#include <itpp/comm/modulator.h>
Public Member Functions | |
QPSK () | |
Class Constructor. | |
virtual | ~QPSK () |
Destructor. | |
virtual void | demodulate_soft_bits (const cvec &rx_symbols, double N0, vec &soft_bits, Soft_Method method=LOGMAP) const |
Soft demodulator for AWGN channel. | |
vec | demodulate_soft_bits (const cvec &rx_symbols, double N0, Soft_Method method=LOGMAP) const |
Soft demodulator for AWGN channel. | |
virtual void | demodulate_soft_bits (const cvec &rx_symbols, const cvec &channel, double N0, vec &soft_bits, Soft_Method method=LOGMAP) const |
Soft demodulator for a known channel in AWGN. | |
vec | demodulate_soft_bits (const cvec &rx_symbols, const cvec &channel, double N0, Soft_Method method=LOGMAP) const |
Soft demodulator for a known channel in AWGN. | |
void | set_M (int M) |
Change the size of the signal constellation. | |
void | demodulate_bits (const cvec &signal, bvec &bits) const |
Hard demodulation of bits. | |
bvec | demodulate_bits (const cvec &signal) const |
Hard demodulation of bits. | |
virtual void | demodulate_bits (const Vec< std::complex< double > > &signal, bvec &bits) const |
Hard demodulation of bits. | |
virtual bvec | demodulate_bits (const Vec< std::complex< double > > &signal) const |
Hard demodulation of bits. | |
virtual void | set (const Vec< std::complex< double > > &symbols, const ivec &bits2symbols) |
Set the constellation to use in the modulator. | |
virtual int | bits_per_symbol () const |
Returns number of bits per symbol. | |
virtual int | get_k () const |
Returns number of bits per symbol. | |
virtual int | get_M () const |
Returns number of modulation symbols. | |
virtual Vec< std::complex< double > > | get_symbols () const |
Get the symbol values used in the modulator. | |
virtual ivec | get_bits2symbols () const |
Get the bitmap, which maps input bits into symbols. | |
virtual void | modulate (const ivec &symbolnumbers, Vec< std::complex< double > > &output) const |
Modulation of symbols. | |
virtual Vec< std::complex< double > > | modulate (const ivec &symbolnumbers) const |
Modulation of symbols. | |
virtual void | demodulate (const Vec< std::complex< double > > &signal, ivec &output) const |
Demodulation of symbols. | |
virtual ivec | demodulate (const Vec< std::complex< double > > &signal) const |
Demodulation of symbols. | |
virtual void | modulate_bits (const bvec &bits, Vec< std::complex< double > > &output) const |
Modulation of bits. | |
virtual Vec< std::complex< double > > | modulate_bits (const bvec &bits) const |
Modulation of bits. | |
virtual void | demodulate_soft_bits (const Vec< std::complex< double > > &rx_symbols, double N0, vec &soft_bits, Soft_Method method=LOGMAP) const |
Soft demodulator for AWGN channels. | |
virtual vec | demodulate_soft_bits (const Vec< std::complex< double > > &rx_symbols, double N0, Soft_Method method=LOGMAP) const |
Soft demodulator for AWGN channels. | |
virtual void | demodulate_soft_bits (const Vec< std::complex< double > > &rx_symbols, const Vec< std::complex< double > > &channel, double N0, vec &soft_bits, Soft_Method method=LOGMAP) const |
Soft demodulator for fading channels. | |
virtual vec | demodulate_soft_bits (const Vec< std::complex< double > > &rx_symbols, const Vec< std::complex< double > > &channel, double N0, Soft_Method method=LOGMAP) const |
Soft demodulator for fading channels. | |
Protected Member Functions | |
void | calculate_softbit_matrices () |
This function calculates the soft bit mapping matrices S0 and S1. | |
Protected Attributes | |
bool | setup_done |
Setup indicator. | |
int | k |
Number of bits per modulation symbol. | |
int | M |
Number of modulation symbols. | |
bmat | bitmap |
Bit to symbol mapping table (size: M x k) | |
ivec | bits2symbols |
Bit to symbol mapping in decimal form (size: M) | |
Vec< std::complex< double > > | symbols |
Corresponding modulation symbols (size: M) | |
imat | S0 |
Matrix where row k contains the constellation points with '0' in bit position k. | |
imat | S1 |
Matrix where row k contains the constellation points with '1' in bit position k. | |
Related Symbols | |
(Note that these are not member symbols.) | |
typedef Modulator< double > | Modulator_1D |
Definition of 1D Modulator (with real symbols) | |
typedef Modulator< std::complex< double > > | Modulator_2D |
Definition of 2D Modulator (with complex symbols) | |
QPSK modulator.
This is a special version of the PSK modulator with
Beside hard demapping, this class can also perform soft demodulation, calculating the log-MAP estimate of the individual bits. To use it properly the received symbols should be equal to:
where
It is also assumed that the channel estimates are perfect when calculating the soft bits.
Definition at line 677 of file modulator.h.
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inline |
Class Constructor.
