shallow zip-file copy from codec2 e9d726bf20

1 files changed, 277 insertions, 0 deletions

diff --git a/src/ofdm_internal.h b/src/ofdm_internal.h
new file mode 100644
index 0000000..caa7876
--- /dev/null
+++ b/src/ofdm_internal.h
@@ -0,0 +1,277 @@
+/*---------------------------------------------------------------------------*\
+
+  FILE........: ofdm_internal.h
+  AUTHORS.....: David Rowe & Steve Sampson
+  DATE CREATED: June 2017
+
+  OFDM Internal definitions.
+
+\*---------------------------------------------------------------------------*/
+
+/*
+  Copyright (C) 2017 David Rowe
+
+  All rights reserved.
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License version 2.1, as
+  published by the Free Software Foundation.  This program is
+  distributed in the hope that it will be useful, but WITHOUT ANY
+  WARRANTY; without even the implied warranty of MERCHANTABILITY or
+  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+  License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef OFDM_INTERNAL_H
+#define OFDM_INTERNAL_H
+
+#include <complex.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "codec2_ofdm.h"
+#include "filter.h"
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+#ifndef M_PI
+#define M_PI        3.14159265358979323846f
+#endif
+
+#define TAU         (2.0f * M_PI)
+#define ROT45       (M_PI / 4.0f)
+#define MAX_UW_BITS 64
+
+#define cmplx(value) (cosf(value) + sinf(value) * I)
+#define cmplxconj(value) (cosf(value) + sinf(value) * -I)
+
+/* modem state machine states */
+typedef enum {
+    search,
+    trial,
+    synced
+} State;
+
+typedef enum {
+    unsync,             /* force sync state machine to lose sync, and search for new sync */
+    autosync,           /* falls out of sync automatically */
+    manualsync          /* fall out of sync only under operator control */
+} Sync;
+
+/* phase estimator bandwidth options */
+
+typedef enum {
+    low_bw,             /* can only track a narrow freq offset, but accurate         */
+    high_bw             /* can track wider freq offset, but less accurate at low SNR */
+} PhaseEstBandwidth;
+
+/*
+ * User-defined configuration for OFDM modem.  Used to set up
+ * constants at init time, e.g. for different bit rate modems.
+ */
+
+struct OFDM_CONFIG {
+    float tx_centre;   /* TX Centre Audio Frequency */
+    float rx_centre;   /* RX Centre Audio Frequency */
+    float fs;          /* Sample Frequency */
+    float rs;          /* Symbol Rate */
+    float ts;          /* symbol duration */
+    float tcp;         /* Cyclic Prefix duration */
+    float timing_mx_thresh;
+
+    int nc;            /* Number of carriers */
+    int ns;            /* Number of Symbol frames */
+    int np;            /* number of modem frames per packet */
+    int bps;           /* Bits per Symbol */
+    int txtbits;       /* number of auxiliary data bits */
+    int nuwbits;       /* number of unique word bits */
+    int bad_uw_errors;
+    int ftwindowwidth;
+    int edge_pilots;
+    char *state_machine;  /* name of sync state machine used for this mode */
+    char *codename;       /* name of LDPC code used with this mode */
+    uint8_t tx_uw[MAX_UW_BITS]; /* user defined unique word */
+    int amp_est_mode;
+    bool tx_bpf_en;       /* default tx (mod) hilbert clipper BPF enable */
+    bool rx_bpf_en;       /* default rx (demod) input BPF enable */
+    bool foff_limiter;    /* tames freq offset updates in low SNR */
+    float amp_scale;      /* used to scale Tx waveform to approx FREEDV_PEAK with clipper off */
+    float clip_gain1;     /* gain we apply to Tx signal before clipping to control PAPR*/
+    float clip_gain2;     /* gain we apply to Tx signal after clipping and BBF to control peak level */
+    bool  clip_en;
+    char mode[16];        /* OFDM mode in string form */
+    char *data_mode;
+    float fmin;
+    float fmax;
+};
+
+struct OFDM {
+    struct OFDM_CONFIG config;
+
+    char mode[16];        /* mode in string form */
+    /*
+     * See 700D Part 4 Acquisition blog post and ofdm_dev.m routines
+     * for how this was set
+     */
+    float timing_mx_thresh;
+
+    int nc;
+    int ns;              	 /* NS-1 = data symbols between pilots  */
+    int bps; 	             /* Bits per symbol */
+    int m; 	               /* duration of each symbol in samples */
+    int ncp; 	             /* duration of CP in samples */
+    int np;                /* number of modem frames per packet. In some modes we want */
+                           /* the total packet of data to span multiple modem frames, e.g. HF data */
+                           /* and/or when the FEC codeword is larger than the one */
+                           /* modem frame.  In other modes (e.g. 700D/2020) Np=1, ie the modem frame */
+                           /* is the same length as the packet/FEC frame. */
+    int ftwindowwidth;
+    int bitsperframe;      /* total bits in all data symbols in modem frame */
+    int bitsperpacket;     /* total bits in all data symbols in a packet */
+    int rowsperframe;
+    int samplespersymbol;
