Density Evolution for Min-Sum Decoding of LDPC Codes Under Unreliable Message Storage

Abstract

We analyze the performance of quantized min-sum decoding of low-density parity-check codes under unreliable message storage. To this end, we introduce a simple bit-level error model and show that decoder symmetry is preserved under this model. Subsequently, we formulate the corresponding density evolution equations to predict the average bit error probability in the limit of infinite blocklength. We present numerical threshold results and we show that using more quantization bits is not always beneficial in the context of faulty decoders.