Constructions of irregular nonbinary QC-LDPC codes: Cyclotomic coset approach

A cyclotomic coset approach for constructions of irregular nonbinary quasi-cyclic low-density parity-check (QC-LDPC) codes of short length is proposed. QC-LDPC codes obtained by this method perform reasonably well over the additive white Gaussian noise (AWGN) channel with iterative decoding in terms of bit-error performance, error-floor, and decoding convergence with low decoding complexity.