/** Initializes the PBCH transmitter and receiver.
* At the receiver, the field nof_ports in the cell structure indicates the
* maximum number of BS transmitter ports to look for.
*/
int pbch_init(pbch_t *q, lte_cell_t cell) {
int ret = LIBLTE_ERROR_INVALID_INPUTS;
if (q != NULL &&
lte_cell_isvalid(&cell))
{
ret = LIBLTE_ERROR;
bzero(q, sizeof(pbch_t));
q->cell = cell;
if (modem_table_lte(&q->mod, LTE_QPSK, true)) {
goto clean;
}
demod_soft_init(&q->demod);
demod_soft_table_set(&q->demod, &q->mod);
demod_soft_alg_set(&q->demod, APPROX);
if (sequence_pbch(&q->seq_pbch, q->cell.cp, q->cell.id)) {
goto clean;
}
uint32_t poly[3] = { 0x6D, 0x4F, 0x57 };
if (viterbi_init(&q->decoder, viterbi_37, poly, 40, true)) {
goto clean;
}
if (crc_init(&q->crc, LTE_CRC16, 16)) {
goto clean;
}
q->encoder.K = 7;
q->encoder.R = 3;
q->encoder.tail_biting = true;
memcpy(q->encoder.poly, poly, 3 * sizeof(int));
q->nof_symbols = (CP_ISNORM(q->cell.cp)) ? PBCH_RE_CPNORM : PBCH_RE_CPEXT;
q->pbch_d = malloc(sizeof(cf_t) * q->nof_symbols);
if (!q->pbch_d) {
goto clean;
}
int i;
for (i = 0; i < q->cell.nof_ports; i++) {
q->ce[i] = malloc(sizeof(cf_t) * q->nof_symbols);
if (!q->ce[i]) {
goto clean;
}
q->pbch_x[i] = malloc(sizeof(cf_t) * q->nof_symbols);
if (!q->pbch_x[i]) {
goto clean;
}
q->pbch_symbols[i] = malloc(sizeof(cf_t) * q->nof_symbols);
if (!q->pbch_symbols[i]) {
goto clean;
}
}
q->pbch_llr = malloc(sizeof(float) * q->nof_symbols * 4 * 2);
if (!q->pbch_llr) {
goto clean;
}
q->temp = malloc(sizeof(float) * q->nof_symbols * 4 * 2);
if (!q->temp) {
goto clean;
}
q->pbch_rm_f = malloc(sizeof(float) * 120);
if (!q->pbch_rm_f) {
goto clean;
}
q->pbch_rm_b = malloc(sizeof(float) * q->nof_symbols * 4 * 2);
if (!q->pbch_rm_b) {
goto clean;
}
q->data = malloc(sizeof(char) * 40);
if (!q->data) {
goto clean;
}
q->data_enc = malloc(sizeof(char) * 120);
if (!q->data_enc) {
goto clean;
}
ret = LIBLTE_SUCCESS;
}
clean:
if (ret == LIBLTE_ERROR) {
pbch_free(q);
}
return ret;
}
int main(int argc, char **argv) {
int i;
modem_table_t mod;
demod_soft_t demod_soft;
char *input, *output;
cf_t *symbols;
float *llr_exact, *llr_approx;
parse_args(argc, argv);
/* initialize objects */
if (modem_table_lte(&mod, modulation, true)) {
fprintf(stderr, "Error initializing modem table\n");
exit(-1);
}
/* check that num_bits is multiple of num_bits x symbol */
num_bits = mod.nbits_x_symbol * (num_bits / mod.nbits_x_symbol);
demod_soft_init(&demod_soft);
demod_soft_table_set(&demod_soft, &mod);
demod_soft_sigma_set(&demod_soft, 2.0 / mod.nbits_x_symbol);
/* allocate buffers */
input = malloc(sizeof(char) * num_bits);
if (!input) {
perror("malloc");
exit(-1);
}
output = malloc(sizeof(char) * num_bits);
if (!output) {
perror("malloc");
exit(-1);
}
symbols = malloc(sizeof(cf_t) * num_bits / mod.nbits_x_symbol);
if (!symbols) {
perror("malloc");
exit(-1);
}
