#include <itpp/comm/modulator_nd.h>
Inheritance diagram for itpp::Modulator_NRD:
Public Member Functions | |
Modulator_NRD () | |
Constructor. | |
~Modulator_NRD () | |
Destructor. | |
Vec< vec > | get_symbols () |
Get modulation symbols per dimension. | |
vec | modulate_bits (const bvec &bits) const |
Modulation of bits. | |
void | map_demod (QLLRvec &LLR_apriori, QLLRvec &LLR_aposteriori, double sigma2, mat &H, vec &y) |
Soft MAP demodulation for multidimensional channel, by "brute-force" enumeration of all constellation points. | |
void | map_demod (QLLRvec &LLR_apriori, QLLRvec &LLR_aposteriori, double sigma2, vec &h, vec &y) |
Soft MAP demodulation for parallel channels without crosstalk. | |
int | get_dim () |
Get number of dimensions. | |
LLR_calc_unit | get_llrcalc () const |
Get LLR calculation unit. | |
ivec | get_k () |
Get number of bits per modulation symbol. | |
ivec | get_M () |
Get number of modulation symbols per dimension. | |
Protected Member Functions | |
void | update_norm (double &norm, int k, int sold, int snew, vec &ytH, mat &HtH, ivec &s) |
For internal use only. | |
QLLRvec | probabilities (QLLR l) |
Convert LLR to log-probabilities. | |
Vec< QLLRvec > | probabilities (QLLRvec &l) |
Convert LLR to log-probabilities, vector version. | |
void | update_LLR (Vec< QLLRvec > &logP_apriori, QLLRvec &numerator, QLLRvec &denominator, ivec &s, QLLR x) |
Update LLR (for internal use). | |
void | update_LLR (Vec< QLLRvec > &logP_apriori, QLLRvec &numerator, QLLRvec &denominator, int s, QLLR scaled_norm, int j) |
Update LLR, for scalar channel (for internal use). | |
Protected Attributes | |
Vec< vec > | symbols |
Vector of modulation symbols (along each dimension). | |
int | nt |
Number of dimensions. | |
LLR_calc_unit | llrcalc |
LLR calculation unit. | |
ivec | k |
Number of bits per modulation symbol. | |
ivec | M |
Number of modulation symbols along each dimension. | |
Vec< bmat > | bitmap |
Bit mapping table (one table per dimension). | |
Vec< ivec > | bits2symbols |
Bit pattern in decimal form ordered and the corresponding symbols (one pattern per dimension). | |
Friends | |
std::ostream & | operator<< (std::ostream &os, const Modulator_NRD &mod) |
Print some properties of the MIMO modulator in plain text (mainly to aid debugging). |
This class can be used to perform modulation and demodulation for a matrix (MIMO) channel of the form
where H is a channel matrix of dimension ,
is a received vector of length
,
is a transmitted vector of length
and
is noise.
The class supports soft-input soft-output demodulation. It can also be used for scalar modulation to take advantage of this feature.
Complex MIMO channels can be handled by using the Modulator_NCD
class. Alternatively, if the signal constellation is separable in I/Q then the complex channel can be first transformed to a real channel
See ND_UPAM
for examples.
Definition at line 146 of file modulator_nd.h.
itpp::Modulator_NRD::Modulator_NRD | ( | ) | [inline] |
itpp::Modulator_NRD::~Modulator_NRD | ( | ) | [inline] |
Vec<vec> itpp::Modulator_NRD::get_symbols | ( | ) | [inline] |
Get modulation symbols per dimension.
Definition at line 154 of file modulator_nd.h.
References symbols.
vec itpp::Modulator_NRD::modulate_bits | ( | const bvec & | bits | ) | const |
Modulation of bits.
Returns a vector of modulated symbols.
bits | vector of the bits to be modulated |
Definition at line 338 of file modulator_nd.cpp.
References itpp::bin2dec(), itpp::Modulator_ND::bits2symbols, it_assert, itpp::Modulator_ND::k, itpp::length(), itpp::Modulator_ND::nt, itpp::sum(), and symbols.
void itpp::Modulator_NRD::map_demod | ( | QLLRvec & | LLR_apriori, | |
QLLRvec & | LLR_aposteriori, | |||
double | sigma2, | |||
mat & | H, | |||
vec & | y | |||
) |
Soft MAP demodulation for multidimensional channel, by "brute-force" enumeration of all constellation points.
This function computes the LLR values
without approximations. It is assumed that H, y and s are real-valued. Complex-valued channels can be handled via the Modulator_NCD
class.
