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use base40 and one more bit to get three more characters

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This commit is contained in:
Ahmet Inan 2025-11-25 03:19:57 +01:00
commit 811a3fbb42
4 changed files with 24 additions and 22 deletions
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16
decode.cc
View file

@ -80,10 +80,10 @@ struct Decoder : Common
} }
return 0; return 0;
} }
static void base37_decoder(char *str, int64_t val, int len) static void base40_decoder(char *str, int64_t val, int len)
{ {
for (int i = len-1; i >= 0; --i, val /= 37) for (int i = len-1; i >= 0; --i, val /= 40)
str[i] = " 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"[val%37]; str[i] = " /0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"[val%40];
} }
const cmplx *mls0_seq() const cmplx *mls0_seq()
{ {
@ -207,11 +207,11 @@ struct Decoder : Common
int64_t meta_data() int64_t meta_data()
{ {
shuffle(code, perm, 8); shuffle(code, perm, 8);
polar_decoder(nullptr, mesg, code, frozen_256_71, 8); polar_decoder(nullptr, mesg, code, frozen_256_72, 8);
int best = -1; int best = -1;
for (int k = 0; k < mesg_type::SIZE; ++k) { for (int k = 0; k < mesg_type::SIZE; ++k) {
crc0.reset(); crc0.reset();
for (int i = 0; i < 71; ++i) for (int i = 0; i < 72; ++i)
crc0(mesg[i].v[k] < 0); crc0(mesg[i].v[k] < 0);
if (crc0() == 0) { if (crc0() == 0) {
best = k; best = k;
@ -221,7 +221,7 @@ struct Decoder : Common
if (best < 0) if (best < 0)
return -1; return -1;
uint64_t md = 0; uint64_t md = 0;
for (int i = 0; i < 55; ++i) for (int i = 0; i < 56; ++i)
md |= uint64_t(mesg[i].v[best] < 0) << i; md |= uint64_t(mesg[i].v[best] < 0) << i;
return md; return md;
} }
@ -375,12 +375,12 @@ struct Decoder : Common
break; break;
} }
int64_t call = meta_info >> 8; int64_t call = meta_info >> 8;
if (call == 0 || call >= 129961739795077L) { if (call == 0 || call >= 262144000000000L) {
std::cerr << "call sign unsupported." << std::endl; std::cerr << "call sign unsupported." << std::endl;
break; break;
} }
char call_sign[10]; char call_sign[10];
base37_decoder(call_sign, call, 9); base40_decoder(call_sign, call, 9);
call_sign[9] = 0; call_sign[9] = 0;
std::cerr << "call sign: " << call_sign << std::endl; std::cerr << "call sign: " << call_sign << std::endl;
int mode = meta_info & 255; int mode = meta_info & 255;

