Iterative Guessing Random Additive Noise Decoder for Universal Decoding of Product Codes

A fully integrated hardware design of the universal maximum likelihood Guessing Random Additive Noise Decoding (GRAND) algorithm implemented in 40 nm CMOS is presented. It is shown how this integrated hard-detection decoder, which is designed to process component codes of up to 128 bits in length, can be extended to efficiently decode product codes as long as 16,384 bits using the Iterative GRAND (IGRAND) algorithm. Pipelined stages provide throughput gain and dynamic energy savings when channel noise conditions improve. The chip allows for decoding product codes with two distinct component codes due to its ability to interleave between two codebooks without any switch-over time. Measurements demonstrate the decoder’s accuracy and efficiency in decoding a broad selection of product codes, including the capacity-achieving random linear product codes. The chip consumes an average energy of 30.6 pJ/b with a latency of 1.04 μs when decoding the BCH(127,106,7) component code at 68 MHz from 1.1 V at a bit flip probability of 10^-5. Using a single chip to decode a BCH(127,106,7)² product code which results in 16,129-bit code of rate 0.68, we demonstrate an average energy consumption of 61.2 pJ/b with an average latency of 265 μs for the same operating conditions.