Two Extended Programmable BCH Soft Decoders Using Least Reliable Bits Reprocessing

Abstract

This paper proposes two Bose---Chaudhuri---Hocquenghem (BCH) soft decoders suitable for high-rate codes with medium to large word length. The proposed decoders extend the correcting capability by providing a programmable performance gain according to the choice of the extra compensated bits p, with a theoretical maximum likelihood decoding when 2t+p approaches the codeword size n, where t is the correcting capability of the code under algebraic decoding. Our proposed architectures for the proposed algorithms use pipelined arithmetic units, leading to a reduction in the critical paths. This allows for an increase in the operating frequency by up to m/2 times compared to algebraic decoders, where m is the Galois field size. Our proposed decoders operate only on the least reliable bits, which leads to a reduction in the decoder complexity by removing the Chien search procedure.