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https://github.com/aicodix/modem.git
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interleave reserved tones with data subcarriers
This commit is contained in:
Ahmet Inan
parent
d5c4bb25f5
commit
efe5b9421d
2 changed files with 31 additions and 24 deletions
31
decode.cc
31
decode.cc
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@ -49,26 +49,27 @@ struct Decoder
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static const int code_max = 16;
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static const int bits_max = 1 << code_max;
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static const int data_max = 1024;
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static const int cols_max = 256 + 32;
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static const int rows_max = 32;
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static const int cons_max = cols_max * rows_max;
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static const int mls0_poly = 0b1100110001;
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static const int mls0_seed = 214;
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static const int mls1_poly = 0b100101011;
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static const int buffer_len = 5 * extended_len;
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static const int search_pos = extended_len;
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static const int comb_cols = 32;
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static const int reserved_tones = 32;
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static const int code_cols = 256;
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static const int comb_dist = 9;
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static const int block_len = 10;
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static const int comb_off = 4;
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static const int cons_cols = code_cols + comb_cols;
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static const int tone_off = 9;
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static const int cons_cols = code_cols + comb_cols + reserved_tones;
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static const int cons_off = - cons_cols / 2;
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static const int cons_max = cons_cols * rows_max;
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DSP::ReadPCM<value> *pcm;
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DSP::FastFourierTransform<symbol_len, cmplx, -1> fwd;
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DSP::BlockDC<value, value> blockdc;
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DSP::Hilbert<cmplx, filter_len> hilbert;
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DSP::BipBuffer<cmplx, buffer_len> input_hist;
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DSP::TheilSenEstimator<value, cols_max> tse;
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DSP::TheilSenEstimator<value, cons_cols> tse;
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SchmidlCox<value, cmplx, search_pos, symbol_len, guard_len> correlator;
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CODE::CRC<uint32_t> crc1;
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CODE::HadamardEncoder<6> hadamardenc;
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@ -78,9 +79,9 @@ struct Decoder
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mesg_type mesg[bits_max];
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code_type code[bits_max], perm[bits_max];
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int8_t mode[32];
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cmplx cons[cons_max], chan[cols_max], scar[cols_max];
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cmplx cons[cons_max], chan[cons_cols], scar[cons_cols];
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cmplx fdom[symbol_len], tdom[symbol_len];
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value index[cols_max], phase[cols_max];
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value index[cons_cols], phase[cons_cols];
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value cfo_rad, sfo_rad;
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const uint32_t *frozen_bits;
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int mod_bits;
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@ -295,7 +296,7 @@ struct Decoder
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CODE::MLS seq1(mls1_poly);
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auto clamp = [](int v){ return v < -127 ? -127 : v > 127 ? 127 : v; };
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for (int i = 0; i < comb_cols; ++i)
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mode[i] = clamp(std::nearbyint(127 * demod_or_erase(scar[i*comb_dist+comb_off], chan[i*comb_dist+comb_off]).real() * nrz(seq1())));
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mode[i] = clamp(std::nearbyint(127 * demod_or_erase(scar[i*block_len+comb_off], chan[i*block_len+comb_off]).real() * nrz(seq1())));
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int oper_mode = hadamarddec(mode);
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if (oper_mode < 0 || oper_mode > 8) {
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std::cerr << "operation mode " << oper_mode << " unsupported." << std::endl;
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@ -324,12 +325,12 @@ struct Decoder
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hadamardenc(mode, oper_mode);
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}
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for (int i = 0; i < comb_cols; ++i)
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scar[comb_dist*i+comb_off] *= nrz(seq1()) * mode[i];
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scar[block_len*i+comb_off] *= nrz(seq1()) * mode[i];
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for (int i = 0; i < cons_cols; ++i)
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cons[cons_cols*j+i] = demod_or_erase(scar[i], chan[i]);
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for (int i = 0; i < comb_cols; ++i) {
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index[i] = cons_off + comb_dist * i + comb_off;
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phase[i] = arg(cons[cons_cols*j+comb_dist*i+comb_off]);
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index[i] = cons_off + block_len * i + comb_off;
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phase[i] = arg(cons[cons_cols*j+block_len*i+comb_off]);
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}
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tse.compute(index, phase, comb_cols);
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//std::cerr << "Theil-Sen slope = " << tse.slope() << std::endl;
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@ -337,7 +338,7 @@ struct Decoder
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for (int i = 0; i < cons_cols; ++i)
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cons[cons_cols*j+i] *= DSP::polar<value>(1, -tse(i+cons_off));
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for (int i = 0; i < cons_cols; ++i)
