mayhem-firmware/firmware/baseband/proc_acars.hpp

/*
 * Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
 * Copyright (C) 2018 Furrtek
 *
 * This file is part of PortaPack.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * 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 General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#ifndef __PROC_ACARS_H__
#define __PROC_ACARS_H__

#include "baseband_processor.hpp"
#include "baseband_thread.hpp"
#include "rssi_thread.hpp"

#include "dsp_decimate.hpp"

#include "spectrum_collector.hpp"

#include <cstdint>

#include "baseband_processor.hpp"
#include "baseband_thread.hpp"
#include "rssi_thread.hpp"

#include "channel_decimator.hpp"
#include "matched_filter.hpp"

#include "clock_recovery.hpp"
#include "symbol_coding.hpp"
#include "packet_builder.hpp"
#include "baseband_packet.hpp"

#include "message.hpp"

#include <cstdint>
#include <cstddef>
#include <bitset>

// AIS:
// IN: 2457600/8/8 = 38400
// Offset: 2457600/4 = 614400 (614400/8/8 = 9600)
// Deviation: 2400
// Symbol: 9600
// Decimate: 2
// 4 taps, 1 symbol, 1/4 cycle

// TPMS:
// IN: 2457600/4/2 = 307200
// Offset: 2457600/4 = 614400 (614400/4/2 = 76800)
// Deviation: 38400
// Symbol: 19200
// Decimate: 8
// 16 taps, 1 symbol, 2 cycles

// ACARS:
// IN: 2457600/8/8 = 38400
// Offset: 2457600/4 = 614400 (614400/8/8 = 9600)
// Deviation: ???
// Symbol: 2400
// Decimate: 8
// 16 taps, 1 symbol, 2 cycles

// Number of taps: size of one symbol in samples (in/symbol)
// Cycles:

// Translate+rectangular filter
// sample=38.4k, deviation=4800, symbol=2400
// Length: 16 taps, 1 symbol, 2 cycles of sinusoid
// This is actually the same as rect_taps_307k2_38k4_1t_19k2_p
constexpr std::array<std::complex<float>, 16> rect_taps_38k4_4k8_1t_2k4_p{{
    {6.2500000000e-02f, 0.0000000000e+00f},
    {4.4194173824e-02f, 4.4194173824e-02f},
    {0.0000000000e+00f, 6.2500000000e-02f},
    {-4.4194173824e-02f, 4.4194173824e-02f},
    {-6.2500000000e-02f, 0.0000000000e+00f},
    {-4.4194173824e-02f, -4.4194173824e-02f},
    {0.0000000000e+00f, -6.2500000000e-02f},
    {4.4194173824e-02f, -4.4194173824e-02f},
    {6.2500000000e-02f, 0.0000000000e+00f},
    {4.4194173824e-02f, 4.4194173824e-02f},
    {0.0000000000e+00f, 6.2500000000e-02f},
    {-4.4194173824e-02f, 4.4194173824e-02f},
    {-6.2500000000e-02f, 0.0000000000e+00f},
    {-4.4194173824e-02f, -4.4194173824e-02f},
    {0.0000000000e+00f, -6.2500000000e-02f},
    {4.4194173824e-02f, -4.4194173824e-02f},
}};

class ACARSProcessor : public BasebandProcessor {
   public:
    ACARSProcessor();

    void execute(const buffer_c8_t& buffer) override;

   private:
    static constexpr size_t baseband_fs = 2457600;

    std::array<complex16_t, 512> dst{};
    const buffer_c16_t dst_buffer{
        dst.data(),
        dst.size()};

    dsp::decimate::FIRC8xR16x24FS4Decim8 decim_0{};  // Translate already done here !
    dsp::decimate::FIRC16xR16x32Decim8 decim_1{};
    dsp::matched_filter::MatchedFilter mf{rect_taps_38k4_4k8_1t_2k4_p, 8};

    clock_recovery::ClockRecovery<clock_recovery::FixedErrorFilter> clock_recovery{
        4800,
        2400,
        {0.0555f},
        [this](const float symbol) { this->consume_symbol(symbol); }};
    symbol_coding::ACARSDecoder acars_decode{};
    /*PacketBuilder<BitPattern, NeverMatch, FixedLength> packet_builder {
                { 0b011010000110100010000000, 24, 1 },	// SYN, SYN, SOH
                { },
                { 128 },
                [this](const baseband::Packet& packet) {
                        this->payload_handler(packet);
                }
        };*/
    baseband::Packet packet{};

    /* NB: Threads should be the last members in the class definition. */
    BasebandThread baseband_thread{
        baseband_fs, this, baseband::Direction::Receive, /*auto_start*/ false};
    RSSIThread rssi_thread{};

    void consume_symbol(const float symbol);
    void payload_handler(const baseband::Packet& packet);
};

#endif /*__PROC_ACARS_H__*/