Joint CRC Aided Soft-GRAND for Decoding of Polar Codes over an Interference Channel with NOMA Protocol

Guessing random additive noise decoding (GRAND) is a universal decoding that estimates the transmitted codewords by guessing the noise bit sequences and reversing their impact until legitimate codewords are found. This paper investigates one of its variants, namely Soft-GRAND (or SGRAND) of Polar codes over an interference channel where power domain non-orthogonal multiple access (NOMA) channel access protocol is in operation. Monte Carlo simulation results confirm the robustness of the SGRAND decoding over these channels. More specifically, the joint CRC-aided SGRAND decoding outperforms state-of-the-art CRC-aided list decoding (of Polar codes) with a list size of 32 by approximately 0.5 dB and 1.5 dB at block error rate (BLER) of 10
⁻⁴
over additive white Gaussian noise (AWGN) and Rayleigh fading channels, respectively, and also offers lower complexity at mid-to-high signal to noise ratios (beyond 5 dB).