s[j] *= (j%2)==0 ? 1.0f : 0.0f;
#endif
} else {
s[j] = 0.0f;
}
}
// run synthesizer
ofdmoqam_execute(qs, s, &y[i*num_channels]);
}
ofdmoqam_destroy(qs);
// channel
for (i=0; i<num_samples; i++)
y[i] *= cexpf(_Complex_I*(phi + dphi*i));
//
// analysis filterbank (receiver)
//
// create filterbank manually
dotprod_cccf dp[num_channels]; // vector dot products
windowcf w[num_channels]; // window buffers
#if DEBUG
// print coefficients
printf("h_prototype:\n");
for (i=0; i<h_len; i++)
printf(" h[%3u] = %12.8f\n", i, h[i]);
#endif
// create objects
unsigned int gc_sub_len = 2*m;
float complex gc_sub[gc_sub_len];
for (i=0; i<num_channels; i++) {
// sub-sample prototype filter, loading coefficients in
// reverse order
#if 0
for (j=0; j<gc_sub_len; j++)
gc_sub[j] = h[j*num_channels+i];
#else
for (j=0; j<gc_sub_len; j++)
gc_sub[gc_sub_len-j-1] = gc[j*num_channels+i];
#endif
// create window buffer and dotprod objects
dp[i] = dotprod_cccf_create(gc_sub, gc_sub_len);
w[i] = windowcf_create(gc_sub_len);
#if DEBUG
printf("gc_sub[%u] : \n", i);
for (j=0; j<gc_sub_len; j++)
printf(" g[%3u] = %12.8f + %12.8f\n", j, crealf(gc_sub[j]), cimagf(gc_sub[j]));
#endif
}
// generate DFT object
float complex x[num_channels]; // time-domain buffer
float complex X[num_channels]; // freq-domain buffer
#if 0
fftplan fft = fft_create_plan(num_channels, X, x, FFT_REVERSE, 0);
#else
fftplan fft = fft_create_plan(num_channels, X, x, FFT_FORWARD, 0);
#endif
//
// run analysis filter bank
//
#if 0
unsigned int filter_index = 0;
#else
unsigned int filter_index = num_channels-1;
#endif
float complex y_hat; // input sample
float complex * r; // read pointer
for (i=0; i<num_frames; i++) {
// load buffers
for (j=0; j<num_channels; j++) {
// grab sample
y_hat = y[i*num_channels + j];
// push sample into buffer at filter index
windowcf_push(w[filter_index], y_hat);
// decrement filter index
filter_index = (filter_index + num_channels - 1) % num_channels;
//filter_index = (filter_index + 1) % num_channels;
}
// execute filter outputs, reversing order of output (not
// sure why this is necessary)
for (j=0; j<num_channels; j++) {
windowcf_read(w[j], &r);
dotprod_cccf_execute(dp[j], r, &X[num_channels-j-1]);
}
#if 1
// compensate for carrier frequency offset (before transform)
for (j=0; j<num_channels; j++) {
X[j] *= cexpf(-_Complex_I*(dphi*i*num_channels));
}
#endif
// execute DFT, store result in buffer 'x'
fft_execute(fft);
#if 0
// compensate for carrier frequency offset (after transform)
for (j=0; j<num_channels; j++) {
x[j] *= cexpf(-_Complex_I*(dphi*i*num_channels));
}
#endif
// move to output array
for (j=0; j<num_channels; j++)
Y0[i][j] = x[j];
}
// destroy objects
for (i=0; i<num_channels; i++) {
dotprod_cccf_destroy(dp[i]);
windowcf_destroy(w[i]);
}
fft_destroy_plan(fft);
#if 0
// print filterbank channelizer
printf("\n");
printf("filterbank channelizer:\n");
for (i=0; i<num_symbols; i++) {
printf("%3u: ", i);
for (j=0; j<num_channels; j++) {
printf(" %8.5f+j%8.5f, ", crealf(Y0[i][j]), cimagf(Y0[i][j]));
}
printf("\n");
}
#endif
//
// export data
//
FILE*fid = fopen(OUTPUT_FILENAME,"w");
fprintf(fid,"%% %s: auto-generated file\n\n", OUTPUT_FILENAME);
