An Even/Odd Error Detection Based Low-Complexity Chase Decoding for Low-Latency RS Decoder Design

This letter presents a modified low-complexity chase (LCC) algorithm, where a fewer number of vectors can be tested with minor error correction performance degradation. The proposed LCC decoding pre-determines whether the number of errors in the received codeword is even or odd, and it processes only necessary test vectors. As a result, the number of test vectors can be reduced by half compared to the conventional LCC decoding. The Reed-Solomon (255,239) decoder with the proposed LCC algorithm has been implemented using 65nm CMOS process. The hardware implementation results show that the proposed decoder shows 48.5% reduced latency with 0.06 dB of coding gain decrease at 10^-6 codeword error rate compared to the state-of-the-art LCC decoder.

I. Introduction

Algebraic soft-decision decoding (ASD) algorithms [1] of Reed-Solomon (RS) codes [2] generally show impressive error correction performance improvement compared to the hard-decision decoding (HDD) when channel information is used. ASD algorithms consist of three stages, which are multiplicity assignment (MA), interpolation, and factorization. Among those, the MA stage mainly determines the overall computational complexity and error correction performance. As one of the ASD algorithms, the low-complexity chase (LCC) decoding [3], [4] achieves comparable error correction capability with other ASD algorithms [1], [5], [6], [7] while having lower computational complexity with only one level of multiplicity.