kopia lustrzana https://github.com/f4exb/sdrangel
592 wiersze
17 KiB
C++
592 wiersze
17 KiB
C++
#pragma once
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#include <QDebug>
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#include <QString>
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#include "FirFilter.h"
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#include "LinkSetupFrame.h"
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#include "CRC16.h"
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#include "Convolution.h"
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#include "PolynomialInterleaver.h"
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#include "M17Randomizer.h"
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#include "Util.h"
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#include "Golay24.h"
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#include "Trellis.h"
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#include <array>
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#include <atomic>
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#include <chrono>
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#include <cstdint>
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#include <future>
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#include <iostream>
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#include <memory>
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#include "export.h"
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namespace modemm17
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{
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/**
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* Common routines extracted from the original asynchronous M17 modulator.
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* It is used to produce the various symbol sequences but modulation is handled at
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* upper level.
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*/
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struct MODEMM17_API M17Modulator
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{
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public:
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using symbols_t = std::array<int8_t, 192>; // One frame of symbols.
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using baseband_t = std::array<int16_t, 1920>; // One frame of baseband data @ 48ksps
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using bitstream_t = std::array<uint8_t, 48>; // M17 frame of bits (in bytes).
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using lsf_t = std::array<uint8_t, 30>; // Link setup frame bytes.
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using lich_segment_t = std::array<uint8_t, 96>; // Golay-encoded LICH bits.
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using lich_t = std::array<lich_segment_t, 6>; // All LICH segments.
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using audio_frame_t = std::array<int16_t, 320>;
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using codec_frame_t = std::array<uint8_t, 16>;
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using payload_t = std::array<uint8_t, 34>; // Bytes in the payload of a data frame.
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using frame_t = std::array<uint8_t, 46>; // M17 frame (without sync word).
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using packet_t = std::array<uint8_t, 25>; // Packet payload
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static const std::array<uint8_t, 2> SYNC_WORD;
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static const std::array<uint8_t, 2> LSF_SYNC_WORD;
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static const std::array<uint8_t, 2> STREAM_SYNC_WORD;
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static const std::array<uint8_t, 2> PACKET_SYNC_WORD;
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static const std::array<uint8_t, 2> BERT_SYNC_WORD;
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static const std::array<uint8_t, 2> EOT_SYNC;
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static int8_t bits_to_symbol(uint8_t bits)
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{
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switch (bits)
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{
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case 0: return 1;
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case 1: return 3;
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case 2: return -1;
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case 3: return -3;
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}
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return 0;
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}
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template <typename T, size_t N>
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static std::array<int8_t, N / 2> bits_to_symbols(const std::array<T, N>& bits)
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{
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std::array<int8_t, N / 2> result;
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size_t index = 0;
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for (size_t i = 0; i != N; i += 2)
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{
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result[index++] = bits_to_symbol((bits[i] << 1) | bits[i + 1]);
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}
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return result;
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}
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template <typename T, size_t N>
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static std::array<int8_t, N * 4> bytes_to_symbols(const std::array<T, N>& bytes)
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{
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std::array<int8_t, N * 4> result;
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size_t index = 0;
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for (auto b : bytes)
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{
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for (size_t i = 0; i != 4; ++i)
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{
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result[index++] = bits_to_symbol(b >> 6);
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b <<= 2;
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}
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}
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return result;
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}
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/*
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* Converts a suite of 192 symbols (from the 384 bits of a frame) into 1920 16 bit integer samples to be used
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* in the final FM modulator (baseband). Sample rate is expected to be 48 kS/s. This is the original 48 kS/s
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* 16 bit audio output of the modulator.
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*/
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template <size_t N>
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std::array<int16_t, N*10> symbols_to_baseband(std::array<int8_t, N> symbols, bool invert = false)
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{
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std::array<int16_t, N*10> baseband;
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baseband.fill(0);
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for (size_t i = 0; i != symbols.size(); ++i) {
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baseband[i * 10] = symbols[i];
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}
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for (auto& b : baseband) {
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b = rrc(b) * 7168.0 * (invert ? -1.0 : 1.0);
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}
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return baseband;
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}
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std::array<int8_t, 368> make_lsf(lsf_t& lsf, bool streamElsePacket = false)
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{
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lsf.fill(0);
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M17Randomizer randomizer;
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PolynomialInterleaver<45, 92, 368> interleaver;
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CRC16 crc(0x5935, 0xFFFF);
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auto rit = std::copy(dest_.begin(), dest_.end(), lsf.begin());
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std::copy(source_.begin(), source_.end(), rit);
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lsf[12] = can_ >> 1;
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lsf[13] = (streamElsePacket ? 5 : 2) | ((can_ & 1) << 7);
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if (gnss_on_)
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{
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lsf[13] |= (1<<5);
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std::copy(gnss_.begin(), gnss_.end(), &lsf[14]);
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}
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crc.reset();
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for (size_t i = 0; i != 28; ++i) {
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crc(lsf[i]);
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}
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std::array<uint8_t, 2> checksum = crc.get_bytes();
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lsf[28] = checksum[0];
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lsf[29] = checksum[1];
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std::array<uint8_t, 488> encoded;
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size_t index = 0;
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uint32_t memory = 0;
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for (auto b : lsf)
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{
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for (size_t i = 0; i != 8; ++i)
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{
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uint32_t x = (b & 0x80) >> 7;
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b <<= 1;
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memory = modemm17::update_memory<4>(memory, x);
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encoded[index++] = modemm17::convolve_bit(031, memory);
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encoded[index++] = modemm17::convolve_bit(027, memory);
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}
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}
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// Flush the encoder.
