Optimisation of low-density parity-check codes with deterministic unequal error protection properties

In this study, the authors propose a systematic method of designing low-density parity-check codes with deterministic unequal-error-protection characteristics over an additive white Gaussian noise channel. The proposed method optimises the code rate or the noise threshold while at the same time guaranteeing that different classes of code bits can achieve their respective target error probabilities within a specified number of decoding iterations. The authors also derive the necessary and sufficient stability condition for the optimisation method.