H | channel matrix (m*n) | |
y | received vector (m*1) | |
sigma2 | noise variance, per real dimension | |
LLR_apriori | vector of a priori LLR values per bit | |
LLR_aposteriori | vector of a posteriori LLR values |
Definition at line 192 of file modulator_nd.cpp.
References it_assert, itpp::Modulator_ND::k, itpp::length(), itpp::Modulator_ND::llrcalc, itpp::Modulator_ND::M, itpp::norm(), itpp::Modulator_ND::nt, itpp::ones_i(), itpp::Modulator_ND::probabilities(), itpp::sqr(), itpp::sum(), symbols, itpp::LLR_calc_unit::to_qllr(), itpp::Modulator_ND::update_LLR(), and update_norm().
void itpp::Modulator_NRD::map_demod | ( | QLLRvec & | LLR_apriori, | |
QLLRvec & | LLR_aposteriori, | |||
double | sigma2, | |||
vec & | h, | |||
vec & | y | |||
) |
Soft MAP demodulation for parallel channels without crosstalk.
This function is equivalent to map_demod
with . However, it is much faster (the complexity is linear in the number of subchannels).
Definition at line 138 of file modulator_nd.cpp.
References it_assert, itpp::Modulator_ND::k, itpp::length(), itpp::Modulator_ND::llrcalc, itpp::Modulator_ND::M, itpp::Modulator_ND::nt, itpp::ones_i(), itpp::Modulator_ND::probabilities(), itpp::sqr(), itpp::sum(), symbols, itpp::LLR_calc_unit::to_qllr(), and itpp::Modulator_ND::update_LLR().
void itpp::Modulator_NRD::update_norm | ( | double & | norm, | |
int | k, | |||
int | sold, | |||
int | snew, | |||
vec & | ytH, | |||
mat & | HtH, | |||
ivec & | s | |||
) | [protected] |
For internal use only.
Update the residual norm when moving from one constellation point to an adjacent point
norm | The norm to be updated | |
k | The position where s changed | |
sold | Old value of s[k] | |
snew | New value of s[k] | |
ytH | The vector y'H | |
HtH | The Grammian matrix H'H | |
s | The s-vector |
Definition at line 111 of file modulator_nd.cpp.
References itpp::length(), itpp::sqr(), and symbols.
Referenced by map_demod().
int itpp::Modulator_ND::get_dim | ( | ) | [inline, inherited] |
Get number of dimensions.
Definition at line 57 of file modulator_nd.h.
References itpp::Modulator_ND::nt.
LLR_calc_unit itpp::Modulator_ND::get_llrcalc | ( | ) | const [inline, inherited] |
Get LLR calculation unit.
Definition at line 60 of file modulator_nd.h.
References itpp::Modulator_ND::llrcalc.
ivec itpp::Modulator_ND::get_k | ( | ) | [inline, inherited] |
Get number of bits per modulation symbol.
Definition at line 63 of file modulator_nd.h.
References itpp::Modulator_ND::k.
ivec itpp::Modulator_ND::get_M | ( | ) | [inline, inherited] |
Get number of modulation symbols per dimension.
Definition at line 66 of file modulator_nd.h.
References itpp::Modulator_ND::M.
QLLRvec itpp::Modulator_ND::probabilities | ( | QLLR | l | ) | [protected, inherited] |
Convert LLR to log-probabilities.
Definition at line 44 of file modulator_nd.cpp.
References itpp::LLR_calc_unit::jaclog(), and itpp::Modulator_ND::llrcalc.
Referenced by itpp::Modulator_NCD::map_demod(), map_demod(), and itpp::Modulator_ND::probabilities().
Vec< QLLRvec > itpp::Modulator_ND::probabilities | ( | QLLRvec & | l | ) | [protected, inherited] |
Convert LLR to log-probabilities, vector version.
Definition at line 58 of file modulator_nd.cpp.
References itpp::length(), and itpp::Modulator_ND::probabilities().
void itpp::Modulator_ND::update_LLR | ( | Vec< QLLRvec > & | logP_apriori, | |
QLLRvec & | numerator, | |||
QLLRvec & | denominator, | |||
ivec & | s, | |||
QLLR | x | |||
) | [protected, inherited] |
Update LLR (for internal use).
This function updates the numerator and denominator in the expression
logP_apriori | vector of a priori probabilities per bit | |
numerator | the logarithm of the numerator in the above expression | |
denominator | the logarithm of the denominator in the above expression | |
s | the symbol vector |
Definition at line 87 of file modulator_nd.cpp.
References itpp::Modulator_ND::bitmap, itpp::LLR_calc_unit::jaclog(), itpp::Modulator_ND::k, itpp::Modulator_ND::llrcalc, and itpp::Modulator_ND::nt.
