Simplified Soft Demapper for APSK with Product Constellation Labeling

Amplitude phase shift keying (APSK) constellation is capable of outperforming quadrature amplitude modulation (QAM) in terms of both the mutual information and the error-control performance. However, the lack of simplified demapper prevents its potential applications due to the inherent high computation complexity. In this paper, the concept of APSK using product constellation labeling is introduced, and two simplified demappers are proposed. Theoretical analysis and simulations show that the performance degradation caused by these simplified demappers is negligible, while the complexity is significantly reduced, compared to the traditional Max-Log-MAP demapper.