I am highly unsure whether this question is appropriate for this site (as it is at no point a math problem), yet searching in the stackexchange universe for similar topics showed the most hits on math. So forgive me, if I'm mistaken ;)
My problem is rather simple at first sight, yet finding the answer proved rather difficult:
I am looking for low rate block codes (i.e. $R < \frac 12$, e.g. $R = 0.25$ or $R = 0.33$) with short block lengths ($n < 1000$). The codes should obviously be as good as possible. Now here is the problem: I used to use LDPC codes, but I don't have any good degree distributions which I could take as a basis (since the LDPCOpt tool of http://ipgdemos.epfl.ch/ldpcopt/ isn't working anymore). And performing such optimizations would be too long.
I have been looking quite some time, but I didn't find anything. Any ideas? Note that I'm only looking for block codes, convolutional or turbo codes are no option.