int main(int argc, char **argv) {
int i;
srslte_modem_table_t mod;
uint8_t *input, *input_bytes, *output;
cf_t *symbols, *symbols_bytes;
float *llr, *llr2;
parse_args(argc, argv);
/* initialize objects */
if (srslte_modem_table_lte(&mod, modulation)) {
fprintf(stderr, "Error initializing modem table\n");
exit(-1);
}
srslte_modem_table_bytes(&mod);
/* check that num_bits is multiple of num_bits x symbol */
if (num_bits % mod.nbits_x_symbol) {
fprintf(stderr, "Error num_bits must be multiple of %d\n", mod.nbits_x_symbol);
exit(-1);
}
/* allocate buffers */
input = srslte_vec_malloc(sizeof(uint8_t) * num_bits);
if (!input) {
perror("malloc");
exit(-1);
}
input_bytes = srslte_vec_malloc(sizeof(uint8_t) * num_bits/8);
if (!input_bytes) {
perror("malloc");
exit(-1);
}
output = srslte_vec_malloc(sizeof(uint8_t) * num_bits);
if (!output) {
perror("malloc");
exit(-1);
}
symbols = srslte_vec_malloc(sizeof(cf_t) * num_bits / mod.nbits_x_symbol);
if (!symbols) {
perror("malloc");
exit(-1);
}
symbols_bytes = srslte_vec_malloc(sizeof(cf_t) * num_bits / mod.nbits_x_symbol);
if (!symbols_bytes) {
perror("malloc");
exit(-1);
}
llr = srslte_vec_malloc(sizeof(float) * num_bits);
if (!llr) {
perror("malloc");
exit(-1);
}
llr2 = srslte_vec_malloc(sizeof(float) * num_bits);
if (!llr2) {
perror("malloc");
exit(-1);
}
/* generate random data */
for (i=0;i<num_bits;i++) {
input[i] = rand()%2;
}
/* modulate */
struct timeval t[3];
gettimeofday(&t[1], NULL);
int ntrials = 100;
for (int i=0;i<ntrials;i++) {
srslte_mod_modulate(&mod, input, symbols, num_bits);
}
gettimeofday(&t[2], NULL);
get_time_interval(t);
printf("Bit: %d us\n", t[0].tv_usec);
/* Test packed implementation */
srslte_bit_pack_vector(input, input_bytes, num_bits);
gettimeofday(&t[1], NULL);
for (int i=0;i<ntrials;i++) {
srslte_mod_modulate_bytes(&mod, input_bytes, symbols_bytes, num_bits);
}
gettimeofday(&t[2], NULL);
get_time_interval(t);
printf("Byte: %d us\n", t[0].tv_usec);
for (int i=0;i<num_bits/mod.nbits_x_symbol;i++) {
if (symbols[i] != symbols_bytes[i]) {
printf("error in symbol %d\n", i);
exit(-1);
}
}
printf("Symbols OK\n");
/* demodulate */
gettimeofday(&x, NULL);
srslte_demod_soft_demodulate(modulation, symbols, llr, num_bits / mod.nbits_x_symbol);
gettimeofday(&y, NULL);
printf("\nElapsed time [ns]: %d\n", (int) y.tv_usec - (int) x.tv_usec);
for (i=0;i<num_bits;i++) {
output[i] = llr[i]>=0 ? 1 : 0;
}
/* check errors */
for (i=0;i<num_bits;i++) {
if (input[i] != output[i]) {
fprintf(stderr, "Error in bit %d\n", i);
exit(-1);
}
}
free(llr);
free(symbols);
free(symbols_bytes);
free(output);
free(input);
free(input_bytes);
srslte_modem_table_free(&mod);
printf("Ok\n");
exit(0);
}
/* Decodes the PCFICH channel and saves the CFI in the cfi pointer.
