Decoder-in-the-Loop: Genetic Optimization-based LDPC Code Design
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Low-Density Parity-Check (LDPC) code design tools typically rely on the asymptotic code behavior and, thus, are affected by an unavoidable performance degradation in the short length regime.We propose an LDPC code design scheme based on an evolutionary algorithm called the Genetic Algorithm (GenAlg), which relies on a 'decoder-in-the-loop' concept. Thus, it inherently takes into consideration the channel, code length and the number of iterations as our proposed algorithm directly optimizes the error-rate of the actual decoder rather than the decoding thresholds. Using our proposed algorithm, we construct short length LDPC codes with error-rate performance comparable to, or even outperforming, that of standardized short length LDPC codes. Our proposed algorithm can be used to design LDPC codes with special graph structure (e.g., accumulator-based codes) to facilitate the encoding step or to satisfy the aforementioned practical requirements. Moreover, for a fixed target error-rate, GenAlg can be used to design LDPC codes with the aim of reducing the decoding complexity.
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