26
encode.cc
View file

@ -163,13 +163,13 @@ struct Encoder : public Common
} }
void meta_data(uint64_t md) void meta_data(uint64_t md)
{ {
for (int i = 0; i < 55; ++i) for (int i = 0; i < 56; ++i)
mesg[i] = nrz((md >> i) & 1); mesg[i] = nrz((md >> i) & 1);
crc0.reset(); crc0.reset();
crc0(md << 9); crc0(md << 8);
for (int i = 0; i < 16; ++i) for (int i = 0; i < 16; ++i)
mesg[i+55] = nrz((crc0() >> i) & 1); mesg[i+56] = nrz((crc0() >> i) & 1);
polar_encoder(code, mesg, frozen_256_71, 8); polar_encoder(code, mesg, frozen_256_72, 8);
shuffle(meta, code, 8); shuffle(meta, code, 8);
} }
cmplx map_bits(code_type *b, int bits) cmplx map_bits(code_type *b, int bits)
@ -330,17 +330,19 @@ struct Encoder : public Common
} }
}; };
int64_t base37_encoder(const char *str) int64_t base40_encoder(const char *str)
{ {
int64_t acc = 0; int64_t acc = 0;
for (char c = *str++; c; c = *str++) { for (char c = *str++; c; c = *str++) {
acc *= 37; acc *= 40;
if (c >= '0' && c <= '9') if (c == '/')
acc += c - '0' + 1; acc += 3;
else if (c >= '0' && c <= '9')
acc += c - '0' + 4;
else if (c >= 'a' && c <= 'z') else if (c >= 'a' && c <= 'z')
acc += c - 'a' + 11; acc += c - 'a' + 14;
else if (c >= 'A' && c <= 'Z') else if (c >= 'A' && c <= 'Z')
acc += c - 'A' + 11; acc += c - 'A' + 14;
else if (c != ' ') else if (c != ' ')
return -1; return -1;
} }
@ -366,8 +368,8 @@ int main(int argc, char **argv)
std::cerr << "Frequency offset must be divisible by 300." << std::endl; std::cerr << "Frequency offset must be divisible by 300." << std::endl;
return 1; return 1;
} }
int64_t call_sign = base37_encoder(argv[6]); int64_t call_sign = base40_encoder(argv[6]);
if (call_sign <= 0 || call_sign >= 129961739795077L) { if (call_sign <= 0 || call_sign >= 262144000000000L) {
std::cerr << "Unsupported call sign." << std::endl; std::cerr << "Unsupported call sign." << std::endl;
return 1; return 1;
} }

2
freezer.cc
View file

@ -28,7 +28,7 @@ void code(int N, int K, double P)
int main() int main()
{ {
// call sign and mode with 16 bit CRC // call sign and mode with 16 bit CRC
code<8>(256, 47+8+16, 0.5); code<8>(256, 48+8+16, 0.5);
// 1/2-rate payload with 32 bit CRC // 1/2-rate payload with 32 bit CRC
code<11>(2048, 1024+32, 0.33); code<11>(2048, 1024+32, 0.33);
code<12>(4096, 2048+32, 0.34); code<12>(4096, 2048+32, 0.34);

2
polar_tables.hh
View file

@ -1,4 +1,4 @@
static const uint32_t frozen_256_71[8] = { 0xffffffff, 0xffffffff, 0x7fffffff, 0x17f7fff, 0x7fffffff, 0x1171fff, 0x17177f, 0x7, }; static const uint32_t frozen_256_72[8] = { 0xffffffff, 0xffffffff, 0x7fffffff, 0x17f7fff, 0x7fffffff, 0x1171fff, 0x17177f, 0x3, };
static const uint32_t frozen_2048_1056[64] = { 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x7fffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x3fffffff, 0xffffffff, 0x177fffff, 0x177f7fff, 0x1013f, 0xffffffff, 0xffffffff, 0xffffffff, 0x177f7fff, 0x7fffffff, 0x11f7fff, 0x11717ff, 0x10117, 0x1fffffff, 0x117177f, 0x7177f, 0x1, 0x1037f, 0x1, 0x1, 0x0, 0xffffffff, 0x7fffffff, 0x7fffffff, 0x11717ff, 0x17ffffff, 0x17177f, 0x1037f, 0x1, 0x77f7fff, 0x1013f, 0x10117, 0x1, 0x10117, 0x1, 0x0, 0x0, 0x1173fff, 0x10117, 0x10117, 0x0, 0x17, 0x0, 0x0, 0x0, 0x3, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, }; static const uint32_t frozen_2048_1056[64] = { 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x7fffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x3fffffff, 0xffffffff, 0x177fffff, 0x177f7fff, 0x1013f, 0xffffffff, 0xffffffff, 0xffffffff, 0x177f7fff, 0x7fffffff, 0x11f7fff, 0x11717ff, 0x10117, 0x1fffffff, 0x117177f, 0x7177f, 0x1, 0x1037f, 0x1, 0x1, 0x0, 0xffffffff, 0x7fffffff, 0x7fffffff, 0x11717ff, 0x17ffffff, 0x17177f, 0x1037f, 0x1, 0x77f7fff, 0x1013f, 0x10117, 0x1, 0x10117, 0x1, 0x0, 0x0, 0x1173fff, 0x10117, 0x10117, 0x0, 0x17, 0x0, 0x0, 0x0, 0x3, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, };
static const uint32_t frozen_4096_2080[128] = { 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x7fffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x177fffff, 0xffffffff, 0xffffffff, 0x7fffffff, 0x37f7fff, 0x7fffffff, 0x1171fff, 0x117177f, 0x117, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x7fffffff, 0x11f7fff, 0xffffffff, 0x7fffffff, 0x17ffffff, 0x117177f, 0x177f7fff, 0x1077f, 0x1013f, 0x1, 0xffffffff, 0x177fffff, 0x77f7fff, 0x1013f, 0x11f7fff, 0x10117, 0x10117, 0x1, 0x11717ff, 0x10117, 0x17, 0x0, 0x3, 0x0, 0x0, 0x0, 0xffffffff, 0xffffffff, 0xffffffff, 0x7fffffff, 0xffffffff, 0x17ffffff, 0x177f7fff, 0x1077f, 0xffffffff, 0x177f7fff, 0x11f7fff, 0x10117, 0x11717ff, 0x10117, 0x117, 0x0, 0x7fffffff, 0x1171fff, 0x117177f, 0x17, 0x7177f, 0x1, 0x1, 0x0, 0x1017f, 0x1, 0x1, 0x0, 0x1, 0x0, 0x0, 0x0, 0x177fffff, 0x17177f, 0x1037f, 0x1, 0x1011f, 0x1, 0x1, 0x0, 0x10117, 0x1, 0x1, 0x0, 0x1, 0x0, 0x0, 0x0, 0x10117, 0x1, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, }; static const uint32_t frozen_4096_2080[128] = { 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x7fffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x177fffff, 0xffffffff, 0xffffffff, 0x7fffffff, 0x37f7fff, 0x7fffffff, 0x1171fff, 0x117177f, 0x117, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x7fffffff, 0x11f7fff, 0xffffffff, 0x7fffffff, 0x17ffffff, 0x117177f, 0x177f7fff, 0x1077f, 0x1013f, 0x1, 0xffffffff, 0x177fffff, 0x77f7fff, 0x1013f, 0x11f7fff, 0x10117, 0x10117, 0x1, 0x11717ff, 0x10117, 0x17, 0x0, 0x3, 0x0, 0x0, 0x0, 0xffffffff, 0xffffffff, 0xffffffff, 0x7fffffff, 0xffffffff, 0x17ffffff, 0x177f7fff, 0x1077f, 0xffffffff, 0x177f7fff, 0x11f7fff, 0x10117, 0x11717ff, 0x10117, 0x117, 0x0, 0x7fffffff, 0x1171fff, 0x117177f, 0x17, 0x7177f, 0x1, 0x1, 0x0, 0x1017f, 0x1, 0x1, 0x0, 0x1, 0x0, 0x0, 0x0, 0x177fffff, 0x17177f, 0x1037f, 0x1, 0x1011f, 0x1, 0x1, 0x0, 0x10117, 0x1, 0x1, 0x0, 0x1, 0x0, 0x0, 0x0, 0x10117, 0x1, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, };
