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; }