Definition at line 681 of file modulator.h.
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inlinevirtual |
Destructor.
Definition at line 683 of file modulator.h.
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virtual |
Soft demodulator for AWGN channel.
This function calculates the log-MAP estimate assuming equally likely bits transmitted:
and
depending on the bit positon in the QPSK symbol.
rx_symbols | The received noisy constellation symbols, ![]() |
N0 | The spectral density of the AWGN noise, ![]() |
soft_bits | The soft bits calculated using the expression above |
method | The method used for demodulation (LOGMAP or APPROX) |
Modulator_1D/Modulator_2D
and
Modulator_ND
is not advised. Definition at line 179 of file modulator.cpp.
References itpp::Modulator< std::complex< double > >::k, and itpp::pi.
Referenced by demodulate_soft_bits(), and demodulate_soft_bits().
vec itpp::QPSK::demodulate_soft_bits | ( | const cvec & | rx_symbols, |
double | N0, | ||
Soft_Method | method = LOGMAP ) const |
Soft demodulator for AWGN channel.
Definition at line 194 of file modulator.cpp.
References demodulate_soft_bits().
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virtual |
Soft demodulator for a known channel in AWGN.
This function calculates the log-MAP estimate assuming equally likely bits transmitted:
and
depending on the bit positon in the QPSK symbol.
rx_symbols | The received noisy constellation symbols, ![]() |
channel | The channel coefficients, ![]() |
N0 | The spectral density of the AWGN noise, ![]() |
soft_bits | The soft bits calculated using the expression above |
method | The method used for demodulation (LOGMAP or APPROX) |
Modulator_1D/Modulator_2D
and
Modulator_ND
is not advised. Definition at line 203 of file modulator.cpp.
References itpp::pi.
vec itpp::QPSK::demodulate_soft_bits | ( | const cvec & | rx_symbols, |
const cvec & | channel, | ||
double | N0, | ||
Soft_Method | method = LOGMAP ) const |
Soft demodulator for a known channel in AWGN.
Definition at line 219 of file modulator.cpp.
References demodulate_soft_bits().
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inherited |
Change the size of the signal constellation.
Definition at line 117 of file modulator.cpp.
References itpp::bin2dec(), itpp::Modulator< std::complex< double > >::bitmap, itpp::Modulator< std::complex< double > >::bits2symbols, itpp::Modulator< std::complex< double > >::calculate_softbit_matrices(), itpp::graycode(), it_assert, itpp::Modulator< std::complex< double > >::k, itpp::levels2bits(), itpp::Modulator< std::complex< double > >::M, itpp::m_2pi, itpp::pow2i(), itpp::Vec< Num_T >::set_size(), itpp::Modulator< std::complex< double > >::setup_done, and itpp::Modulator< std::complex< double > >::symbols.
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inherited |
Hard demodulation of bits.
Definition at line 151 of file modulator.cpp.
References itpp::Modulator< std::complex< double > >::bitmap, it_assert_debug, itpp::Modulator< std::complex< double > >::k, itpp::Modulator< std::complex< double > >::M, itpp::m_2pi, itpp::pi, itpp::round_i(), and itpp::Modulator< std::complex< double > >::setup_done.
Referenced by itpp::PSK::demodulate_bits().
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inherited |
Hard demodulation of bits.
Definition at line 167 of file modulator.cpp.
References itpp::PSK::demodulate_bits().
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virtualinherited |
Hard demodulation of bits.
Definition at line 135 of file modulator.h.
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virtualinherited |
Hard demodulation of bits.
Definition at line 137 of file modulator.h.
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virtualinherited |
Set the constellation to use in the modulator.
Definition at line 86 of file modulator.h.
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inlinevirtualinherited |
Returns number of bits per symbol.
Definition at line 89 of file modulator.h.
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inlinevirtualinherited |
Returns number of bits per symbol.
Definition at line 92 of file modulator.h.
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inlinevirtualinherited |
Returns number of modulation symbols.
Definition at line 95 of file modulator.h.
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inlinevirtualinherited |
Get the symbol values used in the modulator.
Definition at line 98 of file modulator.h.
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inlinevirtualinherited |
Get the bitmap, which maps input bits into symbols.
The mapping is done as follows. An input bit sequence in decimal notation is used for indexing the bits2symbols
table. The indexing result denotes the symbol to be used from the symbols
table, e.g.:
Definition at line 117 of file modulator.h.
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virtualinherited |
Modulation of symbols.
Definition at line 120 of file modulator.h.
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virtualinherited |
Modulation of symbols.
Definition at line 122 of file modulator.h.
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virtualinherited |
Demodulation of symbols.
Definition at line 125 of file modulator.h.
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virtualinherited |
Demodulation of symbols.
Definition at line 127 of file modulator.h.
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virtualinherited |
Modulation of bits.
Definition at line 130 of file modulator.h.
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virtualinherited |
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virtualinherited |
Soft demodulator for AWGN channels.
This function calculates the log-likelihood ratio (LLR) of the received signal from AWGN channels. Depending on the soft demodulation method chosen, either full log-MAP calculation is performed (default method), according to the following equation:
or approximate, but faster calculation is performed.