+    int samplesperframe;
+    int nrxbufhistory;    /* extra storage at start of rxbuf to allow us to step back in time */
+    int nrxbufmin;        /* min number of samples we need in rxbuf to process a modem frame */
+    int rxbufst;          /* start of rxbuf window used for demod of current rx frame */
+    int pre, post;        /* pre-amble and post-amble detections */
+    int max_samplesperframe;
+    int nuwframes;
+    int nrxbuf;
+    int ntxtbits;         /* reserve bits/frame for aux text information */
+    int nuwbits;          /* number of unique word bits used to achieve packet frame sync */
+    int bad_uw_errors;    /* threshold for UW detection check */
+    int uw_fails;         /* number of times we exceeded bad_uw_errors and dropped sync */
+    int edge_pilots;      /* insert pilots at 1 and Nc+2, to support low bandwidth phase est */
+    char *data_mode;      /* "", "streaming", "burst"  */
+    int packetsperburst;  /* for OFDM data modes, how many packets before we reset state machine */
+    int amp_est_mode;     /* amplitude estimtor algorithm */
+    float amp_scale;
+    float clip_gain1;
+    float clip_gain2;
+    bool  clip_en;
+
+    float tx_centre;      /* TX Center frequency */
+    float rx_centre;      /* RX Center frequency */
+    float fs;             /* Sample rate */
+    float ts;             /* Symbol cycle time */
+    float rs;             /* Symbol rate */
+    float tcp;            /* Cyclic prefix duration */
+    float tpacket;        /* time for one packet in ms */
+    float inv_m;          /* 1/m */
+    float tx_nlower;      /* TX lowest carrier freq */
+    float rx_nlower;      /* RX lowest carrier freq */
+    float doc;            /* division of radian circle */
+    
+    float fmin;
+    float fmax;
+
+    // Pointers
+
+    struct quisk_cfFilter *tx_bpf;
+    struct quisk_cfFilter *rx_bpf;
+
+    complex float *pilot_samples;
+    complex float *rxbuf;
+    complex float *pilots;
+    complex float **rx_sym;
+    complex float *rx_np;
+    complex float *tx_uw_syms;
+    COMP          *tx_preamble;
+    COMP          *tx_postamble;
+
+    float *rx_amp;
+    float *aphase_est_pilot_log;
+
+    uint8_t tx_uw[MAX_UW_BITS];
+    int *uw_ind;
+    int *uw_ind_sym;
+
+    // State enums
+    State sync_state;
+    State last_sync_state;
+
+    // Sync enums
+    Sync sync_mode;
+
+    // Phase enums
+    PhaseEstBandwidth phase_est_bandwidth;
+
+    int phase_est_bandwidth_mode;
+
+    // Complex
+    complex float foff_metric;
+
+    // Float
+    float foff_est_gain;
+    bool  foff_limiter;
+    float foff_est_hz;
+    float timing_mx;
+    float coarse_foff_est_hz;
+    float timing_norm;
+    float mean_amp;
+
+    // Integer
+    int clock_offset_counter;
+    int verbose;
+    int sample_point;
+    int timing_est;
+    int timing_valid;
+    int ct_est;
+    int nin;
+    int uw_errors;
+    int sync_counter;
+    int frame_count;  /* general purpose counter of modem frames */
+    int packet_count; /* data mode: number of packets received so far */ 
+    int modem_frame;  /* increments for every modem frame in packet */
+    
+    // Boolean
+    bool sync_start;
+    bool sync_end;
+    bool timing_en;
+    bool foff_est_en;
+    bool phase_est_en;
+    bool tx_bpf_en;
+    bool rx_bpf_en;
+    bool dpsk_en;
+    bool postambledetectoren; /* allows us to optionally disable the postamble detector */
+    
+    char *codename;
+    char *state_machine;
+};
+
+/* Prototypes */
+
+complex float qpsk_mod(int *);
+complex float qam16_mod(int *);
+void qpsk_demod(complex float, int *);
+void qam16_demod(complex float, int *);
+void ofdm_txframe(struct OFDM *, complex float *, complex float []);
+void ofdm_assemble_qpsk_modem_packet(struct OFDM *, uint8_t [], uint8_t [], uint8_t []);
+void ofdm_assemble_qpsk_modem_packet_symbols(struct OFDM *, complex float [], COMP [], uint8_t []);
+void ofdm_disassemble_qpsk_modem_packet(struct OFDM *, complex float rx_syms[], float rx_amps[], COMP [], float [], short []);
+void ofdm_disassemble_qpsk_modem_packet_with_text_amps(struct OFDM *, complex float rx_syms[], float rx_amps[], COMP [], float [], short [], int*);
+void ofdm_extract_uw(struct OFDM *ofdm, complex float rx_syms[], float rx_amps[], uint8_t rx_uw[]);
+void ofdm_rand(uint16_t [], int);
+void ofdm_rand_seed(uint16_t r[], int n, uint64_t seed) ;
+void ofdm_generate_payload_data_bits(uint8_t data_bits[], int n);
+void ofdm_generate_preamble(struct OFDM *ofdm, COMP *tx_preamble, int seed);
+int ofdm_get_phase_est_bandwidth_mode(struct OFDM *);
+void ofdm_set_phase_est_bandwidth_mode(struct OFDM *, int);
+void ofdm_clip(complex float tx[], float clip_thresh, int n);
+void ofdm_hilbert_clipper(struct OFDM *ofdm, complex float *tx, size_t n);
+float ofdm_esno_est_calc(complex float *rx_sym, int nsym);
+float ofdm_snr_from_esno(struct OFDM *ofdm, float EsNodB);
+void ofdm_get_demod_stats(struct OFDM *ofdm, struct MODEM_STATS *stats, complex float *rx_syms, int Nsymsperpacket);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif