Noise thresholds of parallel concatenated LDPC codes

Density evolution can determine the noise threshold of an ensemble of LDPC codes in the limit of large block lengths. In this work, the capacity of code ensembles for the parallel concatenation of LDPC codes on binary-input AWGN channels is analyzed using the density evolution technique. The noise thresholds for the optimized code ensembles show that at low rates <1/3, some good parallel concatenated LDPC codes can outperform conventional ones with a similar complexity.