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for (size_t i = 0; i != 4; ++i)
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{
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memory = modemm17::update_memory<4>(memory, 0);
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encoded[index++] = modemm17::convolve_bit(031, memory);
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encoded[index++] = modemm17::convolve_bit(027, memory);
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}
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std::array<int8_t, 368> punctured;
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auto size = puncture<488, 368, 61>(encoded, punctured, P1);
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if (size != 368) {
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qWarning() << "modemm17::M17Modulator::make_lsf: incorrect size (not 368)" << size;
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}
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interleaver.interleave(punctured);
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randomizer.randomize(punctured);
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return punctured;
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}
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static lich_segment_t make_lich_segment(std::array<uint8_t, 5> segment, uint8_t segment_number)
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{
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lich_segment_t result;
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uint16_t tmp;
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uint32_t encoded;
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tmp = segment[0];
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tmp <<= 4;
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tmp |= ((segment[1] >> 4) & 0x0F);
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// tmp = segment[0] << 4 | ((segment[1] >> 4) & 0x0F);
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encoded = modemm17::Golay24::encode24(tmp);
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for (size_t i = 0; i != 24; ++i)
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{
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result[i] = (encoded & (1 << 23)) != 0 ? 1 : 0;
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encoded <<= 1;
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}
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tmp = segment[1] & 0x0F;
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tmp <<= 8;
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tmp |= segment[2];
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// tmp = ((segment[1] & 0x0F) << 8) | segment[2];
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encoded = modemm17::Golay24::encode24(tmp);
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for (size_t i = 24; i != 48; ++i)
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{
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result[i] = (encoded & (1 << 23)) != 0 ? 1 : 0;
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encoded <<= 1;
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}
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tmp = segment[3];
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tmp <<= 4;
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tmp |= ((segment[4] >> 4) & 0x0F);
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// tmp = segment[3] << 4 | ((segment[4] >> 4) & 0x0F);
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encoded = modemm17::Golay24::encode24(tmp);
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for (size_t i = 48; i != 72; ++i)
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{
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result[i] = (encoded & (1 << 23)) != 0 ? 1 : 0;
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encoded <<= 1;
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}
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tmp = segment[4] & 0x0F;
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tmp <<= 8;
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tmp |= (segment_number << 5);
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// tmp = ((segment[4] & 0x0F) << 8) | (segment_number << 5);
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encoded = modemm17::Golay24::encode24(tmp);
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for (size_t i = 72; i != 96; ++i)
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{
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result[i] = (encoded & (1 << 23)) != 0 ? 1 : 0;
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encoded <<= 1;
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}
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return result;
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}
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static std::array<int8_t, 272> make_stream_data_frame(uint16_t frame_number, const codec_frame_t& payload)
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{
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std::array<uint8_t, 18> data; // FN, payload = 2 + 16;
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data[0] = uint8_t((frame_number >> 8) & 0xFF);
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data[1] = uint8_t(frame_number & 0xFF);
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std::copy(payload.begin(), payload.end(), data.begin() + 2);
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std::array<uint8_t, 296> encoded;
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size_t index = 0;
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uint32_t memory = 0;
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for (auto b : data)
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{
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for (size_t i = 0; i != 8; ++i)
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{
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uint32_t x = (b & 0x80) >> 7;
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b <<= 1;
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memory = modemm17::update_memory<4>(memory, x);
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encoded[index++] = modemm17::convolve_bit(031, memory);
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encoded[index++] = modemm17::convolve_bit(027, memory);
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}
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}
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// Flush the encoder.
