mirror of
https://github.com/f4exb/sdrangel.git
synced 2024-12-12 01:45:16 -05:00
132 lines
3.0 KiB
C++
132 lines
3.0 KiB
C++
// Copyright 2020-2021 Mobilinkd LLC.
|
|
|
|
// make CXXFLAGS="$(pkg-config --cflags gtest) $(pkg-config --libs gtest) -I. -O3" tests/TrellisTest
|
|
|
|
#pragma once
|
|
|
|
#include "Util.h"
|
|
#include "Convolution.h"
|
|
|
|
#include <array>
|
|
#include <cstdlib>
|
|
#include <cstdint>
|
|
|
|
namespace modemm17
|
|
{
|
|
|
|
inline std::array<int8_t, 61> make_p1() {
|
|
std::array<int8_t, 61> result{};
|
|
for (size_t i = 0, j = 2; i != 61; ++i) {
|
|
if (i == j) {
|
|
result[i] = 0;
|
|
j += 4;
|
|
} else {
|
|
result[i] = 1;
|
|
}
|
|
}
|
|
return result;
|
|
};
|
|
|
|
/// Puncture matrix for LSF
|
|
constexpr auto P1 = std::array<int8_t, 61>{
|
|
1,
|
|
1, 0, 1, 1, // M1
|
|
1, 0, 1, 1, // M2
|
|
1, 0, 1, 1, // M3
|
|
1, 0, 1, 1, // M4
|
|
1, 0, 1, 1, // M5
|
|
1, 0, 1, 1, // M6
|
|
1, 0, 1, 1, // M7
|
|
1, 0, 1, 1, // M8
|
|
1, 0, 1, 1, // M9
|
|
1, 0, 1, 1, // M10
|
|
1, 0, 1, 1, // M10
|
|
1, 0, 1, 1, // M12
|
|
1, 0, 1, 1, // M13
|
|
1, 0, 1, 1, // M14
|
|
1, 0, 1, 1 // M15
|
|
};
|
|
|
|
/// Puncture matrix for audio and BERT frames. Rate 11/12.
|
|
constexpr auto P2 = std::array<int8_t, 12>{
|
|
1, 1, 1, 1, 1, 1,
|
|
1, 1, 1, 1, 1, 0};
|
|
|
|
|
|
/// Puncture matrix for packet frames (7/8).
|
|
constexpr auto P3 = std::array<int8_t, 8>{
|
|
1, 1, 1, 1, 1, 1, 1, 0};
|
|
|
|
/**
|
|
* Convert an integer value to an array of bits, with the
|
|
* high-bit at index 0.
|
|
*
|
|
* At anything beyond -O0, the array is constructed at compile time.
|
|
*/
|
|
template <size_t N>
|
|
constexpr std::array<uint8_t, N> toBitArray(int8_t value)
|
|
{
|
|
std::array<uint8_t, N> result{};
|
|
for (size_t i = 0; i != N; ++i)
|
|
{
|
|
result[N - (i + 1)] = (value & 1);
|
|
value >>= 1;
|
|
}
|
|
return result;
|
|
}
|
|
|
|
template <size_t N>
|
|
struct NextStateTable
|
|
{
|
|
using nextStateTable_t = std::array<std::array<int8_t, N>, N>;
|
|
|
|
nextStateTable_t nextStateTable = makeNextStateTable();
|
|
|
|
static constexpr nextStateTable_t makeNextStateTable()
|
|
{
|
|
return nextStateTable_t();
|
|
}
|
|
};
|
|
|
|
/**
|
|
* Compute a cost table for a Trellis of size K, for input n of N,
|
|
* and LLR size of LLR bits + 1. (i.e. LLR = 1 allows 2 bits to
|
|
* represent -1, 0, +1).
|
|
*/
|
|
template <size_t K, size_t N, size_t LLR = 1>
|
|
struct CostTable
|
|
{
|
|
static constexpr int8_t Price = 1 << LLR;
|
|
static constexpr size_t InputValues = 1 << N;
|
|
using cost_table_t = std::array<std::array<uint8_t, InputValues>, K>;
|
|
};
|
|
|
|
|
|
/**
|
|
* Only valid for a k=1 (1:n) convolutional coder.
|
|
*/
|
|
template <size_t K_, size_t n_>
|
|
struct Trellis
|
|
{
|
|
static constexpr size_t K = K_; // Memory depth of convolution.
|
|
static constexpr size_t k = 1; // Number of bits per input symbol.
|
|
static constexpr size_t n = n_; // Number of coefficients / output bits.
|
|
static constexpr size_t NumStates = (1 << K); // Number of states in the convolutional coder.
|
|
|
|
using polynomials_t = std::array<uint32_t, n_>;
|
|
|
|
polynomials_t polynomials;
|
|
|
|
Trellis(polynomials_t polys) :
|
|
polynomials(polys)
|
|
{}
|
|
};
|
|
|
|
template <size_t K, size_t n>
|
|
constexpr Trellis<K, n> makeTrellis(std::array<uint32_t, n> polys)
|
|
{
|
|
return Trellis<K, n>(polys);
|
|
}
|
|
|
|
} // modemm17
|