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merge head and tail to side (information)

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This commit is contained in:
Ahmet Inan 2025-07-29 12:25:45 +02:00
commit cec02bb851
3 changed files with 35 additions and 65 deletions
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62
decode.cc
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@ -51,7 +51,7 @@ struct Decoder : Common
DSP::BipBuffer<cmplx, buffer_len> input_hist;
DSP::TheilSenEstimator<value, tone_count> tse;
SchmidlCox<value, cmplx, search_pos, symbol_len, guard_len> correlator;
CODE::HadamardDecoder<6> hadamard_decoder;
CODE::HadamardDecoder<7> hadamard_decoder;
CODE::PolarListDecoder<mesg_type, code_max> polar_decoder;
mesg_type mesg[bits_max];
code_type code[bits_max], perm[bits_max];
@ -283,8 +283,7 @@ struct Decoder : Common
oper_mode = -1;
symbol_count = 0;
for (int j = 0, k = 0; j < symbol_count + 1; ++j) {
head_off = (block_skew * j + first_head) % block_length;
tail_off = (block_skew * j + first_tail) % block_length;
side_off = (block_skew * j + first_side) % block_length;
if (j) {
for (int i = 0; i < extended_len; ++i)
correlator(buf = next_sample());
@ -297,45 +296,28 @@ struct Decoder : Common
for (int i = 0; i < tone_count; ++i)
tone[i] = fdom[bin(i+tone_off)];
for (int i = 0; i < tone_count; ++i)
if (i % block_length == head_off || i % block_length == tail_off)
if (i % block_length == side_off)
tone[i] *= nrz(seq1());
for (int i = 0; i < tone_count; ++i)
demod[i] = demod_or_erase(tone[i], chan[i]);
for (int i = 0; i < head_tones; ++i)
head[i] = clamp(std::nearbyint(127 * demod[i*block_length+head_off].real()));
int head_data = hadamard_decoder(head);
if (head_data < 0) {
std::cerr << "head data damaged" << std::endl;
for (int i = 0; i < side_tones; ++i)
side[i] = clamp(std::nearbyint(127 * demod[i*block_length+side_off].real()));
int side_data = hadamard_decoder(side);
if (side_data < 0) {
std::cerr << "side data damaged" << std::endl;
oper_mode = -1;
break;
}
hadamard_encoder(head, head_data);
for (int i = 0; i < head_tones; ++i) {
tone[block_length*i+head_off] *= head[i];
demod[block_length*i+head_off] *= head[i];
hadamard_encoder(side, side_data);
for (int i = 0; i < side_tones; ++i) {
tone[block_length*i+side_off] *= side[i];
demod[block_length*i+side_off] *= side[i];
}
for (int i = 0; i < head_tones; ++i) {
index[i] = tone_off + block_length * i + head_off;
phase[i] = arg(demod[block_length*i+head_off]);
for (int i = 0; i < side_tones; ++i) {
index[i] = tone_off + block_length * i + side_off;
phase[i] = arg(demod[block_length*i+side_off]);
}
for (int i = 0; i < tail_tones; ++i)
tail[i] = clamp(std::nearbyint(127 * demod[i*block_length+tail_off].real()));
int tail_data = hadamard_decoder(tail);
if (tail_data < 0) {
std::cerr << "tail data damaged" << std::endl;
oper_mode = -1;
break;
}
hadamard_encoder(tail, tail_data);
for (int i = 0; i < tail_tones; ++i) {
tone[block_length*i+tail_off] *= tail[i];
demod[block_length*i+tail_off] *= tail[i];
}
for (int i = 0; i < tail_tones; ++i) {
index[i+head_tones] = tone_off + block_length * i + tail_off;
phase[i+head_tones] = arg(demod[block_length*i+tail_off]);
}
tse.compute(index, phase, head_tones + tail_tones);
tse.compute(index, phase, side_tones);
//std::cerr << "Theil-Sen slope = " << tse.slope() << std::endl;
//std::cerr << "Theil-Sen yint = " << tse.yint() << std::endl;
for (int i = 0; i < tone_count; ++i)
@ -343,7 +325,7 @@ struct Decoder : Common
for (int i = 0; i < tone_count; ++i)
chan[i] *= DSP::polar<value>(1, tse(i+tone_off));
CODE::XorShiftMask<int, 14, 1, 5, 10, 1> combination;
int trial = (head_data << 6) | tail_data;
int trial = side_data;
int comb = 0;
for (int i = 0; i <= trial; ++i)
comb = combination();
@ -353,12 +335,12 @@ struct Decoder : Common
std::cerr << "reserved seed value detected" << std::endl;
CODE::MLS seq(slm_poly[poly_index], seed_value);
for (int i = 0; i < tone_count; ++i)
if (i % block_length != head_off && i % block_length != tail_off)
if (i % block_length != side_off)
demod[i] *= nrz(seq());
value sp = 0, np = 0;
for (int i = 0, l = k; i < tone_count; ++i) {
cmplx hard(1, 0);
if (i % block_length != head_off && i % block_length != tail_off) {
if (i % block_length != side_off) {
int bits = mod_bits;
if (mod_bits == 3 && l % 32 == 30)
bits = 2;
@ -380,7 +362,7 @@ struct Decoder : Common
snr[j] = precision;
precision = std::min(precision, value(1023));
for (int i = 0; i < tone_count; ++i) {
if (i % block_length != head_off && i % block_length != tail_off) {
if (i % block_length != side_off) {
int bits = mod_bits;
if (mod_bits == 3 && k % 32 == 30)
bits = 2;
@ -417,9 +399,7 @@ struct Decoder : Common
correlator(buf = next_sample());
std::cerr << "oper mode: " << oper_mode << std::endl;
}
for (int i = head_off; i < tone_count; i += block_length)
chan[i] = DSP::lerp(chan[i], tone[i], value(0.5));
for (int i = tail_off; i < tone_count; i += block_length)
for (int i = side_off; i < tone_count; i += block_length)
chan[i] = DSP::lerp(chan[i], tone[i], value(0.5));
}
if (oper_mode < 0)