/* Quadrature amplitude modulation Copyright 2018 Ahmet Inan */ #ifndef QAM_HH #define QAM_HH namespace ldpctool { template struct QuadratureAmplitudeModulation; template struct QuadratureAmplitudeModulation<16, TYPE, CODE> { static const int NUM = 16; static const int BITS = 4; typedef TYPE complex_type; typedef typename TYPE::value_type value_type; typedef CODE code_type; static constexpr value_type FAC = 1.0540925533894596; static constexpr value_type RCP = 3 * FAC; static constexpr value_type AMP = 1 / RCP; static constexpr value_type DIST = 2 * AMP; static constexpr value_type amp(int i) { return AMP * i; } static code_type quantize(value_type precision, value_type value) { value *= DIST * precision; if (std::is_integral::value) value = std::nearbyint(value); if (std::is_same::value) value = std::min(std::max(value, -128), 127); return value; } static void hard(code_type *b, complex_type c) { b[0] = c.real() < amp(0) ? code_type(-1) : code_type(1); b[1] = c.imag() < amp(0) ? code_type(-1) : code_type(1); b[2] = std::abs(c.real()) < amp(2) ? code_type(-1) : code_type(1); b[3] = std::abs(c.imag()) < amp(2) ? code_type(-1) : code_type(1); } static void soft(code_type *b, complex_type c, value_type precision) { b[0] = quantize(precision, c.real()); b[1] = quantize(precision, c.imag()); b[2] = quantize(precision, std::abs(c.real())-amp(2)); b[3] = quantize(precision, std::abs(c.imag())-amp(2)); } static complex_type map(code_type *b) { return AMP * complex_type( b[0]*(b[2]+value_type(2)), b[1]*(b[3]+value_type(2)) ); } }; template struct QuadratureAmplitudeModulation<64, TYPE, CODE> { static const int NUM = 64; static const int BITS = 6; typedef TYPE complex_type; typedef typename TYPE::value_type value_type; typedef CODE code_type; static constexpr value_type FAC = 0.9258200997725516; static constexpr value_type RCP = 7 * FAC; static constexpr value_type AMP = 1 / RCP; static constexpr value_type DIST = 2 * AMP; static constexpr value_type amp(int i) { return AMP * i; } static code_type quantize(value_type precision, value_type value) { value *= DIST * precision; if (std::is_integral::value) value = std::nearbyint(value); if (std::is_same::value) value = std::min(std::max(value, -128), 127); return value; } static void hard(code_type *b, complex_type c) { b[0] = c.real() < amp(0) ? code_type(-1) : code_type(1); b[1] = c.imag() < amp(0) ? code_type(-1) : code_type(1); b[2] = std::abs(c.real()) < amp(4) ? code_type(-1) : code_type(1); b[3] = std::abs(c.imag()) < amp(4) ? code_type(-1) : code_type(1); b[4] = std::abs(std::abs(c.real())-amp(4)) < amp(2) ? code_type(-1) : code_type(1); b[5] = std::abs(std::abs(c.imag())-amp(4)) < amp(2) ? code_type(-1) : code_type(1); } static void soft(code_type *b, complex_type c, value_type precision) { b[0] = quantize(precision, c.real()); b[1] = quantize(precision, c.imag()); b[2] = quantize(precision, std::abs(c.real())-amp(4)); b[3] = quantize(precision, std::abs(c.imag())-amp(4)); b[4] = quantize(precision, std::abs(std::abs(c.real())-amp(4))-amp(2)); b[5] = quantize(precision, std::abs(std::abs(c.imag())-amp(4))-amp(2)); } static complex_type map(code_type *b) { return AMP * complex_type( b[0]*(b[2]*(b[4]+value_type(2))+value_type(4)), b[1]*(b[3]*(b[5]+value_type(2))+value_type(4)) ); } }; template struct QuadratureAmplitudeModulation<256, TYPE, CODE> { static const int NUM = 256; static const int BITS = 8; typedef TYPE complex_type; typedef typename TYPE::value_type value_type; typedef CODE code_type; static constexpr value_type FAC = 0.8692269873603529; static constexpr value_type RCP = 15 * FAC; static constexpr value_type AMP = 1 / RCP; static constexpr value_type DIST = 2 * AMP; static constexpr value_type amp(int i) { return AMP * i; } static code_type quantize(value_type precision, value_type value) { value *= DIST * precision; if (std::is_integral::value) value = std::nearbyint(value); if (std::is_same::value) value = std::min(std::max(value, -128), 127); return value; } static void hard(code_type *b, complex_type