Optimization of multi-channel BCH error decoding for common cases

Abstract

This paper proposes a new method to optimize a BCH error correction decoder in multi-channel configurations. We break the BCH decoding process into its three basic blocks: syndrome calculation, the error locator polynomial generation, and the roots of the error locator polynomial computation. While an existing multi-channel BCH decoder consists of several single-channel BCH decoders operating in parallel, this paper utilizes a pooled group of shared decoding blocks. By considering the frequency of errors, the proposed pooled group approach requires fewer hardware blocks than in a traditional multi-channel configuration with a negligible impact on performance. Combined with a specialized root finding unit for blocks with only 1 error, our scheme reduces hardware area by 47%-71% and dynamic power by 44%-59% with 2% performance degradation in typical NAND flash systems. With a constant hardware area, the proposed scheme can improve throughput by 3x-5x or NAND flash lifetime by 1.4x-4.5x.