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if (i % comb_dist == comb_off)
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if (i % block_len == comb_off)
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chan[i] = scar[i];
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else
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chan[i] *= DSP::polar<value>(1, tse(i+cons_off));
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@ -349,7 +350,7 @@ struct Decoder
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for (int j = 0, k = 0; j < cons_rows; ++j) {
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for (int i = 0; i < comb_cols; ++i) {
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cmplx hard(1, 0);
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cmplx error = cons[cons_cols*j+comb_dist*i+comb_off] - hard;
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cmplx error = cons[cons_cols*j+block_len*i+comb_off] - hard;
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sp += norm(hard);
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np += norm(error);
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}
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@ -360,7 +361,9 @@ struct Decoder
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if (std::is_same<code_type, int8_t>::value && precision > 32)
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precision = 32;
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for (int i = 0; i < cons_cols; ++i) {
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if (i % comb_dist == comb_off)
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if (i % block_len == comb_off)
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continue;
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if (i % block_len == tone_off)
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continue;
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mod_soft(perm+k, cons[cons_cols*j+i], precision);
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k += mod_bits;
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24
encode.cc
24
encode.cc
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@ -38,10 +38,11 @@ struct Encoder
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static const int mls2_poly = 0b100101010001;
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static const int code_cols = 256;
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static const int comb_cols = 32;
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static const int cons_cols = code_cols + comb_cols;
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static const int comb_dist = 9;
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static const int comb_off = 4;
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static const int reserved_tones = 32;
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static const int cons_cols = code_cols + comb_cols + reserved_tones;
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static const int block_len = 10;
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static const int comb_off = 4;
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static const int tone_off = 9;
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DSP::WritePCM<value> *pcm;
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DSP::FastFourierTransform<symbol_len, cmplx, -1> fwd;
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DSP::FastFourierTransform<symbol_len, cmplx, 1> bwd;
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@ -293,12 +294,12 @@ struct Encoder
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void tone_reservation_kernels()
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{
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value mag = 1 / value(10 * reserved_tones);
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for (int i = 0, j = cons_off - reserved_tones / 2; i < reserved_tones; ++i, ++j) {
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if (j == cons_off)
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j += cons_cols;
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temp[bin(j)] = mag;
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}
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for (int i = 0; i < reserved_tones; ++i)
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temp[bin(i*block_len+tone_off)] = mag;
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bwd(kern, temp);
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}
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void guard_interval_weights()
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{
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for (int i = 0; i < guard_len / 4; ++i)
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weight[i] = 0;
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for (int i = guard_len / 4; i < guard_len / 4 + guard_len / 2; ++i) {
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@ -313,6 +314,7 @@ struct Encoder
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{
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setup(oper_mode, freq_off);
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tone_reservation_kernels();
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guard_interval_weights();
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papr_min = 1000, papr_max = -1000;
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pilot_block();
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hadamardenc(mode, oper_mode);
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@ -320,7 +322,7 @@ struct Encoder
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schmidl_cox();
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CODE::MLS seq1(mls1_poly);
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for (int i = 0, m = 0; i < cons_cols; ++i) {
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if (i % comb_dist == comb_off) {
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if (i % block_len == comb_off) {
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cons[i] = nrz(seq1()) * mode[m++];
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} else {
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cons[i] = 0;
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@ -355,8 +357,10 @@ struct Encoder
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CODE::MLS seq1(mls1_poly);
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for (int j = 0, k = 0; j < cons_rows; ++j) {
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for (int i = 0, m = 0; i < cons_cols; ++i) {
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if (i % comb_dist == comb_off) {
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if (i % block_len == comb_off) {
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cons[i] = nrz(seq1()) * mode[m++];
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} else if (i % block_len == tone_off) {
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cons[i] = 0;
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} else {
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cons[i] = mod_map(perm+k);
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k += mod_bits;
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