A 2.267-Gb/s, 93.7-pJ/bit Non-Binary LDPC Decoder With Logarithmic Quantization and Dual-Decoding Algorithm Scheme for Storage Applications

Abstract

Non-binary low-density parity-check (NB-LDPC) codes are a promising class of error-correcting codes that provide excellent coding gain beyond that of their binary counterparts. However, their decoding complexity has thus far limited practicality. We present an NB-LDPC decoder with information throughput of 2.267 Gb/s and power consumption of 212.4 mW, yielding an energy efficiency of 93.7 pJ/bit, implemented in 40-nm CMOS technology. The employed code is long and high-rate without degree-2 variable nodes, resulting in a low error floor and making the code appropriate for storage applications. A logarithmic quantization scheme is proposed to enable aggressive wordlength reduction to alleviate hardware complexity. In addition, a dual-decoding algorithm scheme is employed to alleviate the computational complexity of decoding, realized in an efficient architecture with high parallelism and avoidance of idle clock cycles.