yongsk/bpDecoder

Simple ldpc decoder using belief propagation algorithm for BI-AWGNC

* Decoder with belief propagation algorithm for BI-AWGNC channel
It contains (3,6)-regular ldpc codes from other source.
Since this code is made by an undergradutated-level student, it may have errors.
But, I believe the code looks very intuitive if you know belief-propagation algorithm for ldpc decoders.
(*Still, this decoder requires some verification steps.)