llr_exact = malloc(sizeof(float) * num_bits);
if (!llr_exact) {
perror("malloc");
exit(-1);
}
llr_approx = malloc(sizeof(float) * num_bits);
if (!llr_approx) {
perror("malloc");
exit(-1);
}
/* generate random data */
srand(0);
int ret = -1;
double mse;
struct timeval t[3];
float mean_texec = 0.0;
for (int n=0;n<nof_frames;n++) {
for (i=0;i<num_bits;i++) {
input[i] = rand()%2;
}
/* modulate */
mod_modulate(&mod, input, symbols, num_bits);
/* add noise */
ch_awgn_c(symbols, symbols, ch_awgn_get_variance(5.0, mod.nbits_x_symbol), num_bits / mod.nbits_x_symbol);
/* Compare exact with approximation algorithms */
demod_soft_alg_set(&demod_soft, EXACT);
demod_soft_demodulate(&demod_soft, symbols, llr_exact, num_bits / mod.nbits_x_symbol);
demod_soft_alg_set(&demod_soft, APPROX);
gettimeofday(&t[1], NULL);
demod_soft_demodulate(&demod_soft, symbols, llr_approx, num_bits / mod.nbits_x_symbol);
gettimeofday(&t[2], NULL);
get_time_interval(t);
/* compute exponentially averaged execution time */
if (n > 0) {
mean_texec = EXPAVERAGE((float) t[0].tv_usec, mean_texec, n-1);
}
/* check MSE */
mse = 0.0;
for (i=0;i<num_bits;i++) {
float e = llr_exact[i] - llr_approx[i];
mse += e*e;
}
mse/=num_bits;
if (VERBOSE_ISDEBUG()) {
printf("exact=");
vec_fprint_f(stdout, llr_exact, num_bits);
printf("approx=");
vec_fprint_f(stdout, llr_approx, num_bits);
}
if (mse > mse_threshold()) {
goto clean_exit;
}
}
ret = 0;
clean_exit:
free(llr_exact);
free(llr_approx);
free(symbols);
free(output);
free(input);
modem_table_free(&mod);
if (ret == 0) {
printf("Ok Mean Throughput: %.2f. Mbps ExTime: %.2f us\n", num_bits/mean_texec, mean_texec);
} else {
printf("Error: MSE too large (%f > %f)\n", mse, mse_threshold());
}
exit(ret);
}
int main(int argc, char **argv) {
viterbi_t dec;
convcoder_t cod;
modem_table_t modem;
demod_soft_t demod;
int frame_cnt;
float *llr;
char *data_tx, *data_rx, *symbols;
cf_t *iq;
int i;
parse_args(argc,argv);
if (!seed) {
seed = time(NULL);
}
srand(seed);
int coded_length = 3 * (frame_length + ((tail_biting)?0:6));
printf("Convolutional Code 1/3 K=7 Test\n");
printf(" Frame length: %d\n", frame_length);
printf(" Codeword length: %d\n", coded_length);
printf(" Tail bitting: %s\n", tail_biting?"yes":"no");
printf(" EbNo: %.2f\n", ebno_db);
data_tx = malloc(frame_length * sizeof(char));
if (!data_tx) {
perror("malloc");
exit(-1);
}
data_rx = malloc(frame_length * sizeof(char));
if (!data_rx) {
perror("malloc");
exit(-1);
}
symbols = malloc(coded_length * sizeof(char));
if (!symbols) {
perror("malloc");
exit(-1);
}
llr = malloc(coded_length * sizeof(float));
if (!llr) {
perror("malloc");
exit(-1);
}
iq = malloc(coded_length * sizeof(cf_t));
if (!iq) {
perror("malloc");
exit(-1);
}
cod.K = 7;
cod.R = 3;
cod.tail_biting = tail_biting;
cod.framelength = frame_length;
cod.poly[0] = 0x6D;
cod.poly[1] = 0x4F;
cod.poly[2] = 0x57;