The approximate method finds for each bit the closest constellation points that have zero and one in the corresponding position. Let
This function can be used on channels where the channel gain
When this function is to be used together with MAP-based turbo decoding algorithms then the channel reliability factor
rx_symbols | The received noisy constellation symbols |
N0 | The spectral density of the AWGN noise |
soft_bits | The soft bits calculated using the expression above |
method | The method used for demodulation (LOGMAP or APPROX) |
Modulator_ND
) instead, which is based on the QLLR (quantized) arithmetic and therefore is faster. Please note, however, that mixed use of Modulator_1D/Modulator_2D
and
Modulator_ND
is not advised. Definition at line 178 of file modulator.h.
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virtualinherited |
Soft demodulator for AWGN channels.
Definition at line 182 of file modulator.h.
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virtualinherited |
Soft demodulator for fading channels.
This function calculates the log-likelihood ratio (LLR) of the received signal from fading channels. Depending on the soft demodulation method chosen, either full log-MAP calculation is performed (default method), according to the following equation:
or approximate, but faster calculation is performed.
The approximate method finds for each bit the closest constellation points that have zero and one in the corresponding position. Let
When this function is to be used together with MAP-based turbo decoding algorithms then the channel reliability factor
rx_symbols | The received noisy constellation symbols ![]() |
channel | The channel values ![]() |
N0 | The spectral density of the AWGN noise |
soft_bits | The soft bits calculated using the expression above |
method | The method used for demodulation (LOGMAP or APPROX) |
Modulator_1D/Modulator_2D
and
Modulator_ND
is not advised. Definition at line 223 of file modulator.h.
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virtualinherited |
Soft demodulator for fading channels.
Definition at line 228 of file modulator.h.
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protectedinherited |
This function calculates the soft bit mapping matrices S0 and S1.
Definition at line 254 of file modulator.h.
Referenced by itpp::PAM_c::set_M(), itpp::PSK::set_M(), and itpp::QAM::set_M().
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related |
Definition of 1D Modulator (with real symbols)
Definition at line 266 of file modulator.h.
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related |
Definition of 2D Modulator (with complex symbols)
Definition at line 272 of file modulator.h.
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protectedinherited |
Setup indicator.
Definition at line 235 of file modulator.h.
Referenced by itpp::PAM_c::demodulate_bits(), itpp::PSK::demodulate_bits(), itpp::QAM::demodulate_bits(), itpp::PAM_c::demodulate_soft_bits(), itpp::PAM_c::demodulate_soft_bits(), itpp::PAM_c::set_M(), itpp::PSK::set_M(), and itpp::QAM::set_M().
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protectedinherited |
Number of bits per modulation symbol.
Definition at line 237 of file modulator.h.
Referenced by itpp::PAM_c::demodulate_bits(), itpp::PSK::demodulate_bits(), itpp::QAM::demodulate_bits(), itpp::PAM_c::demodulate_soft_bits(), itpp::PAM_c::demodulate_soft_bits(), demodulate_soft_bits(), itpp::PAM_c::set_M(), itpp::PSK::set_M(), and itpp::QAM::set_M().
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protectedinherited |
Number of modulation symbols.
Definition at line 239 of file modulator.h.
Referenced by itpp::PAM_c::demodulate_bits(), itpp::PSK::demodulate_bits(), itpp::PAM_c::demodulate_soft_bits(), itpp::PAM_c::demodulate_soft_bits(), itpp::PAM_c::set_M(), itpp::PSK::set_M(), and itpp::QAM::set_M().
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protectedinherited |
Bit to symbol mapping table (size: M x k)
Definition at line 241 of file modulator.h.
Referenced by itpp::PAM_c::demodulate_bits(), itpp::PSK::demodulate_bits(), itpp::QAM::demodulate_bits(), itpp::PAM_c::set_M(), itpp::PSK::set_M(), and itpp::QAM::set_M().
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protectedinherited |
Bit to symbol mapping in decimal form (size: M)
Definition at line 243 of file modulator.h.
Referenced by itpp::PAM_c::set_M(), itpp::PSK::set_M(), and itpp::QAM::set_M().
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protectedinherited |
Corresponding modulation symbols (size: M)
Definition at line 245 of file modulator.h.
Referenced by itpp::PAM_c::demodulate_soft_bits(), itpp::PAM_c::demodulate_soft_bits(), itpp::PAM_c::set_M(), itpp::PSK::set_M(), and itpp::QAM::set_M().
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protectedinherited |
Matrix where row k contains the constellation points with '0' in bit position k.
Definition at line 248 of file modulator.h.
Referenced by itpp::PAM_c::demodulate_soft_bits(), and itpp::PAM_c::demodulate_soft_bits().
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protectedinherited |
Matrix where row k contains the constellation points with '1' in bit position k.
Definition at line 251 of file modulator.h.
Referenced by itpp::PAM_c::demodulate_soft_bits(), and itpp::PAM_c::demodulate_soft_bits().
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