// print gmskframegen object internals
void gmskframegen_print(gmskframegen _q)
{
// plot
printf("gmskframegen:\n");
printf(" physical properties\n");
printf(" samples/symbol : %u\n", _q->k);
printf(" filter delay : %u symbols\n", _q->m);
printf(" bandwidth-time : %-8.3f\n", _q->BT);
printf(" framing properties\n");
printf(" preamble : %-4u symbols\n", _q->preamble_len);
printf(" header : %-4u symbols\n", _q->header_len);
printf(" payload : %-4u symbols\n", _q->payload_len);
printf(" tail : %-4u symbols\n", _q->tail_len);
printf(" packet properties\n");
printf(" crc : %s\n", crc_scheme_str[_q->check][1]);
printf(" fec (inner) : %s\n", fec_scheme_str[_q->fec0][1]);
printf(" fec (outer) : %s\n", fec_scheme_str[_q->fec1][1]);
printf(" total samples : %-4u sampels\n", gmskframegen_getframelen(_q));
}
// benchmark regular frame synchronizer with short frames; effectively
// test acquisition complexity
void benchmark_gmskframesync(struct rusage * _start,
struct rusage * _finish,
unsigned long int * _num_iterations)
{
*_num_iterations /= 128;
unsigned long int i;
// options
unsigned int payload_len = 8; // length of payload (bytes)
crc_scheme check = LIQUID_CRC_32; // data validity check
fec_scheme fec0 = LIQUID_FEC_NONE; // inner forward error correction
fec_scheme fec1 = LIQUID_FEC_NONE; // outer forward error correction
float SNRdB = 30.0f; // SNR
// derived values
float nstd = powf(10.0f, -SNRdB/20.0f);
// create gmskframegen object
gmskframegen fg = gmskframegen_create();
// frame data
unsigned char header[14];
unsigned char payload[payload_len];
// initialize header, payload
for (i=0; i<14; i++)
header[i] = i;
for (i=0; i<payload_len; i++)
payload[i] = rand() & 0xff;
framedata fd = {header, payload, 0, 0, 0, 0};
// create gmskframesync object
gmskframesync fs = gmskframesync_create(callback,(void*)&fd);
//gmskframesync_print(fs);
// generate the frame
gmskframegen_assemble(fg, header, payload, payload_len, check, fec0, fec1);
gmskframegen_print(fg);
unsigned int frame_len = gmskframegen_getframelen(fg);
float complex frame[frame_len];
int frame_complete = 0;
unsigned int n=0;
while (!frame_complete) {
assert(n < frame_len);
frame_complete = gmskframegen_write_samples(fg, &frame[n]);
n += 2;
}
// add some noise
for (i=0; i<frame_len; i++)
frame[i] += nstd*(randnf() + _Complex_I*randnf());
//
// start trials
//
getrusage(RUSAGE_SELF, _start);
for (i=0; i<(*_num_iterations); i++) {
gmskframesync_execute(fs, frame, frame_len);
}
getrusage(RUSAGE_SELF, _finish);
// print results
fd.num_frames_tx = *_num_iterations;
printf(" frames detected/header/payload/transmitted: %6u / %6u / %6u / %6u\n",
fd.num_frames_detected,
fd.num_headers_valid,
fd.num_payloads_valid,
fd.num_frames_tx);
// destroy objects
gmskframegen_destroy(fg);
gmskframesync_destroy(fs);
}