EXIT Chart Analysis for Split-LDPC Codes

Abstract

Nonsystematic channel codes are superior to systematic codes in the presence of source redundancy. We study the performance of split-LDPC codes (we recently proposed), which are based on splitting redundant data bits into coded bits. We propose a novel method to build extrinsic information transfer (EXIT) chart to approximate the thresholds of such codes. EXIT charts provide a fast and close to accurate prediction of the thresholds of split-LDPC codes for nonuniform sources. The thresholds approximated by fast EXIT chart analysis are very close to those obtained by density evolution (DE) analysis that we recently proposed for split-LDPC codes. The EXIT chart analysis can thus be used to efficiently search for good split-LDPC codes. Simulations verify good performance close to the approximate thresholds predicted by the EXIT charts