*
* Returns 1 if successfully decoded the CFI, 0 if not and -1 on error
*/
int srslte_pcfich_decode(srslte_pcfich_t *q, cf_t *slot_symbols, cf_t *ce[SRSLTE_MAX_PORTS], float noise_estimate,
uint32_t nsubframe, uint32_t *cfi, float *corr_result)
{
/* Set pointers for layermapping & precoding */
int i;
cf_t *x[SRSLTE_MAX_LAYERS];
cf_t *ce_precoding[SRSLTE_MAX_PORTS];
if (q != NULL &&
slot_symbols != NULL &&
nsubframe < SRSLTE_NSUBFRAMES_X_FRAME)
{
/* number of layers equals number of ports */
for (i = 0; i < SRSLTE_MAX_PORTS; i++) {
x[i] = q->x[i];
}
for (i = 0; i < SRSLTE_MAX_PORTS; i++) {
ce_precoding[i] = q->ce[i];
}
/* extract symbols */
if (q->nof_symbols
!= srslte_regs_pcfich_get(q->regs, slot_symbols, q->symbols[0])) {
fprintf(stderr, "There was an error getting the PCFICH symbols\n");
return SRSLTE_ERROR;
}
/* extract channel estimates */
for (i = 0; i < q->cell.nof_ports; i++) {
if (q->nof_symbols != srslte_regs_pcfich_get(q->regs, ce[i], q->ce[i])) {
fprintf(stderr, "There was an error getting the PCFICH symbols\n");
return SRSLTE_ERROR;
}
}
/* in control channels, only diversity is supported */
if (q->cell.nof_ports == 1) {
/* no need for layer demapping */
srslte_predecoding_single(q->symbols[0], q->ce[0], q->d, q->nof_symbols, noise_estimate);
} else {
srslte_predecoding_diversity(q->symbols[0], ce_precoding, x,
q->cell.nof_ports, q->nof_symbols);
srslte_layerdemap_diversity(x, q->d, q->cell.nof_ports,
q->nof_symbols / q->cell.nof_ports);
}
/* demodulate symbols */
srslte_demod_soft_demodulate(SRSLTE_MOD_QPSK, q->d, q->data_f, q->nof_symbols);
/* Scramble with the sequence for slot nslot */
srslte_scrambling_f(&q->seq[nsubframe], q->data_f);
/* decode CFI */
float corr = srslte_pcfich_cfi_decode(q, cfi);
if (corr_result) {
*corr_result = corr;
}
return 1;
} else {
return SRSLTE_ERROR_INVALID_INPUTS;
}
}
/* Decodes the phich channel and saves the CFI in the cfi pointer.
*
* Returns 1 if successfully decoded the CFI, 0 if not and -1 on error
*/
int srslte_phich_decode(srslte_phich_t *q, cf_t *slot_symbols, cf_t *ce[SRSLTE_MAX_PORTS], float noise_estimate,
uint32_t ngroup, uint32_t nseq, uint32_t subframe, uint8_t *ack, float *distance) {
/* Set pointers for layermapping & precoding */
int i, j;
cf_t *x[SRSLTE_MAX_LAYERS];
cf_t *ce_precoding[SRSLTE_MAX_PORTS];
if (q == NULL || slot_symbols == NULL) {
return SRSLTE_ERROR_INVALID_INPUTS;
}
if (subframe >= SRSLTE_NSUBFRAMES_X_FRAME) {
fprintf(stderr, "Invalid nslot %d\n", subframe);
return SRSLTE_ERROR_INVALID_INPUTS;
}
if (SRSLTE_CP_ISEXT(q->cell.cp)) {
if (nseq >= SRSLTE_PHICH_EXT_NSEQUENCES) {
fprintf(stderr, "Invalid nseq %d\n", nseq);
return SRSLTE_ERROR_INVALID_INPUTS;
}
} else {
if (nseq >= SRSLTE_PHICH_NORM_NSEQUENCES) {
fprintf(stderr, "Invalid nseq %d\n", nseq);
