Soft Input Soft Output (SISO) modules. More...

#include <itpp/comm/siso.h>

Public Member Functions
	SISO ()
	SISO class constructor

void	set_map_metric (const std::string &in_MAP_metric)
	Sets the metric for MAP algorithm (convolutional codes and multipath channels)

void	set_precoder_generator (const itpp::bvec &in_prec_gen)
	Sets the precoder generator polynomial for turbo equalizer.

void	set_precoder_generator (const int &in_prec_gen, const int &constraint_length)

void	set_generators (const itpp::bmat &in_gen)
	Sets convolutional code generator polynomials.

void	set_generators (const itpp::ivec &in_gen, const int &constraint_length)

void	set_tail (const bool &in_tail)
	Signals whether the trellis used in the MAP algorithm is terminated or not (only for convolutional codes and multipath channels)

void	set_viterbi_win_len (const int &win_len)
	Sets the length of the trellis used by the SOVA.

void	set_sova_scaling_factor (const double &scaling_factor)
	Sets the scaling factor used to normalize the reliability value computed by the SOVA.

void	set_sova_threshold (const double &threshold)
	Sets the threshold value used to limit the reliability value computed by SOVA.

void	set_viterbi_scaling_factors (const double &matching_scaling_factor, const double &nonmatching_scaling_factor)
	Sets the Viterbi algorithm scaling factors.

void	set_viterbi_hard_output_flag (const bool &flag)
	Sets the Viterbi algorithm hard output flag (true when only the hard output is needed)

void	set_noise (const double &in_sigma2)
	Sets Additive White Gaussian Noise variance for each dimension.

void	set_impulse_response (const itpp::vec &h)
	Sets channel impulse response for equalizer.

void	set_impulse_response (const itpp::mat &H)
	Sets channel impulse response for Multi-User Detectors.

void	set_impulse_response (const itpp::cvec &h)
	Sets the channel attenuations for demappers (when only a modulator is used)

void	set_impulse_response (const itpp::cmat &cH)
	Sets channel attenuations for demappers (when Space-Time codes are used)

void	set_scrambler_pattern (const itpp::vec &phi)
	Sets scrambler pattern.

void	set_scrambler_pattern (const itpp::bvec &phi)

void	set_mud_method (const std::string &method)
	Sets Multi-User Detector method.

void	set_constellation (const int &in_nb_bits_symb, const itpp::cvec &in_constellation, const itpp::bmat &in_bin_constellation)
	Sets symbol constellation.

void	set_constellation (const int &in_nb_bits_symb, const itpp::cvec &in_constellation, const itpp::ivec &in_int_constellation)

void	set_st_block_code (const int &Q, const itpp::cmat &A, const itpp::cmat &B, const int &N)
	Sets Space-Time block code parameters.

void	set_demapper_method (const std::string &method)
	Sets demapper method.

void	rsc (itpp::vec &extrinsic_coded, itpp::vec &extrinsic_data, const itpp::vec &intrinsic_coded, const itpp::vec &apriori_data)
	SISO decoder for RSC codes

void	rsc (itpp::vec &extrinsic_coded, itpp::vec &extrinsic_data, const itpp::vec &intrinsic_coded, const itpp::vec &apriori_data, const bool &tail)
	SISO decoder for RSC codes (tail is set through input)

void	nsc (itpp::vec &extrinsic_coded, itpp::vec &extrinsic_data, const itpp::vec &intrinsic_coded, const itpp::vec &apriori_data)
	SISO decoder for NSC codes

void	nsc (itpp::vec &extrinsic_coded, itpp::vec &extrinsic_data, const itpp::vec &intrinsic_coded, const itpp::vec &apriori_data, const bool &tail)
	SISO decoder for NSC codes (tail is set through input)

void	equalizer (itpp::vec &extrinsic_data, const itpp::vec &rec_sig, const itpp::vec &apriori_data)
	SISO equalizer

void	equalizer (itpp::vec &extrinsic_data, const itpp::vec &rec_sig, const itpp::vec &apriori_data, const bool &tail)
	SISO equalizer (tail is set through input)

void	descrambler (itpp::vec &extrinsic_coded, itpp::vec &extrinsic_data, const itpp::vec &intrinsic_coded, const itpp::vec &apriori_data)
	SISO descrambler

void	mud (itpp::mat &extrinsic_data, const itpp::vec &rec_sig, const itpp::mat &apriori_data)
	SISO Multi-User Detector

void	demapper (itpp::vec &extrinsic_data, const itpp::cvec &rec_sig, const itpp::vec &apriori_data)
	SISO demapper (when only a modulator is used)

void	demapper (itpp::vec &extrinsic_data, const itpp::cmat &rec_sig, const itpp::vec &apriori_data)
	SISO demapper (when Space-Time codes are used)

Static Public Member Functions
static double	threshold (const double &x, const double &value)
	Functions used to limit values at a given +- threshold.

static itpp::vec	threshold (const itpp::vec &in, const double &value)

static itpp::mat	threshold (const itpp::mat &in, const double &value)

Detailed Description

Soft Input Soft Output (SISO) modules.