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for (size_t i = 0; i != 4; ++i)
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{
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memory = modemm17::update_memory<4>(memory, 0);
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encoded[index++] = modemm17::convolve_bit(031, memory);
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encoded[index++] = modemm17::convolve_bit(027, memory);
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}
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std::array<int8_t, 272> punctured;
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auto size = modemm17::puncture<296, 272, 12>(encoded, punctured, modemm17::P2);
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if (size != 272) {
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qWarning() << "modemm17::M17Modulator::make_stream_data_frame: incorrect size (not 272)" << size;
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}
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return punctured;
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}
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std::array<int8_t, 368> make_packet_frame(
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uint8_t packet_number,
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int packet_size,
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bool last_packet,
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const std::array<uint8_t, 25> packet
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)
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{
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M17Randomizer randomizer;
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PolynomialInterleaver<45, 92, 368> interleaver;
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std::array<uint8_t, 26> packet_assembly;
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packet_assembly.fill(0);
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std::copy(packet.begin(), packet.begin() + packet_size, packet_assembly.begin());
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if (packet_number == 0) {
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crc_.reset();
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}
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for (int i = 0; i < packet_size; i++) {
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crc_(packet[i]);
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}
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if (last_packet)
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{
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packet_assembly[25] = 0x80 | ((packet_size+2)<<2); // sent packet size includes CRC
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packet_assembly[packet_size] = crc_.get_bytes()[0];
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packet_assembly[packet_size+1] = crc_.get_bytes()[1];
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}
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else
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{
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packet_assembly[25] = (packet_number<<2);
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}
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std::array<uint8_t, 420> encoded;
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size_t index = 0;
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uint32_t memory = 0;
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uint8_t b;
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for (int bi = 0; bi < 25; bi++)
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{
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b = packet_assembly[bi];
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for (size_t i = 0; i != 8; ++i)
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{
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uint32_t x = (b & 0x80) >> 7;
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b <<= 1;
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memory = modemm17::update_memory<4>(memory, x);
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encoded[index++] = modemm17::convolve_bit(031, memory);
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encoded[index++] = modemm17::convolve_bit(027, memory);
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}
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}
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b = packet_assembly[25];
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for (size_t i = 0; i != 6; ++i)
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{
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uint32_t x = (b & 0x80) >> 7;
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b <<= 1;
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memory = modemm17::update_memory<4>(memory, x);
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encoded[index++] = modemm17::convolve_bit(031, memory);
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encoded[index++] = modemm17::convolve_bit(027, memory);
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}
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// Flush the encoder.
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for (size_t i = 0; i != 4; ++i)
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{
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memory = modemm17::update_memory<4>(memory, 0);
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encoded[index++] = modemm17::convolve_bit(031, memory);
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encoded[index++] = modemm17::convolve_bit(027, memory);
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}
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std::array<int8_t, 368> punctured;
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auto size = puncture<420, 368, 8>(encoded, punctured, P3);
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if (size != 368) {
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qWarning() << "modemm17::M17Modulator::make_packet_frame: incorrect size (not 368)" << size;
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}
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interleaver.interleave(punctured);
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randomizer.randomize(punctured);
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return punctured;
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}
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static std::array<int8_t, 368> make_bert_frame(PRBS9& prbs)
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{
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std::array<uint8_t, 25> data; // 24.6125 bytes, 197 bits
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// Generate the data (24*8 = 192 bits).
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for (size_t i = 0; i != data.size() - 1; ++i)
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{
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uint8_t byte = 0;
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for (int i = 0; i != 8; ++i)
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{
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byte <<= 1;
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byte |= prbs.generate();
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}
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data[i] = byte;
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}
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// Generate the data (last 5 bits).
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uint8_t byte = 0;
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for (int i = 0; i != 5; ++i)
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{
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byte <<= 1;
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byte |= prbs.generate();
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}
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byte <<= 3;
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data[24] = byte;
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// Convolutional encode
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std::array<uint8_t, 402> encoded;
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size_t index = 0;
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uint32_t memory = 0;
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// 24*8 = 192 first bits
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for (size_t i = 0; i != data.size() - 1; ++i)
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{
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auto b = data[i];
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for (size_t j = 0; j != 8; ++j)
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{
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uint32_t x = (b & 0x80) >> 7;
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b <<= 1;
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memory = update_memory<4>(memory, x);
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encoded[index++] = convolve_bit(031, memory);
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encoded[index++] = convolve_bit(027, memory);
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}
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}
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// last 5 bits
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auto b = data[24];
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for (size_t j = 0; j != 5; ++j)
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{
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uint32_t x = (b & 0x80) >> 7;
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b <<= 1;
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memory = update_memory<4>(memory, x);
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encoded[index++] = convolve_bit(031, memory);
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encoded[index++] = convolve_bit(027, memory);
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}
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// Flush the encoder.
