High-Speed and Energy-Efficient Gray Mapping Polar Codes

Abstract

: A significant attention has received for polar codes due to their capacity-achieving performance and low encoding and decoding complexity. Successive cancellation decoding (SCD) and belief propagation decoding (BPD) are the two popular approaches for decoding polar codes. SCD is having less computational complexity when compared with BPD, but suffers from long latency due to the serial nature of the SC algorithm. BPD is parallel in nature and is more attractive for low-latency applications. However, due to the iterative nature of BPD, the required latency and energy dissipation increase linearly with the number of iterations. In this paper presents an efficient multi-strategy ECC scheme called pre-check scheme which consists of hard, quantized-soft, and pure-soft decoders geared to MLC NAND flash memory based on polar code. The hard decoder is designed to correct the majority of erroneous codewords in the initial phase of the flash memory, while the soft decoders aim to correct codewords which contain larger amount of errors. In addition, we clarify that the mapping scheme using Gray code can achieve best performance compared to other alternatives.