diff options
Diffstat (limited to 'src/freedv_2020.c')
| -rw-r--r-- | src/freedv_2020.c | 342 |
1 files changed, 342 insertions, 0 deletions
diff --git a/src/freedv_2020.c b/src/freedv_2020.c new file mode 100644 index 0000000..135bcd2 --- /dev/null +++ b/src/freedv_2020.c @@ -0,0 +1,342 @@ +/*---------------------------------------------------------------------------*\ + + FILE........: freedv_2020.c + AUTHOR......: David Rowe + DATE CREATED: May 2020 + + Functions that implement the FreeDV 2020 modes. + +\*---------------------------------------------------------------------------*/ + +#include <assert.h> +#include <stdlib.h> +#include <stdbool.h> +#include <stdint.h> +#include <stdio.h> +#include <string.h> +#include <math.h> + +#include "fsk.h" +#include "fmfsk.h" +#include "codec2.h" +#include "codec2_fdmdv.h" +#include "varicode.h" +#include "freedv_api.h" +#include "freedv_api_internal.h" +#include "comp_prim.h" + +#include "codec2_ofdm.h" +#include "ofdm_internal.h" +#include "mpdecode_core.h" +#include "gp_interleaver.h" +#include "ldpc_codes.h" +#include "interldpc.h" +#include "debug_alloc.h" + +extern char *ofdm_statemode[]; + +#ifdef __LPCNET__ +void freedv_2020x_open(struct freedv *f) { + f->speech_sample_rate = FREEDV_FS_16000; + f->snr_squelch_thresh = 4.0; + f->squelch_en = 0; + + struct OFDM_CONFIG ofdm_config; + switch (f->mode) { + case FREEDV_MODE_2020: + ofdm_init_mode("2020", &ofdm_config); + break; + case FREEDV_MODE_2020B: + ofdm_init_mode("2020B", &ofdm_config); + break; + case FREEDV_MODE_2020C: + ofdm_init_mode("2020C", &ofdm_config); + break; + default: + assert(0); + } + + f->ofdm = ofdm_create(&ofdm_config); + + f->ldpc = (struct LDPC*)MALLOC(sizeof(struct LDPC)); + assert(f->ldpc != NULL); + + ldpc_codes_setup(f->ldpc, f->ofdm->codename); + ldpc_mode_specific_setup(f->ofdm, f->ldpc); + int vq_type; + switch (f->mode) { + case FREEDV_MODE_2020: + vq_type = 1; /* vanilla VQ */ + break; + case FREEDV_MODE_2020B: + vq_type = 2; /* index optimised VQ for increased robustness to single bit errors */ + break; + case FREEDV_MODE_2020C: + vq_type = 2; /* index optimised VQ for increased robustness to single bit errors */ + break; + default: + assert(0); + } + + int coded_syms_per_frame = f->ldpc->coded_bits_per_frame/f->ofdm->bps; + f->ofdm_bitsperframe = ofdm_get_bits_per_frame(f->ofdm); + f->ofdm_nuwbits = f->ofdm->config.nuwbits; + f->ofdm_ntxtbits = f->ofdm->config.txtbits; + assert(f->ofdm_ntxtbits == 4); + + if (f->verbose) { + fprintf(stderr, "f->mode = %d\n", f->mode); + fprintf(stderr, "vq_type = %d\n", vq_type); + fprintf(stderr, "ldpc_data_bits_per_frame = %d\n", f->ldpc->ldpc_data_bits_per_frame); + fprintf(stderr, "ldpc_coded_bits_per_frame = %d\n", f->ldpc->ldpc_coded_bits_per_frame); + fprintf(stderr, "data_bits_per_frame = %d\n", f->ldpc->data_bits_per_frame); + fprintf(stderr, "coded_bits_per_frame = %d\n", f->ldpc->coded_bits_per_frame); + fprintf(stderr, "coded_syms_per_frame = %d\n", f->ldpc->coded_bits_per_frame/f->ofdm->bps); + fprintf(stderr, "ofdm_bits_per_frame = %d\n", f->ofdm_bitsperframe); + fprintf(stderr, "ofdm_nuwbits = %d\n", f->ofdm_nuwbits); + fprintf(stderr, "ofdm_ntxtbits = %d\n", f->ofdm_ntxtbits); + } + + f->codeword_symbols = (COMP*)MALLOC(sizeof(COMP) * coded_syms_per_frame); + assert(f->codeword_symbols != NULL); + + f->codeword_amps = (float*)MALLOC(sizeof(float) * coded_syms_per_frame); + assert(f->codeword_amps != NULL); + + for (int i=0; i< coded_syms_per_frame; i++) { + f->codeword_symbols[i].real = 0.0f; + f->codeword_symbols[i].imag = 0.0f; + f->codeword_amps[i] = 0.0f; + } + + f->nin = f->nin_prev = ofdm_get_samples_per_frame(f->ofdm); + f->n_nat_modem_samples = ofdm_get_samples_per_frame(f->ofdm); + f->n_nom_modem_samples = ofdm_get_samples_per_frame(f->ofdm); + f->n_max_modem_samples = ofdm_get_max_samples_per_frame(f->ofdm); + f->modem_sample_rate = f->ofdm->config.fs; + f->clip_en = false; + f->sz_error_pattern = f->ofdm_bitsperframe; + + /* storage for pass through audio interpolating filter. These are + the rate FREEDV_FS_8000 modem input samples before interpolation */ + f->passthrough_2020 = CALLOC(1, sizeof(float)*(FDMDV_OS_TAPS_16K + freedv_get_n_max_modem_samples(f))); + assert(f->passthrough_2020 != NULL); + + // make sure we have enough storage for worst case nin with passthrough, in 2020 + // we oversample the 8 kHz input Rx audio to 16 kHz + int nout_max = 2*freedv_get_n_max_modem_samples(f); + assert(nout_max <= freedv_get_n_max_speech_samples(f)); + + f->lpcnet = lpcnet_freedv_create(vq_type); assert(f->lpcnet != NULL); + f->codec2 = NULL; + + /* should be exactly an integer number of Codec frames in a OFDM modem frame */ + assert((f->ldpc->data_bits_per_frame % lpcnet_bits_per_frame(f->lpcnet)) == 0); + + f->n_codec_frames = f->ldpc->data_bits_per_frame/lpcnet_bits_per_frame(f->lpcnet); + f->n_speech_samples = f->n_codec_frames*lpcnet_samples_per_frame(f->lpcnet); + f->bits_per_codec_frame = lpcnet_bits_per_frame(f->lpcnet); + f->bits_per_modem_frame = f->n_codec_frames*f->bits_per_codec_frame; + + f->tx_payload_bits = (unsigned char*)MALLOC(f->bits_per_modem_frame); + assert(f->tx_payload_bits != NULL); + f->rx_payload_bits = (unsigned char*)MALLOC(f->bits_per_modem_frame); + assert(f->rx_payload_bits != NULL); + + /* attenuate audio 12dB as channel noise isn't that pleasant */ + f->passthrough_gain = 0.25; +} + +void freedv_comptx_2020(struct freedv *f, COMP mod_out[]) { + int i, k; + + int data_bits_per_frame = f->ldpc->data_bits_per_frame; + uint8_t tx_bits[data_bits_per_frame]; + + memcpy(tx_bits, f->tx_payload_bits, data_bits_per_frame); + + // Generate Varicode txt bits. Txt bits in OFDM frame come just + // after Unique Word (UW). Txt bits aren't protected by FEC, and need to be + // added to each frame after interleaver as done it's thing + + int nspare = f->ofdm_ntxtbits; + uint8_t txt_bits[nspare]; + + for(k=0; k<nspare; k++) { + if (f->nvaricode_bits == 0) { + /* get new char and encode */ + char s[2]; + if (f->freedv_get_next_tx_char != NULL) { + s[0] = (*f->freedv_get_next_tx_char)(f->callback_state); + f->nvaricode_bits = varicode_encode(f->tx_varicode_bits, s, VARICODE_MAX_BITS, 1, f->varicode_dec_states.code_num); + f->varicode_bit_index = 0; + } + } + if (f->nvaricode_bits) { + txt_bits[k] = f->tx_varicode_bits[f->varicode_bit_index++]; + f->nvaricode_bits--; + } else txt_bits[k] = 0; + } + + /* optionally replace codec payload bits with test frames known to rx */ + + if (f->test_frames) { + uint8_t payload_data_bits[data_bits_per_frame]; + ofdm_generate_payload_data_bits(payload_data_bits, data_bits_per_frame); + + for (i = 0; i < data_bits_per_frame; i++) { + tx_bits[i] = payload_data_bits[i]; + } + } + + /* OK now ready to LDPC encode, interleave, and OFDM modulate */ + ofdm_ldpc_interleave_tx(f->ofdm, f->ldpc, (complex float*)mod_out, tx_bits, txt_bits); +} + +int freedv_comprx_2020(struct freedv *f, COMP demod_in[]) { + int i, k; + int n_ascii; + char ascii_out; + struct OFDM *ofdm = f->ofdm; + struct LDPC *ldpc = f->ldpc; + + int data_bits_per_frame = ldpc->data_bits_per_frame; + int coded_bits_per_frame = ldpc->coded_bits_per_frame; + int coded_syms_per_frame = ldpc->coded_bits_per_frame/ofdm->bps; + COMP *codeword_symbols = f->codeword_symbols; + float *codeword_amps = f->codeword_amps; + int rx_bits[f->ofdm_bitsperframe]; + short txt_bits[f->ofdm_ntxtbits]; + COMP payload_syms[coded_syms_per_frame]; + float payload_amps[coded_syms_per_frame]; + + int rx_status = 0; + + int Nerrs_raw = 0; + int Nerrs_coded = 0; + int Ncoded; + int iter = 0; + int parityCheckCount = 0; + uint8_t rx_uw[f->ofdm_nuwbits]; + + f->sync = 0; + + // TODO: should be higher for 2020? + float EsNo = 3.0; + + /* looking for modem sync */ + + if (ofdm->sync_state == search) { + ofdm_sync_search(f->ofdm, demod_in); + f->snr_est = -5.0; + } + + /* OK modem is in sync */ + + if ((ofdm->sync_state == synced) || (ofdm->sync_state == trial)) { + rx_status |= FREEDV_RX_SYNC; + if (ofdm->sync_state == trial) rx_status |= FREEDV_RX_TRIAL_SYNC; + + int txt_sym_index = 0; + + ofdm_demod(ofdm, rx_bits, demod_in); + ofdm_extract_uw(ofdm, ofdm->rx_np, ofdm->rx_amp, rx_uw); + ofdm_disassemble_qpsk_modem_packet_with_text_amps(ofdm, ofdm->rx_np, ofdm->rx_amp, payload_syms, payload_amps, txt_bits, &txt_sym_index); + + f->sync = 1; + + assert((f->ofdm_nuwbits+f->ofdm_ntxtbits+coded_bits_per_frame) == f->ofdm_bitsperframe); + + /* newest symbols at end of buffer (uses final i from last loop), note we + change COMP formats from what modem uses internally */ + + for(i=0; i< coded_syms_per_frame; i++) { + codeword_symbols[i] = payload_syms[i]; + codeword_amps[i] = payload_amps[i]; + } + + /* run de-interleaver */ + + COMP