diff options
Diffstat (limited to 'src/ofdm.c')
| -rw-r--r-- | src/ofdm.c | 3926 |
1 files changed, 1998 insertions, 1928 deletions
@@ -26,22 +26,22 @@ along with this program; if not, see <http://www.gnu.org/licenses/>. */ -#include <stdio.h> -#include <stdlib.h> +#include <assert.h> +#include <complex.h> +#include <math.h> #include <stdbool.h> #include <stdint.h> +#include <stdio.h> +#include <stdlib.h> #include <string.h> -#include <math.h> -#include <assert.h> -#include <complex.h> -#include "comp.h" -#include "ofdm_internal.h" #include "codec2_ofdm.h" -#include "filter.h" -#include "wval.h" +#include "comp.h" #include "debug_alloc.h" +#include "filter.h" #include "machdep.h" +#include "ofdm_internal.h" +#include "wval.h" #ifdef __EMBEDDED__ #include "codec2_math.h" @@ -58,74 +58,52 @@ static void deallocate_rx_bpf(struct OFDM *); static void dft(struct OFDM *, complex float *, complex float *); static void idft(struct OFDM *, complex float *, complex float *); static complex float vector_sum(complex float *, int); -static int est_timing(struct OFDM *, complex float *, int, int, float *, int *, int); -static float est_freq_offset_pilot_corr(struct OFDM *, complex float *, int, int); +static int est_timing(struct OFDM *, complex float *, int, int, float *, int *, + int); +static float est_freq_offset_pilot_corr(struct OFDM *, complex float *, int, + int); static int ofdm_sync_search_core(struct OFDM *); static void ofdm_demod_core(struct OFDM *, int *); /* Defines */ -#define max( a, b ) ( ((a) > (b)) ? (a) : (b) ) -#define min( a, b ) ( ((a) < (b)) ? (a) : (b) ) +#define max(a, b) (((a) > (b)) ? (a) : (b)) +#define min(a, b) (((a) < (b)) ? (a) : (b)) /* * QPSK Quadrant bit-pair values - Gray Coded */ -static const complex float qpsk[] = { - 1.0f + 0.0f * I, - 0.0f + 1.0f * I, - 0.0f - 1.0f * I, - -1.0f + 0.0f * I -}; +static const complex float qpsk[] = {1.0f + 0.0f * I, 0.0f + 1.0f * I, + 0.0f - 1.0f * I, -1.0f + 0.0f * I}; static const complex float qam16[] = { - 1.0f + 1.0f * I, - 1.0f + 3.0f * I, - 3.0f + 1.0f * I, - 3.0f + 3.0f * I, - 1.0f - 1.0f * I, - 1.0f - 3.0f * I, - 3.0f - 1.0f * I, - 3.0f - 3.0f * I, - -1.0f + 1.0f * I, - -1.0f + 3.0f * I, - -3.0f + 1.0f * I, - -3.0f + 3.0f * I, - -1.0f - 1.0f * I, - -1.0f - 3.0f * I, - -3.0f - 1.0f * I, - -3.0f - 3.0f * I -}; + 1.0f + 1.0f * I, 1.0f + 3.0f * I, 3.0f + 1.0f * I, 3.0f + 3.0f * I, + 1.0f - 1.0f * I, 1.0f - 3.0f * I, 3.0f - 1.0f * I, 3.0f - 3.0f * I, + -1.0f + 1.0f * I, -1.0f + 3.0f * I, -3.0f + 1.0f * I, -3.0f + 3.0f * I, + -1.0f - 1.0f * I, -1.0f - 3.0f * I, -3.0f - 1.0f * I, -3.0f - 3.0f * I}; /* * These pilots are compatible with Octave version */ static const int8_t pilotvalues[] = { - -1,-1, 1, 1,-1,-1,-1, 1, - -1, 1,-1, 1, 1, 1, 1, 1, - 1, 1, 1,-1,-1, 1,-1, 1, - -1, 1, 1, 1, 1, 1, 1, 1, - 1, 1, 1,-1, 1, 1, 1, 1, - 1,-1,-1,-1,-1,-1,-1, 1, - -1, 1,-1, 1,-1,-1, 1,-1, - 1, 1, 1, 1,-1, 1,-1, 1 -}; + -1, -1, 1, 1, -1, -1, -1, 1, -1, 1, -1, 1, 1, 1, 1, 1, + 1, 1, 1, -1, -1, 1, -1, 1, -1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, -1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, 1, + -1, 1, -1, 1, -1, -1, 1, -1, 1, 1, 1, 1, -1, 1, -1, 1}; /* Local Functions ----------------------------------------------------------*/ static float cnormf(complex float val) { - float realf = crealf(val); - float imagf = cimagf(val); + float realf = crealf(val); + float imagf = cimagf(val); - return realf * realf + imagf * imagf; + return realf * realf + imagf * imagf; } /* * Gray coded QPSK modulation function */ -complex float qpsk_mod(int *bits) { - return qpsk[(bits[1] << 1) | bits[0]]; -} +complex float qpsk_mod(int *bits) { return qpsk[(bits[1] << 1) | bits[0]]; } /* * Gray coded QPSK demodulation function @@ -135,41 +113,38 @@ complex float qpsk_mod(int *bits) { * 11 | 10 */ void qpsk_demod(complex float symbol, int *bits) { - complex float rotate = symbol * cmplx(ROT45); + complex float rotate = symbol * cmplx(ROT45); - bits[0] = crealf(rotate) <= 0.0f; - bits[1] = cimagf(rotate) <= 0.0f; + bits[0] = crealf(rotate) <= 0.0f; + bits[1] = cimagf(rotate) <= 0.0f; } complex float qam16_mod(int *bits) { - return qam16[ - (bits[3] << 3) | (bits[2] << 2) | - (bits[1] << 1) | bits[0] - ]; + return qam16[(bits[3] << 3) | (bits[2] << 2) | (bits[1] << 1) | bits[0]]; } void qam16_demod(complex float symbol, int *bits) { - float dist[16]; - int i; + float dist[16]; + int i; - for (i = 0; i < 16; i++) { - dist[i] = cnormf(symbol - qam16[i]); - } + for (i = 0; i < 16; i++) { + dist[i] = cnormf(symbol - qam16[i]); + } - int row = 0; - float mdist = 10000.0f; + int row = 0; + float mdist = 10000.0f; - for (i = 0; i < 16; i++) { - if (dist[i] < mdist) { - mdist = dist[i]; - row = i; - } + for (i = 0; i < 16; i++) { + if (dist[i] < mdist) { + mdist = dist[i]; + row = i; } + } - bits[0] = row & 1; - bits[1] = (row >> 1) & 1; - bits[2] = (row >> 2) & 1; - bits[3] = (row >> 3) & 1; + bits[0] = row & 1; + bits[1] = (row >> 1) & 1; + bits[2] = (row >> 2) & 1; + bits[3] = (row >> 3) & 1; } /* @@ -185,472 +160,485 @@ void qam16_demod(complex float symbol, int *bits) { * default values of the original OFDM modem. */ struct OFDM *ofdm_create(const struct OFDM_CONFIG *config) { - struct OFDM *ofdm; - float tval; - int i, j; - - ofdm = (struct OFDM *) CALLOC(1, sizeof (struct OFDM)); - assert(ofdm != NULL); - - if (config == NULL) { - /* Fill in default values */ - - strcpy(ofdm->mode, "700D"); - ofdm->nc = 17; /* Number of carriers */ - ofdm->np = 1; - ofdm->ns = 8; /* Number of Symbols per modem frame */ - ofdm->ts = 0.018f; - ofdm->rs = (1.0f / ofdm->ts); /* Modulation Symbol Rate */ - ofdm->tcp = .002f; /* Cyclic Prefix duration */ - ofdm->tx_centre = 1500.0f; /* TX Carrier Frequency */ - ofdm->rx_centre = 1500.0f; /* RX Carrier Frequency */ - ofdm->fs = 8000.0f; /* Sample rate */ - ofdm->ntxtbits = 4; - ofdm->bps = 2; /* Bits per Symbol */ - ofdm->nuwbits = 5 * ofdm->bps; /* default is 5 symbols of Unique Word bits */ - ofdm->bad_uw_errors = 3; - ofdm->ftwindowwidth = 32; - ofdm->timing_mx_thresh = 0.30f; - ofdm->state_machine = "voice1"; - ofdm->edge_pilots = 1; - ofdm->codename = "HRA_112_112"; - ofdm->amp_est_mode = 0; - ofdm->tx_bpf_en = true; - ofdm->rx_bpf_en = false; - ofdm->amp_scale = 245E3; - ofdm->clip_gain1 = 2.0; - ofdm->clip_gain2 = 0.9; - ofdm->clip_en = false; - ofdm->foff_limiter = false; - ofdm->data_mode = ""; - ofdm->fmin = -50.0; /* frequency minimum for ofdm acquisition range */ - ofdm->fmax = 50.0; /* frequency maximum for ofdm acquisition range */ - memset(ofdm->tx_uw, 0, ofdm->nuwbits); - } else { - /* Use the users values */ - - - strcpy(ofdm->mode, config->mode); - ofdm->nc = config->nc; /* Number of carriers */ - ofdm->np = config->np; /* Number of modem Frames per Packet */ - ofdm->ns = config->ns; /* Number of Symbol frames */ - ofdm->bps = config->bps; /* Bits per Symbol */ - ofdm->ts = config->ts; - ofdm->tcp = config->tcp; /* Cyclic Prefix duration */ - ofdm->tx_centre = config->tx_centre; /* TX Centre Audio Frequency */ - ofdm->rx_centre = config->rx_centre; /* RX Centre Audio Frequency */ - ofdm->fs = config->fs; /* Sample Frequency */ - ofdm->rs = config->rs; /* Symbol Rate */ - ofdm->ntxtbits = config->txtbits; - ofdm->nuwbits = config->nuwbits; - ofdm->bad_uw_errors = config->bad_uw_errors; - ofdm->ftwindowwidth = config->ftwindowwidth; - ofdm->timing_mx_thresh = config->timing_mx_thresh; - ofdm->state_machine = config->state_machine; - ofdm->edge_pilots = config->edge_pilots; - ofdm->codename = config->codename; - ofdm->amp_est_mode = config->amp_est_mode; - ofdm->tx_bpf_en = config->tx_bpf_en; - ofdm->rx_bpf_en = config->rx_bpf_en; - ofdm->foff_limiter = config->foff_limiter; - ofdm->amp_scale = config->amp_scale; - ofdm->clip_gain1 = config->clip_gain1; - ofdm->clip_gain2 = config->clip_gain2; - ofdm->clip_en = config->clip_en; - memcpy(ofdm->tx_uw, config->tx_uw, ofdm->nuwbits); - ofdm->data_mode = config->data_mode; - ofdm->fmin = config->fmin; /* frequency minimum for ofdm acquisition range */ - ofdm->fmax = config->fmax; /* frequency maximum for ofdm acquisition range */ - - } - - ofdm->rs = (1.0f / ofdm->ts); /* Modulation Symbol Rate */ - ofdm->m = (int) (ofdm->fs / ofdm->rs); /* 700D: 144 */ - ofdm->ncp = (int) (ofdm->tcp * ofdm->fs); /* 700D: 16 */ - ofdm->inv_m = (1.0f / (float) ofdm->m); - - /* basic sanity checks */ - assert((int)floorf(ofdm->fs / ofdm->rs) == ofdm->m); - assert(!strcmp(ofdm->state_machine, "voice1") || - !strcmp(ofdm->state_machine, "data") || - !strcmp(ofdm->state_machine, "voice2")); - assert(ofdm->nuwbits <= MAX_UW_BITS); - - /* Copy constants into states */ - - strcpy(ofdm->config.mode, ofdm->mode); - ofdm->config.tx_centre = ofdm->tx_centre; - ofdm->config.rx_centre = ofdm->rx_centre; - ofdm->config.fs = ofdm->fs; - ofdm->config.rs = ofdm->rs; - ofdm->config.ts = ofdm->ts; - ofdm->config.tcp = ofdm->tcp; - ofdm->config.timing_mx_thresh = ofdm->timing_mx_thresh; - ofdm->config.nc = ofdm->nc; - ofdm->config.ns = ofdm->ns; - ofdm->config.np = ofdm->np; - ofdm->config.bps = ofdm->bps; - ofdm->config.nuwbits = ofdm->nuwbits; - ofdm->config.txtbits = ofdm->ntxtbits; - ofdm->config.bad_uw_errors = ofdm->bad_uw_errors; - ofdm->config.ftwindowwidth = ofdm->ftwindowwidth; - ofdm->config.state_machine = ofdm->state_machine; - ofdm->config.edge_pilots = ofdm->edge_pilots; - ofdm->config.codename = ofdm->codename; - ofdm->config.amp_est_mode = ofdm->amp_est_mode; - ofdm->config.tx_bpf_en = ofdm->tx_bpf_en; - ofdm->config.rx_bpf_en = ofdm->rx_bpf_en; - ofdm->config.foff_limiter = ofdm->foff_limiter; - ofdm->config.amp_scale = ofdm->amp_scale; - ofdm->config.clip_gain1 = ofdm->clip_gain1; - ofdm->config.clip_gain2 = ofdm->clip_gain2; - ofdm->config.clip_en = ofdm->clip_en; - memcpy(ofdm->config.tx_uw, ofdm->tx_uw, ofdm->nuwbits); - ofdm->config.data_mode = ofdm->data_mode; - ofdm->config.fmin = ofdm->fmin; - ofdm->config.fmax = ofdm->fmax; - - - /* Calculate sizes from config param */ - - ofdm->bitsperframe = (ofdm->ns - 1) * (ofdm->nc * ofdm->bps); // 238 for nc = 17 - ofdm->bitsperpacket = ofdm->np * ofdm->bitsperframe; - ofdm->tpacket = (float)(ofdm->np * ofdm->ns) * (ofdm->tcp + ofdm->ts); /* time for one packet */ - ofdm->rowsperframe = ofdm->bitsperframe / (ofdm->nc * ofdm->bps); - ofdm->samplespersymbol = (ofdm->m + ofdm->ncp); - ofdm->samplesperframe = ofdm->ns * ofdm->samplespersymbol; - if (*ofdm->data_mode != 0) - // in burst data modes we skip ahead one frame to jump over preamble - ofdm->max_samplesperframe = 2*ofdm->samplesperframe; - else - ofdm->max_samplesperframe = ofdm->samplesperframe + (ofdm->samplespersymbol / 4); - /* extra storage at start of rxbuf to allow us to step back in time */ - if (strlen(ofdm->data_mode)) - ofdm->nrxbufhistory = (ofdm->np+2)*ofdm->samplesperframe; - else - ofdm->nrxbufhistory = 0; - ofdm->rxbufst = ofdm->nrxbufhistory; - ofdm->nrxbufmin = 3*ofdm->samplesperframe + 3*ofdm->samplespersymbol; - ofdm->nrxbuf = ofdm->nrxbufhistory + ofdm->nrxbufmin; - - ofdm->pilot_samples = (complex float *) MALLOC(sizeof (complex float) * ofdm->samplespersymbol); - assert(ofdm->pilot_samples != NULL); - - ofdm->rxbuf = (complex float *) MALLOC(sizeof (complex float) * ofdm->nrxbuf); - assert(ofdm->rxbuf != NULL); - for(int i=0; i<ofdm->nrxbuf; i++) ofdm->rxbuf[i] = 0; - - ofdm->pilots = (complex float *) MALLOC(sizeof (complex float) * (ofdm->nc + 2)); - assert(ofdm->pilots != NULL); - - /* - * rx_sym is a 2D array of variable size - * - * allocate rx_sym row storage. It is a pointer to a pointer - */ - ofdm->rx_sym = MALLOC(sizeof (complex float) * (ofdm->ns + 3)); - assert(ofdm->rx_sym != NULL); - - /* allocate rx_sym column storage */ - - for (i = 0; i < (ofdm->ns + 3); i++) { - ofdm->rx_sym[i] = (complex float *) MALLOC(sizeof(complex float) * (ofdm->nc + 2)); - assert(ofdm->rx_sym[i] != NULL); - } - - /* The rest of these are 1D arrays of variable size */ - - ofdm->rx_np = MALLOC(sizeof (complex float) * (ofdm->rowsperframe * ofdm->nc)); - assert(ofdm->rx_np != NULL); - - ofdm->rx_amp = MALLOC(sizeof (float) * (ofdm->rowsperframe * ofdm->nc)); - assert(ofdm->rx_amp != NULL); - - ofdm->aphase_est_pilot_log = MALLOC(sizeof (float) * (ofdm->rowsperframe * ofdm->nc)); - assert(ofdm->aphase_est_pilot_log != NULL); - - /* store complex BPSK pilot symbols */ - - assert(sizeof (pilotvalues) >= (ofdm->nc + 2) * sizeof (int8_t)); - - /* There are only 64 pilot values available */ - - for (i = 0; i < (ofdm->nc + 2); i++) { - ofdm->pilots[i] = ((float) pilotvalues[i]) + 0.0f * I; - } - if (ofdm->edge_pilots == 0) { - ofdm->pilots[0] = ofdm->pilots[ofdm->nc + 1] = 0.0f; - } - /* carrier tables for up and down conversion */ - - ofdm->doc = (TAU / (ofdm->fs / ofdm->rs)); - tval = ((float) ofdm->nc / 2.0f); - ofdm->tx_nlower = roundf((ofdm->tx_centre / ofdm->rs) - tval) - 1.0f; - ofdm->rx_nlower = roundf((ofdm->rx_centre / ofdm->rs) - tval) - 1.0f; - - /* Tx and Rx band pass filters */ - ofdm->tx_bpf = NULL; - if (ofdm->tx_bpf_en) - allocate_tx_bpf(ofdm); - ofdm->rx_bpf = NULL; - if (ofdm->rx_bpf_en) - allocate_rx_bpf(ofdm); - - for (i = 0; i < ofdm->nrxbuf; i++) { - ofdm->rxbuf[i] = 0.0f; - } - - for (i = 0; i < (ofdm->ns + 3); i++) { - for (j = 0; j < (ofdm->nc + 2); j++) { - ofdm->rx_sym[i][j] = 0.0f; - } - } - - for (i = 0; i < ofdm->rowsperframe * ofdm->nc; i++) { - ofdm->rx_np[i] = 0.0f; - } - - for (i = 0; i < ofdm->rowsperframe; i++) { - for (j = 0; j < ofdm->nc; j++) { - ofdm->aphase_est_pilot_log[ofdm->nc * i + j] = 0.0f; - ofdm->rx_amp[ofdm->nc * i + j] = 0.0f; - } - } - - /* default settings of options and states */ - - ofdm->verbose = 0; - ofdm->timing_en = true; - ofdm->foff_est_en = true; - ofdm->phase_est_en = true; - ofdm->phase_est_bandwidth = high_bw; - ofdm->phase_est_bandwidth_mode = AUTO_PHASE_EST; - ofdm->packetsperburst = 0; // default: never lose syn in raw data mode - - ofdm->coarse_foff_est_hz = 0.0f; - ofdm->foff_est_gain = 0.1f; - ofdm->foff_est_hz = 0.0f; - ofdm->sample_point = 0; - ofdm->timing_est = 0; - ofdm->timing_valid = 0; - ofdm->timing_mx = 0.0f; - ofdm->nin = ofdm->samplesperframe; - ofdm->mean_amp = 0.0f; - ofdm->foff_metric = 0.0f; - - ofdm->fmin = -50.0f; - ofdm->fmax = 50.0f; - - /* - * Unique Word symbol placement. Note we need to group the UW - * bits so they fit into symbols. The LDPC decoder works on - * symbols so we can't break up any symbols into UW/payload bits. - */ - ofdm->uw_ind = MALLOC(sizeof (int) * ofdm->nuwbits); - assert(ofdm->uw_ind != NULL); - - ofdm->uw_ind_sym = MALLOC(sizeof (int) * (ofdm->nuwbits / ofdm->bps)); - assert(ofdm->uw_ind_sym != NULL); + struct OFDM *ofdm; + float tval; + int i, j; + + ofdm = (struct OFDM *)CALLOC(1, sizeof(struct OFDM)); + assert(ofdm != NULL); + + if (config == NULL) { + /* Fill in default values */ + + strcpy(ofdm->mode, "700D"); + ofdm->nc = 17; /* Number of carriers */ + ofdm->np = 1; + ofdm->ns = 8; /* Number of Symbols per modem frame */ + ofdm->ts = 0.018f; + ofdm->rs = (1.0f / ofdm->ts); /* Modulation Symbol Rate */ + ofdm->tcp = .002f; /* Cyclic Prefix duration */ + ofdm->tx_centre = 1500.0f; /* TX Carrier Frequency */ + ofdm->rx_centre = 1500.0f; /* RX Carrier Frequency */ + ofdm->fs = 8000.0f; /* Sample rate */ + ofdm->ntxtbits = 4; + ofdm->bps = 2; /* Bits per Symbol */ + ofdm->nuwbits = + 5 * ofdm->bps; /* default is 5 symbols of Unique Word bits */ + ofdm->bad_uw_errors = 3; + ofdm->ftwindowwidth = 32; + ofdm->timing_mx_thresh = 0.30f; + ofdm->state_machine = "voice1"; + ofdm->edge_pilots = 1; + ofdm->codename = "HRA_112_112"; + ofdm->amp_est_mode = 0; + ofdm->tx_bpf_en = true; + ofdm->rx_bpf_en = false; + ofdm->amp_scale = 245E3; + ofdm->clip_gain1 = 2.0; + ofdm->clip_gain2 = 0.9; + ofdm->clip_en = false; + ofdm->foff_limiter = false; + ofdm->data_mode = ""; + ofdm->fmin = -50.0; /* frequency minimum for ofdm acquisition range */ + ofdm->fmax = 50.0; /* frequency maximum for ofdm acquisition range */ + memset(ofdm->tx_uw, 0, ofdm->nuwbits); + } else { + /* Use the users values */ + + strcpy(ofdm->mode, config->mode); + ofdm->nc = config->nc; /* Number of carriers */ + ofdm->np = config->np; /* Number of modem Frames per Packet */ + ofdm->ns = config->ns; /* Number of Symbol frames */ + ofdm->bps = config->bps; /* Bits per Symbol */ + ofdm->ts = config->ts; + ofdm->tcp = config->tcp; /* Cyclic Prefix duration */ + ofdm->tx_centre = config->tx_centre; /* TX Centre Audio Frequency */ + ofdm->rx_centre = config->rx_centre; /* RX Centre Audio Frequency */ + ofdm->fs = config->fs; /* Sample Frequency */ + ofdm->rs = config->rs; /* Symbol Rate */ + ofdm->ntxtbits = config->txtbits; + ofdm->nuwbits = config->nuwbits; + ofdm->bad_uw_errors = config->bad_uw_errors; + ofdm->ftwindowwidth = config->ftwindowwidth; + ofdm->timing_mx_thresh = config->timing_mx_thresh; + ofdm->state_machine = config->state_machine; + ofdm->edge_pilots = config->edge_pilots; + ofdm->codename = config->codename; + ofdm->amp_est_mode = config->amp_est_mode; + ofdm->tx_bpf_en = config->tx_bpf_en; + ofdm->rx_bpf_en = config->rx_bpf_en; + ofdm->foff_limiter = config->foff_limiter; + ofdm->amp_scale = config->amp_scale; + ofdm->clip_gain1 = config->clip_gain1; + ofdm->clip_gain2 = config->clip_gain2; + ofdm->clip_en = config->clip_en; + memcpy(ofdm->tx_uw, config->tx_uw, ofdm->nuwbits); + ofdm->data_mode = config->data_mode; + ofdm->fmin = + config->fmin; /* frequency minimum for ofdm acquisition range */ + ofdm->fmax = + config->fmax; /* frequency maximum for ofdm acquisition range */ + } + + ofdm->rs = (1.0f / ofdm->ts); /* Modulation Symbol Rate */ + ofdm->m = (int)(ofdm->fs / ofdm->rs); /* 700D: 144 */ + ofdm->ncp = (int)(ofdm->tcp * ofdm->fs); /* 700D: 16 */ + ofdm->inv_m = (1.0f / (float)ofdm->m); + + /* basic sanity checks */ + assert((int)floorf(ofdm->fs / ofdm->rs) == ofdm->m); + assert(!strcmp(ofdm->state_machine, "voice1") || + !strcmp(ofdm->state_machine, "data") || + !strcmp(ofdm->state_machine, "voice2")); + assert(ofdm->nuwbits <= MAX_UW_BITS); + + /* Copy constants into states */ + + strcpy(ofdm->config.mode, ofdm->mode); + ofdm->config.tx_centre = ofdm->tx_centre; + ofdm->config.rx_centre = ofdm->rx_centre; + ofdm->config.fs = ofdm->fs; + ofdm->config.rs = ofdm->rs; + ofdm->config.ts = ofdm->ts; + ofdm->config.tcp = ofdm->tcp; + ofdm->config.timing_mx_thresh = ofdm->timing_mx_thresh; + ofdm->config.nc = ofdm->nc; + ofdm->config.ns = ofdm->ns; + ofdm->config.np = ofdm->np; + ofdm->config.bps = ofdm->bps; + ofdm->config.nuwbits = ofdm->nuwbits; + ofdm->config.txtbits = ofdm->ntxtbits; + ofdm->config.bad_uw_errors = ofdm->bad_uw_errors; + ofdm->config.ftwindowwidth = ofdm->ftwindowwidth; + ofdm->config.state_machine = ofdm->state_machine; + ofdm->config.edge_pilots = ofdm->edge_pilots; + ofdm->config.codename = ofdm->codename; + ofdm->config.amp_est_mode = ofdm->amp_est_mode; + ofdm->config.tx_bpf_en = ofdm->tx_bpf_en; + ofdm->config.rx_bpf_en = ofdm->rx_bpf_en; + ofdm->config.foff_limiter = ofdm->foff_limiter; + ofdm->config.amp_scale = ofdm->amp_scale; + ofdm->config.clip_gain1 = ofdm->clip_gain1; + ofdm->config.clip_gain2 = ofdm->clip_gain2; + ofdm->config.clip_en = ofdm->clip_en; + memcpy(ofdm->config.tx_uw, ofdm->tx_uw, ofdm->nuwbits); + ofdm->config.data_mode = ofdm->data_mode; + ofdm->config.fmin = ofdm->fmin; + ofdm->config.fmax = ofdm->fmax; + + /* Calculate sizes from config param */ + + ofdm->bitsperframe = + (ofdm->ns - 1) * (ofdm->nc * ofdm->bps); // 238 for nc = 17 + ofdm->bitsperpacket = ofdm->np * ofdm->bitsperframe; + ofdm->tpacket = (float)(ofdm->np * ofdm->ns) * + (ofdm->tcp + ofdm->ts); /* time for one packet */ + ofdm->rowsperframe = ofdm->bitsperframe / (ofdm->nc * ofdm->bps); + ofdm->samplespersymbol = (ofdm->m + ofdm->ncp); + ofdm->samplesperframe = ofdm->ns * ofdm->samplespersymbol; + if (*ofdm->data_mode != 0) + // in burst data modes we skip ahead one frame to jump over preamble + ofdm->max_samplesperframe = 2 * ofdm->samplesperframe; + else + ofdm->max_samplesperframe = + ofdm->samplesperframe + (ofdm->samplespersymbol / 4); + /* extra storage at start of rxbuf to allow us to step back in time */ + if (strlen(ofdm->data_mode)) + ofdm->nrxbufhistory = (ofdm->np + 2) * ofdm->samplesperframe; + else + ofdm->nrxbufhistory = 0; + ofdm->rxbufst = ofdm->nrxbufhistory; + ofdm->nrxbufmin = 3 * ofdm->samplesperframe + 3 * ofdm->samplespersymbol; + ofdm->nrxbuf = ofdm->nrxbufhistory + ofdm->nrxbufmin; + + ofdm->pilot_samples = + (complex float *)MALLOC(sizeof(complex float) * ofdm->samplespersymbol); + assert(ofdm->pilot_samples != NULL); + + ofdm->rxbuf = (complex float *)MALLOC(sizeof(complex float) * ofdm->nrxbuf); + assert(ofdm->rxbuf != NULL); + for (int i = 0; i < ofdm->nrxbuf; i++) ofdm->rxbuf[i] = 0; + + ofdm->pilots = + (complex float *)MALLOC(sizeof(complex float) * (ofdm->nc + 2)); + assert(ofdm->pilots != NULL); + + /* + * rx_sym is a 2D array of variable size + * + * allocate rx_sym row storage. It is a pointer to a pointer + */ + ofdm->rx_sym = MALLOC(sizeof(complex float) * (ofdm->ns + 3)); + assert(ofdm->rx_sym != NULL); + + /* allocate rx_sym column storage */ + + for (i = 0; i < (ofdm->ns + 3); i++) { + ofdm->rx_sym[i] = + (complex float *)MALLOC(sizeof(complex float) * (ofdm->nc + 2)); + assert(ofdm->rx_sym[i] != NULL); + } + + /* The rest of these are 1D arrays of variable size */ + + ofdm->rx_np = MALLOC(sizeof(complex float) * (ofdm->rowsperframe * ofdm->nc)); + assert(ofdm->rx_np != NULL); + + ofdm->rx_amp = MALLOC(sizeof(float) * (ofdm->rowsperframe * ofdm->nc)); + assert(ofdm->rx_amp != NULL); + + ofdm->aphase_est_pilot_log = + MALLOC(sizeof(float) * (ofdm->rowsperframe * ofdm->nc)); + assert(ofdm->aphase_est_pilot_log != NULL); + + /* store complex BPSK pilot symbols */ + + assert(sizeof(pilotvalues) >= (ofdm->nc + 2) * sizeof(int8_t)); + + /* There are only 64 pilot values available */ + + for (i = 0; i < (ofdm->nc + 2); i++) { + ofdm->pilots[i] = ((float)pilotvalues[i]) + 0.0f * I; + } + if (ofdm->edge_pilots == 0) { + ofdm->pilots[0] = ofdm->pilots[ofdm->nc + 1] = 0.0f; + } + /* carrier tables for up and down conversion */ + + ofdm->doc = (TAU / (ofdm->fs / ofdm->rs)); + tval = ((float)ofdm->nc / 2.0f); + ofdm->tx_nlower = roundf((ofdm->tx_centre / ofdm->rs) - tval) - 1.0f; + ofdm->rx_nlower = roundf((ofdm->rx_centre / ofdm->rs) - tval) - 1.0f; + + /* Tx and Rx band pass filters */ + ofdm->tx_bpf = NULL; + if (ofdm->tx_bpf_en) allocate_tx_bpf(ofdm); + ofdm->rx_bpf = NULL; + if (ofdm->rx_bpf_en) allocate_rx_bpf(ofdm); + + for (i = 0; i < ofdm->nrxbuf; i++) { + ofdm->rxbuf[i] = 0.0f; + } + + for (i = 0; i < (ofdm->ns + 3); i++) { + for (j = 0; j < (ofdm->nc + 2); j++) { + ofdm->rx_sym[i][j] = 0.0f; + } + } + + for (i = 0; i < ofdm->rowsperframe * ofdm->nc; i++) { + ofdm->rx_np[i] = 0.0f; + } + + for (i = 0; i < ofdm->rowsperframe; i++) { + for (j = 0; j < ofdm->nc; j++) { + ofdm->aphase_est_pilot_log[ofdm->nc * i + j] = 0.0f; + ofdm->rx_amp[ofdm->nc * i + j] = 0.0f; + } + } + + /* default settings of options and states */ + + ofdm->verbose = 0; + ofdm->timing_en = true; + ofdm->foff_est_en = true; + ofdm->phase_est_en = true; + ofdm->phase_est_bandwidth = high_bw; + ofdm->phase_est_bandwidth_mode = AUTO_PHASE_EST; + ofdm->packetsperburst = 0; // default: never lose syn in raw data mode + + ofdm->coarse_foff_est_hz = 0.0f; + ofdm->foff_est_gain = 0.1f; + ofdm->foff_est_hz = 0.0f; + ofdm->sample_point = 0; + ofdm->timing_est = 0; + ofdm->timing_valid = 0; + ofdm->timing_mx = 0.0f; + ofdm->nin = ofdm->samplesperframe; + ofdm->mean_amp = 0.0f; + ofdm->foff_metric = 0.0f; + + ofdm->fmin = -50.0f; + ofdm->fmax = 50.0f; + + /* + * Unique Word symbol placement. Note we need to group the UW + * bits so they fit into symbols. The LDPC decoder works on + * symbols so we can't break up any symbols into UW/payload bits. + */ + ofdm->uw_ind = MALLOC(sizeof(int) * ofdm->nuwbits); + assert(ofdm->uw_ind != NULL); + + ofdm->uw_ind_sym = MALLOC(sizeof(int) * (ofdm->nuwbits / ofdm->bps)); + assert(ofdm->uw_ind_sym != NULL); + + /* + * The Unique Word is placed in different indexes based on + * the number of carriers requested. + */ + int nuwsyms = ofdm->nuwbits / ofdm->bps; + int Ndatasymsperframe = (ofdm->ns - 1) * ofdm->nc; + int uw_step = ofdm->nc + 1; // default step size + int last_sym = floorf(nuwsyms * uw_step / ofdm->bps); + if (last_sym >= ofdm->np * Ndatasymsperframe) + uw_step = ofdm->nc - 1; // try a different step + last_sym = floorf(nuwsyms * uw_step / ofdm->bps); + assert(last_sym < + ofdm->np * Ndatasymsperframe); // bail if we still can't fit them all + + for (i = 0, j = 0; i < nuwsyms; i++, j += ofdm->bps) { + int val = floorf((i + 1) * uw_step / ofdm->bps); + + ofdm->uw_ind_sym[i] = val; // symbol index + + for (int b = 0; b < ofdm->bps; b++) { + ofdm->uw_ind[j + b] = (val * ofdm->bps) + b; + } + } + + // work out how many frames UW is spread over + int symsperframe = ofdm->bitsperframe / ofdm->bps; + ofdm->nuwframes = + (int)ceilf((float)(ofdm->uw_ind_sym[nuwsyms - 1] + 1) / symsperframe); + + ofdm->tx_uw_syms = + MALLOC(sizeof(complex float) * (ofdm->nuwbits / ofdm->bps)); + assert(ofdm->tx_uw_syms != NULL); + + assert(ofdm->bps == 2); // TODO generalise + for (int s = 0; s < (ofdm->nuwbits / ofdm->bps); s++) { + int dibit[2]; + dibit[1] = ofdm->tx_uw[2 * s]; + dibit[0] = ofdm->tx_uw[2 * s + 1]; + ofdm->tx_uw_syms[s] = qpsk_mod(dibit); + } - /* - * The Unique Word is placed in different indexes based on - * the number of carriers requested. - */ - int nuwsyms = ofdm->nuwbits / ofdm->bps; - int Ndatasymsperframe = (ofdm->ns-1)*ofdm->nc; - int uw_step = ofdm->nc + 1; // default step size - int last_sym = floorf(nuwsyms*uw_step/ofdm->bps); - if (last_sym >= ofdm->np*Ndatasymsperframe) - uw_step = ofdm->nc - 1; // try a different step - last_sym = floorf(nuwsyms*uw_step/ofdm->bps); - assert(last_sym < ofdm->np*Ndatasymsperframe);// bail if we still can't fit them all - - for (i = 0, j = 0; i < nuwsyms; i++, j += ofdm->bps) { - int val = floorf((i + 1) * uw_step / ofdm->bps); - - ofdm->uw_ind_sym[i] = val; // symbol index - - for (int b = 0; b < ofdm->bps ; b++) { - ofdm->uw_ind[j + b] = (val * ofdm->bps) + b; - } - } + /* sync state machine */ - // work out how many frames UW is spread over - int symsperframe = ofdm->bitsperframe / ofdm->bps; - ofdm->nuwframes = (int) ceilf((float)(ofdm->uw_ind_sym[nuwsyms-1]+1)/symsperframe); - - ofdm->tx_uw_syms = MALLOC(sizeof (complex float) * (ofdm->nuwbits / ofdm->bps)); - assert(ofdm->tx_uw_syms != NULL); - - assert(ofdm->bps == 2); // TODO generalise - for (int s = 0; s < (ofdm->nuwbits / ofdm->bps); s++) { - int dibit[2]; - dibit[1] = ofdm->tx_uw[2*s]; - dibit[0] = ofdm->tx_uw[2*s+1]; - ofdm->tx_uw_syms[s] = qpsk_mod(dibit); - } + ofdm->sync_state = search; + ofdm->last_sync_state = search; - /* sync state machine */ + ofdm->uw_errors = 0; + ofdm->sync_counter = 0; + ofdm->frame_count = 0; + ofdm->sync_start = false; + ofdm->sync_end = false; + ofdm->sync_mode = autosync; + ofdm->modem_frame = 0; - ofdm->sync_state = search; - ofdm->last_sync_state = search; + /* create the OFDM pilot time-domain waveform */ - ofdm->uw_errors = 0; - ofdm->sync_counter = 0; - ofdm->frame_count = 0; - ofdm->sync_start = false; - ofdm->sync_end = false; - ofdm->sync_mode = autosync; - ofdm->modem_frame = 0; + complex float *temp = MALLOC(sizeof(complex float) * ofdm->m); + assert(temp != NULL); - /* create the OFDM pilot time-domain waveform */ + idft(ofdm, temp, ofdm->pilots); - complex float *temp = MALLOC(sizeof (complex float) * ofdm->m); - assert(temp != NULL); + /* + * pilot_samples is 160 samples, but timing and freq offset est + * were found by experiment to work better without a cyclic + * prefix, so we uses zeroes instead. + */ - idft(ofdm, temp, ofdm->pilots); + /* zero out Cyclic Prefix (CP) time-domain values */ - /* - * pilot_samples is 160 samples, but timing and freq offset est - * were found by experiment to work better without a cyclic - * prefix, so we uses zeroes instead. - */ + for (i = 0; i < ofdm->ncp; i++) { + ofdm->pilot_samples[i] = 0.0f; + } - /* zero out Cyclic Prefix (CP) time-domain values */ + /* Now copy the whole thing after the above */ - for (i = 0; i < ofdm->ncp; i++) { - ofdm->pilot_samples[i] = 0.0f; - } + for (i = ofdm->ncp, j = 0; j < ofdm->m; i++, j++) { + ofdm->pilot_samples[i] = temp[j]; + } - /* Now copy the whole thing after the above */ + FREE(temp); - for (i = ofdm->ncp, j = 0; j < ofdm->m; i++, j++) { - ofdm->pilot_samples[i] = temp[j]; - } + /* calculate constant used to normalise timing correlation maximum */ + float acc = 0.0f; + for (i = 0; i < ofdm->samplespersymbol; i++) { + acc += cnormf(ofdm->pilot_samples[i]); + } - FREE(temp); + ofdm->timing_norm = ofdm->samplespersymbol * acc; + ofdm->clock_offset_counter = 0; + ofdm->dpsk_en = false; - /* calculate constant used to normalise timing correlation maximum */ - float acc = 0.0f; - for (i = 0; i < ofdm->samplespersymbol; i++) { - acc += cnormf(ofdm->pilot_samples[i]); - } + if (strlen(ofdm->data_mode)) { + ofdm->tx_preamble = (COMP *)malloc(sizeof(COMP) * ofdm->samplesperframe); + assert(ofdm->tx_preamble != NULL); + ofdm_generate_preamble(ofdm, ofdm->tx_preamble, 2); + ofdm->tx_postamble = (COMP *)malloc(sizeof(COMP) * ofdm->samplesperframe); + assert(ofdm->tx_postamble != NULL); + ofdm_generate_preamble(ofdm, ofdm->tx_postamble, 3); + } + ofdm->postambledetectoren = !strcmp(ofdm->data_mode, "burst"); - ofdm->timing_norm = ofdm->samplespersymbol * acc; - ofdm->clock_offset_counter = 0; - ofdm->dpsk_en = false; - - if (strlen(ofdm->data_mode)) { - ofdm->tx_preamble = (COMP*)malloc(sizeof(COMP)*ofdm->samplesperframe); - assert(ofdm->tx_preamble != NULL); - ofdm_generate_preamble(ofdm, ofdm->tx_preamble, 2); - ofdm->tx_postamble = (COMP*)malloc(sizeof(COMP)*ofdm->samplesperframe); - assert(ofdm->tx_postamble != NULL); - ofdm_generate_preamble(ofdm, ofdm->tx_postamble, 3); - } - ofdm->postambledetectoren = !strcmp(ofdm->data_mode,"burst"); - - return ofdm; /* Success */ + return ofdm; /* Success */ } static void allocate_tx_bpf(struct OFDM *ofdm) { - ofdm->tx_bpf = MALLOC(sizeof(struct quisk_cfFilter)); - assert(ofdm->tx_bpf != NULL); - - /* Transmit bandpass filter; complex coefficients, center frequency */ - - if (!strcmp(ofdm->mode, "700D")) { - quisk_filt_cfInit(ofdm->tx_bpf, filtP650S900, sizeof (filtP650S900) / sizeof (float)); - quisk_cfTune(ofdm->tx_bpf, ofdm->tx_centre / ofdm->fs); - } - else if (!strcmp(ofdm->mode, "700E") || !strcmp(ofdm->mode, "2020") || !strcmp(ofdm->mode, "datac1")) { - quisk_filt_cfInit(ofdm->tx_bpf, filtP900S1100, sizeof (filtP900S1100) / sizeof (float)); - quisk_cfTune(ofdm->tx_bpf, ofdm->tx_centre / ofdm->fs); - } - else if (!strcmp(ofdm->mode, "2020B") || !strcmp(ofdm->mode, "2020C")) { - quisk_filt_cfInit(ofdm->tx_bpf, filtP1100S1300, sizeof (filtP1100S1300) / sizeof (float)); - quisk_cfTune(ofdm->tx_bpf, ofdm->tx_centre / ofdm->fs); - } - else if (!strcmp(ofdm->mode, "datac0") || !strcmp(ofdm->mode, "datac3")) { - quisk_filt_cfInit(ofdm->tx_bpf, filtP400S600, sizeof (filtP400S600) / sizeof (float)); - quisk_cfTune(ofdm->tx_bpf, ofdm->tx_centre / ofdm->fs); - } - else if (!strcmp(ofdm->mode, "datac4") || !strcmp(ofdm->mode, "datac13")) { - quisk_filt_cfInit(ofdm->tx_bpf, filtP200S400, sizeof (filtP200S400) / sizeof (float)); - // centre the filter on the mean carrier freq, allows a narrower filter to be used - float tx_centre = find_carrier_centre(ofdm); - quisk_cfTune(ofdm->tx_bpf, tx_centre / ofdm->fs); - } - else assert(0); + ofdm->tx_bpf = MALLOC(sizeof(struct quisk_cfFilter)); + assert(ofdm->tx_bpf != NULL); + + /* Transmit bandpass filter; complex coefficients, center frequency */ + + if (!strcmp(ofdm->mode, "700D")) { + quisk_filt_cfInit(ofdm->tx_bpf, filtP650S900, + sizeof(filtP650S900) / sizeof(float)); + quisk_cfTune(ofdm->tx_bpf, ofdm->tx_centre / ofdm->fs); + } else if (!strcmp(ofdm->mode, "700E") || !strcmp(ofdm->mode, "2020") || + !strcmp(ofdm->mode, "datac1")) { + quisk_filt_cfInit(ofdm->tx_bpf, filtP900S1100, + sizeof(filtP900S1100) / sizeof(float)); + quisk_cfTune(ofdm->tx_bpf, ofdm->tx_centre / ofdm->fs); + } else if (!strcmp(ofdm->mode, "2020B") || !strcmp(ofdm->mode, "2020C")) { + quisk_filt_cfInit(ofdm->tx_bpf, filtP1100S1300, + sizeof(filtP1100S1300) / sizeof(float)); + quisk_cfTune(ofdm->tx_bpf, ofdm->tx_centre / ofdm->fs); + } else if (!strcmp(ofdm->mode, "datac0") || !strcmp(ofdm->mode, "datac3")) { + quisk_filt_cfInit(ofdm->tx_bpf, filtP400S600, + sizeof(filtP400S600) / sizeof(float)); + quisk_cfTune(ofdm->tx_bpf, ofdm->tx_centre / ofdm->fs); + } else if (!strcmp(ofdm->mode, "datac4") || !strcmp(ofdm->mode, "datac13")) { + quisk_filt_cfInit(ofdm->tx_bpf, filtP200S400, + sizeof(filtP200S400) / sizeof(float)); + // centre the filter on the mean carrier freq, allows a narrower filter to + // be used + float tx_centre = find_carrier_centre(ofdm); + quisk_cfTune(ofdm->tx_bpf, tx_centre / ofdm->fs); + } else + assert(0); } static void deallocate_tx_bpf(struct OFDM *ofdm) { - assert(ofdm->tx_bpf != NULL); - quisk_filt_destroy(ofdm->tx_bpf); - FREE(ofdm->tx_bpf); - ofdm->tx_bpf = NULL; + assert(ofdm->tx_bpf != NULL); + quisk_filt_destroy(ofdm->tx_bpf); + FREE(ofdm->tx_bpf); + ofdm->tx_bpf = NULL; } static float find_carrier_centre(struct OFDM *ofdm) { - float rx_centre = 0.0; - for(int c=0; c<ofdm->nc+2; c++) - rx_centre += (ofdm->rx_nlower + c) * ofdm->doc; - return (ofdm->fs/TAU)*rx_centre/(ofdm->nc+2); + float rx_centre = 0.0; + for (int c = 0; c < ofdm->nc + 2; c++) + rx_centre += (ofdm->rx_nlower + c) * ofdm->doc; + return (ofdm->fs / TAU) * rx_centre / (ofdm->nc + 2); } static void allocate_rx_bpf(struct OFDM *ofdm) { - ofdm->rx_bpf = MALLOC(sizeof(struct quisk_cfFilter)); - assert(ofdm->rx_bpf != NULL); - - /* Receive bandpass filter; complex coefficients, center frequency */ - - if (!strcmp(ofdm->mode, "datac4") || !strcmp(ofdm->mode, "datac13")) { - quisk_filt_cfInit(ofdm->rx_bpf, filtP200S400, sizeof (filtP200S400) / sizeof (float)); - // centre the filter on the mean carrier freq, allows a narrower filter to be used - float rx_centre = find_carrier_centre(ofdm); - //fprintf(stderr, " rx_centre: %f\n", rx_centre); - quisk_cfTune(ofdm->rx_bpf, rx_centre / ofdm->fs); - } - else assert(0); + ofdm->rx_bpf = MALLOC(sizeof(struct quisk_cfFilter)); + assert(ofdm->rx_bpf != NULL); + + /* Receive bandpass filter; complex coefficients, center frequency */ + + if (!strcmp(ofdm->mode, "datac4") || !strcmp(ofdm->mode, "datac13")) { + quisk_filt_cfInit(ofdm->rx_bpf, filtP200S400, + sizeof(filtP200S400) / sizeof(float)); + // centre the filter on the mean carrier freq, allows a narrower filter to + // be used + float rx_centre = find_carrier_centre(ofdm); + // fprintf(stderr, " rx_centre: %f\n", rx_centre); + quisk_cfTune(ofdm->rx_bpf, rx_centre / ofdm->fs); + } else + assert(0); } static void deallocate_rx_bpf(struct OFDM *ofdm) { - assert(ofdm->rx_bpf != NULL); - quisk_filt_destroy(ofdm->rx_bpf); - FREE(ofdm->rx_bpf); - ofdm->rx_bpf = NULL; + assert(ofdm->rx_bpf != NULL); + quisk_filt_destroy(ofdm->rx_bpf); + FREE(ofdm->rx_bpf); + ofdm->rx_bpf = NULL; } void ofdm_destroy(struct OFDM *ofdm) { - int i; - - if (strlen(ofdm->data_mode)) { - free(ofdm->tx_preamble); - free(ofdm->tx_postamble); - } - if (ofdm->tx_bpf) { - deallocate_tx_bpf(ofdm); - } - if (ofdm->rx_bpf) { - deallocate_rx_bpf(ofdm); - } - - FREE(ofdm->pilot_samples); - FREE(ofdm->rxbuf); - FREE(ofdm->pilots); - - for (i = 0; i < (ofdm->ns + 3); i++) { /* 2D array */ - FREE(ofdm->rx_sym[i]); - } - - FREE(ofdm->rx_sym); - FREE(ofdm->rx_np); - FREE(ofdm->rx_amp); - FREE(ofdm->aphase_est_pilot_log); - FREE(ofdm->tx_uw_syms); - FREE(ofdm->uw_ind); - FREE(ofdm->uw_ind_sym); - FREE(ofdm); + int i; + + if (strlen(ofdm->data_mode)) { + free(ofdm->tx_preamble); + free(ofdm->tx_postamble); + } + if (ofdm->tx_bpf) { + deallocate_tx_bpf(ofdm); + } + if (ofdm->rx_bpf) { + deallocate_rx_bpf(ofdm); + } + + FREE(ofdm->pilot_samples); + FREE(ofdm->rxbuf); + FREE(ofdm->pilots); + + for (i = 0; i < (ofdm->ns + 3); i++) { /* 2D array */ + FREE(ofdm->rx_sym[i]); + } + + FREE(ofdm->rx_sym); + FREE(ofdm->rx_np); + FREE(ofdm->rx_amp); + FREE(ofdm->aphase_est_pilot_log); + FREE(ofdm->tx_uw_syms); + FREE(ofdm->uw_ind); + FREE(ofdm->uw_ind_sym); + FREE(ofdm); } /* @@ -658,30 +646,31 @@ void ofdm_destroy(struct OFDM *ofdm) { * * This algorithm was optimized for speed */ -static void idft(struct OFDM *ofdm, complex float *result, complex float *vector) { - int row, col; +static void idft(struct OFDM *ofdm, complex float *result, + complex float *vector) { + int row, col; - result[0] = 0.0f; + result[0] = 0.0f; - for (col = 0; col < (ofdm->nc + 2); col++) { - result[0] += vector[col]; // cexp(j0) == 1 - } - - result[0] *= ofdm->inv_m; + for (col = 0; col < (ofdm->nc + 2); col++) { + result[0] += vector[col]; // cexp(j0) == 1 + } - for (row = 1; row < ofdm->m; row++) { - complex float c = cmplx(ofdm->tx_nlower * ofdm->doc *row); - complex float delta = cmplx(ofdm->doc * row); + result[0] *= ofdm->inv_m; - result[row] = 0.0f; + for (row = 1; row < ofdm->m; row++) { + complex float c = cmplx(ofdm->tx_nlower * ofdm->doc * row); + complex float delta = cmplx(ofdm->doc * row); - for (col = 0; col < (ofdm->nc + 2); col++) { - result[row] += (vector[col] * c); - c *= delta; - } + result[row] = 0.0f; - result[row] *= ofdm->inv_m; + for (col = 0; col < (ofdm->nc + 2); col++) { + result[row] += (vector[col] * c); + c *= delta; } + + result[row] *= ofdm->inv_m; + } } /* @@ -689,48 +678,48 @@ static void idft(struct OFDM *ofdm, complex float *result, complex float *vector * * This algorithm was optimized for speed */ -static void dft(struct OFDM *ofdm, complex float *result, complex float *vector) { - int row, col; +static void dft(struct OFDM *ofdm, complex float *result, + complex float *vector) { + int row, col; - for (col = 0; col < (ofdm->nc + 2); col++) { - result[col] = vector[0]; // conj(cexp(j0)) == 1 - } + for (col = 0; col < (ofdm->nc + 2); col++) { + result[col] = vector[0]; // conj(cexp(j0)) == 1 + } - for (col = 0; col < (ofdm->nc + 2); col++) { - float tval = (ofdm->rx_nlower + col) * ofdm->doc; - complex float c = cmplxconj(tval); - complex float delta = c; + for (col = 0; col < (ofdm->nc + 2); col++) { + float tval = (ofdm->rx_nlower + col) * ofdm->doc; + complex float c = cmplxconj(tval); + complex float delta = c; - for (row = 1; row < ofdm->m; row++) { - result[col] += (vector[row] * c); - c *= delta; - } + for (row = 1; row < ofdm->m; row++) { + result[col] += (vector[row] * c); + c *= delta; } + } } static complex float vector_sum(complex float *a, int num_elements) { - complex float sum = 0.0f; - int i; + complex float sum = 0.0f; + int i; - for (i = 0; i < num_elements; i++) { - sum += a[i]; - } + for (i = 0; i < num_elements; i++) { + sum += a[i]; + } - return sum; + return sum; } /* Determine if we can use vector ops below. Only for non-embedded platforms as double can be significantly slower on those. */ #ifndef __EMBEDDED__ -#if __GNUC__ > 4 || \ - (__GNUC__ == 4 && (__GNUC_MINOR__ > 6 || \ - (__GNUC_MINOR__ == 6 && \ - __GNUC_PATCHLEVEL__ > 0))) +#if __GNUC__ > 4 || \ + (__GNUC__ == 4 && \ + (__GNUC_MINOR__ > 6 || (__GNUC_MINOR__ == 6 && __GNUC_PATCHLEVEL__ > 0))) #define USE_VECTOR_OPS 1 #elif __clang_major__ > 3 || \ - (__clang_minor__ == 3 && (__clang_minor__ > 7 || \ - (__clang_minor__ == 7 && \ - __clang_patchlevel__ > 0))) + (__clang_minor__ == 3 && \ + (__clang_minor__ > 7 || \ + (__clang_minor__ == 7 && __clang_patchlevel__ > 0))) #define USE_VECTOR_OPS 1 #endif #else @@ -738,68 +727,67 @@ static complex float vector_sum(complex float *a, int num_elements) { #endif /* __EMBEDDED__ */ #if USE_VECTOR_OPS -typedef float float4 __attribute__ ((vector_size (16))); +typedef float float4 __attribute__((vector_size(16))); #endif /* USE_VECTOR_OPS */ -static complex float ofdm_complex_dot_product(complex float *left, complex float *right, int numSamples) -{ - complex float result = 0; +static complex float ofdm_complex_dot_product(complex float *left, + complex float *right, + int numSamples) { + complex float result = 0; #if USE_VECTOR_OPS - float *leftPtr = (float*)left; - float *rightPtr = (float*)right; - float4 accumPos = { 0, 0, 0, 0 }; - float4 accumNeg = { 0, 0, 0, 0 }; - float4 accumImag = { 0, 0, 0, 0 }; - float resultReal = 0; - float resultImag = 0; - int numBlocks = numSamples >> 1; - for (int i = 0; i < numBlocks; i++) - { - /* Lay out vectors as follows: - vec1 = rx[0].a, rx[0].b, rx[1].a, rx[1].b, ... - vec2 = mvec[0].c, mvec[0].d, mvec[1].c, mvec1[1].d, ... */ - float4 vec1 = { leftPtr[0], leftPtr[1], leftPtr[2], leftPtr[3] }; - float4 vec2 = { rightPtr[0], rightPtr[1], rightPtr[2], rightPtr[3] }; - - accumPos += vec1 * vec2; - accumNeg -= vec1 * vec2; - - /* Lay out vec3 as { rx[0].b, rx[0].a, rx[1].b, rx[0].b, ... }. - Multiply vec3 by vec2 to get us bc, ad, bc, ad - and add to second accumulator. */ - float4 vec3 = { leftPtr[1], leftPtr[0], leftPtr[3], leftPtr[2] }; - accumImag += vec3 * vec2; - - /* Shift pointers forward by 4 (2 complex floats). */ - leftPtr += 4; rightPtr += 4; - } - - /* dot product: (a + bi)(c + di) = (ac - bd) + i(bc + ad) */ - resultReal = accumPos[0] + accumNeg[1] + accumPos[2] + accumNeg[3]; - resultImag = accumImag[0] + accumImag[1] + accumImag[2] + accumImag[3]; - result = resultReal + I * resultImag; - - /* Add remaining values to corr that couldn't be vectorized above. */ - for (int i = numBlocks << 1; i < numSamples; i++) - { - result += left[i] * right[i]; - } + float *leftPtr = (float *)left; + float *rightPtr = (float *)right; + float4 accumPos = {0, 0, 0, 0}; + float4 accumNeg = {0, 0, 0, 0}; + float4 accumImag = {0, 0, 0, 0}; + float resultReal = 0; + float resultImag = 0; + int numBlocks = numSamples >> 1; + for (int i = 0; i < numBlocks; i++) { + /* Lay out vectors as follows: + vec1 = rx[0].a, rx[0].b, rx[1].a, rx[1].b, ... + vec2 = mvec[0].c, mvec[0].d, mvec[1].c, mvec1[1].d, ... */ + float4 vec1 = {leftPtr[0], leftPtr[1], leftPtr[2], leftPtr[3]}; + float4 vec2 = {rightPtr[0], rightPtr[1], rightPtr[2], rightPtr[3]}; + + accumPos += vec1 * vec2; + accumNeg -= vec1 * vec2; + + /* Lay out vec3 as { rx[0].b, rx[0].a, rx[1].b, rx[0].b, ... }. + Multiply vec3 by vec2 to get us bc, ad, bc, ad + and add to second accumulator. */ + float4 vec3 = {leftPtr[1], leftPtr[0], leftPtr[3], leftPtr[2]}; + accumImag += vec3 * vec2; + + /* Shift pointers forward by 4 (2 complex floats). */ + leftPtr += 4; + rightPtr += 4; + } + + /* dot product: (a + bi)(c + di) = (ac - bd) + i(bc + ad) */ + resultReal = accumPos[0] + accumNeg[1] + accumPos[2] + accumNeg[3]; + resultImag = accumImag[0] + accumImag[1] + accumImag[2] + accumImag[3]; + result = resultReal + I * resultImag; + + /* Add remaining values to corr that couldn't be vectorized above. */ + for (int i = numBlocks << 1; i < numSamples; i++) { + result += left[i] * right[i]; + } #elif __EMBEDDED__ - float resultReal = 0, resultImag = 0; - codec2_complex_dot_product_f32((COMP*)left, (COMP*)right, numSamples, &resultReal, &resultImag); - result = resultReal + I * resultImag; + float resultReal = 0, resultImag = 0; + codec2_complex_dot_product_f32((COMP *)left, (COMP *)right, numSamples, + &resultReal, &resultImag); + result = resultReal + I * resultImag; #else - for (int i = 0; i < numSamples; i++) - { - result += left[i] * right[i]; - } + for (int i = 0; i < numSamples; i++) { + result += left[i] * right[i]; + } #endif /* USE_VECTOR_OPS */ - return result; + return result; } - /* * Correlates the OFDM pilot symbol samples with a window of received * samples to determine the most likely timing offset. Combines two @@ -811,120 +799,134 @@ static complex float ofdm_complex_dot_product(complex float *left, complex float * +/- 25 Hz for 700D). */ static int est_timing(struct OFDM *ofdm, complex float *rx, int length, - int fcoarse, float *timing_mx, int *timing_valid, int step) { - complex float corr_st, corr_en; - int Ncorr = length - (ofdm->samplesperframe + ofdm->samplespersymbol); - float corr[Ncorr]; - int i, j; - float acc = 0.0f; - - for (i = 0; i < length; i++) { - acc += cnormf(rx[i]); - } + int fcoarse, float *timing_mx, int *timing_valid, + int step) { + complex float corr_st, corr_en; + int Ncorr = length - (ofdm->samplesperframe + ofdm->samplespersymbol); + float corr[Ncorr]; + int i, j; + float acc = 0.0f; - float av_level = 1.0f/(2.0f * sqrtf(ofdm->timing_norm * acc / length) + 1E-12f); + for (i = 0; i < length; i++) { + acc += cnormf(rx[i]); + } - /* precompute the freq shift multiplied by pilot samples outside of main loop */ + float av_level = + 1.0f / (2.0f * sqrtf(ofdm->timing_norm * acc / length) + 1E-12f); - PROFILE_VAR(wvecpilot); - PROFILE_SAMPLE(wvecpilot); + /* precompute the freq shift multiplied by pilot samples outside of main loop + */ - complex float wvec_pilot[ofdm->samplespersymbol]; + PROFILE_VAR(wvecpilot); + PROFILE_SAMPLE(wvecpilot); - switch(fcoarse) { + complex float wvec_pilot[ofdm->samplespersymbol]; + + switch (fcoarse) { case -40: for (j = 0; j < ofdm->samplespersymbol; j++) - wvec_pilot[j] = conjf(ofdm_wval[j]*ofdm->pilot_samples[j]); + wvec_pilot[j] = conjf(ofdm_wval[j] * ofdm->pilot_samples[j]); break; case 0: for (j = 0; j < ofdm->samplespersymbol; j++) - wvec_pilot[j] = conjf(ofdm->pilot_samples[j]); + wvec_pilot[j] = conjf(ofdm->pilot_samples[j]); break; case 40: for (j = 0; j < ofdm->samplespersymbol; j++) - wvec_pilot[j] = ofdm_wval[j]*conjf(ofdm->pilot_samples[j]); + wvec_pilot[j] = ofdm_wval[j] * conjf(ofdm->pilot_samples[j]); break; default: assert(0); - } + } - /* use of __REAL__ provides a speed in increase of 10ms/frame during acquisition, however complex - is fast enough for real time operation */ + /* use of __REAL__ provides a speed in increase of 10ms/frame during + acquisition, however complex is fast enough for real time operation */ #if defined(__EMBEDDED__) && defined(__REAL__) - float rx_real[length]; - float wvec_pilot_real[ofdm->samplespersymbol]; - float wvec_pilot_imag[ofdm->samplespersymbol]; + float rx_real[length]; + float wvec_pilot_real[ofdm->samplespersymbol]; + float wvec_pilot_imag[ofdm->samplespersymbol]; - for (i = 0; i < length; i++) { - rx_real[i] = crealf(rx[i]); - } + for (i = 0; i < length; i++) { + rx_real[i] = crealf(rx[i]); + } - for (i = 0; i < ofdm->samplespersymbol; i++) { - wvec_pilot_real[i] = crealf(wvec_pilot[i]); - wvec_pilot_imag[i] = cimagf(wvec_pilot[i]); - } + for (i = 0; i < ofdm->samplespersymbol; i++) { + wvec_pilot_real[i] = crealf(wvec_pilot[i]); + wvec_pilot_imag[i] = cimagf(wvec_pilot[i]); + } #endif - PROFILE_SAMPLE_AND_LOG2(wvecpilot, " wvecpilot"); - PROFILE_VAR(corr_start); - PROFILE_SAMPLE(corr_start); + PROFILE_SAMPLE_AND_LOG2(wvecpilot, " wvecpilot"); + PROFILE_VAR(corr_start); + PROFILE_SAMPLE(corr_start); - for (i = 0; i < Ncorr; i += step) { - corr_st = 0.0f; - corr_en = 0.0f; + for (i = 0; i < Ncorr; i += step) { + corr_st = 0.0f; + corr_en = 0.0f; #ifdef __EMBEDDED__ #ifdef __REAL__ - float re,im; - - codec2_dot_product_f32(&rx_real[i], wvec_pilot_real, ofdm->samplespersymbol, &re); - codec2_dot_product_f32(&rx_real[i], wvec_pilot_imag, ofdm->samplespersymbol, &im); - corr_st = re + im * I; - - codec2_dot_product_f32(&rx_real[i+ ofdm->samplesperframe], wvec_pilot_real, ofdm->samplespersymbol, &re); - codec2_dot_product_f32(&rx_real[i+ ofdm->samplesperframe], wvec_pilot_imag, ofdm->samplespersymbol, &im); - corr_en = re + im * I; - + float re, im; + + codec2_dot_product_f32(&rx_real[i], wvec_pilot_real, ofdm->samplespersymbol, + &re); + codec2_dot_product_f32(&rx_real[i], wvec_pilot_imag, ofdm->samplespersymbol, + &im); + corr_st = re + im * I; + + codec2_dot_product_f32(&rx_real[i + ofdm->samplesperframe], wvec_pilot_real, + ofdm->samplespersymbol, &re); + codec2_dot_product_f32(&rx_real[i + ofdm->samplesperframe], wvec_pilot_imag, + ofdm->samplespersymbol, &im); + corr_en = re + im * I; + #else - float re,im; - - codec2_complex_dot_product_f32((COMP*)&rx[i], (COMP*)wvec_pilot, ofdm->samplespersymbol, &re, &im); - corr_st = re + im * I; + float re, im; + + codec2_complex_dot_product_f32((COMP *)&rx[i], (COMP *)wvec_pilot, + ofdm->samplespersymbol, &re, &im); + corr_st = re + im * I; - codec2_complex_dot_product_f32((COMP*)&rx[i+ ofdm->samplesperframe], (COMP*)wvec_pilot, ofdm->samplespersymbol, &re, &im); - corr_en = re + im * I; + codec2_complex_dot_product_f32((COMP *)&rx[i + ofdm->samplesperframe], + (COMP *)wvec_pilot, ofdm->samplespersymbol, + &re, &im); + corr_en = re + im * I; #endif #else - corr_st = ofdm_complex_dot_product(&rx[i], wvec_pilot, ofdm->samplespersymbol); - corr_en = ofdm_complex_dot_product(&rx[i + ofdm->samplesperframe], wvec_pilot, ofdm->samplespersymbol); -#endif // __EMBEDDED__ - corr[i] = (cabsf(corr_st) + cabsf(corr_en)) * av_level; - } + corr_st = + ofdm_complex_dot_product(&rx[i], wvec_pilot, ofdm->samplespersymbol); + corr_en = ofdm_complex_dot_product(&rx[i + ofdm->samplesperframe], + wvec_pilot, ofdm->samplespersymbol); +#endif // __EMBEDDED__ + corr[i] = (cabsf(corr_st) + cabsf(corr_en)) * av_level; + } - PROFILE_SAMPLE_AND_LOG2(corr_start, " corr"); + PROFILE_SAMPLE_AND_LOG2(corr_start, " corr"); - /* find the max magnitude and its index */ + /* find the max magnitude and its index */ - int timing_est = 0; - *timing_mx = 0.0f; + int timing_est = 0; + *timing_mx = 0.0f; - for (i = 0; i < Ncorr; i+=step) { - if (corr[i] > *timing_mx) { - *timing_mx = corr[i]; - timing_est = i; - } + for (i = 0; i < Ncorr; i += step) { + if (corr[i] > *timing_mx) { + *timing_mx = corr[i]; + timing_est = i; } + } - // only declare timing valid if there are enough samples in rxbuf to demodulate a frame - *timing_valid = (cabsf(rx[timing_est]) > 0.0) && (*timing_mx > ofdm->timing_mx_thresh); + // only declare timing valid if there are enough samples in rxbuf to + // demodulate a frame + *timing_valid = + (cabsf(rx[timing_est]) > 0.0) && (*timing_mx > ofdm->timing_mx_thresh); - if (ofdm->verbose > 2) { - fprintf(stderr, " av_level: %f max: %f timing_est: %d timing_valid: %d\n", (double) av_level, - (double) *timing_mx, timing_est, *timing_valid); - } + if (ofdm->verbose > 2) { + fprintf(stderr, " av_level: %f max: %f timing_est: %d timing_valid: %d\n", + (double)av_level, (double)*timing_mx, timing_est, *timing_valid); + } - return timing_est; + return timing_est; } /* @@ -932,18 +934,23 @@ static int est_timing(struct OFDM *ofdm, complex float *rx, int length, * coarse freq offset estimation during acquisition. Works up to +/- * the symbol rate, e.g. +/- 25Hz for the FreeDV 700D configuration. */ -static float est_freq_offset_pilot_corr(struct OFDM *ofdm, complex float *rx, int timing_est, int fcoarse) { - int st = -20; int en = 20; float foff_est = 0.0f; float Cabs_max = 0.0f; +static float est_freq_offset_pilot_corr(struct OFDM *ofdm, complex float *rx, + int timing_est, int fcoarse) { + int st = -20; + int en = 20; + float foff_est = 0.0f; + float Cabs_max = 0.0f; - /* precompute the freq shift multiplied by pilot samples outside of main loop */ + /* precompute the freq shift multiplied by pilot samples outside of main loop + */ - complex float wvec_pilot[ofdm->samplespersymbol]; - int j; + complex float wvec_pilot[ofdm->samplespersymbol]; + int j; - switch(fcoarse) { + switch (fcoarse) { case -40: for (j = 0; j < ofdm->samplespersymbol; j++) - wvec_pilot[j] = conjf(ofdm_wval[j]*ofdm->pilot_samples[j]); + wvec_pilot[j] = conjf(ofdm_wval[j] * ofdm->pilot_samples[j]); break; case 0: for (j = 0; j < ofdm->samplespersymbol; j++) @@ -951,218 +958,221 @@ static float est_freq_offset_pilot_corr(struct OFDM *ofdm, complex float *rx, in break; case 40: for (j = 0; j < ofdm->samplespersymbol; j++) - wvec_pilot[j] = ofdm_wval[j]*conjf(ofdm->pilot_samples[j]); + wvec_pilot[j] = ofdm_wval[j] * conjf(ofdm->pilot_samples[j]); break; default: assert(0); - } + } + + // sample sum of DFT magnitude of correlated signals at each freq offset and + // look for peak + for (int f = st; f < en; f++) { + complex float corr_st = 0.0f; + complex float corr_en = 0.0f; + float tmp = TAU * f / ofdm->fs; + complex float delta = cmplxconj(tmp); + complex float w = cmplxconj(0.0f); + int i; + + for (i = 0; i < ofdm->samplespersymbol; i++) { + // "mix" down (correlate) the pilot sequences from frame with 0 Hz offset + // pilot samples + complex float csam = wvec_pilot[i] * w; + int est = timing_est + i; - // sample sum of DFT magnitude of correlated signals at each freq offset and look for peak - for (int f = st; f < en; f++) { - complex float corr_st = 0.0f; - complex float corr_en = 0.0f; - float tmp = TAU * f / ofdm->fs; - complex float delta = cmplxconj(tmp); - complex float w = cmplxconj(0.0f); - int i; - - for (i = 0; i < ofdm->samplespersymbol; i++) { - // "mix" down (correlate) the pilot sequences from frame with 0 Hz offset pilot samples - complex float csam = wvec_pilot[i] * w; - int est = timing_est + i; - - corr_st += rx[est ] * csam; - corr_en += rx[est + ofdm->samplesperframe] * csam; - w = w * delta; - } - - float Cabs = cabsf(corr_st) + cabsf(corr_en); - - if (Cabs > Cabs_max) { - Cabs_max = Cabs; - foff_est = f; - } + corr_st += rx[est] * csam; + corr_en += rx[est + ofdm->samplesperframe] * csam; + w = w * delta; } - ofdm->foff_metric = 0.0f; // not used in this version of freq est algorithm + float Cabs = cabsf(corr_st) + cabsf(corr_en); - if (ofdm->verbose > 2) { - fprintf(stderr, "cabs_max: %f foff_est: %f\n", (double) Cabs_max, (double) foff_est); + if (Cabs > Cabs_max) { + Cabs_max = Cabs; + foff_est = f; } + } - return foff_est; -} + ofdm->foff_metric = 0.0f; // not used in this version of freq est algorithm + + if (ofdm->verbose > 2) { + fprintf(stderr, "cabs_max: %f foff_est: %f\n", (double)Cabs_max, + (double)foff_est); + } + return foff_est; +} /* * ---------------------------------------------- * ofdm_txframe - modulates one frame of symbols * ---------------------------------------------- */ -void ofdm_txframe(struct OFDM *ofdm, complex float *tx, complex float *tx_sym_lin) { - complex float aframe[ofdm->np * ofdm->ns][ofdm->nc + 2]; - complex float asymbol[ofdm->m]; - complex float asymbol_cp[ofdm->samplespersymbol]; - int i, j, k, m; - - /* initialize