Hardware-efficient Precise and Flexible Soft-demapping for Multi-Dimensional Complementary APSK Signals

We propose the combination of log-likelihood ratio (LLR) table and min-sum algorithm-based LLR updates for simple, precise, and flexible soft-demapping of multi-dimensional complementary APSK signals. Transmission experiment verifies the demapping loss is limited to 0.15 dB in Q-factor.