return SRSLTE_ERROR_INVALID_INPUTS;
}
}
if (ngroup >= srslte_regs_phich_ngroups(q->regs)) {
fprintf(stderr, "Invalid ngroup %d\n", ngroup);
return SRSLTE_ERROR_INVALID_INPUTS;
}
DEBUG("Decoding PHICH Ngroup: %d, Nseq: %d\n", ngroup, nseq);
/* number of layers equals number of ports */
for (i = 0; i < SRSLTE_MAX_PORTS; i++) {
x[i] = q->x[i];
}
for (i = 0; i < SRSLTE_MAX_PORTS; i++) {
ce_precoding[i] = q->ce[i];
}
/* extract symbols */
if (SRSLTE_PHICH_MAX_NSYMB
!= srslte_regs_phich_get(q->regs, slot_symbols, q->symbols[0], ngroup)) {
fprintf(stderr, "There was an error getting the phich symbols\n");
return SRSLTE_ERROR;
}
/* extract channel estimates */
for (i = 0; i < q->cell.nof_ports; i++) {
if (SRSLTE_PHICH_MAX_NSYMB != srslte_regs_phich_get(q->regs, ce[i], q->ce[i], ngroup)) {
fprintf(stderr, "There was an error getting the phich symbols\n");
return SRSLTE_ERROR;
}
}
/* in control channels, only diversity is supported */
if (q->cell.nof_ports == 1) {
/* no need for layer demapping */
srslte_predecoding_single(q->symbols[0], q->ce[0], q->d0, SRSLTE_PHICH_MAX_NSYMB, noise_estimate);
} else {
srslte_predecoding_diversity(&q->precoding, q->symbols[0], ce_precoding, x,
q->cell.nof_ports, SRSLTE_PHICH_MAX_NSYMB, noise_estimate);
srslte_layerdemap_diversity(x, q->d0, q->cell.nof_ports,
SRSLTE_PHICH_MAX_NSYMB / q->cell.nof_ports);
}
DEBUG("Recv!!: \n", 0);
DEBUG("d0: ", 0);
if (SRSLTE_VERBOSE_ISDEBUG())
srslte_vec_fprint_c(stdout, q->d0, SRSLTE_PHICH_MAX_NSYMB);
if (SRSLTE_CP_ISEXT(q->cell.cp)) {
if (ngroup % 2) {
for (i = 0; i < SRSLTE_PHICH_EXT_MSYMB / 2; i++) {
q->d[2 * i + 0] = q->d0[4 * i + 2];
q->d[2 * i + 1] = q->d0[4 * i + 3];
}
} else {
for (i = 0; i < SRSLTE_PHICH_EXT_MSYMB / 2; i++) {
q->d[2 * i + 0] = q->d0[4 * i];
q->d[2 * i + 1] = q->d0[4 * i + 1];
}
}
} else {
memcpy(q->d, q->d0, SRSLTE_PHICH_MAX_NSYMB * sizeof(cf_t));
}
DEBUG("d: ", 0);
if (SRSLTE_VERBOSE_ISDEBUG())
srslte_vec_fprint_c(stdout, q->d, SRSLTE_PHICH_EXT_MSYMB);
srslte_scrambling_c(&q->seq[subframe], q->d);
/* De-spreading */
if (SRSLTE_CP_ISEXT(q->cell.cp)) {
for (i = 0; i < SRSLTE_PHICH_NBITS; i++) {
q->z[i] = 0;
for (j = 0; j < SRSLTE_PHICH_EXT_NSF; j++) {
q->z[i] += conjf(w_ext[nseq][j])
* q->d[i * SRSLTE_PHICH_EXT_NSF + j] / SRSLTE_PHICH_EXT_NSF;
}
}
} else {
for (i = 0; i < SRSLTE_PHICH_NBITS; i++) {
q->z[i] = 0;
for (j = 0; j < SRSLTE_PHICH_NORM_NSF; j++) {
q->z[i] += conjf(w_normal[nseq][j])
* q->d[i * SRSLTE_PHICH_NORM_NSF + j] / SRSLTE_PHICH_NORM_NSF;
}
}
}
DEBUG("z: ", 0);
if (SRSLTE_VERBOSE_ISDEBUG())
srslte_vec_fprint_c(stdout, q->z, SRSLTE_PHICH_NBITS);
srslte_demod_soft_demodulate(SRSLTE_MOD_BPSK, q->z, q->data_rx, SRSLTE_PHICH_NBITS);
if (ack) {
*ack = srslte_phich_ack_decode(q->data_rx, distance);
}
return SRSLTE_SUCCESS;
}