aframe to complex zero */ - - for (i = 0; i < (ofdm->np * ofdm->ns); i++) { - for (j = 0; j < (ofdm->nc + 2); j++) { - aframe[i][j] = 0.0f; - } - } - - /* - * Place symbols in multi-carrier frame with pilots - * This will place boundary values of complex zero around data - */ - int s = 0; - for (int r = 0; r < ofdm->np*ofdm->ns; r++) { - - if ((r % ofdm->ns) == 0) { - /* copy in a row of complex pilots to first row of each frame */ - for (i = 0; i < (ofdm->nc + 2); i++) { - aframe[r][i] = ofdm->pilots[i]; - } - } - else { - /* copy in the Nc complex data symbols with [0 Nc 0] or (Nc + 2) total */ - for (j = 1; j < (ofdm->nc + 1); j++) { - aframe[r][j] = tx_sym_lin[s++]; - if (ofdm->dpsk_en == true) { - aframe[r][j] *= aframe[r-1][j]; - } - } +void ofdm_txframe(struct OFDM *ofdm, complex float *tx, + complex float *tx_sym_lin) { + complex float aframe[ofdm->np * ofdm->ns][ofdm->nc + 2]; + complex float asymbol[ofdm->m]; + complex float asymbol_cp[ofdm->samplespersymbol]; + int i, j, k, m; + + /* initialize aframe to complex zero */ + + for (i = 0; i < (ofdm->np * ofdm->ns); i++) { + for (j = 0; j < (ofdm->nc + 2); j++) { + aframe[i][j] = 0.0f; + } + } + + /* + * Place symbols in multi-carrier frame with pilots + * This will place boundary values of complex zero around data + */ + int s = 0; + for (int r = 0; r < ofdm->np * ofdm->ns; r++) { + if ((r % ofdm->ns) == 0) { + /* copy in a row of complex pilots to first row of each frame */ + for (i = 0; i < (ofdm->nc + 2); i++) { + aframe[r][i] = ofdm->pilots[i]; + } + } else { + /* copy in the Nc complex data symbols with [0 Nc 0] or (Nc + 2) total */ + for (j = 1; j < (ofdm->nc + 1); j++) { + aframe[r][j] = tx_sym_lin[s++]; + if (ofdm->dpsk_en == true) { + aframe[r][j] *= aframe[r - 1][j]; } + } } + } - /* OFDM up-convert symbol by symbol so we can add CP */ + /* OFDM up-convert symbol by symbol so we can add CP */ - for (i = 0, m = 0; i < (ofdm->np * ofdm->ns); i++, m += ofdm->samplespersymbol) { - idft(ofdm, asymbol, aframe[i]); + for (i = 0, m = 0; i < (ofdm->np * ofdm->ns); + i++, m += ofdm->samplespersymbol) { + idft(ofdm, asymbol, aframe[i]); - /* Copy the last Ncp samples to the front */ + /* Copy the last Ncp samples to the front */ - for (j = (ofdm->m - ofdm->ncp), k = 0; j < ofdm->m; j++, k++) { - asymbol_cp[k] = asymbol[j]; - } + for (j = (ofdm->m - ofdm->ncp), k = 0; j < ofdm->m; j++, k++) { + asymbol_cp[k] = asymbol[j]; + } - /* Now copy the all samples for this row after it */ + /* Now copy the all samples for this row after it */ - for (j = ofdm->ncp, k = 0; k < ofdm->m; j++, k++) { - asymbol_cp[j] = asymbol[k]; - } + for (j = ofdm->ncp, k = 0; k < ofdm->m; j++, k++) { + asymbol_cp[j] = asymbol[k]; + } - /* Now move row to the tx output */ + /* Now move row to the tx output */ - for (j = 0; j < ofdm->samplespersymbol; j++) { - tx[m + j] = asymbol_cp[j]; - } + for (j = 0; j < ofdm->samplespersymbol; j++) { + tx[m + j] = asymbol_cp[j]; } + } - size_t samplesperpacket = ofdm->np*ofdm->samplesperframe; - ofdm_hilbert_clipper(ofdm, tx, samplesperpacket); + size_t samplesperpacket = ofdm->np * ofdm->samplesperframe; + ofdm_hilbert_clipper(ofdm, tx, samplesperpacket); } - -/* Scale Tx signal and optionally apply two stage Hilbert clipper to improve PAPR */ +/* Scale Tx signal and optionally apply two stage Hilbert clipper to improve + * PAPR */ void ofdm_hilbert_clipper(struct OFDM *ofdm, complex float *tx, size_t n) { + /* vanilla Tx output waveform should be about OFDM_PEAK */ + for (int i = 0; i < n; i++) tx[i] *= ofdm->amp_scale; - /* vanilla Tx output waveform should be about OFDM_PEAK */ - for(int i=0; i<n; i++) tx[i] *= ofdm->amp_scale; + if (ofdm->clip_en) { + // this gain sets the drive into the Hilbert Clipper and sets PAPR + for (int i = 0; i < n; i++) tx[i] *= ofdm->clip_gain1; + ofdm_clip(tx, OFDM_PEAK, n); + } - if (ofdm->clip_en) { - // this gain sets the drive into the Hilbert Clipper and sets PAPR - for(int i=0; i<n; i++) tx[i] *= ofdm->clip_gain1; - ofdm_clip(tx, OFDM_PEAK, n); - } + /* BPF to remove out of band energy clipper introduces */ + if (ofdm->tx_bpf_en) { + assert(ofdm->tx_bpf != NULL); + complex float tx_filt[n]; - /* BPF to remove out of band energy clipper introduces */ - if (ofdm->tx_bpf_en) { - assert(ofdm->tx_bpf != NULL); - complex float tx_filt[n]; + quisk_ccfFilter(tx, tx_filt, n, ofdm->tx_bpf); + memmove(tx, tx_filt, n * sizeof(complex float)); + } - quisk_ccfFilter(tx, tx_filt, n, ofdm->tx_bpf); - memmove(tx, tx_filt, n * sizeof (complex float)); - } + /* BPF messes up peak levels, this gain gets back to approx OFDM_PEAK */ + if (ofdm->tx_bpf_en && ofdm->clip_en) + for (int i = 0; i < n; i++) tx[i] *= ofdm->clip_gain2; - /* BPF messes up peak levels, this gain gets back to approx OFDM_PEAK */ - if (ofdm->tx_bpf_en && ofdm->clip_en) - for(int i=0; i<n; i++) tx[i] *= ofdm->clip_gain2; + /* a very small percentage of samples may still exceed OFDM_PEAK, in + clipped or unclipped mode. Lets remove them so we present consistent + levels to the transmitter */ - /* a very small percentage of samples may still exceed OFDM_PEAK, in - clipped or unclipped mode. Lets remove them so we present consistent - levels to the transmitter */ - - ofdm_clip(tx, OFDM_PEAK, n); + ofdm_clip(tx, OFDM_PEAK, n); } - -struct OFDM_CONFIG *ofdm_get_config_param(struct OFDM *ofdm) { return &ofdm->config; } -int ofdm_get_nin(struct OFDM *ofdm) {return ofdm->nin;} -int ofdm_get_samples_per_frame(struct OFDM *ofdm) { return ofdm->samplesperframe;} -int ofdm_get_samples_per_packet(struct OFDM *ofdm) { return ofdm->samplesperframe*ofdm->np;} -int ofdm_get_max_samples_per_frame(struct OFDM *ofdm) {return ofdm->max_samplesperframe; } -int ofdm_get_bits_per_frame(struct OFDM *ofdm) {return ofdm->bitsperframe; } -int ofdm_get_bits_per_packet(struct OFDM *ofdm) {return ofdm->bitsperpacket; } +struct OFDM_CONFIG *ofdm_get_config_param(struct OFDM *ofdm) { + return &ofdm->config; +} +int ofdm_get_nin(struct OFDM *ofdm) { return ofdm->nin; } +int ofdm_get_samples_per_frame(struct OFDM *ofdm) { + return ofdm->samplesperframe; +} +int ofdm_get_samples_per_packet(struct OFDM *ofdm) { + return ofdm->samplesperframe * ofdm->np; +} +int ofdm_get_max_samples_per_frame(struct OFDM *ofdm) { + return ofdm->max_samplesperframe; +} +int ofdm_get_bits_per_frame(struct OFDM *ofdm) { return ofdm->bitsperframe; } +int ofdm_get_bits_per_packet(struct OFDM *ofdm) { return ofdm->bitsperpacket; } void ofdm_set_verbose(struct OFDM *ofdm, int level) { ofdm->verbose = level; } void ofdm_set_timing_enable(struct OFDM *ofdm, bool val) { - ofdm->timing_en = val; + ofdm->timing_en = val; - if (ofdm->timing_en == false) { - /* manually set ideal timing instant */ + if (ofdm->timing_en == false) { + /* manually set ideal timing instant */ - ofdm->sample_point = (ofdm->ncp - 1); - } + ofdm->sample_point = (ofdm->ncp - 1); + } } int ofdm_get_phase_est_bandwidth_mode(struct OFDM *ofdm) { - return ofdm->phase_est_bandwidth_mode; /* int version of enum */ + return ofdm->phase_est_bandwidth_mode; /* int version of enum */ } void ofdm_set_phase_est_bandwidth_mode(struct OFDM *ofdm, int val) { - assert((val == AUTO_PHASE_EST) || (val == LOCKED_PHASE_EST)); - ofdm->phase_est_bandwidth_mode = val; + assert((val == AUTO_PHASE_EST) || (val == LOCKED_PHASE_EST)); + ofdm->phase_est_bandwidth_mode = val; } void ofdm_set_foff_est_enable(struct OFDM *ofdm, bool val) { - ofdm->foff_est_en = val; + ofdm->foff_est_en = val; } void ofdm_set_phase_est_enable(struct OFDM *ofdm, bool val) { - ofdm->phase_est_en = val; + ofdm->phase_est_en = val; } void ofdm_set_off_est_hz(struct OFDM *ofdm, float val) { - ofdm->foff_est_hz = val; + ofdm->foff_est_hz = val; } void ofdm_set_tx_bpf(struct OFDM *ofdm, bool val) { - if (val == true) { - if (ofdm->tx_bpf == NULL) - allocate_tx_bpf(ofdm); + if (val == true) { + if (ofdm->tx_bpf == NULL) allocate_tx_bpf(ofdm); - ofdm->tx_bpf_en = true; - } - else { - if (ofdm->tx_bpf != NULL) - deallocate_tx_bpf(ofdm); + ofdm->tx_bpf_en = true; + } else { + if (ofdm->tx_bpf != NULL) deallocate_tx_bpf(ofdm); - ofdm->tx_bpf_en = false; - } + ofdm->tx_bpf_en = false; + } } -void ofdm_set_dpsk(struct OFDM *ofdm, bool val) { - ofdm->dpsk_en = val; -} +void ofdm_set_dpsk(struct OFDM *ofdm, bool val) { ofdm->dpsk_en = val; } // select burst mode, and set packets per burst void ofdm_set_packets_per_burst(struct OFDM *ofdm, int packetsperburst) { - ofdm->data_mode = "burst"; - ofdm->packetsperburst = packetsperburst; - ofdm->postambledetectoren = true; + ofdm->data_mode = "burst"; + ofdm->packetsperburst = packetsperburst; + ofdm->postambledetectoren = true; } /* @@ -1171,35 +1181,37 @@ void ofdm_set_packets_per_burst(struct OFDM *ofdm, int packetsperburst) { * -------------------------------------- */ void ofdm_mod(struct OFDM *ofdm, COMP *result, const int *tx_bits) { - int length = ofdm->bitsperpacket / ofdm->bps; - complex float *tx = (complex float *) result; // complex has same memory layout - complex float tx_sym_lin[length]; - int dibit[2]; - int s, i; + int length = ofdm->bitsperpacket / ofdm->bps; + complex float *tx = + (complex float *)result; // complex has same memory layout + complex float tx_sym_lin[length]; + int dibit[2]; + int s, i; - if (ofdm->bps == 1) { - /* Here we will have Nbitsperpacket / 1 */ + if (ofdm->bps == 1) { + /* Here we will have Nbitsperpacket / 1 */ - for (s = 0; s < length; s++) { - tx_sym_lin[s] = (float) (2 * tx_bits[s] - 1); - } - } else if (ofdm->bps == 2) { - /* Here we will have Nbitsperpacket / 2 */ + for (s = 0; s < length; s++) { + tx_sym_lin[s] = (float)(2 * tx_bits[s] - 1); + } + } else if (ofdm->bps == 2) { + /* Here we will have Nbitsperpacket / 2 */ - for (s = 0, i = 0; i < length; s += 2, i++) { - dibit[0] = tx_bits[s + 1] & 0x1; - dibit[1] = tx_bits[s ] & 0x1; + for (s = 0, i = 0; i < length; s += 2, i++) { + dibit[0] = tx_bits[s + 1] & 0x1; + dibit[1] = tx_bits[s] & 0x1; - tx_sym_lin[i] = qpsk_mod(dibit); - } - } /* else if (ofdm->bps == 3) { } TODO */ + tx_sym_lin[i] = qpsk_mod(dibit); + } + } /* else if (ofdm->bps == 3) { } TODO */ - ofdm_txframe(ofdm, tx, tx_sym_lin); + ofdm_txframe(ofdm, tx, tx_sym_lin); } /* * ---------------------------------------------------------------------------------- - * ofdm_sync_search - attempts to find coarse sync parameters for modem initial sync + * ofdm_sync_search - attempts to find coarse sync parameters for modem initial + * sync * ---------------------------------------------------------------------------------- */ @@ -1208,18 +1220,18 @@ void ofdm_mod(struct OFDM *ofdm, COMP *result, const int *tx_bits) { * with an array of COMPs as input */ int ofdm_sync_search(struct OFDM *ofdm, COMP *rxbuf_in) { - /* - * insert latest input samples into rxbuf - * so it is primed for when we have to call ofdm_demod() - */ - - /* note can't use memcpy when src and dest overlap */ - memmove(&ofdm->rxbuf[0], &ofdm->rxbuf[ofdm->nin], - (ofdm->nrxbuf - ofdm->nin) * sizeof (complex float)); - memmove(&ofdm->rxbuf[(ofdm->nrxbuf - ofdm->nin)], - rxbuf_in, ofdm->nin * sizeof (complex float)); - - return(ofdm_sync_search_core(ofdm)); + /* + * insert latest input samples into rxbuf + * so it is primed for when we have to call ofdm_demod() + */ + + /* note can't use memcpy when src and dest overlap */ + memmove(&ofdm->rxbuf[0], &ofdm->rxbuf[ofdm->nin], + (ofdm->nrxbuf - ofdm->nin) * sizeof(complex float)); + memmove(&ofdm->rxbuf[(ofdm->nrxbuf - ofdm->nin)], rxbuf_in, + ofdm->nin * sizeof(complex float)); + + return (ofdm_sync_search_core(ofdm)); } /* @@ -1227,227 +1239,247 @@ int ofdm_sync_search(struct OFDM *ofdm, COMP *rxbuf_in) { * This works with ofdm_demod and freedv_api. Gain is not used here. */ int ofdm_sync_search_shorts(struct OFDM *ofdm, short *rxbuf_in, float gain) { - int i, j; + int i, j; - /* shift the buffer left based on nin */ + /* shift the buffer left based on nin */ - memmove(&ofdm->rxbuf[0], &ofdm->rxbuf[ofdm->nin], - (ofdm->nrxbuf - ofdm->nin) * sizeof (complex float)); + memmove(&ofdm->rxbuf[0], &ofdm->rxbuf[ofdm->nin], + (ofdm->nrxbuf - ofdm->nin) * sizeof(complex float)); - /* insert latest input samples onto tail of rxbuf */ + /* insert latest input samples onto tail of rxbuf */ - for (j = 0, i = (ofdm->nrxbuf - ofdm->nin); i < ofdm->nrxbuf; j++, i++) { - ofdm->rxbuf[i] = ((float)rxbuf_in[j] / 32767.0f); - } + for (j = 0, i = (ofdm->nrxbuf - ofdm->nin); i < ofdm->nrxbuf; j++, i++) { + ofdm->rxbuf[i] = ((float)rxbuf_in[j] / 32767.0f); + } - return ofdm_sync_search_core(ofdm); + return ofdm_sync_search_core(ofdm); } /* Joint estimation of timing and freq used for burst data acquisition */ -static float est_timing_and_freq(struct OFDM *ofdm, - int *t_est, float *foff_est, - complex float *rx, int Nrx, +static float est_timing_and_freq(struct OFDM *ofdm, int *t_est, float *foff_est, + complex float *rx, int Nrx, complex float *known_samples, int Npsam, - int tstep, float fmin, float fmax, float fstep) { - int Ncorr = Nrx - Npsam + 1; - float max_corr = 0; - *t_est = 0; *foff_est = 0.0; - for (float afcoarse=fmin; afcoarse<=fmax; afcoarse += fstep) { - float w = TAU * afcoarse / ofdm->fs; - complex float mvec[Npsam]; - for(int i=0; i<Npsam; i++) { - complex float ph = cmplx(w*i); - mvec[i] = conjf(known_samples[i]*ph); - } - for(int t=0; t<Ncorr; t+=tstep) { - complex float corr = ofdm_complex_dot_product(&rx[t], mvec, Npsam); - - if (cabsf(corr) > max_corr) { - max_corr = cabsf(corr); - *t_est = t; - *foff_est = afcoarse; - } - } - } - - /* obtain normalised real number for timing_mx */ - float mag1=0, mag2=0; - for(int i=0; i<Npsam; i++) { - mag1 += cabsf(known_samples[i]*conjf(known_samples[i])); - mag2 += cabsf(rx[i+*t_est]*conjf(rx[i+*t_est])); - } - float timing_mx = max_corr*max_corr/(mag1*mag2+1E-12); - if (ofdm->verbose > 2) { - fprintf(stderr, " t_est: %4d timing:mx: %f foff_est: %f\n", *t_est, (double)timing_mx, (double)*foff_est); - } - - return timing_mx; + int tstep, float fmin, float fmax, + float fstep) { + int Ncorr = Nrx - Npsam + 1; + float max_corr = 0; + *t_est = 0; + *foff_est = 0.0; + for (float afcoarse = fmin; afcoarse <= fmax; afcoarse += fstep) { + float w = TAU * afcoarse / ofdm->fs; + complex float mvec[Npsam]; + for (int i = 0; i < Npsam; i++) { + complex float ph = cmplx(w * i); + mvec[i] = conjf(known_samples[i] * ph); + } + for (int t = 0; t < Ncorr; t += tstep) { + complex float corr = ofdm_complex_dot_product(&rx[t], mvec, Npsam); + + if (cabsf(corr) > max_corr) { + max_corr = cabsf(corr); + *t_est = t; + *foff_est = afcoarse; + } + } + } + + /* obtain normalised real number for timing_mx */ + float mag1 = 0, mag2 = 0; + for (int i = 0; i < Npsam; i++) { + mag1 += cabsf(known_samples[i] * conjf(known_samples[i])); + mag2 += cabsf(rx[i + *t_est] * conjf(rx[i + *t_est])); + } + float timing_mx = max_corr * max_corr / (mag1 * mag2 + 1E-12); + if (ofdm->verbose > 2) { + fprintf(stderr, " t_est: %4d timing:mx: %f foff_est: %f\n", *t_est, + (double)timing_mx, (double)*foff_est); + } + + return timing_mx; } /* Two stage burst mode acquisition */ -static void burst_acquisition_detector(struct OFDM *ofdm, - complex float *rx, int n, - complex float *known_sequence, - int *ct_est, float *foff_est, float *timing_mx) -{ - - float fmin, fmax, fstep; - int tstep; - - // initial search over coarse grid - tstep = 4; fstep = 5; fmin = ofdm->fmin; fmax = ofdm->fmax; - *timing_mx = est_timing_and_freq(ofdm, ct_est, foff_est, - &rx[n], 2*ofdm->samplesperframe, - known_sequence, ofdm->samplesperframe, - tstep, fmin, fmax, fstep); - - // refine estimate over finer grid - fmin = *foff_est - ceilf(fstep/2.0); fmax = *foff_est + ceilf(fstep/2.0); - int fine_st = n + *ct_est - tstep/2.0; - *timing_mx = est_timing_and_freq(ofdm, ct_est, foff_est, - &rx[fine_st], ofdm->samplesperframe + tstep, - known_sequence, ofdm->samplesperframe, - 1, fmin, fmax, 1.0); - - // refer ct_est to nominal start of frame rx[n] - *ct_est += fine_st - n; +static void burst_acquisition_detector(struct OFDM *ofdm, complex float *rx, + int n, complex float *known_sequence, + int *ct_est, float *foff_est, + float *timing_mx) { + float fmin, fmax, fstep; + int tstep; + + // initial search over coarse grid + tstep = 4; + fstep = 5; + fmin = ofdm->fmin; + fmax = ofdm->fmax; + *timing_mx = est_timing_and_freq( + ofdm, ct_est, foff_est, &rx[n], 2 * ofdm->samplesperframe, known_sequence, + ofdm->samplesperframe, tstep, fmin, fmax, fstep); + + // refine estimate over finer grid + fmin = *foff_est - ceilf(fstep / 2.0); + fmax = *foff_est + ceilf(fstep / 2.0); + int fine_st = n + *ct_est - tstep / 2.0; + *timing_mx = est_timing_and_freq( + ofdm, ct_est, foff_est, &rx[fine_st], ofdm->samplesperframe + tstep, + known_sequence, ofdm->samplesperframe, 1, fmin, fmax, 1.0); + + // refer ct_est to nominal start of frame rx[n] + *ct_est += fine_st - n; } - + static int ofdm_sync_search_burst(struct OFDM *ofdm) { - - int st = ofdm->rxbufst + ofdm->m + ofdm->ncp + ofdm->samplesperframe; - char *pre_post = ""; - - int pre_ct_est; float pre_foff_est, pre_timing_mx; - burst_acquisition_detector(ofdm, ofdm->rxbuf, st, (complex float*)ofdm->tx_preamble, - &pre_ct_est, &pre_foff_est, &pre_timing_mx); - - int post_ct_est; float post_foff_est, post_timing_mx; - if (ofdm->postambledetectoren) - burst_acquisition_detector(ofdm, ofdm->rxbuf, st, (complex float*)ofdm->tx_postamble, - &post_ct_est, &post_foff_est, &post_timing_mx); - - int ct_est; float foff_est, timing_mx; - if (!ofdm->postambledetectoren || (pre_timing_mx > post_timing_mx)) { - timing_mx = pre_timing_mx; ct_est = pre_ct_est; foff_est = pre_foff_est; - pre_post = "pre"; + int st = ofdm->rxbufst + ofdm->m + ofdm->ncp + ofdm->samplesperframe; + char *pre_post = ""; + + int pre_ct_est; + float pre_foff_est, pre_timing_mx; + burst_acquisition_detector(ofdm, ofdm->rxbuf, st, + (complex float *)ofdm->tx_preamble, &pre_ct_est, + &pre_foff_est, &pre_timing_mx); + + int post_ct_est; + float post_foff_est, post_timing_mx; + if (ofdm->postambledetectoren) + burst_acquisition_detector(ofdm, ofdm->rxbuf, st, + (complex