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for (size_t i = 0; i != 4; ++i)
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{
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memory = update_memory<4>(memory, 0);
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encoded[index++] = convolve_bit(031, memory);
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encoded[index++] = convolve_bit(027, memory);
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}
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std::array<int8_t, 368> punctured;
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auto size = puncture<402, 368, 12>(encoded, punctured, P2);
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if (size != 368) {
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qWarning() << "modemm17::M17Modulator::make_bert_frame: incorrect size (not 368)" << size;
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}
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return punctured;
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}
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static void interleave_and_randomize(std::array<int8_t, 368>& punctured)
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{
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M17Randomizer randomizer;
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PolynomialInterleaver<45, 92, 368> interleaver;
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interleaver.interleave(punctured);
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randomizer.randomize(punctured);
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}
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M17Modulator(const std::string& source, const std::string& dest = "") :
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source_(encode_callsign(source)),
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dest_(encode_callsign(dest)),
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can_(10),
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rrc(makeFirFilter(rrc_taps)),
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crc_(0x5935, 0xFFFF)
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{
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gnss_.fill(0);
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gnss_on_ = false;
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}
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/**
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* Set the source identifier (callsign) for the transmitter.
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*/
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void source(const std::string& callsign) {
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source_ = encode_callsign(callsign);
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}
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/**
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* Set the destination identifier for the transmitter. A blank value is
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* interpreted as the broadcast address. This is the default.
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*/
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void dest(const std::string& callsign) {
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dest_ = encode_callsign(callsign);
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}
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/**
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* Set the Channel Access Number (0..15)
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*/
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void can(uint8_t can) {
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can_ = can & 0xF;
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}
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/**
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* Set GNSS data
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*/
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void set_gnss(float lat, float lon, float alt)
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{
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gnss_ = LinkSetupFrame::encode_gnss(lat, lon, alt);
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gnss_on_ = true;
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}
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/**
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* Reset GNSS data
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*/
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void reset_gnss()
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{
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gnss_.fill(0);
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gnss_on_ = false;
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}
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private:
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LinkSetupFrame::encoded_call_t source_;
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LinkSetupFrame::encoded_call_t dest_;
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LinkSetupFrame::gnss_t gnss_;
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bool gnss_on_;
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uint8_t can_;
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BaseFirFilter<150> rrc;
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static const std::array<float, 150> rrc_taps;
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CRC16 crc_;
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static LinkSetupFrame::encoded_call_t encode_callsign(std::string callsign)
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{
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LinkSetupFrame::encoded_call_t encoded_call = {0xff,0xff,0xff,0xff,0xff,0xff};
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|
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if (callsign.empty() || callsign.size() > 9) {
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return encoded_call;
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}
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modemm17::LinkSetupFrame::call_t call;
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call.fill(0);
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std::copy(callsign.begin(), callsign.end(), call.begin());
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encoded_call = LinkSetupFrame::encode_callsign(call);
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return encoded_call;
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}
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template <typename T, size_t N>
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static std::array<T, N * 2 + 1> conv_encode(std::array<T, N> data)
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|
{
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std::array<T, N * 2 + 1> result;
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|
|
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uint8_t bit_index = 0;
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|
uint8_t byte_index = 0;
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|
uint8_t tmp = 0;
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|
|
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uint32_t memory = 0;
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|
|
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for (auto b : data)
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{
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|
for (size_t i = 0; i != 8; ++i)
|
|
{
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|
uint32_t x = (b & 0x80) >> 7;
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b <<= 1;
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memory = update_memory<4>(memory, x);
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tmp = (tmp << 1) | convolve_bit(031, memory);
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|
tmp = (tmp << 1) | convolve_bit(027, memory);
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bit_index += 2;
|
|
|
|
if (bit_index == 8)
|
|
{
|
|
bit_index = 0;
|
|
result[byte_index++] = tmp;
|
|
tmp = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Flush the encoder.
|
|
for (size_t i = 0; i != 4; ++i)
|
|
{
|
|
memory = update_memory<4>(memory, 0);
|
|
tmp = (tmp << 1) | convolve_bit(031, memory);
|
|
tmp = (tmp << 1) | convolve_bit(027, memory);
|
|
bit_index += 2;
|
|
|
|
if (bit_index == 8)
|
|
{
|
|
bit_index = 0;
|
|
result[byte_index++] = tmp;
|
|
tmp = 0;
|
|
}
|
|
}
|
|
|
|
// Frame may not end on a byte boundary.
|
|
if (bit_index != 0)
|
|
{
|
|
while (bit_index++ != 8) {
|
|
tmp <<= 1;
|
|
}
|
|
|
|
result[byte_index] = tmp;
|
|
}
|
|
|
|
return result;
|
|
}
|
|
};
|
|
|
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} // modemm17
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