Referenced by itpp::Modulator_NCD::map_demod(), and map_demod().
void itpp::Modulator_ND::update_LLR | ( | Vec< QLLRvec > & | logP_apriori, | |
QLLRvec & | numerator, | |||
QLLRvec & | denominator, | |||
int | s, | |||
QLLR | scaled_norm, | |||
int | j | |||
) | [protected, inherited] |
Update LLR, for scalar channel (for internal use).
This function updates the numerator and denominator in the expression
logP_apriori | vector of a priori probabilities per bit | |
numerator | the logarithm of the numerator in the above expression | |
denominator | the logarithm of the denominator in the above expression | |
s | the symbol vector |
Definition at line 67 of file modulator_nd.cpp.
References itpp::Modulator_ND::bitmap, itpp::LLR_calc_unit::jaclog(), itpp::Modulator_ND::k, and itpp::Modulator_ND::llrcalc.
std::ostream & operator<< | ( | std::ostream & | os, | |
const Modulator_NRD & | mod | |||
) | [friend] |
Print some properties of the MIMO modulator in plain text (mainly to aid debugging).
Definition at line 374 of file modulator_nd.cpp.
Vec<vec> itpp::Modulator_NRD::symbols [protected] |
Vector of modulation symbols (along each dimension).
Definition at line 206 of file modulator_nd.h.
Referenced by get_symbols(), map_demod(), modulate_bits(), itpp::ND_UPAM::set_Gray_PAM(), and update_norm().
int itpp::Modulator_ND::nt [protected, inherited] |
Number of dimensions.
Definition at line 70 of file modulator_nd.h.
Referenced by itpp::Modulator_ND::get_dim(), itpp::Modulator_NCD::map_demod(), map_demod(), itpp::Modulator_NCD::modulate_bits(), modulate_bits(), itpp::ND_UPAM::ND_UPAM(), itpp::ND_UPSK::ND_UPSK(), itpp::ND_UQAM::ND_UQAM(), itpp::ND_UPAM::set_Gray_PAM(), itpp::ND_UPSK::set_Gray_PSK(), itpp::ND_UQAM::set_Gray_QAM(), itpp::ND_UPAM::sphere_decoding(), and itpp::Modulator_ND::update_LLR().
LLR_calc_unit itpp::Modulator_ND::llrcalc [protected, inherited] |
LLR calculation unit.
Definition at line 72 of file modulator_nd.h.
Referenced by itpp::Modulator_ND::get_llrcalc(), itpp::Modulator_NCD::map_demod(), map_demod(), itpp::Modulator_ND::Modulator_ND(), itpp::Modulator_ND::probabilities(), and itpp::Modulator_ND::update_LLR().
ivec itpp::Modulator_ND::k [protected, inherited] |
Number of bits per modulation symbol.
Definition at line 74 of file modulator_nd.h.
Referenced by itpp::Modulator_ND::get_k(), itpp::Modulator_NCD::map_demod(), map_demod(), itpp::Modulator_NCD::modulate_bits(), modulate_bits(), itpp::ND_UPAM::set_Gray_PAM(), itpp::ND_UPSK::set_Gray_PSK(), itpp::ND_UQAM::set_Gray_QAM(), itpp::ND_UPAM::sphere_decoding(), and itpp::Modulator_ND::update_LLR().
ivec itpp::Modulator_ND::M [protected, inherited] |
Number of modulation symbols along each dimension.
Definition at line 76 of file modulator_nd.h.
Referenced by itpp::Modulator_ND::get_M(), itpp::Modulator_NCD::map_demod(), map_demod(), itpp::ND_UPAM::set_Gray_PAM(), itpp::ND_UPSK::set_Gray_PSK(), itpp::ND_UQAM::set_Gray_QAM(), and itpp::ND_UPAM::sphere_decoding().
Vec<bmat> itpp::Modulator_ND::bitmap [protected, inherited] |
Bit mapping table (one table per dimension).
Definition at line 78 of file modulator_nd.h.
Referenced by itpp::ND_UPAM::set_Gray_PAM(), itpp::ND_UPSK::set_Gray_PSK(), itpp::ND_UQAM::set_Gray_QAM(), itpp::ND_UPAM::sphere_decoding(), and itpp::Modulator_ND::update_LLR().
Vec<ivec> itpp::Modulator_ND::bits2symbols [protected, inherited] |
Bit pattern in decimal form ordered and the corresponding symbols (one pattern per dimension).
Definition at line 80 of file modulator_nd.h.
Referenced by itpp::Modulator_NCD::modulate_bits(), modulate_bits(), itpp::ND_UPAM::set_Gray_PAM(), itpp::ND_UPSK::set_Gray_PSK(), and itpp::ND_UQAM::set_Gray_QAM().
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