void ofdmflexframegen_setprops(ofdmflexframegen _q,
ofdmflexframegenprops_s * _props)
{
// if properties object is NULL, initialize with defaults
if (_props == NULL) {
ofdmflexframegen_setprops(_q, &ofdmflexframegenprops_default);
return;
}
// validate input
if (_props->check == LIQUID_CRC_UNKNOWN || _props->check >= LIQUID_CRC_NUM_SCHEMES) {
fprintf(stderr, "error: ofdmflexframegen_setprops(), invalid/unsupported CRC scheme\n");
exit(1);
} else if (_props->fec0 == LIQUID_FEC_UNKNOWN || _props->fec1 == LIQUID_FEC_UNKNOWN) {
fprintf(stderr, "error: ofdmflexframegen_setprops(), invalid/unsupported FEC scheme\n");
exit(1);
} else if (_props->mod_scheme == LIQUID_MODEM_UNKNOWN ) {
fprintf(stderr, "error: ofdmflexframegen_setprops(), invalid/unsupported modulation scheme\n");
exit(1);
}
// TODO : determine if re-configuration is necessary
// copy properties to internal structure
memmove(&_q->props, _props, sizeof(ofdmflexframegenprops_s));
// reconfigure internal buffers, objects, etc.
ofdmflexframegen_reconfigure(_q);
}
void LiquidOfdmModComponent::parameterHasChanged(std::string name)
{
ofdmflexframegenprops_s fgProps;
ofdmflexframegen_getprops(frameGenerator_, &fgProps);
if (name == "modulation") {
modulation_scheme ms = liquid_getopt_str2mod(modulationScheme_x.c_str());
fgProps.mod_scheme = ms;
}
if (name == "fec0") {
fec_scheme fec0 = liquid_getopt_str2fec(fecZero_x.c_str());
fgProps.fec0 = fec0;
}
if (name == "fec1") {
fec_scheme fec1 = liquid_getopt_str2fec(fecOne_x.c_str());
fgProps.fec1 = fec1;
}
if (name == "crc") {
crc_scheme check = liquid_getopt_str2crc(crcScheme_x.c_str());
fgProps.check = check;
}
ofdmflexframegen_setprops(frameGenerator_, &fgProps);
if (name == "gain") {
gain_factor_ = powf(10.0f, gain_x/20.0f);
}
if (name == "subcarriers" ||
name == "prefixlength" ||
name == "taperlength")
{
//Need to destroy and recreate the frame generator
if (frameGenerator_)
ofdmflexframegen_destroy(frameGenerator_);
initialize();
}
}
// create OFDM flexible framing generator object
// _M : number of subcarriers, >10 typical
// _cp_len : cyclic prefix length
// _taper_len : taper length (OFDM symbol overlap)
// _p : subcarrier allocation (null, pilot, data), [size: _M x 1]
// _fgprops : frame properties (modulation scheme, etc.)
ofdmflexframegen ofdmflexframegen_create(unsigned int _M,
unsigned int _cp_len,
unsigned int _taper_len,
unsigned char * _p,
ofdmflexframegenprops_s * _fgprops)
{
// validate input
if (_M < 2) {
fprintf(stderr,"error: ofdmflexframegen_create(), number of subcarriers must be at least 2\n");
exit(1);
} else if (_M % 2) {
fprintf(stderr,"error: ofdmflexframegen_create(), number of subcarriers must be even\n");
exit(1);
}
ofdmflexframegen q = (ofdmflexframegen) malloc(sizeof(struct ofdmflexframegen_s));
q->M = _M; // number of subcarriers
q->cp_len = _cp_len; // cyclic prefix length
q->taper_len = _taper_len; // taper length
// allocate memory for transform buffers
q->X = (float complex*) malloc((q->M)*sizeof(float complex));
// allocate memory for subcarrier allocation IDs
q->p = (unsigned char*) malloc((q->M)*sizeof(unsigned char));
if (_p == NULL) {
// initialize default subcarrier allocation
ofdmframe_init_default_sctype(q->M, q->p);
} else {
// copy user-defined subcarrier allocation
memmove(q->p, _p, q->M*sizeof(unsigned char));
}
// validate and count subcarrier allocation
ofdmframe_validate_sctype(q->p, q->M, &q->M_null, &q->M_pilot, &q->M_data);
// create internal OFDM frame generator object
q->fg = ofdmframegen_create(q->M, q->cp_len, q->taper_len, q->p);
// create header objects
q->mod_header = modem_create(OFDMFLEXFRAME_H_MOD);
q->p_header = packetizer_create(OFDMFLEXFRAME_H_DEC,
OFDMFLEXFRAME_H_CRC,
OFDMFLEXFRAME_H_FEC,
LIQUID_FEC_NONE);
assert(packetizer_get_enc_msg_len(q->p_header)==OFDMFLEXFRAME_H_ENC);
// compute number of header symbols
div_t d = div(OFDMFLEXFRAME_H_SYM, q->M_data);
q->num_symbols_header = d.quot + (d.rem ? 1 : 0);
// initial memory allocation for payload
q->payload_dec_len = 1;
q->p_payload = packetizer_create(q->payload_dec_len,
LIQUID_CRC_NONE,
LIQUID_FEC_NONE,
LIQUID_FEC_NONE);
q->payload_enc_len = packetizer_get_enc_msg_len(q->p_payload);
q->payload_enc = (unsigned char*) malloc(q->payload_enc_len*sizeof(unsigned char));
q->payload_mod_len = 1;
q->payload_mod = (unsigned char*) malloc(q->payload_mod_len*sizeof(unsigned char));
// create payload modem (initially QPSK, overridden by properties)
q->mod_payload = modem_create(LIQUID_MODEM_QPSK);
// initialize properties
ofdmflexframegen_setprops(q, _fgprops);
// reset
ofdmflexframegen_reset(q);
// return pointer to main object
return q;
}