codeword_symbols_de[coded_syms_per_frame]; + float codeword_amps_de[coded_syms_per_frame]; + + gp_deinterleave_comp (codeword_symbols_de, codeword_symbols, coded_syms_per_frame); + gp_deinterleave_float(codeword_amps_de , codeword_amps , coded_syms_per_frame); + + float llr[coded_bits_per_frame]; + uint8_t out_char[coded_bits_per_frame]; + + if (f->test_frames) { + Nerrs_raw = count_uncoded_errors(ldpc, &f->ofdm->config, codeword_symbols_de, 0); + f->total_bit_errors += Nerrs_raw; + f->total_bits += f->ofdm_bitsperframe; + } + + symbols_to_llrs(llr, codeword_symbols_de, codeword_amps_de, + EsNo, ofdm->mean_amp, coded_syms_per_frame); + ldpc_decode_frame(ldpc, &parityCheckCount, &iter, out_char, llr); + if (parityCheckCount != ldpc->NumberParityBits) rx_status |= FREEDV_RX_BIT_ERRORS; + + if (f->test_frames) { + uint8_t payload_data_bits[data_bits_per_frame]; + ofdm_generate_payload_data_bits(payload_data_bits, data_bits_per_frame); + count_errors_protection_mode(ldpc->protection_mode, &Nerrs_coded, &Ncoded, payload_data_bits, out_char, data_bits_per_frame); + f->total_bit_errors_coded += Nerrs_coded; + f->total_bits_coded += Ncoded; + if (Nerrs_coded) f->total_packet_errors++; + f->total_packets++; + } else { + memcpy(f->rx_payload_bits, out_char, data_bits_per_frame); + } + + rx_status |= FREEDV_RX_BITS; + + /* If modem is synced we can decode txt bits */ + + for(k=0; k<f->ofdm_ntxtbits; k++) { + if (k % 2 == 0 && (f->freedv_put_next_rx_symbol != NULL)) + { + (*f->freedv_put_next_rx_symbol)(f->callback_state_sym, + ofdm->rx_np[txt_sym_index], + ofdm->rx_amp[txt_sym_index]); + txt_sym_index++; + } + + //fprintf(stderr, "txt_bits[%d] = %d\n", k, rx_bits[i]); + n_ascii = varicode_decode(&f->varicode_dec_states, &ascii_out, &txt_bits[k], 1, 1); + if (n_ascii && (f->freedv_put_next_rx_char != NULL)) { + (*f->freedv_put_next_rx_char)(f->callback_state, ascii_out); + } + } + + /* estimate uncoded BER from UW. Coded bit errors could + probably be estimated as half of all failed LDPC parity + checks */ + + for(i=0; i<f->ofdm_nuwbits; i++) { + if (rx_uw[i] != ofdm->tx_uw[i]) { + f->total_bit_errors++; + } + } + f->total_bits += f->ofdm_nuwbits; + + ofdm_get_demod_stats(f->ofdm, &f->stats, ofdm->rx_np, ofdm->rowsperframe*ofdm->nc); + f->snr_est = f->stats.snr_est; + } + + /* iterate state machine and update nin for next call */ + + f->nin = ofdm_get_nin(ofdm); + ofdm_sync_state_machine(ofdm, rx_uw); + + if ((f->verbose && (ofdm->last_sync_state == search)) || (f->verbose == 2)) { + assert(rx_status <= 15); + fprintf(stderr, "%3d st: %-6s euw: %2d %1d f: %5.1f pbw: %d snr: %4.1f eraw: %3d ecdd: %3d iter: %3d pcc: %3d rxst: %s\n", + f->frames++, ofdm_statemode[ofdm->last_sync_state], ofdm->uw_errors, ofdm->sync_counter, + (double)ofdm->foff_est_hz, ofdm->phase_est_bandwidth, + f->snr_est, Nerrs_raw, Nerrs_coded, iter, parityCheckCount, rx_sync_flags_to_text[rx_status]); + } + + return rx_status; +} +#endif |