The following SISO modules are implemented:

decoder for an Recursive Systematic Convolutional (RSC) code
decoder for an Non-recursive non-Systematic Convolutional (NSC) code
equalizer (without and with precoding)
descrambler used in Interleave Division Multiple Access (IDMA) systems
Multi User Detectors (MUDs) for IDMA systems
demappers for Bit Interleaved Coded Modulation (BICM) systems
demappers for Space Time (ST) BICM systems
Note
BPSK mapping is realized as follows: 0 -> +1 and 1 -> -1. Thus the xor truth table is preserved when multiplying BPSK symbols.
There is some overlap in functionality between the SISO class and the Modulator_ND class as follows:
- When used for ST-BICM systems, both SISO and Modulator_ND classes can be used for iterative (turbo reception), but the for the SISO class the emitter part is implemented by the STC class, while for the Modulator_ND class the emitter is implemented by the same class.
- When used for reception, the SISO class is more generic than the Modulator_ND class since it allows the use of several ST codes following Hassibi's model (see STC class) and several reception algorithms.
- The SISO demapper for ST-BICM systems when using V-BLAST as ST code can be replaced by the ND demodulator (see Modulator_ND class). The best performance could be achieved with the ND demodulator using FULL_ENUM_LOGMAP algorithm followed by the SISO demapper with Hassibi_maxlogMAP algorithm (less complex than FULL_ENUM_LOGMAP). There is no configuration in which the ND demodulator and the SISO demapper can be considered completely equivalent (from an implementation point of view).

Definition at line 71 of file siso.h.

Constructor & Destructor Documentation

itpp::SISO::SISO ( )

inline

SISO class constructor

Internal variables are initialized with default values:

the trellis used in MAP algorithm is not terminated
maxlogMAP metric is used
simplified GCD is selected
no scrambler is used
GA demapper is selected, etc.

Definition at line 495 of file siso.h.

Member Function Documentation

void itpp::SISO::set_map_metric ( const std::string & in_MAP_metric )

inline

Sets the metric for MAP algorithm (convolutional codes and multipath channels)

Possible input values are:

logMAP
maxlogMAP
SOVA
Viterbi

Note: Soft Output Viterbi Algorithm (SOVA) is equivalent to the MAP algorithm only when the a priori information is zero.

Definition at line 574 of file siso.h.

void itpp::SISO::set_precoder_generator ( const itpp::bvec & in_prec_gen )

inline

Sets the precoder generator polynomial for turbo equalizer.

The precoder is used in turbo equalization. The generator polynomial describes the feedback connections of the precoder.

Definition at line 579 of file siso.h.

void itpp::SISO::set_generators ( const itpp::bmat & in_gen )

inline

Sets convolutional code generator polynomials.

The generator polynomials are specified as rows of the input binary matrix.

Definition at line 590 of file siso.h.

void itpp::SISO::set_tail ( const bool & in_tail )

inline

Signals whether the trellis used in the MAP algorithm is terminated or not (only for convolutional codes and multipath channels)

If the input value is true, the trellis is terminated. In order to terminate the trellis an ending bit tail is added to the input stream of the encoder.

Definition at line 604 of file siso.h.

Referenced by equalizer(), nsc(), and rsc().

void itpp::SISO::set_viterbi_scaling_factors	(	const double &	matching_scaling_factor,
		const double &	nonmatching_scaling_factor
	)

inline

Sets the Viterbi algorithm scaling factors.

Parameters

matching_scaling_factor	scaling factor for matching bits
nonmatching_scaling_factor	scaling factor for non matching bits

Definition at line 624 of file siso.h.

void itpp::SISO::set_impulse_response ( const itpp::vec & h )

inline

Sets channel impulse response for equalizer.

The input is a real channel impulse response.

Definition at line 641 of file siso.h.

void itpp::SISO::set_impulse_response ( const itpp::mat & H )

inline

Sets channel impulse response for Multi-User Detectors.

The input is a real matrix with each row represented by the channel impulse response of one user.

