Soft-output Guessing Codeword Decoding

We establish that it is possible to extract accurate blockwise and bitwise soft output (SO) from Guessing Codeword Decoding (GCD) with minimal additional computational complexity by considering it through the lens of Guessing Random Additive Noise Decoding (GRAND). Blockwise SO can be used to control decoding misdetection rate, while bitwise SO results in a soft-input soft-output (SISO) decoder that can be used for efficient iterative decoding of long, high redundancy codes.