A forward error correction scheme for ultra long haul optical transmission systems based on low-density parity-check codes

FEC scheme based on LDPC codes is presented in this paper. We show that LDPC codes provide a significant system performance improvement with respect to the state-of-the-art FEC schemes, such as turbo BCH and RS codes, employed in optical communications systems. The system performance is further improved by a code design that eliminates short cycles in a graph employed in iterative decoding. As opposed to additive white Gaussian noise (AWGN) model for optical fiber channel, which is used very often in the analysis of error controlling schemes, our model takes into account all major impairments in a long-haul optical transmission such as amplifier spontaneous emission (ASE) noise, pulse distortion due to fiber nonlinearities, chromatic dispersion, crosstalk, intersymbol-interference, etc.