On rate-adaptability of nonbinary LDPC codes

This paper examines rate-adaptability of nonbinary C codes at sort block lengths over the nary input WGN channel. Starting from a mother code, higher rate codes are obtained via puncturing, and lower rates are obtained by shortening. We propose algorithms both for puncturing and shortening and design a highly flexible, one encoder/decoder system that supports code rates ranging from 0.1 to 0.9. Our results show that properly designed rate-adaptable nonbinary LDPC codes can significantly outperform their binary counterparts throughout the entire range of code rates.