Structured eIRA codes with low floors

TLDR

Extended irregular repeat‑accumulate (eIRA) codes are efficiently encodable LDPC codes with very low error‑rate floors suitable for rates ½ or higher, but their random left‑most submatrix complicates efficient decoder implementation. This paper introduces structured eIRA (SeIRA) codes. The authors first present ensemble results for the general eIRA class and then define the structured subclass SeIRA. Software and hardware performance evaluations show that SeIRA designs achieve strong results for rates 0.5 to 0.9.

Abstract

In a recent paper, Yang et al. presented the class of extended irregular repeat-accumulate (eIRA) codes which are efficiently encodable LDPC codes possessing very low error-rate floors and are appropriate for code rates 1/2 or greater. While efficiently encodable, the left-most (n-k)-by-k submatrix of an eIRA code parity-check matrix is random in nature, making efficient decoder implementation problematic. In the present paper, we present structured eIRA codes. We first present some ensemble results for the general class of eIRA codes, after which the subclass of structured eIRA (SeIRA) codes is defined. Software- and hardware-based performance results for SeIRA code designs (rates 0.5 to 0.9) are then presented.