fprintf(fid,"clear all;\nclose all;\n\n");
fprintf(fid,"num_channels=%u;\n", num_channels);
fprintf(fid,"num_symbols=%u;\n", num_symbols);
fprintf(fid,"num_frames = %u;\n", num_frames);
fprintf(fid,"num_samples = num_frames*num_channels;\n");
fprintf(fid,"y = zeros(1,%u);\n", num_samples);
fprintf(fid,"Y0 = zeros(%u,%u);\n", num_frames, num_channels);
fprintf(fid,"Y1 = zeros(%u,%u);\n", num_frames, num_channels);
for (i=0; i<num_frames; i++) {
for (j=0; j<num_channels; j++) {
fprintf(fid,"Y0(%4u,%4u) = %12.4e + j*%12.4e;\n", i+1, j+1, crealf(Y0[i][j]), cimagf(Y0[i][j]));
fprintf(fid,"Y1(%4u,%4u) = %12.4e + j*%12.4e;\n", i+1, j+1, crealf(Y1[i][j]), cimagf(Y1[i][j]));
}
}
// plot BPSK results
fprintf(fid,"figure;\n");
fprintf(fid,"plot(Y0(:,1:2:end),'x');\n");
fprintf(fid,"axis([-1 1 -1 1]*1.2*sqrt(num_channels));\n");
fprintf(fid,"axis square;\n");
fprintf(fid,"grid on;\n");
fclose(fid);
printf("results written to '%s'\n", OUTPUT_FILENAME);
printf("done.\n");
return 0;
}
// compute ISI for entire system
// _gt : transmit filter [size: _gt_len x 1]
// _hc : channel filter [size: _hc_len x 1]
// _gr : receive filter [size: _gr_len x 1]
float eqlms_cccf_isi(unsigned int _k,
float complex * _gt,
unsigned int _gt_len,
float complex * _hc,
unsigned int _hc_len,
float complex * _gr,
unsigned int _gr_len)
{
// generate composite by convolving all filters together
unsigned int i;
#if 0
printf("\n");
for (i=0; i<_gt_len; i++)
printf(" gt(%3u) = %16.12f + j*%16.12f;\n", i+1, crealf(_gt[i]), cimagf(_gt[i]));
printf("\n");
for (i=0; i<_hc_len; i++)
printf(" hc(%3u) = %16.12f + j*%16.12f;\n", i+1, crealf(_hc[i]), cimagf(_hc[i]));
printf("\n");
for (i=0; i<_gr_len; i++)
printf(" gr(%3u) = %16.12f + j*%16.12f;\n", i+1, crealf(_gr[i]), cimagf(_gr[i]));
printf("\n");
#endif
windowcf w;
float complex * rc;
// start by convolving transmit and channel filters
unsigned int gthc_len = _gt_len + _hc_len - 1;
float complex gthc[gthc_len];
w = windowcf_create(_gt_len);
for (i=0; i<gthc_len; i++) {
if (i < _hc_len) windowcf_push(w, conjf(_hc[_hc_len-i-1]));
else windowcf_push(w, 0.0f);
windowcf_read(w, &rc);
dotprod_cccf_run(_gt, rc, _gt_len, >hc[i]);
}
windowcf_destroy(w);
#if 0
printf("composite filter:\n");
for (i=0; i<gthc_len; i++)
printf(" gthc(%3u) = %16.12f + j*%16.12f;\n", i+1, crealf(gthc[i]), cimagf(gthc[i]));
#endif
// convolve result with equalizer
unsigned int h_len = gthc_len + _gr_len - 1;
float complex h[h_len];
w = windowcf_create(gthc_len);
for (i=0; i<h_len; i++) {
if (i < _gr_len) windowcf_push(w, conjf(_gr[i]));
else windowcf_push(w, 0.0f);
windowcf_read(w, &rc);
dotprod_cccf_run(gthc, rc, gthc_len, &h[i]);
}
windowcf_destroy(w);
#if 0
printf("composite filter:\n");
for (i=0; i<h_len; i++)
printf(" h(%3u) = %16.12f + j*%16.12f;\n", i+1, crealf(h[i]), cimagf(h[i]));
#endif
// compute resulting ISI
unsigned int n0 = (_gt_len + _gr_len + (_gt_len + _gr_len)%2)/2 - 1;
float isi = 0.0f;
unsigned int n=0;
for (i=0; i<h_len; i++) {
if (i == n0)
continue;
else if ( (i%_k)==0 ) {
isi += crealf( h[i]*conjf(h[i]) );
n++;
}
}
isi /= crealf( h[n0]*conjf(h[n0]) );
isi = sqrtf(isi / (float)n);
return isi;
}
