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shuffle bits to improve decoding with burst errors

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Ahmet Inan 2023-05-11 09:07:02 +02:00
commit 5afd9fa8d6
2 changed files with 6 additions and 0 deletions
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3
decode.cc
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@ -13,6 +13,7 @@ namespace DSP { using std::abs; using std::min; using std::cos; using std::sin;
#include "xorshift.hh"
#include "trigger.hh"
#include "complex.hh"
#include "permute.hh"
#include "decibel.hh"
#include "blockdc.hh"
#include "hilbert.hh"
@ -192,6 +193,7 @@ struct Decoder
CODE::HadamardDecoder<8> hadamard;
CODE::PolarEncoder<mesg_type> polarenc;
CODE::PolarListDecoder<mesg_type, code_order> polardec;
CODE::ReverseFisherYatesShuffle<code_len> shuffle;
mesg_type mesg[mesg_bits], mess[code_len];
code_type code[code_len];
cmplx cons[cons_total], prev[subcarrier_count];
@ -352,6 +354,7 @@ struct Decoder
mod_soft(code+mod_bits*i, cons[i], precision);
}
CODE::PolarHelper<mesg_type>::PATH metric[mesg_type::SIZE];
shuffle(code);
polardec(metric, mesg, code, frozen_bits, code_order);
systematic();
int order[mesg_type::SIZE];

3
encode.cc
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@ -9,6 +9,7 @@ Copyright 2023 Ahmet Inan <inan@aicodix.de>
#include <cmath>
#include "xorshift.hh"
#include "complex.hh"
#include "permute.hh"
#include "phasor.hh"
#include "bitman.hh"
#include "utils.hh"
@ -44,6 +45,7 @@ struct Encoder
CODE::CRC<uint32_t> crc;
CODE::HadamardEncoder<8> hadamard;
CODE::PolarSysEnc<code_type> polarenc;
CODE::FisherYatesShuffle<code_len> shuffle;
code_type code[code_len], mesg[mesg_bits];
cmplx fdom[symbol_len], tdom[symbol_len], guard[guard_len];
@ -118,6 +120,7 @@ struct Encoder
for (int i = 0; i < 32; ++i)
mesg[i+data_bits] = nrz((crc()>>i)&1);
polarenc(code, mesg, frozen_4096_2080, code_order);
shuffle(code);
for (int j = 0; j < payload_symbols; ++j) {
for (int i = 0; i < subcarrier_count; ++i)
fdom[first_subcarrier+i] *=