float *)ofdm->tx_postamble, + &post_ct_est, &post_foff_est, &post_timing_mx); + + int ct_est; + float foff_est, timing_mx; + if (!ofdm->postambledetectoren || (pre_timing_mx > post_timing_mx)) { + timing_mx = pre_timing_mx; + ct_est = pre_ct_est; + foff_est = pre_foff_est; + pre_post = "pre"; + } else { + timing_mx = post_timing_mx; + ct_est = post_ct_est; + foff_est = post_foff_est; + pre_post = "post"; + } + + int timing_valid = timing_mx > ofdm->timing_mx_thresh; + if (timing_valid) { + if (!strcmp(pre_post, "post")) { + ofdm->post++; + // we won't be need any new samples for a while .... + ofdm->nin = 0; + // backup to first modem frame in packet + ofdm->rxbufst -= ofdm->np * ofdm->samplesperframe; + ofdm->rxbufst += ct_est; } else { - timing_mx = post_timing_mx; ct_est = post_ct_est; foff_est = post_foff_est; - pre_post = "post"; + ofdm->pre++; + // ct_est is start of preamble, so advance past that to start of first + // modem frame + ofdm->nin = ofdm->samplesperframe + ct_est - 1; } - - int timing_valid = timing_mx > ofdm->timing_mx_thresh; - if (timing_valid) { - if (!strcmp(pre_post, "post")) { - ofdm->post++; - // we won't be need any new samples for a while .... - ofdm->nin = 0; - // backup to first modem frame in packet - ofdm->rxbufst -= ofdm->np*ofdm->samplesperframe; - ofdm->rxbufst += ct_est; - } else { - ofdm->pre++; - // ct_est is start of preamble, so advance past that to start of first modem frame - ofdm->nin = ofdm->samplesperframe + ct_est - 1; - } - } else - ofdm->nin = ofdm->samplesperframe; - - ofdm->ct_est = ct_est; - ofdm->foff_est_hz = foff_est; - ofdm->timing_mx = timing_mx; - ofdm->timing_valid = timing_valid; + } else + ofdm->nin = ofdm->samplesperframe; - if (ofdm->verbose > 1) { - fprintf(stderr, " ct_est: %4d nin: %4d mx: %3.2f foff_est: % 5.1f timing_valid: %d %4s\n", - ct_est, ofdm->nin, (double)timing_mx, (double)foff_est, timing_valid, pre_post); - } + ofdm->ct_est = ct_est; + ofdm->foff_est_hz = foff_est; + ofdm->timing_mx = timing_mx; + ofdm->timing_valid = timing_valid; + + if (ofdm->verbose > 1) { + fprintf(stderr, + " ct_est: %4d nin: %4d mx: %3.2f foff_est: % 5.1f timing_valid: " + "%d %4s\n", + ct_est, ofdm->nin, (double)timing_mx, (double)foff_est, + timing_valid, pre_post); + } - return ofdm->timing_valid; + return ofdm->timing_valid; } /* - * Attempts to find coarse sync parameters for modem initial sync (streaming mode) + * Attempts to find coarse sync parameters for modem initial sync (streaming + * mode) */ static int ofdm_sync_search_stream(struct OFDM *ofdm) { - int act_est, afcoarse; + int act_est, afcoarse; - /* Attempt coarse timing estimate (i.e. detect start of frame) at a range of frequency offsets */ + /* Attempt coarse timing estimate (i.e. detect start of frame) at a range of + * frequency offsets */ - int st = ofdm->rxbufst + ofdm->samplesperframe + ofdm->samplespersymbol; - int en = st + 2 * ofdm->samplesperframe + ofdm->samplespersymbol; + int st = ofdm->rxbufst + ofdm->samplesperframe + ofdm->samplespersymbol; + int en = st + 2 * ofdm->samplesperframe + ofdm->samplespersymbol; - int fcoarse = 0; - float atiming_mx, timing_mx = 0.0f; - int ct_est = 0; - int atiming_valid, timing_valid = 0; + int fcoarse = 0; + float atiming_mx, timing_mx = 0.0f; + int ct_est = 0; + int atiming_valid, timing_valid = 0; - PROFILE_VAR(timing_start); - PROFILE_SAMPLE(timing_start); + PROFILE_VAR(timing_start); + PROFILE_SAMPLE(timing_start); - for (afcoarse = -40; afcoarse <= 40; afcoarse += 40) { - act_est = est_timing(ofdm, &ofdm->rxbuf[st], (en - st), afcoarse, &atiming_mx, &atiming_valid, 2); + for (afcoarse = -40; afcoarse <= 40; afcoarse += 40) { + act_est = est_timing(ofdm, &ofdm->rxbuf[st], (en - st), afcoarse, + &atiming_mx, &atiming_valid, 2); - if (atiming_mx > timing_mx) { - ct_est = act_est; - timing_mx = atiming_mx; - fcoarse = afcoarse; - timing_valid = atiming_valid; - } + if (atiming_mx > timing_mx) { + ct_est = act_est; + timing_mx = atiming_mx; + fcoarse = afcoarse; + timing_valid = atiming_valid; } + } - PROFILE_SAMPLE_AND_LOG2(timing_start, " timing"); - - /* refine freq est within -/+ 20 Hz window */ + PROFILE_SAMPLE_AND_LOG2(timing_start, " timing"); - PROFILE_VAR(freq_start); - PROFILE_SAMPLE(freq_start); + /* refine freq est within -/+ 20 Hz window */ - ofdm->coarse_foff_est_hz = est_freq_offset_pilot_corr(ofdm, &ofdm->rxbuf[st], ct_est, fcoarse); - ofdm->coarse_foff_est_hz += fcoarse; + PROFILE_VAR(freq_start); + PROFILE_SAMPLE(freq_start); - PROFILE_SAMPLE_AND_LOG2(freq_start, " freq"); + ofdm->coarse_foff_est_hz = + est_freq_offset_pilot_corr(ofdm, &ofdm->rxbuf[st], ct_est, fcoarse); + ofdm->coarse_foff_est_hz += fcoarse; - if (ofdm->verbose > 1) { - fprintf(stderr, " ct_est: %4d foff_est: %4.1f timing_valid: %d timing_mx: %5.4f\n", - ct_est, (double) ofdm->coarse_foff_est_hz, timing_valid, - (double)timing_mx); - } + PROFILE_SAMPLE_AND_LOG2(freq_start, " freq"); - ofdm->timing_valid = timing_valid; - if (ofdm->timing_valid != 0) { - /* potential candidate found .... */ + if (ofdm->verbose > 1) { + fprintf( + stderr, + " ct_est: %4d foff_est: %4.1f timing_valid: %d timing_mx: %5.4f\n", + ct_est, (double)ofdm->coarse_foff_est_hz, timing_valid, + (double)timing_mx); + } - /* calculate number of samples we need on next buffer to get into sync */ + ofdm->timing_valid = timing_valid; + if (ofdm->timing_valid != 0) { + /* potential candidate found .... */ - ofdm->nin = ct_est; + /* calculate number of samples we need on next buffer to get into sync */ - /* reset modem states */ + ofdm->nin = ct_est; - ofdm->sample_point = ofdm->timing_est = 0; - ofdm->foff_est_hz = ofdm->coarse_foff_est_hz; - ofdm->timing_mx = timing_mx; - } else { - ofdm->nin = ofdm->samplesperframe; - } + /* reset modem states */ + ofdm->sample_point = ofdm->timing_est = 0; + ofdm->foff_est_hz = ofdm->coarse_foff_est_hz; ofdm->timing_mx = timing_mx; + } else { + ofdm->nin = ofdm->samplesperframe; + } - return ofdm->timing_valid; + ofdm->timing_mx = timing_mx; + + return ofdm->timing_valid; } static int ofdm_sync_search_core(struct OFDM *ofdm) { - if (ofdm->rx_bpf_en) { - assert(ofdm->rx_bpf != NULL); - complex float *rxbuf_in = &ofdm->rxbuf[(ofdm->nrxbuf - ofdm->nin)]; - quisk_ccfFilter(rxbuf_in, rxbuf_in, ofdm->nin, ofdm->rx_bpf); - } - if (!strcmp(ofdm->data_mode, "burst")) - return ofdm_sync_search_burst(ofdm); - else - return ofdm_sync_search_stream(ofdm); + if (ofdm->rx_bpf_en) { + assert(ofdm->rx_bpf != NULL); + complex float *rxbuf_in = &ofdm->rxbuf[(ofdm->nrxbuf - ofdm->nin)]; + quisk_ccfFilter(rxbuf_in, rxbuf_in, ofdm->nin, ofdm->rx_bpf); + } + if (!strcmp(ofdm->data_mode, "burst")) + return ofdm_sync_search_burst(ofdm); + else + return ofdm_sync_search_stream(ofdm); } /* @@ -1460,41 +1492,43 @@ static int ofdm_sync_search_core(struct OFDM *ofdm) { * This wrapper accepts an array of COMPs as input */ void ofdm_demod(struct OFDM *ofdm, int *rx_bits, COMP *rxbuf_in) { - complex float *rx = (complex float *) &rxbuf_in[0]; // complex has same memory layout - int i, j; + complex float *rx = + (complex float *)&rxbuf_in[0]; // complex has same memory layout + int i, j; - /* shift the buffer left based on nin */ - for (i = 0, j = ofdm->nin; i < (ofdm->nrxbuf - ofdm->nin); i++, j++) { - ofdm->rxbuf[i] = ofdm->rxbuf[j]; - } + /* shift the buffer left based on nin */ + for (i = 0, j = ofdm->nin; i < (ofdm->nrxbuf - ofdm->nin); i++, j++) { + ofdm->rxbuf[i] = ofdm->rxbuf[j]; + } - /* insert latest input samples onto tail of rxbuf */ - for (j = 0, i = (ofdm->nrxbuf - ofdm->nin); i < ofdm->nrxbuf; j++, i++) { - ofdm->rxbuf[i] = rx[j]; - } + /* insert latest input samples onto tail of rxbuf */ + for (j = 0, i = (ofdm->nrxbuf - ofdm->nin); i < ofdm->nrxbuf; j++, i++) { + ofdm->rxbuf[i] = rx[j]; + } - ofdm_demod_core(ofdm, rx_bits); + ofdm_demod_core(ofdm, rx_bits); } /* * This is a wrapper with a real short interface to minimise allocated memory. * This works with ofdm_demod and freedv_api. Gain is not used here. */ -void ofdm_demod_shorts(struct OFDM *ofdm, int *rx_bits, short *rxbuf_in, float gain) { - int i, j; +void ofdm_demod_shorts(struct OFDM *ofdm, int *rx_bits, short *rxbuf_in, + float gain) { + int i, j; - /* shift the buffer left based on nin */ + /* shift the buffer left based on nin */ - for (i = 0, j = ofdm->nin; i < (ofdm->nrxbuf - ofdm->nin); i++, j++) { - ofdm->rxbuf[i] = ofdm->rxbuf[j]; - } + for (i = 0, j = ofdm->nin; i < (ofdm->nrxbuf - ofdm->nin); i++, j++) { + ofdm->rxbuf[i] = ofdm->rxbuf[j]; + } - /* insert latest input samples onto tail of rxbuf */ - for (j = 0, i = (ofdm->nrxbuf - ofdm->nin); i < ofdm->nrxbuf; j++, i++) { - ofdm->rxbuf[i] = ((float)rxbuf_in[j] / 32767.0f); - } - - ofdm_demod_core(ofdm, rx_bits); + /* insert latest input samples onto tail of rxbuf */ + for (j = 0, i = (ofdm->nrxbuf - ofdm->nin); i < ofdm->nrxbuf; j++, i++) { + ofdm->rxbuf[i] = ((float)rxbuf_in[j] / 32767.0f); + } + + ofdm_demod_core(ofdm, rx_bits); } /* @@ -1502,734 +1536,756 @@ void ofdm_demod_shorts(struct OFDM *ofdm, int *rx_bits, short *rxbuf_in, float g * already in ofdm->rxbuf */ static void ofdm_demod_core(struct OFDM *ofdm, int *rx_bits) { - int prev_timing_est = ofdm->timing_est; - int i, j, k, rr, st, en; + int prev_timing_est = ofdm->timing_est; + int i, j, k, rr, st, en; - if (ofdm->rx_bpf_en) { - assert(ofdm->rx_bpf != NULL); - complex float *rxbuf_in = &ofdm->rxbuf[(ofdm->nrxbuf - ofdm->nin)]; - quisk_ccfFilter(rxbuf_in, rxbuf_in, ofdm->nin, ofdm->rx_bpf); - } - - /* - * get user and calculated freq offset - */ - float woff_est = TAU * ofdm->foff_est_hz / ofdm->fs; - - /* update timing estimate ---------------------------------------------- */ - - if (ofdm->timing_en == true) { - /* update timing at start of every frame */ - - st = ofdm->rxbufst + ofdm->samplespersymbol + ofdm->samplesperframe - (int) floorf((float)ofdm->ftwindowwidth / 2) + ofdm->timing_est; - en = st + ofdm->samplesperframe - 1 + ofdm->samplespersymbol + ofdm->ftwindowwidth; - - complex float work[(en - st)]; - - /* - * Adjust for the frequency error by shifting the phase - * using a conjugate multiply - */ - for (j = 0, i = st; i < en; j++, i++) { - work[j] = ofdm->rxbuf[i] * cmplxconj(woff_est * i); - } - - int ft_est = est_timing(ofdm, work, (en - st), 0.0f, &ofdm->timing_mx, &ofdm->timing_valid, 1); + if (ofdm->rx_bpf_en) { + assert(ofdm->rx_bpf != NULL); + complex float *rxbuf_in = &ofdm->rxbuf[(ofdm->nrxbuf - ofdm->nin)]; + quisk_ccfFilter(rxbuf_in, rxbuf_in, ofdm->nin, ofdm->rx_bpf); + } - ofdm->timing_est += ft_est - (int) ceilf((float)ofdm->ftwindowwidth / 2) + 1; + /* + * get user and calculated freq offset + */ + float woff_est = TAU * ofdm->foff_est_hz / ofdm->fs; - if (ofdm->verbose > 2) { - fprintf(stderr, " ft_est: %2d timing_est: %2d sample_point: %2d\n", ft_est, ofdm->timing_est, - ofdm->sample_point); - } + /* update timing estimate ---------------------------------------------- */ - /* Black magic to keep sample_point inside cyclic prefix. Or something like that. */ + if (ofdm->timing_en == true) { + /* update timing at start of every frame */ - ofdm->sample_point = max(ofdm->timing_est + 4, ofdm->sample_point); - ofdm->sample_point = min(ofdm->timing_est + ofdm->ncp-4, ofdm->sample_point); - } + st = ofdm->rxbufst + ofdm->samplespersymbol + ofdm->samplesperframe - + (int)floorf((float)ofdm->ftwindowwidth / 2) + ofdm->timing_est; + en = st + ofdm->samplesperframe - 1 + ofdm->samplespersymbol + + ofdm->ftwindowwidth; - /* - * Convert the time-domain samples to the frequency-domain using the rx_sym - * data matrix. This will be Nc+2 carriers of 11 symbols. - * - * You will notice there are Nc+2 BPSK symbols for each pilot symbol, and - * that there are Nc QPSK symbols for each data symbol. - * - * XXXXXXXXXXXXXXXXX <-- Timing Slip - * PPPPPPPPPPPPPPPPPPP <-- Previous Frames Pilot - * DDDDDDDDDDDDDDDDD - * DDDDDDDDDDDDDDDDD - * DDDDDDDDDDDDDDDDD - * DDDDDDDDDDDDDDDDD Ignore these past data symbols - * DDDDDDDDDDDDDDDDD - * DDDDDDDDDDDDDDDDD - * DDDDDDDDDDDDDDDDD - * PPPPPPPPPPPPPPPPPPP <-- This Frames Pilot - * DDDDDDDDDDDDDDDDD - * DDDDDDDDDDDDDDDDD - * DDDDDDDDDDDDDDDDD - * DDDDDDDDDDDDDDDDD These are the current data symbols to be decoded - * DDDDDDDDDDDDDDDDD - * DDDDDDDDDDDDDDDDD - * DDDDDDDDDDDDDDDDD - * PPPPPPPPPPPPPPPPPPP <-- Next Frames Pilot - * DDDDDDDDDDDDDDDDD - * DDDDDDDDDDDDDDDDD - * DDDDDDDDDDDDDDDDD - * DDDDDDDDDDDDDDDDD Ignore these next data symbols - * DDDDDDDDDDDDDDDDD - * DDDDDDDDDDDDDDDDD - * DDDDDDDDDDDDDDDDD - * PPPPPPPPPPPPPPPPPPP <-- Future Frames Pilot - * XXXXXXXXXXXXXXXXX <-- Timing Slip - * - * So this algorithm will have seven data symbols and four pilot symbols to process. - * The average of the four pilot symbols is our phase estimation. - */ - for (i = 0; i < (ofdm->ns + 3); i++) { - for (j = 0; j < (ofdm->nc + 2); j++) { - ofdm->rx_sym[i][j] = 0.0f; - } - } + complex float work[(en - st)]; /* - * "Previous" pilot symbol is one modem frame above. + * Adjust for the frequency error by shifting the phase + * using a conjugate multiply */ - st = ofdm->rxbufst + ofdm->samplespersymbol + 1 + ofdm->sample_point; - en = st + ofdm->m; - - complex float work[ofdm->m]; - - /* down-convert at current timing instant------------------------------- */ - - for (k = 0, j = st; j < en; k++, j++) { - work[k] = ofdm->rxbuf[j] * cmplxconj(woff_est * j); + for (j = 0, i = st; i < en; j++, i++) { + work[j] = ofdm->rxbuf[i] * cmplxconj(woff_est * i); } - /* - * Each symbol is of course ofdm->samplespersymbol samples long and - * becomes Nc+2 carriers after DFT. - * - * We put this carrier pilot symbol at the top of our matrix: - * - * 1 .................. Nc+2 - * - * +----------------------+ - * | Previous Pilot | rx_sym[0] - * +----------------------+ - * | | - * - */ - dft(ofdm, ofdm->rx_sym[0], work); - - /* - * "This" pilot comes after the extra symbol allotted at the top, and after - * the "previous" pilot and previous data symbols (let's call it, the previous - * modem frame). - * - * So we will now be starting at "this" pilot symbol, and continuing to the - * "next" pilot symbol. - * - * In this routine we also process the current data symbols. - */ - for (rr = 0; rr < (ofdm->ns + 1); rr++) { - st = ofdm->rxbufst + ofdm->samplespersymbol + ofdm->samplesperframe + (rr * ofdm->samplespersymbol) + 1 + ofdm->sample_point; - en = st + ofdm->m; + int ft_est = est_timing(ofdm, work, (en - st), 0.0f, &ofdm->timing_mx, + &ofdm->timing_valid, 1); - /* down-convert at current timing instant---------------------------------- */ + ofdm->timing_est += ft_est - (int)ceilf((float)ofdm->ftwindowwidth / 2) + 1; - for (k = 0, j = st; j < en; k++, j++) { - work[k] = ofdm->rxbuf[j] * cmplxconj(woff_est * j); - } - - /* - * We put these Nc+2 carrier symbols into our matrix after the previous pilot: - * - * 1 .................. Nc+2 - * | Previous Pilot | rx_sym[0] - * +----------------------+ - * | This Pilot | rx_sym[1] - * +----------------------+ - * | Data | rx_sym[2] - * +----------------------+ - * | Data | rx_sym[3] - * +----------------------+ - * | Data | rx_sym[4] - * +----------------------+ - * | Data | rx_sym[5] - * +----------------------+ - * | Data | rx_sym[6] - * +----------------------+ - * | Data | rx_sym[7] - * +----------------------+ - * | Data | rx_sym[8] - * +----------------------+ - * | Next Pilot | rx_sym[9] - * +----------------------+ - * | | rx_sym[10] - */ - dft(ofdm, ofdm->rx_sym[rr + 1], work); - } - - /* - * OK, now we want to process to the "future" pilot symbol. This is after - * the "next" modem frame. - * - * We are ignoring the data symbols between the "next" pilot and "future" pilot. - * We only want the "future" pilot symbol, to perform the averaging of all pilots. - */ - st = ofdm->rxbufst + ofdm->samplespersymbol + (3 * ofdm->samplesperframe) + 1 + ofdm->sample_point; + if (ofdm->verbose > 2) { + fprintf(stderr, " ft_est: %2d timing_est: %2d sample_point: %2d\n", + ft_est, ofdm->timing_est, ofdm->sample_point); + } + + /* Black magic to keep sample_point inside cyclic prefix. Or something like + * that. */ + + ofdm->sample_point = max(ofdm->timing_est + 4, ofdm->sample_point); + ofdm->sample_point = + min(ofdm->timing_est + ofdm->ncp - 4, ofdm->sample_point); + } + + /* + * Convert the time-domain samples to the frequency-domain using the rx_sym + * data matrix. This will be Nc+2 carriers of 11 symbols. + * + * You will notice there are Nc+2 BPSK symbols for each pilot symbol, and + * that there are Nc QPSK symbols for each data symbol. + * + * XXXXXXXXXXXXXXXXX <-- Timing Slip + * PPPPPPPPPPPPPPPPPPP <-- Previous Frames Pilot + * DDDDDDDDDDDDDDDDD + * DDDDDDDDDDDDDDDDD + * DDDDDDDDDDDDDDDDD + * DDDDDDDDDDDDDDDDD Ignore these past data symbols + * DDDDDDDDDDDDDDDDD + * DDDDDDDDDDDDDDDDD + * DDDDDDDDDDDDDDDDD + * PPPPPPPPPPPPPPPPPPP <-- This Frames Pilot + * DDDDDDDDDDDDDDDDD + * DDDDDDDDDDDDDDDDD + * DDDDDDDDDDDDDDDDD + * DDDDDDDDDDDDDDDDD These are the current data symbols to be decoded + * DDDDDDDDDDDDDDDDD + * DDDDDDDDDDDDDDDDD + * DDDDDDDDDDDDDDDDD + * PPPPPPPPPPPPPPPPPPP <-- Next Frames Pilot + * DDDDDDDDDDDDDDDDD + * DDDDDDDDDDDDDDDDD + * DDDDDDDDDDDDDDDDD + * DDDDDDDDDDDDDDDDD Ignore these next data symbols + * DDDDDDDDDDDDDDDDD + * DDDDDDDDDDDDDDDDD + * DDDDDDDDDDDDDDDDD + * PPPPPPPPPPPPPPPPPPP <-- Future Frames Pilot + * XXXXXXXXXXXXXXXXX <-- Timing Slip + * + * So this algorithm will have seven data symbols and four pilot symbols to + * process. The average of the four pilot symbols is our phase estimation. + */ + for (i = 0; i < (ofdm->ns + 3); i++) { + for (j = 0; j < (ofdm->nc + 2); j++) { + ofdm->rx_sym[i][j] = 0.0f; + } + } + + /* + * "Previous" pilot symbol is one modem frame above. + */ + st = ofdm->rxbufst + ofdm->samplespersymbol + 1 + ofdm->sample_point; + en = st + ofdm->m; + + complex float work[ofdm->m]; + + /* down-convert at current timing instant------------------------------- */ + + for (k = 0, j = st; j < en; k++, j++) { + work[k] = ofdm->rxbuf[j] * cmplxconj(woff_est * j); + } + + /* + * Each symbol is of course ofdm->samplespersymbol samples long and + * becomes Nc+2 carriers after DFT. + * + * We put this carrier pilot symbol at the top of our matrix: + * + * 1 .................. Nc+2 + * + * +----------------------+ + * | Previous Pilot | rx_sym[0] + * +----------------------+ + * | | + * + */ + dft(ofdm, ofdm->rx_sym[0], work); + + /* + * "This" pilot comes after the extra symbol allotted at the top, and after + * the "previous" pilot and previous data symbols (let's call it, the previous + * modem frame). + * + * So we will now be starting at "this" pilot symbol, and continuing to the + * "next" pilot symbol. + * + * In this routine we also process the current data symbols. + */ + for (rr = 0; rr < (ofdm->ns + 1); rr++) { + st = ofdm->rxbufst + ofdm->samplespersymbol + ofdm->samplesperframe + + (rr * ofdm->samplespersymbol) + 1 + ofdm->sample_point; en = st + ofdm->m; - /* down-convert at current timing instant------------------------------- */ + /* down-convert at current timing instant---------------------------------- + */ for (k = 0, j = st; j < en; k++, j++) { - work[k] = ofdm->rxbuf[j] * cmplxconj(woff_est * j); + work[k] = ofdm->rxbuf[j] * cmplxconj(woff_est * j); } /* - * We put the future pilot after all the previous symbols in the matrix: + * We put these Nc+2 carrier symbols into our matrix after the previous + * pilot: * * 1 .................. Nc+2 - * - * | | rx_sym[9] + * | Previous Pilot | rx_sym[0] + * +----------------------+ + * | This Pilot | rx_sym[1] + * +----------------------+ + * | Data | rx_sym[2] + * +----------------------+ + * | Data | rx_sym[3] * +----------------------+ - * | Future Pilot | rx_sym[10] + * | Data | rx_sym[4] * +----------------------+ + * | Data | rx_sym[5] + * +----------------------+ + * | Data | rx_sym[6] + * +----------------------+ + * | Data | rx_sym[7] + * +----------------------+ + * | Data | rx_sym[8] + * +----------------------+ + * | Next Pilot | rx_sym[9] + * +----------------------+ + * | | rx_sym[10] */ - dft(ofdm, ofdm->rx_sym[ofdm->ns + 2], work); - + dft(ofdm, ofdm->rx_sym[rr + 1], work); + } + + /* + * OK, now we want to process to the "future" pilot symbol. This is after + * the "next" modem frame. + * + * We are ignoring the data symbols between the "next" pilot and "future" + * pilot. We only want the "future" pilot symbol, to perform the averaging of + * all pilots. + */ + st = ofdm->rxbufst + ofdm->samplespersymbol + (3 * ofdm->samplesperframe) + + 1 + ofdm->sample_point; + en = st + ofdm->m; + + /* down-convert at current timing instant------------------------------- */ + + for (k = 0, j = st; j < en; k++, j++) { + work[k] = ofdm->rxbuf[j] * cmplxconj(woff_est * j); + } + + /* + * We put the future pilot after all the previous symbols in the matrix: + * + * 1 .................. Nc+2 + * + * | | rx_sym[9] + * +----------------------+ + * | Future Pilot | rx_sym[10] + * +----------------------+ + */ + dft(ofdm, ofdm->rx_sym[ofdm->ns + 2], work); + + /* + * We are finished now with the DFT and down conversion + * From here on down we are in the frequency domain + */ + + /* est freq err based on all carriers ---------------------------------- */ + + if (ofdm->foff_est_en == true) { /* - * We are finished now with the DFT and down conversion - * From here on down we are in the frequency domain + * sym[1] is 'this' pilot symbol, sym[9] is 'next' pilot symbol. + * + * By subtracting the two averages of these pilots, we find the frequency + * by the change in phase over time. */ + complex float freq_err_rect = + conjf(vector_sum(ofdm->rx_sym[1], ofdm->nc + 2)) * + vector_sum(ofdm->rx_sym[ofdm->ns + 1], ofdm->nc + 2); - /* est freq err based on all carriers ---------------------------------- */ - - if (ofdm->foff_est_en == true) { - /* - * sym[1] is 'this' pilot symbol, sym[9] is 'next' pilot symbol. - * - * By subtracting the two averages of these pilots, we find the frequency - * by the change in phase over time. - */ - complex float freq_err_rect = - conjf(vector_sum(ofdm->rx_sym[1], ofdm->nc + 2)) * - vector_sum(ofdm->rx_sym[ofdm->ns + 1], ofdm->nc + 2); + /* prevent instability in atan(im/re) when real part near 0 */ - /* prevent instability in atan(im/re) when real part near 0 */ + freq_err_rect += 1E-6f; - freq_err_rect += 1E-6f; - - float freq_err_hz = cargf(freq_err_rect) * ofdm->rs / (TAU * ofdm->ns); - if (ofdm->foff_limiter) { - /* optionally tame updates in low SNR channels */ - if (freq_err_hz > 1.0) freq_err_hz = 1.0; - if (freq_err_hz < -1.0) freq_err_hz = -1.0; - } - ofdm->foff_est_hz += (ofdm->foff_est_gain * freq_err_hz); + float freq_err_hz = cargf(freq_err_rect) * ofdm->rs / (TAU * ofdm->ns); + if (ofdm->foff_limiter) { + /* optionally tame updates in low SNR channels */ + if (freq_err_hz > 1.0) freq_err_hz = 1.0; + if (freq_err_hz < -1.0) freq_err_hz = -1.0; } + ofdm->foff_est_hz += (ofdm->foff_est_gain * freq_err_hz); + } - /* OK - now estimate and correct pilot phase -------------------------- */ + /* OK - now estimate and correct pilot phase -------------------------- */ - complex float aphase_est_pilot_rect; - float aphase_est_pilot[ofdm->nc + 2]; - float aamp_est_pilot[ofdm->nc + 2]; + complex float aphase_est_pilot_rect; + float aphase_est_pilot[ofdm->nc + 2]; + float aamp_est_pilot[ofdm->nc + 2]; - for (i = 0; i < (ofdm->nc + 2); i++) { - aphase_est_pilot[i] = 10.0f; - aamp_est_pilot[i] = 0.0f; - } + for (i = 0; i < (ofdm->nc + 2); i++) { + aphase_est_pilot[i] = 10.0f; + aamp_est_pilot[i] = 0.0f; + } - for (i = 1; i < (ofdm->nc + 1); i++) { /* ignore first and last carrier for count */ - if (ofdm->phase_est_bandwidth == low_bw) { - complex float symbol[3]; + for (i = 1; i < (ofdm->nc + 1); + i++) { /* ignore first and last carrier for count */ + if (ofdm->phase_est_bandwidth == low_bw) { + complex float symbol[3]; - /* - * Use all pilots normally, results in low SNR performance, - * but will fall over in high Doppler propagation - * - * Basically we divide the Nc+2 pilots into groups of 3 - * Then average the phase surrounding each of the data symbols. - */ - for (k = 0, j = (i - 1); k < 3; k++, j++) { - symbol[k] = ofdm->rx_sym[1][j] * conjf(ofdm->pilots[j]); /* this pilot conjugate */ - } + /* + * Use all pilots normally, results in low SNR performance, + * but will fall over in high Doppler propagation + * + * Basically we divide the Nc+2 pilots into groups of 3 + * Then average the phase surrounding each of the data symbols. + */ + for (k = 0, j = (i - 1); k < 3; k++, j++) { + symbol[k] = ofdm->rx_sym[1][j] * + conjf(ofdm->pilots[j]); /* this pilot conjugate */ + } - aphase_est_pilot_rect = vector_sum(symbol, 3); + aphase_est_pilot_rect = vector_sum(symbol, 3); - for (k = 0, j = (i - 1); k < 3; k++, j++) { - symbol[k] = ofdm->rx_sym[ofdm->ns + 1][j] * conjf(ofdm->pilots[j]); /* next pilot conjugate */ - } + for (k = 0, j = (i - 1); k < 3; k++, j++) { + symbol[k] = ofdm->rx_sym[ofdm->ns + 1][j] * + conjf(ofdm->pilots[j]); /* next pilot conjugate */ + } - aphase_est_pilot_rect += vector_sum(symbol, 3); + aphase_est_pilot_rect += vector_sum(symbol, 3); - /* use pilots in past and future */ + /* use pilots in past and future */ - for (k = 0, j = (i - 1); k < 3; k++, j++) { - symbol[k] = ofdm->rx_sym[0][j] * conjf(ofdm->pilots[j]); /* previous pilot */ - } + for (k = 0, j = (i - 1); k < 3; k++, j++) { + symbol[k] = + ofdm->rx_sym[0][j] * conjf(ofdm->pilots[j]); /* previous pilot */ + } - aphase_est_pilot_rect += vector_sum(symbol, 3); + aphase_est_pilot_rect += vector_sum(symbol, 3); - for (k = 0, j = (i - 1); k < 3; k++, j++) { - symbol[k] = ofdm->rx_sym[ofdm->ns + 2][j] * conjf(ofdm->pilots[j]); /* future pilot */ - } + for (k = 0, j = (i - 1); k < 3; k++, j++) { + symbol[k] = ofdm->rx_sym[ofdm->ns + 2][j] * + conjf(ofdm->pilots[j]); /* future pilot */ + } - aphase_est_pilot_rect += vector_sum(symbol, 3); + aphase_est_pilot_rect += vector_sum(symbol, 3); - /* amplitude is estimated over 12 pilots */ - aphase_est_pilot_rect /= 12.0f; + /* amplitude is estimated over 12 pilots */ + aphase_est_pilot_rect /= 12.0f; - aphase_est_pilot[i] = cargf(aphase_est_pilot_rect); - aamp_est_pilot[i] = cabsf(aphase_est_pilot_rect); - } else { - assert(ofdm->phase_est_bandwidth == high_bw); - - /* - * Use only symbols at 'this' and 'next' to quickly track changes - * in phase due to high Doppler spread in propagation (no neighbor averaging). - * - * As less pilots are averaged, low SNR performance will be poorer - */ - aphase_est_pilot_rect = ofdm->rx_sym[1][i] * conjf(ofdm->pilots[i]); /* "this" pilot conjugate */ - aphase_est_pilot_rect += ofdm->rx_sym[ofdm->ns + 1][i] * conjf(ofdm->pilots[i]); /* "next" pilot conjugate */ - - /* we estimate over 2 pilots */ - aphase_est_pilot_rect /= 2.0f; - aphase_est_pilot[i] = cargf(aphase_est_pilot_rect); - - if (ofdm->amp_est_mode == 0) { - // legacy 700D ampl est method - aamp_est_pilot[i] = cabsf(aphase_est_pilot_rect); - } else { - aamp_est_pilot[i] = cabsf(ofdm->rx_sym[1][i]) + cabsf(ofdm->rx_sym[ofdm->ns + 1][i])/2.0; - } - } - - aphase_est_pilot[i] = cargf(aphase_est_pilot_rect); + aphase_est_pilot[i] = cargf(aphase_est_pilot_rect); + aamp_est_pilot[i] = cabsf(aphase_est_pilot_rect); + } else { + assert(ofdm->phase_est_bandwidth == high_bw); + + /* + * Use only symbols at 'this' and 'next' to quickly track changes + * in phase due to high Doppler spread in propagation (no neighbor + * averaging). + * + * As less pilots are averaged, low SNR performance will be poorer + */ + aphase_est_pilot_rect = + ofdm->rx_sym[1][i] * + conjf(ofdm->pilots[i]); /* "this" pilot conjugate */ + aphase_est_pilot_rect += + ofdm->rx_sym[ofdm->ns + 1][i] * + conjf(ofdm->pilots[i]); /* "next" pilot conjugate */ + + /* we estimate over 2 pilots */ + aphase_est_pilot_rect /= 2.0f; + aphase_est_pilot[i] = cargf(aphase_est_pilot_rect); + + if (ofdm->amp_est_mode == 0) { + // legacy 700D ampl est method aamp_est_pilot[i] = cabsf(aphase_est_pilot_rect); - } - + } else { + aamp_est_pilot[i] = cabsf(ofdm->rx_sym[1][i]) + + cabsf(ofdm->rx_sym[ofdm->ns + 1][i]) / 2.0; + } + } + + aphase_est_pilot[i] = cargf(aphase_est_pilot_rect); + aamp_est_pilot[i] = cabsf(aphase_est_pilot_rect); + } + + /* + * correct the phase offset using phase estimate, and demodulate + * bits, separate loop as it runs across cols (carriers) to get + * frame bit ordering correct + */ + complex float rx_corr; + int abit[2]; + int bit_index = 0; + float sum_amp = 0.0f; + + for (rr = 0; rr < ofdm->rowsperframe; rr++) { /* - * correct the phase offset using phase estimate, and demodulate - * bits, separate loop as it runs across cols (carriers) to get - * frame bit ordering correct + * Note the i starts with the second carrier, ends with Nc+1. + * so we ignore the first and last carriers. + * + * Also note we are using sym[2..8] or the seven data symbols. */ - complex float rx_corr; - int abit[2]; - int bit_index = 0; - float sum_amp = 0.0f; - - for (rr = 0; rr < ofdm->rowsperframe; rr++) { + for (i = 1; i < (ofdm->nc + 1); i++) { + if (ofdm->phase_est_en == true) { + if (ofdm->dpsk_en == true) { + /* differential detection, using pilot as reference at start of frame + */ + rx_corr = ofdm->rx_sym[rr + 2][i] * + cmplxconj(cargf(ofdm->rx_sym[rr + 1][i])); + } else { + /* regular coherent detection */ + rx_corr = ofdm->rx_sym[rr + 2][i] * cmplxconj(aphase_est_pilot[i]); + } + } else { + rx_corr = ofdm->rx_sym[rr + 2][i]; + } + + /* + * Output complex data symbols after phase correction; + * (_np = no pilots) the pilot symbols have been removed + */ + ofdm->rx_np[(rr * ofdm->nc) + (i - 1)] = rx_corr; + + /* + * Note even though amp ests are the same for each col, + * the FEC decoder likes to have one amplitude per symbol + * so convenient to log them all + */ + ofdm->rx_amp[(rr * ofdm->nc) + (i - 1)] = aamp_est_pilot[i]; + sum_amp += aamp_est_pilot[i]; + + /* + * Note like amps in this implementation phase ests are the + * same for each col, but we log them for each symbol anyway + */ + ofdm->aphase_est_pilot_log[(rr * ofdm->nc) + (i - 1)] = + aphase_est_pilot[i]; + + if (ofdm->bps == 1) { + rx_bits[bit_index++] = crealf(rx_corr) > 0.0f; + } else if (ofdm->bps == 2) { /* - * Note the i starts with the second carrier, ends with Nc+1. - * so we ignore the first and last carriers. - * - * Also note we are using sym[2..8] or the seven data symbols. + * Only one final task, decode what quadrant the phase + * is in, and return the dibits */ - for (i = 1; i < (ofdm->nc + 1); i++) { - if (ofdm->phase_est_en == true) { - if (ofdm->dpsk_en == true) { - /* differential detection, using pilot as reference at start of frame */ - rx_corr = ofdm->rx_sym[rr + 2][i] * cmplxconj(cargf(ofdm->rx_sym[rr + 1][i])); - } else { - /* regular coherent detection */ - rx_corr = ofdm->rx_sym[rr + 2][i] * cmplxconj(aphase_est_pilot[i]); - } - } else { - rx_corr = ofdm->rx_sym[rr + 2][i]; - } - - /* - * Output complex data symbols after phase correction; - * (_np = no pilots) the pilot symbols have been removed - */ - ofdm->rx_np[(rr * ofdm->nc) + (i - 1)] = rx_corr; - - /* - * Note even though amp ests are the same for each col, - * the FEC decoder likes to have one amplitude per symbol - * so convenient to log them all - */ - ofdm->rx_amp[(rr * ofdm->nc) + (i - 1)] = aamp_est_pilot[i]; - sum_amp += aamp_est_pilot[i]; - - /* - * Note like amps in this implementation phase ests are the - * same for each col, but we log them for each symbol anyway - */ - ofdm->aphase_est_pilot_log[(rr * ofdm->nc) + (i - 1)] = aphase_est_pilot[i]; - - if (ofdm->bps == 1) { - rx_bits[bit_index++] = crealf(rx_corr) > 0.0f; - } else if (ofdm->bps == 2) { - /* - * Only one final task, decode what quadrant the phase - * is in, and return the dibits - */ - qpsk_demod(rx_corr, abit); - rx_bits[bit_index++] = abit[1]; - rx_bits[bit_index++] = abit[0]; - } - } + qpsk_demod(rx_corr, abit); + rx_bits[bit_index++] = abit[1]; + rx_bits[bit_index++] = abit[0]; + } } + } - /* update mean amplitude estimate for LDPC decoder scaling */ + /* update mean amplitude estimate for LDPC decoder scaling */ - ofdm->mean_amp = 0.9f * ofdm->mean_amp + 0.1f * sum_amp / (ofdm->rowsperframe * ofdm->nc); + ofdm->mean_amp = + 0.9f * ofdm->mean_amp + 0.1f * sum_amp / (ofdm->rowsperframe * ofdm->nc); - /* Adjust nin to take care of sample clock offset */ + /* Adjust nin to take care of sample clock offset */ - ofdm->nin = ofdm->samplesperframe; + ofdm->nin = ofdm->samplesperframe; - if (ofdm->timing_en == true) { - ofdm->clock_offset_counter += (prev_timing_est - ofdm->timing_est); + if (ofdm->timing_en == true) { + ofdm->clock_offset_counter += (prev_timing_est - ofdm->timing_est); - int thresh = ofdm->samplespersymbol / 8; - int tshift = ofdm->samplespersymbol / 4; + int thresh = ofdm->samplespersymbol / 8; + int tshift = ofdm->samplespersymbol / 4; - if (ofdm->timing_est > thresh) { - ofdm->nin = ofdm->samplesperframe + tshift; - ofdm->timing_est -= tshift; - ofdm->sample_point -= tshift; - } else if (ofdm->timing_est < -thresh) { - ofdm->nin = ofdm->samplesperframe - tshift; - ofdm->timing_est += tshift; - ofdm->sample_point += tshift; - } + if (ofdm->timing_est > thresh) { + ofdm->nin = ofdm->samplesperframe + tshift; + ofdm->timing_est -= tshift; + ofdm->sample_point -= tshift; + } else if (ofdm->timing_est < -thresh) { + ofdm->nin = ofdm->samplesperframe - tshift; + ofdm->timing_est += tshift; + ofdm->sample_point += tshift; } + } - // use internal rxbuf samples if they are available - int rxbufst_next = ofdm->rxbufst + ofdm->nin; - if (rxbufst_next + ofdm->nrxbufmin <= ofdm->nrxbuf) { - ofdm->rxbufst = rxbufst_next; - ofdm->nin = 0; - } + // use internal rxbuf samples if they are available + int rxbufst_next = ofdm->rxbufst + ofdm->nin; + if (rxbufst_next + ofdm->nrxbufmin <= ofdm->nrxbuf) { + ofdm->rxbufst = rxbufst_next; + ofdm->nin = 0; + } } - /* * Returns an estimate of Es/No in dB - see esno_est.m for more info */ float ofdm_esno_est_calc(complex float *rx_sym, int nsym) { - - float sig_var = 0; - float step = 1.0f/nsym; - for (int i = 0; i < nsym; i++) - sig_var += (cnormf(rx_sym[i]) * step); - float sig_rms = sqrtf(sig_var); - - float sum_x = 0.0f; float sum_xx = 0.0f; int n = 0; - for (int i = 0; i < nsym; i++) { - complex float s = rx_sym[i]; - - if (cabsf(s) > sig_rms) { - if (fabs(crealf(s)) > fabs(cimagf(s))) { - sum_x += cimagf(s); - sum_xx += cimagf(s) * cimagf(s); - } else { - sum_x += crealf(s); - sum_xx += crealf(s) * crealf(s); - } - n++; - } - } - - float noise_var; - if (n > 1) - noise_var = (n * sum_xx - sum_x * sum_x) / (n * (n - 1)); - else - noise_var = sig_var; - noise_var *= 2.0f; - - float EsNodB = 10.0f * log10f((1E-12f + sig_var) / (1E-12f + noise_var)); - assert(isnan(EsNodB) == 0); - return EsNodB; + float sig_var = 0; + float step = 1.0f / nsym; + for (int i = 0; i < nsym; i++) sig_var += (cnormf(rx_sym[i]) * step); + float sig_rms = sqrtf(sig_var); + + float sum_x = 0.0f; + float sum_xx = 0.0f; + int n = 0; + for (int i = 0; i < nsym; i++) { + complex float s = rx_sym[i]; + + if (cabsf(s) > sig_rms) { + if (fabs(crealf(s)) > fabs(cimagf(s))) { + sum_x += cimagf(s); + sum_xx += cimagf(s) * cimagf(s); + } else { + sum_x += crealf(s); + sum_xx += crealf(s) * crealf(s); + } + n++; + } + } + + float noise_var; + if (n > 1) + noise_var = (n * sum_xx - sum_x * sum_x) / (n * (n - 1)); + else + noise_var = sig_var; + noise_var *= 2.0f; + + float EsNodB = 10.0f * log10f((1E-12f + sig_var) / (1E-12f + noise_var)); + assert(isnan(EsNodB) == 0); + return EsNodB; } - float ofdm_snr_from_esno(struct OFDM *ofdm, float EsNodB) { - float cyclic_power = 10.0f * log10f((float)(ofdm->ncp + ofdm->m) / ofdm->m); - return EsNodB + 10.0f * log10f((float)(ofdm->nc * ofdm->rs) / 3000.0f) + cyclic_power; + float cyclic_power = 10.0f * log10f((float)(ofdm->ncp + ofdm->m) / ofdm->m); + return EsNodB + 10.0f * log10f((float)(ofdm->nc * ofdm->rs) / 3000.0f) + + cyclic_power; } /* * state machine for 700D/2020 */ void ofdm_sync_state_machine_voice1(struct OFDM *ofdm, uint8_t *rx_uw) { - int i; + int i; - State next_state = ofdm->sync_state; + State next_state = ofdm->sync_state; - ofdm->sync_start = false; - ofdm->sync_end = false; + ofdm->sync_start = false; + ofdm->sync_end = false; - if (ofdm->sync_state == search) { - if (ofdm->timing_valid) { - ofdm->frame_count = 0; - ofdm->sync_counter = 0; - ofdm->sync_start = true; - ofdm->clock_offset_counter = 0; - next_state = trial; - } + if (ofdm->sync_state == search) { + if (ofdm->timing_valid) { + ofdm->frame_count = 0; + ofdm->sync_counter = 0; + ofdm->sync_start = true; + ofdm->clock_offset_counter = 0; + next_state = trial; } + } - if ((ofdm->sync_state == synced) || (ofdm->sync_state == trial)) { - ofdm->frame_count++; + if ((ofdm->sync_state == synced) || (ofdm->sync_state == trial)) { + ofdm->frame_count++; - /* - * freq offset est may be too far out, and has aliases every 1/Ts, so - * we use a Unique Word to get a really solid indication of sync. - */ - ofdm->uw_errors = 0; + /* + * freq offset est may be too far out, and has aliases every 1/Ts, so + * we use a Unique Word to get a really solid indication of sync. + */ + ofdm->uw_errors = 0; - for (i = 0; i < ofdm->nuwbits; i++) { - ofdm->uw_errors += ofdm->tx_uw[i] ^ rx_uw[i]; - } + for (i = 0; i < ofdm->nuwbits; i++) { + ofdm->uw_errors += ofdm->tx_uw[i] ^ rx_uw[i]; + } - /* - * during trial sync we don't tolerate errors so much, we look - * for 3 consecutive frames with low error rate to confirm sync - */ - if (ofdm->sync_state == trial) { - if (ofdm->uw_errors > 2) { - /* if we exceed thresh stay in trial sync */ + /* + * during trial sync we don't tolerate errors so much, we look + * for 3 consecutive frames with low error rate to confirm sync + */ + if (ofdm->sync_state == trial) { + if (ofdm->uw_errors > 2) { + /* if we exceed thresh stay in trial sync */ - ofdm->sync_counter++; - ofdm->frame_count = 0; - } + ofdm->sync_counter++; + ofdm->frame_count = 0; + } - if (ofdm->sync_counter == 2) { - /* if we get two bad frames drop sync and start again */ + if (ofdm->sync_counter == 2) { + /* if we get two bad frames drop sync and start again */ - next_state = search; - ofdm->phase_est_bandwidth = high_bw; - } + next_state = search; + ofdm->phase_est_bandwidth = high_bw; + } - if (ofdm->frame_count == 4) { - /* three good frames, sync is OK! */ + if (ofdm->frame_count == 4) { + /* three good frames, sync is OK! */ - next_state = synced; - /* change to low bandwidth, but more accurate phase estimation */ - /* but only if not locked to high */ + next_state = synced; + /* change to low bandwidth, but more accurate phase estimation */ + /* but only if not locked to high */ - if (ofdm->phase_est_bandwidth_mode != LOCKED_PHASE_EST) { - ofdm->phase_est_bandwidth = low_bw; - } - } + if (ofdm->phase_est_bandwidth_mode != LOCKED_PHASE_EST) { + ofdm->phase_est_bandwidth = low_bw; } + } + } - /* once we have synced up we tolerate a higher error rate to wait out fades */ + /* once we have synced up we tolerate a higher error rate to wait out fades + */ - if (ofdm->sync_state == synced) { - if (ofdm->uw_errors > 2) { - ofdm->sync_counter++; - } else { - ofdm->sync_counter = 0; - } + if (ofdm->sync_state == synced) { + if (ofdm->uw_errors > 2) { + ofdm->sync_counter++; + } else { + ofdm->sync_counter = 0; + } - if ((ofdm->sync_mode == autosync) && (ofdm->sync_counter > 6)) { - /* run of consecutive bad frames ... drop sync */ + if ((ofdm->sync_mode == autosync) && (ofdm->sync_counter > 6)) { + /* run of consecutive bad frames ... drop sync */ - next_state = search; - ofdm->phase_est_bandwidth = high_bw; - } - } + next_state = search; + ofdm->phase_est_bandwidth = high_bw; + } } + } - ofdm->last_sync_state = ofdm->sync_state; - ofdm->sync_state = next_state; + ofdm->last_sync_state = ofdm->sync_state; + ofdm->sync_state = next_state; } /* * data (streaming mode) state machine */ void ofdm_sync_state_machine_data_streaming(struct OFDM *ofdm, uint8_t *rx_uw) { - State next_state = ofdm->sync_state; - int i; + State next_state = ofdm->sync_state; + int i; - ofdm->sync_start = ofdm->sync_end = 0; + ofdm->sync_start = ofdm->sync_end = 0; - if (ofdm->sync_state == search) { - if (ofdm->timing_valid != 0) { - ofdm->sync_start = true; - ofdm->sync_counter = 0; - next_state = trial; - } - } + if (ofdm->sync_state == search) { + if (ofdm->timing_valid != 0) { + ofdm->sync_start = true; + ofdm->sync_counter = 0; + next_state = trial; + } + } + + ofdm->uw_errors = 0; + for (i = 0; i < ofdm->nuwbits; i++) { + ofdm->uw_errors += ofdm->tx_uw[i] ^ rx_uw[i]; + } + + if (ofdm->sync_state == trial) { + if (ofdm->uw_errors < ofdm->bad_uw_errors) { + next_state = synced; + ofdm->packet_count = 0; + ofdm->modem_frame = ofdm->nuwframes; + } else { + ofdm->sync_counter++; - ofdm->uw_errors = 0; - for (i = 0; i < ofdm->nuwbits; i++) { - ofdm->uw_errors += ofdm->tx_uw[i] ^ rx_uw[i]; + if (ofdm->sync_counter > ofdm->np) { + next_state = search; + } } + } - if (ofdm->sync_state == trial) { - if (ofdm->uw_errors < ofdm->bad_uw_errors) { - next_state = synced; - ofdm->packet_count = 0; - ofdm->modem_frame = ofdm->nuwframes; - } else { - ofdm->sync_counter++; + // Note if frameperburst==0 we don't ever lose sync, which is useful for + // stream based testing or external control of state machine - if (ofdm->sync_counter > ofdm->np) { - next_state = search; - } - } - } + if (ofdm->sync_state == synced) { + ofdm->modem_frame++; - // Note if frameperburst==0 we don't ever lose sync, which is useful for - // stream based testing or external control of state machine - - if (ofdm->sync_state == synced) { - ofdm->modem_frame++; - - if (ofdm->modem_frame >= ofdm->np) { - ofdm->modem_frame = 0; - ofdm->packet_count++; - if (ofdm->packetsperburst) { - if (ofdm->packet_count >= ofdm->packetsperburst) - next_state = search; - } - } - + if (ofdm->modem_frame >= ofdm->np) { + ofdm->modem_frame = 0; + ofdm->packet_count++; + if (ofdm->packetsperburst) { + if (ofdm->packet_count >= ofdm->packetsperburst) next_state = search; + } } + } - ofdm->last_sync_state = ofdm->sync_state; - ofdm->sync_state = next_state; + ofdm->last_sync_state = ofdm->sync_state; + ofdm->sync_state = next_state; } /* * data (burst mode) state machine */ void ofdm_sync_state_machine_data_burst(struct OFDM *ofdm, uint8_t *rx_uw) { - State next_state = ofdm->sync_state; - int i; + State next_state = ofdm->sync_state; + int i; - ofdm->sync_start = ofdm->sync_end = 0; + ofdm->sync_start = ofdm->sync_end = 0; - if (ofdm->sync_state == search) { - if (ofdm->timing_valid != 0) { - ofdm->sync_start = true; - ofdm->sync_counter = 0; - next_state = trial; + if (ofdm->sync_state == search) { + if (ofdm->timing_valid != 0) { + ofdm->sync_start = true; + ofdm->sync_counter = 0; + next_state = trial; + } + } + + ofdm->uw_errors = 0; + for (i = 0; i < ofdm->nuwbits; i++) { + ofdm->uw_errors += ofdm->tx_uw[i] ^ rx_uw[i]; + } + + /* pre or post-amble has told us this is the start of the packet. Confirm we + have a valid frame by checking the UW after the modem frames containing + the UW have been received */ + if (ofdm->sync_state == trial) { + ofdm->sync_counter++; + if (ofdm->sync_counter == ofdm->nuwframes) { + if (ofdm->uw_errors < ofdm->bad_uw_errors) { + next_state = synced; + ofdm->packet_count = 0; + ofdm->modem_frame = ofdm->nuwframes; + } else { + next_state = search; + // reset rxbuf to make sure we only ever do a postamble loop once + // through same samples + ofdm->rxbufst = ofdm->nrxbufhistory; + for (int i = 0; i < ofdm->nrxbuf; i++) ofdm->rxbuf[i] = 0; + ofdm->uw_fails++; + } + } + } + + if (ofdm->sync_state == synced) { + ofdm->modem_frame++; + if (ofdm->modem_frame >= ofdm->np) { + ofdm->modem_frame = 0; + ofdm->packet_count++; + if (ofdm->packetsperburst) { + if (ofdm->packet_count >= ofdm->packetsperburst) { + next_state = search; + // reset rxbuf to make sure we only ever do a postamble loop once + // through same samples + ofdm->rxbufst = ofdm->nrxbufhistory; + for (int i = 0; i < ofdm->nrxbuf; i++) ofdm->rxbuf[i] = 0; } + } } + } - ofdm->uw_errors = 0; - for (i = 0; i < ofdm->nuwbits; i++) { - ofdm->uw_errors += ofdm->tx_uw[i] ^ rx_uw[i]; - } - - /* pre or post-amble has told us this is the start of the packet. Confirm we - have a valid frame by checking the UW after the modem frames containing - the UW have been received */ - if (ofdm->sync_state == trial) { - ofdm->sync_counter++; - if (ofdm->sync_counter == ofdm->nuwframes) { - if (ofdm->uw_errors < ofdm->bad_uw_errors) { - next_state = synced; - ofdm->packet_count = 0; - ofdm->modem_frame = ofdm->nuwframes; - } else { - next_state = search; - // reset rxbuf to make sure we only ever do a postamble loop once through same samples - ofdm->rxbufst = ofdm->nrxbufhistory; - for(int i=0; i<ofdm->nrxbuf; i++) ofdm->rxbuf[i] = 0; - ofdm->uw_fails++; - } - } - } - - if (ofdm->sync_state == synced) { - ofdm->modem_frame++; - if (ofdm->modem_frame >= ofdm->np) { - ofdm->modem_frame = 0; - ofdm->packet_count++; - if (ofdm->packetsperburst) { - if (ofdm->packet_count >= ofdm->packetsperburst) { - next_state = search; - // reset rxbuf to make sure we only ever do a postamble loop once through same samples - ofdm->rxbufst = ofdm->nrxbufhistory; - for(int i=0; i<ofdm->nrxbuf; i++) ofdm->rxbuf[i] = 0; - } - } - } - } - - ofdm->last_sync_state = ofdm->sync_state; - ofdm->sync_state = next_state; + ofdm->last_sync_state = ofdm->sync_state; + ofdm->sync_state = next_state; } - void ofdm_sync_state_machine_voice2(struct OFDM *ofdm, uint8_t *rx_uw) { - int i; + int i; - State next_state = ofdm->sync_state; + State next_state = ofdm->sync_state; - ofdm->sync_start = false; - ofdm->sync_end = false; + ofdm->sync_start = false; + ofdm->sync_end = false; - if (ofdm->sync_state == search) { - if (ofdm->timing_valid) { - ofdm->frame_count = 0; - ofdm->sync_counter = 0; - ofdm->sync_start = true; - ofdm->clock_offset_counter = 0; - next_state = trial; - } + if (ofdm->sync_state == search) { + if (ofdm->timing_valid) { + ofdm->frame_count = 0; + ofdm->sync_counter = 0; + ofdm->sync_start = true; + ofdm->clock_offset_counter = 0; + next_state = trial; } + } - if ((ofdm->sync_state == synced) || (ofdm->sync_state == trial)) { - ofdm->frame_count++; + if ((ofdm->sync_state == synced) || (ofdm->sync_state == trial)) { + ofdm->frame_count++; - ofdm->uw_errors = 0; - for (i = 0; i < ofdm->nuwbits; i++) { - ofdm->uw_errors += ofdm->tx_uw[i] ^ rx_uw[i]; - } + ofdm->uw_errors = 0; + for (i = 0; i < ofdm->nuwbits; i++) { + ofdm->uw_errors += ofdm->tx_uw[i] ^ rx_uw[i]; + } - if (ofdm->sync_state == trial) { - if (ofdm->uw_errors <= ofdm->bad_uw_errors) - next_state = synced; - else - next_state = search; - } + if (ofdm->sync_state == trial) { + if (ofdm->uw_errors <= ofdm->bad_uw_errors) + next_state = synced; + else + next_state = search; + } - if (ofdm->sync_state == synced) { - if (ofdm->uw_errors > ofdm->bad_uw_errors) { - ofdm->sync_counter++; - } else { - ofdm->sync_counter = 0; - } - - if (ofdm->sync_counter == 6) { - /* run of consecutive bad frames ... drop sync */ - next_state = search; - } - } + if (ofdm->sync_state == synced) { + if (ofdm->uw_errors > ofdm->bad_uw_errors) { + ofdm->sync_counter++; + } else { + ofdm->sync_counter = 0; + } + + if (ofdm->sync_counter == 6) { + /* run of consecutive bad frames ... drop sync */ + next_state = search; + } } + } - ofdm->last_sync_state = ofdm->sync_state; - ofdm->sync_state = next_state; + ofdm->last_sync_state = ofdm->sync_state; + ofdm->sync_state = next_state; } - /* mode based dispatcher for sync state machines */ void ofdm_sync_state_machine(struct OFDM *ofdm, uint8_t *rx_uw) { - if (!strcmp(ofdm->state_machine, "voice1")) - ofdm_sync_state_machine_voice1(ofdm, rx_uw); - if (!strcmp(ofdm->state_machine, "data")) { - if (strcmp(ofdm->data_mode,"streaming") == 0) - ofdm_sync_state_machine_data_streaming(ofdm, rx_uw); - else - ofdm_sync_state_machine_data_burst(ofdm, rx_uw); - } - if (!strcmp(ofdm->state_machine, "voice2")) - ofdm_sync_state_machine_voice2(ofdm, rx_uw); + if (!strcmp(ofdm->state_machine, "voice1")) + ofdm_sync_state_machine_voice1(ofdm, rx_uw); + if (!strcmp(ofdm->state_machine, "data")) { + if (strcmp(ofdm->data_mode, "streaming") == 0) + ofdm_sync_state_machine_data_streaming(ofdm, rx_uw); + else + ofdm_sync_state_machine_data_burst(ofdm, rx_uw); + } + if (!strcmp(ofdm->state_machine, "voice2")) + ofdm_sync_state_machine_voice2(ofdm, rx_uw); } - /*---------------------------------------------------------------------------* \ FUNCTIONS...: ofdm_set_sync @@ -2242,31 +2298,31 @@ void ofdm_sync_state_machine(struct OFDM *ofdm, uint8_t *rx_uw) { \*---------------------------------------------------------------------------*/ void ofdm_set_sync(struct OFDM *ofdm, int sync_cmd) { - assert(ofdm != NULL); - - switch (sync_cmd) { - case UN_SYNC: - /* force manual unsync, which will cause sync state machine to - have re-attempt sync */ - ofdm->sync_state = search; - /* clear rxbuf so we don't try to sync on any existing OFDM signals - in buffer */ - for (int i = 0; i < ofdm->nrxbuf; i++) ofdm->rxbuf[i] = 0.0f; - break; - case AUTO_SYNC: - /* normal operating mode - sync state machine decides when to unsync */ - ofdm->sync_mode = autosync; - break; - case MANUAL_SYNC: - /* - * allow sync state machine to sync, but not to unsync, the - * operator will decide that manually - */ - ofdm->sync_mode = manualsync; - break; - default: - assert(0); - } + assert(ofdm != NULL); + + switch (sync_cmd) { + case UN_SYNC: + /* force manual unsync, which will cause sync state machine to + have re-attempt sync */ + ofdm->sync_state = search; + /* clear rxbuf so we don't try to sync on any existing OFDM signals + in buffer */ + for (int i = 0; i < ofdm->nrxbuf; i++) ofdm->rxbuf[i] = 0.0f; + break; + case AUTO_SYNC: + /* normal operating mode - sync state machine decides when to unsync */ + ofdm->sync_mode = autosync; + break; + case MANUAL_SYNC: + /* + * allow sync state machine to sync, but not to unsync, the + * operator will decide that manually + */ + ofdm->sync_mode = manualsync; + break; + default: + assert(0); + } } /*---------------------------------------------------------------------------*\ @@ -2280,50 +2336,51 @@ void ofdm_set_sync(struct OFDM *ofdm, int sync_cmd) { \*---------------------------------------------------------------------------*/ -void ofdm_get_demod_stats(struct OFDM *ofdm, struct MODEM_STATS *stats, complex float *rx_syms, int Nsymsperpacket) { - stats->Nc = ofdm->nc; - assert(stats->Nc <= MODEM_STATS_NC_MAX); - - float EsNodB = ofdm_esno_est_calc(rx_syms, Nsymsperpacket); - float SNR3kdB = ofdm_snr_from_esno(ofdm, EsNodB); - - if (strlen(ofdm->data_mode)) - /* no smoothing as we have a large number of symbols per packet */ - stats->snr_est = SNR3kdB; - else { - /* in voice modes we further smooth SNR est, fast attack, slow decay */ - if (SNR3kdB > stats->snr_est) - stats->snr_est = SNR3kdB; - else - stats->snr_est = 0.9f * stats->snr_est + 0.1f * SNR3kdB; - } - stats->sync = ((ofdm->sync_state == synced) || (ofdm->sync_state == trial)); - stats->foff = ofdm->foff_est_hz; - stats->rx_timing = ofdm->timing_est; - - float total = ofdm->frame_count * ofdm->samplesperframe; - stats->clock_offset = 0; - if (total != 0.0f) { - stats->clock_offset = ofdm->clock_offset_counter / total; - } +void ofdm_get_demod_stats(struct OFDM *ofdm, struct MODEM_STATS *stats, + complex float *rx_syms, int Nsymsperpacket) { + stats->Nc = ofdm->nc; + assert(stats->Nc <= MODEM_STATS_NC_MAX); + + float EsNodB = ofdm_esno_est_calc(rx_syms, Nsymsperpacket); + float SNR3kdB = ofdm_snr_from_esno(ofdm, EsNodB); + + if (strlen(ofdm->data_mode)) + /* no smoothing as we have a large number of symbols per packet */ + stats->snr_est = SNR3kdB; + else { + /* in voice modes we further smooth SNR est, fast attack, slow decay */ + if (SNR3kdB > stats->snr_est) + stats->snr_est = SNR3kdB; + else + stats->snr_est = 0.9f * stats->snr_est + 0.1f * SNR3kdB; + } + stats->sync = ((ofdm->sync_state == synced) || (ofdm->sync_state == trial)); + stats->foff = ofdm->foff_est_hz; + stats->rx_timing = ofdm->timing_est; + + float total = ofdm->frame_count * ofdm->samplesperframe; + stats->clock_offset = 0; + if (total != 0.0f) { + stats->clock_offset = ofdm->clock_offset_counter / total; + } + + stats->sync_metric = ofdm->timing_mx; + stats->pre = ofdm->pre; + stats->post = ofdm->post; + stats->uw_fails = ofdm->uw_fails; - stats->sync_metric = ofdm->timing_mx; - stats->pre = ofdm->pre; - stats->post = ofdm->post; - stats->uw_fails = ofdm->uw_fails; - #ifndef __EMBEDDED__ - assert(Nsymsperpacket % ofdm->nc == 0); - int Nrowsperpacket = Nsymsperpacket/ofdm->nc; - assert(Nrowsperpacket <= MODEM_STATS_NR_MAX); - stats->nr = Nrowsperpacket; - for (int c = 0; c < ofdm->nc; c++) { - for (int r = 0; r < Nrowsperpacket; r++) { - complex float rot = rx_syms[r * ofdm->nc + c] * cmplx(ROT45); - stats->rx_symbols[r][c].real = crealf(rot); - stats->rx_symbols[r][c].imag = cimagf(rot); - } - } + assert(Nsymsperpacket % ofdm->nc == 0); + int Nrowsperpacket = Nsymsperpacket / ofdm->nc; + assert(Nrowsperpacket <= MODEM_STATS_NR_MAX); + stats->nr = Nrowsperpacket; + for (int c = 0; c < ofdm->nc; c++) { + for (int r = 0; r < Nrowsperpacket; r++) { + complex float rot = rx_syms[r * ofdm->nc + c] * cmplx(ROT45); + stats->rx_symbols[r][c].real = crealf(rot); + stats->rx_symbols[r][c].imag = cimagf(rot); + } + } #endif } @@ -2331,174 +2388,187 @@ void ofdm_get_demod_stats(struct OFDM *ofdm, struct MODEM_STATS *stats, complex * Assemble packet of bits from UW, payload bits, and txt bits */ void ofdm_assemble_qpsk_modem_packet(struct OFDM *ofdm, uint8_t modem_frame[], - uint8_t payload_bits[], uint8_t txt_bits[]) { - int s, t; + uint8_t payload_bits[], + uint8_t txt_bits[]) { + int s, t; - int p = 0; - int u = 0; + int p = 0; + int u = 0; - for (s = 0; s < (ofdm->bitsperpacket - ofdm->ntxtbits); s++) { - if ((u < ofdm->nuwbits) && (s == ofdm->uw_ind[u])) { - modem_frame[s] = ofdm->tx_uw[u++]; - } else { - modem_frame[s] = payload_bits[p++]; - } + for (s = 0; s < (ofdm->bitsperpacket - ofdm->ntxtbits); s++) { + if ((u < ofdm->nuwbits) && (s == ofdm->uw_ind[u])) { + modem_frame[s] = ofdm->tx_uw[u++]; + } else { + modem_frame[s] = payload_bits[p++]; } + } - assert(u == ofdm->nuwbits); - assert(p == (ofdm->bitsperpacket - ofdm->nuwbits - ofdm->ntxtbits)); + assert(u == ofdm->nuwbits); + assert(p == (ofdm->bitsperpacket - ofdm->nuwbits - ofdm->ntxtbits)); - for (t = 0; s < ofdm->bitsperframe; s++, t++) { - modem_frame[s] = txt_bits[t]; - } + for (t = 0; s < ofdm->bitsperframe; s++, t++) { + modem_frame[s] = txt_bits[t]; + } - assert(t == ofdm->ntxtbits); + assert(t == ofdm->ntxtbits); } /* * Assemble packet of symbols from UW, payload symbols, and txt bits */ -void ofdm_assemble_qpsk_modem_packet_symbols(struct OFDM *ofdm, complex float modem_packet[], - COMP payload_syms[], uint8_t txt_bits[]) { - complex float *payload = (complex float *) &payload_syms[0]; // complex has same memory layout - int Nsymsperpacket = ofdm->bitsperpacket / ofdm->bps; - int Nuwsyms = ofdm->nuwbits / ofdm->bps; - int Ntxtsyms = ofdm->ntxtbits / ofdm->bps; - int dibit[2]; - int s, t; - - int p = 0; - int u = 0; - - assert(ofdm->bps == 2); /* this only works for QPSK at this stage (e.g. modem packet mod) */ - - for (s = 0; s < (Nsymsperpacket - Ntxtsyms); s++) { - if ((u < Nuwsyms) && (s == ofdm->uw_ind_sym[u])) { - modem_packet[s] = ofdm->tx_uw_syms[u++]; - } else { - modem_packet[s] = payload[p++]; - } +void ofdm_assemble_qpsk_modem_packet_symbols(struct OFDM *ofdm, + complex float modem_packet[], + COMP payload_syms[], + uint8_t txt_bits[]) { + complex float *payload = + (complex float *)&payload_syms[0]; // complex has same memory layout + int Nsymsperpacket = ofdm->bitsperpacket / ofdm->bps; + int Nuwsyms = ofdm->nuwbits / ofdm->bps; + int Ntxtsyms = ofdm->ntxtbits / ofdm->bps; + int dibit[2]; + int s, t; + + int p = 0; + int u = 0; + + assert( + ofdm->bps == + 2); /* this only works for QPSK at this stage (e.g. modem packet mod) */ + + for (s = 0; s < (Nsymsperpacket - Ntxtsyms); s++) { + if ((u < Nuwsyms) && (s == ofdm->uw_ind_sym[u])) { + modem_packet[s] = ofdm->tx_uw_syms[u++]; + } else { + modem_packet[s] = payload[p++]; } + } - assert(u == Nuwsyms); - assert(p == (Nsymsperpacket - Nuwsyms - Ntxtsyms)); + assert(u == Nuwsyms); + assert(p == (Nsymsperpacket - Nuwsyms - Ntxtsyms)); - for (t = 0; s < Nsymsperpacket; s++, t += 2) { - dibit[1] = txt_bits[t ] & 0x1; - dibit[0] = txt_bits[t + 1] & 0x1; - modem_packet[s] = qpsk_mod(dibit); - } + for (t = 0; s < Nsymsperpacket; s++, t += 2) { + dibit[1] = txt_bits[t] & 0x1; + dibit[0] = txt_bits[t + 1] & 0x1; + modem_packet[s] = qpsk_mod(dibit); + } - assert(t == ofdm->ntxtbits); + assert(t == ofdm->ntxtbits); } /* - * Disassemble a received packet of symbols into UW bits and payload data symbols + * Disassemble a received packet of symbols into UW bits and payload data + * symbols */ -void ofdm_disassemble_qpsk_modem_packet(struct OFDM *ofdm, complex float rx_syms[], float rx_amps[], - COMP codeword_syms[], float codeword_amps[], short txt_bits[]) -{ - complex float *codeword = (complex float *) &codeword_syms[0]; // complex has same memory layout - int Nsymsperpacket = ofdm->bitsperpacket / ofdm->bps; - int Nuwsyms = ofdm->nuwbits / ofdm->bps; - int Ntxtsyms = ofdm->ntxtbits / ofdm->bps; - int dibit[2]; - int s, t; - - int p = 0; - int u = 0; - - assert(ofdm->bps == 2); /* this only works for QPSK at this stage */ - - for (s = 0; s < (Nsymsperpacket - Ntxtsyms); s++) { - if ((u < Nuwsyms) && (s == ofdm->uw_ind_sym[u])) { - u++; - } else { - codeword[p] = rx_syms[s]; - codeword_amps[p] = rx_amps[s]; - p++; - } +void ofdm_disassemble_qpsk_modem_packet(struct OFDM *ofdm, + complex float rx_syms[], + float rx_amps[], COMP codeword_syms[], + float codeword_amps[], + short txt_bits[]) { + complex float *codeword = + (complex float *)&codeword_syms[0]; // complex has same memory layout + int Nsymsperpacket = ofdm->bitsperpacket / ofdm->bps; + int Nuwsyms = ofdm->nuwbits / ofdm->bps; + int Ntxtsyms = ofdm->ntxtbits / ofdm->bps; + int dibit[2]; + int s, t; + + int p = 0; + int u = 0; + + assert(ofdm->bps == 2); /* this only works for QPSK at this stage */ + + for (s = 0; s < (Nsymsperpacket - Ntxtsyms); s++) { + if ((u < Nuwsyms) && (s == ofdm->uw_ind_sym[u])) { + u++; + } else { + codeword[p] = rx_syms[s]; + codeword_amps[p] = rx_amps[s]; + p++; } + } - assert(u == Nuwsyms); - assert(p == (Nsymsperpacket - Nuwsyms - Ntxtsyms)); + assert(u == Nuwsyms); + assert(p == (Nsymsperpacket - Nuwsyms - Ntxtsyms)); - for (t = 0; s < Nsymsperpacket; s++, t += 2) { - qpsk_demod(rx_syms[s], dibit); + for (t = 0; s < Nsymsperpacket; s++, t += 2) { + qpsk_demod(rx_syms[s], dibit); - txt_bits[t ] = dibit[1]; - txt_bits[t + 1] = dibit[0]; - } + txt_bits[t] = dibit[1]; + txt_bits[t + 1] = dibit[0]; + } - assert(t == ofdm->ntxtbits); + assert(t == ofdm->ntxtbits); } /* - * Disassemble a received packet of symbols into UW bits and payload data symbols + * Disassemble a received packet of symbols into UW bits and payload data + * symbols */ void ofdm_disassemble_qpsk_modem_packet_with_text_amps( - struct OFDM *ofdm, complex float rx_syms[], float rx_amps[], - COMP codeword_syms[], float codeword_amps[], short txt_bits[], - int* textIndex) -{ - complex float *codeword = (complex float *) &codeword_syms[0]; // complex has same memory layout - int Nsymsperpacket = ofdm->bitsperpacket / ofdm->bps; - int Nuwsyms = ofdm->nuwbits / ofdm->bps; - int Ntxtsyms = ofdm->ntxtbits / ofdm->bps; - int dibit[2]; - int s, t; - - int p = 0; - int u = 0; - - assert(ofdm->bps == 2); /* this only works for QPSK at this stage */ - assert(textIndex != NULL); - - for (s = 0; s < (Nsymsperpacket - Ntxtsyms); s++) { - if ((u < Nuwsyms) && (s == ofdm->uw_ind_sym[u])) { - u++; - } else { - codeword[p] = rx_syms[s]; - codeword_amps[p] = rx_amps[s]; - p++; - } + struct OFDM *ofdm, complex float rx_syms[], float rx_amps[], + COMP codeword_syms[], float codeword_amps[], short txt_bits[], + int *textIndex) { + complex float *codeword = + (complex float *)&codeword_syms[0]; // complex has same memory layout + int Nsymsperpacket = ofdm->bitsperpacket / ofdm->bps; + int Nuwsyms = ofdm->nuwbits / ofdm->bps; + int Ntxtsyms = ofdm->ntxtbits / ofdm->bps; + int dibit[2]; + int s, t; + + int p = 0; + int u = 0; + + assert(ofdm->bps == 2); /* this only works for QPSK at this stage */ + assert(textIndex != NULL); + + for (s = 0; s < (Nsymsperpacket - Ntxtsyms); s++) { + if ((u < Nuwsyms) && (s == ofdm->uw_ind_sym[u])) { + u++; + } else { + codeword[p] = rx_syms[s]; + codeword_amps[p] = rx_amps[s]; + p++; } + } - assert(u == Nuwsyms); - assert(p == (Nsymsperpacket - Nuwsyms - Ntxtsyms)); + assert(u == Nuwsyms); + assert(p == (Nsymsperpacket - Nuwsyms - Ntxtsyms)); - *textIndex = s; - for (t = 0; s < Nsymsperpacket; s++, t += 2) { - qpsk_demod(rx_syms[s], dibit); + *textIndex = s; + for (t = 0; s < Nsymsperpacket; s++, t += 2) { + qpsk_demod(rx_syms[s], dibit); - txt_bits[t ] = dibit[1]; - txt_bits[t + 1] = dibit[0]; - } + txt_bits[t] = dibit[1]; + txt_bits[t + 1] = dibit[0]; + } - assert(t == ofdm->ntxtbits); + assert(t == ofdm->ntxtbits); } /* * Extract just the UW from the packet */ -void ofdm_extract_uw(struct OFDM *ofdm, complex float rx_syms[], float rx_amps[], uint8_t rx_uw[]) { - int Nsymsperframe = ofdm->bitsperframe / ofdm->bps; - int Nuwsyms = ofdm->nuwbits / ofdm->bps; - int dibit[2]; - int s,u; - - assert(ofdm->bps == 2); /* this only works for QPSK at this stage (e.g. UW demod) */ - - for (s = 0, u = 0; s < Nsymsperframe*ofdm->nuwframes; s++) { - if ((u < Nuwsyms) && (s == ofdm->uw_ind_sym[u])) { - qpsk_demod(rx_syms[s], dibit); - rx_uw[2 * u ] = dibit[1]; - rx_uw[2 * u + 1] = dibit[0]; - u++; - } - } - - assert(u == Nuwsyms); +void ofdm_extract_uw(struct OFDM *ofdm, complex float rx_syms[], + float rx_amps[], uint8_t rx_uw[]) { + int Nsymsperframe = ofdm->bitsperframe / ofdm->bps; + int Nuwsyms = ofdm->nuwbits / ofdm->bps; + int dibit[2]; + int s, u; + + assert(ofdm->bps == + 2); /* this only works for QPSK at this stage (e.g. UW demod) */ + + for (s = 0, u = 0; s < Nsymsperframe * ofdm->nuwframes; s++) { + if ((u < Nuwsyms) && (s == ofdm->uw_ind_sym[u])) { + qpsk_demod(rx_syms[s], dibit); + rx_uw[2 * u] = dibit[1]; + rx_uw[2 * u + 1] = dibit[0]; + u++; + } + } + + assert(u == Nuwsyms); } /* @@ -2506,30 +2576,29 @@ void ofdm_extract_uw(struct OFDM *ofdm, complex float rx_syms[], float rx_amps[] * identical results to Octave. Returns an unsigned int between 0 * and 32767. Used for generating test frames of various lengths. */ -void ofdm_rand(uint16_t r[], int n) { - ofdm_rand_seed(r, n, 1); -} +void ofdm_rand(uint16_t r[], int n) { ofdm_rand_seed(r, n, 1); } void ofdm_rand_seed(uint16_t r[], int n, uint64_t seed) { - for (int i = 0; i < n; i++) { - seed = (1103515245l * seed + 12345) % 32768; - r[i] = seed; - } + for (int i = 0; i < n; i++) { + seed = (1103515245l * seed + 12345) % 32768; + r[i] = seed; + } } void ofdm_generate_payload_data_bits(uint8_t payload_data_bits[], int n) { - uint16_t r[n]; - int i; + uint16_t r[n]; + int i; - ofdm_rand(r, n); + ofdm_rand(r, n); - for (i = 0; i < n; i++) { - payload_data_bits[i] = r[i] > 16384; - } + for (i = 0; i < n; i++) { + payload_data_bits[i] = r[i] > 16384; + } } void ofdm_generate_preamble(struct OFDM *ofdm, COMP *tx_preamble, int seed) { - // need to modify bits per packet to set up pre-amble of a few modem frames in length + // need to modify bits per packet to set up pre-amble of a few modem frames in + // length struct OFDM ofdm_preamble; memcpy(&ofdm_preamble, ofdm, sizeof(struct OFDM)); ofdm_preamble.np = 1; @@ -2537,92 +2606,93 @@ void ofdm_generate_preamble(struct OFDM *ofdm, COMP *tx_preamble, int seed) { uint16_t r[ofdm_preamble.bitsperpacket]; ofdm_rand_seed(r, ofdm_preamble.bitsperpacket, seed); int preamble_bits[ofdm_preamble.bitsperpacket]; - for(int i=0; i<ofdm_preamble.bitsperpacket; i++) - preamble_bits[i] = r[i] > 16384; + for (int i = 0; i < ofdm_preamble.bitsperpacket; i++) + preamble_bits[i] = r[i] > 16384; // ensures the signal passes through hilbert clipper unchanged - ofdm_preamble.amp_scale = 1.0; + ofdm_preamble.amp_scale = 1.0; ofdm_preamble.tx_bpf_en = false; ofdm_preamble.clip_en = false; ofdm_mod(&ofdm_preamble, tx_preamble, preamble_bits); } void ofdm_print_info(struct OFDM *ofdm) { - char *syncmode[] = { - "unsync", - "autosync", - "manualsync" - }; - char *phase_est_bandwidth_mode[] = { - "auto", - "locked_high" - }; - - fprintf(stderr, "ofdm->tx_centre = %g\n", (double)ofdm->tx_centre); - fprintf(stderr, "ofdm->rx_centre = %g\n", (double)ofdm->rx_centre); - fprintf(stderr, "ofdm->fs = %g\n", (double)ofdm->fs); - fprintf(stderr, "ofdm->ts = %g\n", (double)ofdm->ts); - fprintf(stderr, "ofdm->rs = %g\n", (double)ofdm->rs); - fprintf(stderr, "ofdm->tcp = %g\n", (double)ofdm->tcp); - fprintf(stderr, "ofdm->inv_m = %g\n", (double)ofdm->inv_m); - fprintf(stderr, "ofdm->tx_nlower = %g\n", (double)ofdm->tx_nlower); - fprintf(stderr, "ofdm->rx_nlower = %g\n", (double)ofdm->rx_nlower); - fprintf(stderr, "ofdm->doc = %g\n", (double)ofdm->doc); - fprintf(stderr, "ofdm->timing_mx_thresh = %g\n", (double)ofdm->timing_mx_thresh); - fprintf(stderr, "ofdm->nc = %d\n", ofdm->nc); - fprintf(stderr, "ofdm->np = %d\n", ofdm->np); - fprintf(stderr, "ofdm->ns = %d\n", ofdm->ns); - fprintf(stderr, "ofdm->bps = %d\n", ofdm->bps); - fprintf(stderr, "ofdm->m = %d\n", ofdm->m); - fprintf(stderr, "ofdm->ncp = %d\n", ofdm->ncp); - fprintf(stderr, "ofdm->ftwindowwidth = %d\n", ofdm->ftwindowwidth); - fprintf(stderr, "ofdm->bitsperframe = %d\n", ofdm->bitsperframe); - fprintf(stderr, "ofdm->bitsperpacket = %d\n", ofdm->bitsperpacket); - fprintf(stderr, "ofdm->rowsperframe = %d\n", ofdm->rowsperframe); - fprintf(stderr, "ofdm->samplespersymbol = %d\n", ofdm->samplespersymbol); - fprintf(stderr, "ofdm->samplesperframe = %d\n", ofdm->samplesperframe); - fprintf(stderr, "ofdm->max_samplesperframe = %d\n", ofdm->max_samplesperframe); - fprintf(stderr, "ofdm->nrxbuf = %d\n", ofdm->nrxbuf); - fprintf(stderr, "ofdm->ntxtbits = %d\n", ofdm->ntxtbits); - fprintf(stderr, "ofdm->nuwbits = %d\n", ofdm->nuwbits); - fprintf(stderr, "ofdm->foff_est_gain = %g\n", (double)ofdm->foff_est_gain); - fprintf(stderr, "ofdm->foff_est_hz = %g\n", (double)ofdm->foff_est_hz); - fprintf(stderr, "ofdm->timing_mx = %g\n", (double)ofdm->timing_mx); - fprintf(stderr, "ofdm->coarse_foff_est_hz = %g\n", (double)ofdm->coarse_foff_est_hz); - fprintf(stderr, "ofdm->timing_norm = %g\n", (double)ofdm->timing_norm); - fprintf(stderr, "ofdm->mean_amp = %g\n", (double)ofdm->mean_amp); - fprintf(stderr, "ofdm->clock_offset_counter = %d\n", ofdm->clock_offset_counter); - fprintf(stderr, "ofdm->verbose = %d\n", ofdm->verbose); - fprintf(stderr, "ofdm->sample_point = %d\n", ofdm->sample_point); - fprintf(stderr, "ofdm->timing_est = %d\n", ofdm->timing_est); - fprintf(stderr, "ofdm->timing_valid = %d\n", ofdm->timing_valid); - fprintf(stderr, "ofdm->nin = %d\n", ofdm->nin); - fprintf(stderr, "ofdm->uw_errors = %d\n", ofdm->uw_errors); - fprintf(stderr, "ofdm->sync_counter = %d\n", ofdm->sync_counter); - fprintf(stderr, "ofdm->frame_count = %d\n", ofdm->frame_count); - fprintf(stderr, "ofdm->sync_start = %s\n", ofdm->sync_start ? "true" : "false"); - fprintf(stderr, "ofdm->sync_end = %s\n", ofdm->sync_end ? "true" : "false"); - fprintf(stderr, "ofdm->sync_mode = %s\n", syncmode[ofdm->sync_mode]); - fprintf(stderr, "ofdm->timing_en = %s\n", ofdm->timing_en ? "true" : "false"); - fprintf(stderr, "ofdm->foff_est_en = %s\n", ofdm->foff_est_en ? "true" : "false"); - fprintf(stderr, "ofdm->phase_est_en = %s\n", ofdm->phase_est_en ? "true" : "false"); - fprintf(stderr, "ofdm->tx_bpf_en = %s\n", ofdm->tx_bpf_en ? "true" : "false"); - fprintf(stderr, "ofdm->rx_bpf_en = %s\n", ofdm->rx_bpf_en ? "true" : "false"); - fprintf(stderr, "ofdm->dpsk_en = %s\n", ofdm->dpsk_en ? "true" : "false"); - fprintf(stderr, "ofdm->phase_est_bandwidth_mode = %s\n", phase_est_bandwidth_mode[ofdm->phase_est_bandwidth_mode]); + char *syncmode[] = {"unsync", "autosync", "manualsync"}; + char *phase_est_bandwidth_mode[] = {"auto", "locked_high"}; + + fprintf(stderr, "ofdm->tx_centre = %g\n", (double)ofdm->tx_centre); + fprintf(stderr, "ofdm->rx_centre = %g\n", (double)ofdm->rx_centre); + fprintf(stderr, "ofdm->fs = %g\n", (double)ofdm->fs); + fprintf(stderr, "ofdm->ts = %g\n", (double)ofdm->ts); + fprintf(stderr, "ofdm->rs = %g\n", (double)ofdm->rs); + fprintf(stderr, "ofdm->tcp = %g\n", (double)ofdm->tcp); + fprintf(stderr, "ofdm->inv_m = %g\n", (double)ofdm->inv_m); + fprintf(stderr, "ofdm->tx_nlower = %g\n", (double)ofdm->tx_nlower); + fprintf(stderr, "ofdm->rx_nlower = %g\n", (double)ofdm->rx_nlower); + fprintf(stderr, "ofdm->doc = %g\n", (double)ofdm->doc); + fprintf(stderr, "ofdm->timing_mx_thresh = %g\n", + (double)ofdm->timing_mx_thresh); + fprintf(stderr, "ofdm->nc = %d\n", ofdm->nc); + fprintf(stderr, "ofdm->np = %d\n", ofdm->np); + fprintf(stderr, "ofdm->ns = %d\n", ofdm->ns); + fprintf(stderr, "ofdm->bps = %d\n", ofdm->bps); + fprintf(stderr, "ofdm->m = %d\n", ofdm->m); + fprintf(stderr, "ofdm->ncp = %d\n", ofdm->ncp); + fprintf(stderr, "ofdm->ftwindowwidth = %d\n", ofdm->ftwindowwidth); + fprintf(stderr, "ofdm->bitsperframe = %d\n", ofdm->bitsperframe); + fprintf(stderr, "ofdm->bitsperpacket = %d\n", ofdm->bitsperpacket); + fprintf(stderr, "ofdm->rowsperframe = %d\n", ofdm->rowsperframe); + fprintf(stderr, "ofdm->samplespersymbol = %d\n", ofdm->samplespersymbol); + fprintf(stderr, "ofdm->samplesperframe = %d\n", ofdm->samplesperframe); + fprintf(stderr, "ofdm->max_samplesperframe = %d\n", + ofdm->max_samplesperframe); + fprintf(stderr, "ofdm->nrxbuf = %d\n", ofdm->nrxbuf); + fprintf(stderr, "ofdm->ntxtbits = %d\n", ofdm->ntxtbits); + fprintf(stderr, "ofdm->nuwbits = %d\n", ofdm->nuwbits); + fprintf(stderr, "ofdm->foff_est_gain = %g\n", (double)ofdm->foff_est_gain); + fprintf(stderr, "ofdm->foff_est_hz = %g\n", (double)ofdm->foff_est_hz); + fprintf(stderr, "ofdm->timing_mx = %g\n", (double)ofdm->timing_mx); + fprintf(stderr, "ofdm->coarse_foff_est_hz = %g\n", + (double)ofdm->coarse_foff_est_hz); + fprintf(stderr, "ofdm->timing_norm = %g\n", (double)ofdm->timing_norm); + fprintf(stderr, "ofdm->mean_amp = %g\n", (double)ofdm->mean_amp); + fprintf(stderr, "ofdm->clock_offset_counter = %d\n", + ofdm->clock_offset_counter); + fprintf(stderr, "ofdm->verbose = %d\n", ofdm->verbose); + fprintf(stderr, "ofdm->sample_point = %d\n", ofdm->sample_point); + fprintf(stderr, "ofdm->timing_est = %d\n", ofdm->timing_est); + fprintf(stderr, "ofdm->timing_valid = %d\n", ofdm->timing_valid); + fprintf(stderr, "ofdm->nin = %d\n", ofdm->nin); + fprintf(stderr, "ofdm->uw_errors = %d\n", ofdm->uw_errors); + fprintf(stderr, "ofdm->sync_counter = %d\n", ofdm->sync_counter); + fprintf(stderr, "ofdm->frame_count = %d\n", ofdm->frame_count); + fprintf(stderr, "ofdm->sync_start = %s\n", + ofdm->sync_start ? "true" : "false"); + fprintf(stderr, "ofdm->sync_end = %s\n", ofdm->sync_end ? "true" : "false"); + fprintf(stderr, "ofdm->sync_mode = %s\n", syncmode[ofdm->sync_mode]); + fprintf(stderr, "ofdm->timing_en = %s\n", ofdm->timing_en ? "true" : "false"); + fprintf(stderr, "ofdm->foff_est_en = %s\n", + ofdm->foff_est_en ? "true" : "false"); + fprintf(stderr, "ofdm->phase_est_en = %s\n", + ofdm->phase_est_en ? "true" : "false"); + fprintf(stderr, "ofdm->tx_bpf_en = %s\n", ofdm->tx_bpf_en ? "true" : "false"); + fprintf(stderr, "ofdm->rx_bpf_en = %s\n", ofdm->rx_bpf_en ? "true" : "false"); + fprintf(stderr, "ofdm->dpsk_en = %s\n", ofdm->dpsk_en ? "true" : "false"); + fprintf(stderr, "ofdm->phase_est_bandwidth_mode = %s\n", + phase_est_bandwidth_mode[ofdm->phase_est_bandwidth_mode]); } // hilbert clipper void ofdm_clip(complex float tx[], float clip_thresh, int n) { - complex float sam; - float mag; - int i; - - for(i=0; i<n; i++) { - sam = tx[i]; - mag = cabsf(sam); - if (mag > clip_thresh) { - sam *= clip_thresh/mag; - } - tx[i] = sam; - } - } + complex float sam; + float mag; + int i; + + for (i = 0; i < n; i++) { + sam = tx[i]; + mag = cabsf(sam); + if (mag > clip_thresh) { + sam *= clip_thresh / mag; + } + tx[i] = sam; + } +} |