Definition at line 647 of file siso.h.

void itpp::SISO::set_impulse_response ( const itpp::cvec & h )

inline

Sets the channel attenuations for demappers (when only a modulator is used)

The input is the vector of channel attenuations for each received symbol

Definition at line 652 of file siso.h.

void itpp::SISO::set_impulse_response ( const itpp::cmat & cH )

inline

Sets channel attenuations for demappers (when Space-Time codes are used)

The input is a complex matrix of dimension $MN\times tx\_duration$ , where $M$ and $N$ is the number of emission and reception antennas, respectively and $tx\_duration$ is the transmission duration expressed in symbol durations.

This input matrix is formed as follows:

the starting point is an $M\times N$ complex matrix (channel matrix) with one row represented by the atenuations seen by each of reception antennas during one symbol duration, when the signal is emitted by a given emission antenna. The row number represents the number of emission antenna.
the $M\times N$ channel matrix is then transformed into a vector of length , with the first elements the first column of the channel matrix
the vector of length represents one column of the input matrix
in the input matrix, the vector is repeated $\tau_c$ times and $tx\_duration/\tau_c$ different vectors are used. Thus, the channel is supposed constant over $\tau_c$ symbol durations (channel coherence time) and $tx\_duration/\tau_c$ different channel realisations are used.
in our implementation $\tau_c$ must be and integer multiple of , where is the ST block code duration expressed in symbol durations. This means that the channel matrix must be constant over at least symbol durations.

Definition at line 658 of file siso.h.

void itpp::SISO::set_scrambler_pattern ( const itpp::vec & phi )

inline

Sets scrambler pattern.

The scrambler pattern must be a sequence of $\pm1$ and is used by the SISO NSC module in IDMA systems reception. At emission side the bits are first encoded by an NSC code, BPSK modulated and then scrambled with the given pattern.

Definition at line 663 of file siso.h.

void itpp::SISO::set_mud_method ( const std::string & method )

inline

Sets Multi-User Detector method.

Possible input values are:

maxlogMAP
GCD
sGCD (simplified GCD)

Definition at line 678 of file siso.h.

void itpp::SISO::set_constellation	(	const int &	in_nb_bits_symb,
		const itpp::cvec &	in_constellation,
		const itpp::bmat &	in_bin_constellation
	)

inline

Sets symbol constellation.

The correspondence between each symbol and its binary representation is given. Note that if the symbols are normalized to the square root of the number of emission antenna you should use the normalized constellation as input for this method.

Parameters

in_nb_bits_symb	the number of symbols
in_constellation	all possible symbols as a complex vector
in_bin_constellation	binary representations of symbols as a binary matrix (each row corresponds to one symbol)

Definition at line 683 of file siso.h.

void itpp::SISO::set_constellation	(	const int &	in_nb_bits_symb,
		const itpp::cvec &	in_constellation,
		const itpp::ivec &	in_int_constellation
	)

inline

Parameters

in_nb_bits_symb	the number of symbols
in_constellation	all possible symbols as a complex vector
in_int_constellation	integer representations of symbols as a vector

Definition at line 691 of file siso.h.

References itpp::dec2bin().

void itpp::SISO::set_st_block_code	(	const int &	Q,
		const itpp::cmat &	A,
		const itpp::cmat &	B,
		const int &	N
	)

inline

Sets Space-Time block code parameters.

ST block codes are generated using Hassibi's model.

Parameters

Q	the number of symbols per block
A	generator matrices
B	of the ST block code
N	the number of reception antennas

Definition at line 705 of file siso.h.

void itpp::SISO::set_demapper_method ( const std::string & method )

inline

Sets demapper method.

Possible input values are:

Hassibi_maxlogMAP (maxlogMAP algorithm applied for ST block codes represented using Hassibi's model)
GA
sGA (simplified GA)
mmsePIC
zfPIC (simplified mmsePIC)
Alamouti_maxlogMAP (maxlogMAP algorithm applied to Alamouti code using matched-filter reception method)

Definition at line 716 of file siso.h.

void itpp::SISO::rsc	(	itpp::vec &	extrinsic_coded,
		itpp::vec &	extrinsic_data,
		const itpp::vec &	intrinsic_coded,
		const itpp::vec &	apriori_data
	)

inline

SISO decoder for RSC codes

Parameters

extrinsic_coded	extrinsic information of coded bits
extrinsic_data	extrinsic information of data bits
intrinsic_coded	intrinsic information of coded bits
apriori_data	a priori information of data bits

Definition at line 728 of file siso.h.

Referenced by rsc().

void itpp::SISO::rsc	(	itpp::vec &	extrinsic_coded,
		itpp::vec &	extrinsic_data,
		const itpp::vec &	intrinsic_coded,
		const itpp::vec &	apriori_data,
		const bool &	tail
	)

inline

SISO decoder for RSC codes (tail is set through input)

Parameters

extrinsic_coded	extrinsic information of coded bits
extrinsic_data	extrinsic information of data bits
intrinsic_coded	intrinsic information of coded bits
apriori_data	a priori information of data bits
tail	if true the trellis is terminated

Definition at line 721 of file siso.h.

