Genetic Algorithm Aided Design of Near-Capacity Irregular Variable Length Codes

In this paper we demonstrate that our ability to match the Extrinsic Information Transfer (EXIT) function of an Irregular Variable Length Code (IrVLC) to that of a serially-concatenated inner code depends on the availability of a suite of component Variable Length Error Correction (VLEC) codebooks having a wide variety of inverted EXIT function shapes. We also show that the inverted EXIT function shape of a VLEC codebook depends on its coding rate and Error Correction Capability (ECC). This motivates the design of a Genetic Algorithm (GA) that searches the large VLEC parameter space to find codebooks having specific coding rates, ECCs and, hence, EXIT function shapes. The employment of this GA therefore facilitates the design of component VLEC codebook suites without the manual trial-and-error that is required when employing the state-of- the-art Heuristic Algorithm (HA) used as our bench marker, which cannot design component codebooks having specific EXIT function shapes.