c) { b[0] = c.real() < amp(0) ? code_type(-1) : code_type(1); b[1] = c.imag() < amp(0) ? code_type(-1) : code_type(1); b[2] = std::abs(c.real()) < amp(8) ? code_type(-1) : code_type(1); b[3] = std::abs(c.imag()) < amp(8) ? code_type(-1) : code_type(1); b[4] = std::abs(std::abs(c.real())-amp(8)) < amp(4) ? code_type(-1) : code_type(1); b[5] = std::abs(std::abs(c.imag())-amp(8)) < amp(4) ? code_type(-1) : code_type(1); b[6] = std::abs(std::abs(std::abs(c.real())-amp(8))-amp(4)) < amp(2) ? code_type(-1) : code_type(1); b[7] = std::abs(std::abs(std::abs(c.imag())-amp(8))-amp(4)) < amp(2) ? code_type(-1) : code_type(1); } static void soft(code_type *b, complex_type c, value_type precision) { b[0] = quantize(precision, c.real()); b[1] = quantize(precision, c.imag()); b[2] = quantize(precision, std::abs(c.real())-amp(8)); b[3] = quantize(precision, std::abs(c.imag())-amp(8)); b[4] = quantize(precision, std::abs(std::abs(c.real())-amp(8))-amp(4)); b[5] = quantize(precision, std::abs(std::abs(c.imag())-amp(8))-amp(4)); b[6] = quantize(precision, std::abs(std::abs(std::abs(c.real())-amp(8))-amp(4))-amp(2)); b[7] = quantize(precision, std::abs(std::abs(std::abs(c.imag())-amp(8))-amp(4))-amp(2)); } static complex_type map(code_type *b) { return AMP * complex_type( b[0]*(b[2]*(b[4]*(b[6]+value_type(2))+value_type(4))+value_type(8)), b[1]*(b[3]*(b[5]*(b[7]+value_type(2))+value_type(4))+value_type(8)) ); } }; template struct QuadratureAmplitudeModulation<1024, TYPE, CODE> { static const int NUM = 1024; static const int BITS = 10; typedef TYPE complex_type; typedef typename TYPE::value_type value_type; typedef CODE code_type; static constexpr value_type FAC = 0.8424235391742344; static constexpr value_type RCP = 31 * FAC; static constexpr value_type AMP = 1 / RCP; static constexpr value_type DIST = 2 * AMP; static constexpr value_type amp(int i) { return AMP * i; } static code_type quantize(value_type precision, value_type value) { value *= DIST * precision; if (std::is_integral::value) value = std::nearbyint(value); if (std::is_same::value) value = std::min(std::max(value, -128), 127); return value; } static void hard(code_type *b, complex_type c) { b[0] = c.real() < amp(0) ? code_type(-1) : code_type(1); b[1] = c.imag() < amp(0) ? code_type(-1) : code_type(1); b[2] = std::abs(c.real()) < amp(16) ? code_type(-1) : code_type(1); b[3] = std::abs(c.imag()) < amp(16) ? code_type(-1) : code_type(1); b[4] = std::abs(std::abs(c.real())-amp(16)) < amp(8) ? code_type(-1) : code_type(1); b[5] = std::abs(std::abs(c.imag())-amp(16)) < amp(8) ? code_type(-1) : code_type(1); b[6] = std::abs(std::abs(std::abs(c.real())-amp(16))-amp(8)) < amp(4) ? code_type(-1) : code_type(1); b[7] = std::abs(std::abs(std::abs(c.imag())-amp(16))-amp(8)) < amp(4) ? code_type(-1) : code_type(1); b[8] = std::abs(std::abs(std::abs(std::abs(c.real())-amp(16))-amp(8))-amp(4)) < amp(2) ? code_type(-1) : code_type(1); b[9] = std::abs(std::abs(std::abs(std::abs(c.imag())-amp(16))-amp(8))-amp(4)) < amp(2) ? code_type(-1) : code_type(1); } static void soft(code_type *b, complex_type c, value_type precision) { b[0] = quantize(precision, c.real()); b[1] = quantize(precision, c.imag()); b[2] = quantize(precision, std::abs(c.real())-amp(16)); b[3] = quantize(precision, std::abs(c.imag())-amp(16)); b[4] = quantize(precision, std::abs(std::abs(c.real())-amp(16))-amp(8)); b[5] = quantize(precision, std::abs(std::abs(c.imag())-amp(16))-amp(8)); b[6] = quantize(precision, std::abs(std::abs(std::abs(c.real())-amp(16))-amp(8))-amp(4)); b[7] = quantize(precision, std::abs(std::abs(std::abs(c.imag())-amp(16))-amp(8))-amp(4)); b[8] = quantize(precision, std::abs(std::abs(std::abs(std::abs(c.real())-amp(16))-amp(8))-amp(4))-amp(2)); b[9] = quantize(precision, std::abs(std::abs(std::abs(std::abs(c.imag())-amp(16))-amp(8))-amp(4))-amp(2)); } static complex_type map(code_type *b) { return AMP * complex_type( b[0]*(b[2]*(b[4]*(b[6]*(b[8]+value_type(2))+value_type(4))+value_type(8))+value_type(16)), b[1]*(b[3]*(b[5]*(b[7]*(b[9]+value_type(2))+value_type(4))+value_type(8))+value_type(16)) ); } }; } // namespace ldpctool #endif