References rsc(), and set_tail().

void itpp::SISO::nsc	(	itpp::vec &	extrinsic_coded,
		itpp::vec &	extrinsic_data,
		const itpp::vec &	intrinsic_coded,
		const itpp::vec &	apriori_data
	)

inline

SISO decoder for NSC codes

Parameters

extrinsic_coded	extrinsic information of coded bits
extrinsic_data	extrinsic information of data bits
intrinsic_coded	intrinsic information of coded bits
apriori_data	a priori information of data bits

Definition at line 763 of file siso.h.

Referenced by nsc().

void itpp::SISO::nsc	(	itpp::vec &	extrinsic_coded,
		itpp::vec &	extrinsic_data,
		const itpp::vec &	intrinsic_coded,
		const itpp::vec &	apriori_data,
		const bool &	tail
	)

inline

SISO decoder for NSC codes (tail is set through input)

Parameters

extrinsic_coded	extrinsic information of coded bits
extrinsic_data	extrinsic information of data bits
intrinsic_coded	intrinsic information of coded bits
apriori_data	a priori information of data bits
tail	if true the trellis is terminated

Definition at line 756 of file siso.h.

References nsc(), and set_tail().

void itpp::SISO::equalizer	(	itpp::vec &	extrinsic_data,
		const itpp::vec &	rec_sig,
		const itpp::vec &	apriori_data
	)

inline

SISO equalizer

Channel trellis is generated so that BPSK mapping is assumed: 0->+1 and 1->-1 (xor truth table is preserved)

Parameters

extrinsic_data	extrinsic informations of input symbols
rec_sig	received signal
apriori_data	a priori informations of input symbols

Definition at line 790 of file siso.h.

Referenced by equalizer().

void itpp::SISO::equalizer	(	itpp::vec &	extrinsic_data,
		const itpp::vec &	rec_sig,
		const itpp::vec &	apriori_data,
		const bool &	tail
	)

inline

SISO equalizer (tail is set through input)

Channel trellis is generated so that BPSK mapping is assumed: 0->+1 and 1->-1 (xor truth table is preserved)

Parameters

extrinsic_data	extrinsic informations of input symbols
rec_sig	received signal
apriori_data	a priori informations of input symbols
tail	if true the trellis is terminated

Definition at line 780 of file siso.h.

References equalizer(), and set_tail().

void itpp::SISO::descrambler	(	itpp::vec &	extrinsic_coded,
		itpp::vec &	extrinsic_data,
		const itpp::vec &	intrinsic_coded,
		const itpp::vec &	apriori_data
	)

SISO descrambler

Parameters

extrinsic_coded	extrinsic information of scrambled bits
extrinsic_data	extrinsic information of informational bits
intrinsic_coded	intrinsic information of scrambled bits
apriori_data	a priori information of informational bits

Definition at line 37 of file siso_mud.cpp.

void itpp::SISO::mud	(	itpp::mat &	extrinsic_data,
		const itpp::vec &	rec_sig,
		const itpp::mat &	apriori_data
	)

inline

SISO Multi-User Detector

Parameters

extrinsic_data	extrinsic informations of emitted chips from all users
rec_sig	received signal
apriori_data	a priori informations of emitted chips from all users

Definition at line 812 of file siso.h.

void itpp::SISO::demapper	(	itpp::vec &	extrinsic_data,
		const itpp::cvec &	rec_sig,
		const itpp::vec &	apriori_data
	)

inline

SISO demapper (when only a modulator is used)

Parameters

extrinsic_data	extrinsic informations of emitted bits
rec_sig	received signal
apriori_data	a priori informations of emitted bits

Definition at line 836 of file siso.h.

void itpp::SISO::demapper	(	itpp::vec &	extrinsic_data,
		const itpp::cmat &	rec_sig,
		const itpp::vec &	apriori_data
	)

inline

SISO demapper (when Space-Time codes are used)

Parameters

extrinsic_data	extrinsic informations of emitted bits
rec_sig	received signal
apriori_data	a priori informations of emitted bits

Definition at line 857 of file siso.h.

The documentation for this class was generated from the following files:

itpp/comm/siso.h
itpp/comm/siso_dem.cpp
itpp/comm/siso_eq.cpp
itpp/comm/siso_mud.cpp
itpp/comm/siso_nsc.cpp
itpp/comm/siso_rsc.cpp

Public Member Functions

Static Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation