Mirror/aicodix___modem
1
0
Fork 0
mirror of https://github.com/aicodix/modem.git synced 2026-04-27 14:30:34 +00:00
Code Issues Projects Releases Packages Wiki Activity

simplified precision estimation

Browse source
This commit is contained in:
Ahmet Inan 2022-05-18 12:05:47 +02:00
commit 44fae606fd
1 changed files with 2 additions and 5 deletions
Download patch file Download diff file Expand all files Collapse all files

7
decode.cc
View file

@ -512,12 +512,9 @@ struct Decoder
sp += norm(hard);
np += norm(error);
}
value snr = DSP::decibel(sp / np);
precision = sp / np;
value snr = DSP::decibel(precision);
std::cerr << "init Es/N0: " << snr << " dB" << std::endl;
// $LLR=log(\frac{p(x=+1|y)}{p(x=-1|y)})$
// $p(x|\mu,\sigma)=\frac{1}{\sqrt{2\pi}\sigma}}e^{-\frac{(x-\mu)^2}{2\sigma^2}}$
value sigma = std::sqrt(np / (2 * sp));
precision = 1 / (sigma * sigma);
}
for (int i = 0; i < cons_cnt; ++i)
mod_soft(code+mod_bits*i, cons[i], precision);