Reduced Complexity of a Successive Cancellation Based Decoder for NB-Polar Codes

This paper proposes a simplified version of the Successive Cancellation (SC) decoder for Non-Binary Polar (NB-Polar) codes. The proposed decoder, named Successive Cancellation Min-Sum (SC-MS), is exclusively formulated in the Log-Likelihood Ratio (LLR) domain to reduce the decoding complexity of the SC decoder. The NB-Polar codes are associated with Cyclic Code-Shift Keying (CCSK) modulation to obtain a new coded modulation scheme for ultra-low signal-to-noise ratios (SNRs). The quantized version of the SC-MS decoder is investigated using quantized LLRs on optimized size of bits. Our simulation results show that the SC-MS decoder presents a negligible performance degradation with respect to the SC decoder for code length N< 2048. Additionally, the 2-bit SCMS and 3-bit SC-MS offer a good trade-off between decoding performance and complexity.