static const uint32_t frozen_8192_4128[256] = { 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x17ffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x177f7fff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x7fffffff, 0x7fffffff, 0x11717ff, 0xffffffff, 0x1fffffff, 0x177fffff, 0x17177f, 0x177f7fff, 0x1013f, 0x10117, 0x1, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x7fffffff, 0xffffffff, 0x7fffffff, 0x17ffffff, 0x117177f, 0xffffffff, 0xffffffff, 0xffffffff, 0x1fffffff, 0xffffffff, 0x177f7fff, 0x77f7fff, 0x1011f, 0x7fffffff, 0x13f7fff, 0x11717ff, 0x10117, 0x117177f, 0x117, 0x7, 0x0, 0xffffffff, 0xffffffff, 0x7fffffff, 0x37f7fff, 0x7fffffff, 0x1171fff, 0x117177f, 0x10117, 0x17ffffff, 0x117177f, 0x3177f, 0x1, 0x1013f, 0x1, 0x1, 0x0, 0x177f7fff, 0x1017f, 0x1011f, 0x1, 0x10117, 0x1, 0x1, 0x0, 0x10117, 0x1, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x17ffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x177f7fff, 0x7fffffff, 0x11f7fff, 0x11717ff, 0x10117, 0xffffffff, 0x7fffffff, 0x7fffffff, 0x1171fff, 0x17ffffff, 0x117177f, 0x7177f, 0x1, 0x177f7fff, 0x1077f, 0x1011f, 0x1, 0x10117, 0x1, 0x1, 0x0, 0xffffffff, 0x17ffffff, 0x177f7fff, 0x7177f, 0x37f7fff, 0x1011f, 0x10117, 0x1, 0x1171fff, 0x10117, 0x10117, 0x1, 0x10117, 0x0, 0x0, 0x0, 0x117177f, 0x10117, 0x17, 0x0, 0x3, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x7fffffff, 0x37f7fff, 0x1173fff, 0x10117, 0x11717ff, 0x10117, 0x117, 0x0, 0x117177f, 0x7, 0x1, 0x0, 0x1, 0x0, 0x0, 0x0, 0x1077f, 0x1, 0x1, 0x0, 0x1, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1011f, 0x1, 0x1, 0x0, 0x1, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, }; static const uint32_t frozen_8192_4128[256] = { 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x17ffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x177f7fff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x7fffffff, 0x7fffffff, 0x11717ff, 0xffffffff, 0x1fffffff, 0x177fffff, 0x17177f, 0x177f7fff, 0x1013f, 0x10117, 0x1, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x7fffffff, 0xffffffff, 0x7fffffff, 0x17ffffff, 0x117177f, 0xffffffff, 0xffffffff, 0xffffffff, 0x1fffffff, 0xffffffff, 0x177f7fff, 0x77f7fff, 0x1011f, 0x7fffffff, 0x13f7fff, 0x11717ff, 0x10117, 0x117177f, 0x117, 0x7, 0x0, 0xffffffff, 0xffffffff, 0x7fffffff, 0x37f7fff, 0x7fffffff, 0x1171fff, 0x117177f, 0x10117, 0x17ffffff, 0x117177f, 0x3177f, 0x1, 0x1013f, 0x1, 0x1, 0x0, 0x177f7fff, 0x1017f, 0x1011f, 0x1, 0x10117, 0x1, 0x1, 0x0, 0x10117, 0x1, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x17ffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x177f7fff, 0x7fffffff, 0x11f7fff, 0x11717ff, 0x10117, 0xffffffff, 0x7fffffff, 0x7fffffff, 0x1171fff, 0x17ffffff, 0x117177f, 0x7177f, 0x1, 0x177f7fff, 0x1077f, 0x1011f, 0x1, 0x10117, 0x1, 0x1, 0x0, 0xffffffff, 0x17ffffff, 0x177f7fff, 0x7177f, 0x37f7fff, 0x1011f, 0x10117, 0x1, 0x1171fff, 0x10117, 0x10117, 0x1, 0x10117, 0x0, 0x0, 0x0, 0x117177f, 0x10117, 0x17, 0x0, 0x3, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x7fffffff, 0x37f7fff, 0x1173fff, 0x10117, 0x11717ff, 0x10117, 0x117, 0x0, 0x117177f, 0x7, 0x1, 0x0, 0x1, 0x0, 0x0, 0x0, 0x1077f, 0x1, 0x1, 0x0, 0x1, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1011f, 0x1, 0x1, 0x0, 0x1, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, };