Enhanced Precision Through Multiple Reads for LDPC Decoding in Flash Memories
| Autor: | Tsung-Yi Chen, Guiqiang Dong, Hari Shankar, Jiadong Wang, Kasra Vakilinia, Richard D. Wesel, Tong Zhang, Thomas A. Courtade |
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| Rok vydání: | 2014 |
| Předmět: |
FOS: Computer and information sciences
Computer Networks and Communications Computer science Error floor Computer Science - Information Theory Information Theory (cs.IT) Concatenated error correction code Real-time computing Data_CODINGANDINFORMATIONTHEORY Flash memory Quantization (physics) Electrical and Electronic Engineering Low-density parity-check code Algorithm BCH code Decoding methods Computer Science::Information Theory Communication channel |
| Zdroj: | IEEE Journal on Selected Areas in Communications. 32:880-891 |
| ISSN: | 0733-8716 |
| DOI: | 10.1109/jsac.2014.140508 |
| Popis: | Multiple reads of the same Flash memory cell with distinct word-line voltages provide enhanced precision for LDPC decoding. In this paper, the word-line voltages are optimized by maximizing the mutual information (MI) of the quantized channel. The enhanced precision from a few additional reads allows FER performance to approach that of full-precision soft information and enables an LDPC code to significantly outperform a BCH code. A constant-ratio constraint provides a significant simplification in the optimization with no noticeable loss in performance. For a well-designed LDPC code, the quantization that maximizes the mutual information also minimizes the frame error rate in our simulations. However, for an example LDPC code with a high error floor caused by small absorbing sets, the MMI quantization does not provide the lowest frame error rate. The best quantization in this case introduces more erasures than would be optimal for the channel MI in order to mitigate the absorbing sets of the poorly designed code. The paper also identifies a trade-off in LDPC code design when decoding is performed with multiple precision levels; the best code at one level of precision will typically not be the best code at a different level of precision. Comment: arXiv admin note: substantial text overlap with arXiv:1210.0149 |
| Databáze: | OpenAIRE |
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