float var = sqrt(pow(10,-ebno_db/10));
modem_table_init(&modem);
modem_table_std(&modem, LTE_QPSK, true);
demod_soft_init(&demod);
demod_soft_table_set(&demod, &modem);
demod_soft_alg_set(&demod, APPROX);
demod_soft_sigma_set(&demod, var);
viterbi_init(&dec, viterbi_37, cod.poly, frame_length, tail_biting);
/* read all file or nof_frames */
frame_cnt = 0;
unsigned int errors=0;
while (frame_cnt < nof_slots) {
/* generate data_tx */
for (i=0;i<frame_length;i++) {
data_tx[i] = message[i];
}
convcoder_encode(&cod, data_tx, symbols);
bit_fprint(stdout, symbols, 120);
mod_modulate(&modem, symbols, iq, coded_length);
if (ebno_db < 100.0) {
ch_awgn(iq, iq, var, coded_length/2);
}
demod_soft_demodulate(&demod, iq, llr, coded_length/2);
viterbi_decode(&dec, llr, data_rx);
errors += bit_diff(data_tx, data_rx, frame_length);
frame_cnt++;
}
printf("BER:\t%g\t%u errors\n", (float) errors/(frame_cnt*frame_length), errors);
viterbi_free(&dec);
free(data_tx);
free(symbols);
free(iq);
free(llr);
free(data_rx);
printf("Done\n");
exit(0);
}
/** Initializes the PBCH transmitter and receiver */
int pbch_init(pbch_t *q, int nof_prb, int cell_id, lte_cp_t cp) {
int ret = -1;
if (cell_id < 0) {
return -1;
}
bzero(q, sizeof(pbch_t));
q->cell_id = cell_id;
q->cp = cp;
q->nof_prb = nof_prb;
if (modem_table_std(&q->mod, LTE_QPSK, true)) {
goto clean;
}
demod_soft_init(&q->demod);
demod_soft_table_set(&q->demod, &q->mod);
demod_soft_alg_set(&q->demod, APPROX);
if (sequence_pbch(&q->seq_pbch, q->cp, q->cell_id)) {
goto clean;
}
int poly[3] = { 0x6D, 0x4F, 0x57 };
if (viterbi_init(&q->decoder, viterbi_37, poly, 40, true)) {
goto clean;
}
if (crc_init(&q->crc, LTE_CRC16, 16)) {
goto clean;
}
q->encoder.K = 7;
q->encoder.R = 3;
q->encoder.tail_biting = true;
memcpy(q->encoder.poly, poly, 3 * sizeof(int));
q->nof_symbols = (CP_ISNORM(q->cp)) ? PBCH_RE_CPNORM : PBCH_RE_CPEXT;
q->pbch_d = malloc(sizeof(cf_t) * q->nof_symbols);
if (!q->pbch_d) {
goto clean;
}
int i;
for (i = 0; i < MAX_PORTS_CTRL; i++) {
q->ce[i] = malloc(sizeof(cf_t) * q->nof_symbols);
if (!q->ce[i]) {
goto clean;
}
q->pbch_x[i] = malloc(sizeof(cf_t) * q->nof_symbols);
if (!q->pbch_x[i]) {
goto clean;
}
q->pbch_symbols[i] = malloc(sizeof(cf_t) * q->nof_symbols);
if (!q->pbch_symbols[i]) {
goto clean;
}
}
q->pbch_llr = malloc(sizeof(float) * q->nof_symbols * 4 * 2);
if (!q->pbch_llr) {
goto clean;
}
q->temp = malloc(sizeof(float) * q->nof_symbols * 4 * 2);
if (!q->temp) {
goto clean;
}
q->pbch_rm_f = malloc(sizeof(float) * 120);
if (!q->pbch_rm_f) {
goto clean;
}
q->pbch_rm_b = malloc(sizeof(float) * q->nof_symbols * 4 * 2);
if (!q->pbch_rm_b) {
goto clean;
}
q->data = malloc(sizeof(char) * 40);
if (!q->data) {
goto clean;
}
q->data_enc = malloc(sizeof(char) * 120);
if (!q->data_enc) {
goto clean;
}
ret = 0;
clean: if (ret == -1) {
pbch_free(q);
}
return ret;
}