City Research Online

Abstract

In this paper, we present an efficient fault tolerant solution for multi-level per cell (MLC) flash memory that concatenates trellis coded modulation (TCM) with an outer low-density parity-check (LDPC) code. Traditional flash coding systems employ simple hard-decisions based codes, such as Bose-Chaudhuri-Hocquenghem (BCH) codes, that can correct a fixed, specified number of errors. Thanks to the Bahl, Cocke, Jelinek, and Raviv (BCJR) algorithm, the TCM decoder within the proposed design can provide soft decisions which make it possible to use the more powerful LDPC codes. Moreover, the error-correction performance is further improved since TCM can decrease the raw error rate of MLC and hence relieve the burden of outer LDPC code. The effectiveness of concatenated LDPC-TCM systems has been successfully demonstrated through computer simulations.

Publication Type:	Article
Additional Information:	c) 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.
Publisher Keywords:	error correction; flash memory; LDPC codes; soft decisions; trellis coded modulation
Subjects:	Q Science > QA Mathematics > QA75 Electronic computers. Computer science
Departments:	School of Science & Technology > Engineering

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