#include <itpp/comm/rec_syst_conv_code.h>
Public Member Functions | |
Rec_Syst_Conv_Code (void) | |
Class constructor. | |
virtual | ~Rec_Syst_Conv_Code (void) |
Class constructor. | |
void | set_generator_polynomials (const ivec &gen, int constraint_length) |
Set generator polynomials. | |
void | set_awgn_channel_parameters (double Ec, double N0) |
Sets the channel parameters needed for MAP-decoding. | |
void | set_scaling_factor (double in_Lc) |
Set scaling factor for the decoder. | |
void | set_llrcalc (LLR_calc_unit in_llrcalc) |
Set the lookup table for algebra with quantized LLR values (see LLR_calc_unit class). | |
void | encode_tail (const bvec &input, bvec &tail, bmat &parity_bits) |
Encode a binary vector of inputs and also adds a tail of K-1 zeros to force the encoder into the zero state. | |
void | encode (const bvec &input, bmat &parity_bits) |
Encode a binary vector of inputs starting from zero state without adding of a tail. | |
virtual void | map_decode (const vec &rec_systematic, const mat &rec_parity, const vec &extrinsic_input, vec &extrinsic_output, bool set_terminated=false) |
Maximum A Posteriori (MAP) Probability symbol-by-symbol decoder. | |
virtual void | log_decode (const vec &rec_systematic, const mat &rec_parity, const vec &extrinsic_input, vec &extrinsic_output, bool set_terminated=false, std::string metric="LOGMAX") |
Log domain implementation of the Maximum A Posteriori (MAP) Probability symbol-by-symbol decoder. | |
virtual void | log_decode_n2 (const vec &rec_systematic, const vec &rec_parity, const vec &extrinsic_input, vec &extrinsic_output, bool set_terminated=false, std::string metric="LOGMAX") |
Special Log-MAP/Log-MAX decoder implementation for n = 2. | |
virtual void | log_decode (const QLLRvec &rec_systematic, const QLLRmat &rec_parity, const QLLRvec &extrinsic_input, QLLRvec &extrinsic_output, bool set_terminated=false) |
Implementation of the log-map decoder using quantized LLR values (the QLLR type) and table-lookup (using the LLR_calc_unit class). | |
virtual void | log_decode_n2 (const QLLRvec &rec_systematic, const QLLRvec &rec_parity, const QLLRvec &extrinsic_input, QLLRvec &extrinsic_output, bool set_terminated=false) |
Implementation of the log-map decoder for the n=2 case using quantized LLR values (the QLLR type) and table-lookup (using the LLR_calc_unit class). |
The main purpose of this class is to be used by the Turbo_Codec class which uses two recursive systematic convolutional encoders. It can however be used as a stand alone class. The map_decode member function implementation follows the paper "A Turbo Code Tutorial" by William E. Ryan, New Mexico State University. This paper was found on the web and is probably unpublished.
Definition at line 54 of file rec_syst_conv_code.h.
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Class constructor.
Definition at line 58 of file rec_syst_conv_code.h. |
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Class constructor.
Definition at line 61 of file rec_syst_conv_code.h. |
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Set generator polynomials. The generator polynomials are given in Proakis integer form. First generator (gen(0)) is the recursive polynomial.
Definition at line 88 of file rec_syst_conv_code.cpp. References itpp::reverse_int(). Referenced by itpp::Turbo_Codec::set_parameters(). |
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Sets the channel parameters needed for MAP-decoding.
Definition at line 133 of file rec_syst_conv_code.cpp. References itpp::sqrt(). |
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Set scaling factor for the decoder.
Definition at line 138 of file rec_syst_conv_code.cpp. |
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Set the lookup table for algebra with quantized LLR values (see
Definition at line 716 of file rec_syst_conv_code.cpp. Referenced by itpp::Turbo_Codec::set_metric(), and itpp::Turbo_Codec::set_parameters(). |
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Encode a binary vector of inputs and also adds a tail of K-1 zeros to force the encoder into the zero state. The encoder remembers that the trellis is terminated in the zero state at the end of the input block. This is then utilized by the decoder when going through the trellis in the reverse direction. The tailbits used are returned in tail. Parity bits for both the input part and the tail part of the data are returned in the matrix parity bits. Definition at line 143 of file rec_syst_conv_code.cpp. References itpp::length(). Referenced by itpp::Turbo_Codec::encode_block(). |
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Encode a binary vector of inputs starting from zero state without adding of a tail.
Definition at line 169 of file rec_syst_conv_code.cpp. References itpp::length(). |
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Maximum A Posteriori (MAP) Probability symbol-by-symbol decoder. The extrinsic_input is the a priori information on each systematic bit. If no a priori information is available, this vector should contain only zeros. The extrinsic_output term may be passed to a subsequent decoder in a Turbo scheme. The decision variable is L = Lc*rec_systematic + extrinsic_output + extrinsic_input Lc = 4*sqrt(Ec)/N0
Definition at line 184 of file rec_syst_conv_code.cpp. References itpp::Mat< Num_T >::set_size(). |
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Log domain implementation of the Maximum A Posteriori (MAP) Probability symbol-by-symbol decoder. The extrinsic_input is the a priori information on each systematic bit. If no a priori information is available, this vector should contain only zeros. The extrinsic_output term may be passed to a subsequent decoder in a Turbo scheme. The decision variable is L = Lc*rec_systematic + extrinsic_output + extrinsic_input Lc = 4*sqrt(Ec)/N0
Definition at line 298 of file rec_syst_conv_code.cpp. References itpp::com_log, itpp::com_logmap(), itpp::com_logmax(), INF, it_error, itpp::length(), itpp::Mat< Num_T >::set_size(), itpp::LLR_calc_unit::to_double(), and itpp::LLR_calc_unit::to_qllr(). |
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Special Log-MAP/Log-MAX decoder implementation for n = 2.
Definition at line 414 of file rec_syst_conv_code.cpp. References itpp::com_log, itpp::com_logmap(), itpp::com_logmax(), INF, it_assert, it_error, itpp::length(), itpp::norm(), itpp::Mat< Num_T >::set_size(), itpp::LLR_calc_unit::to_double(), and itpp::LLR_calc_unit::to_qllr(). |
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Implementation of the log-map decoder using quantized LLR values (the
Definition at line 521 of file rec_syst_conv_code.cpp. References QLLR_MAX. |
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Implementation of the log-map decoder for the n=2 case using quantized LLR values (the
Definition at line 626 of file rec_syst_conv_code.cpp. References it_assert, itpp::norm(), and QLLR_MAX. |
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