A Probabilistic Shaping Scheme for MIMO Systems with Signal Space Diversity

In this paper, a probabilistic shaping (PS) scheme for multiple-input multiple-output (MIMO) systems with signal space diversity (SSD) is proposed. The proposed scheme can obtain shaping gain compared with the conventional MIMO systems with SSD. The optimal rotation angles of quadrature amplitude modulation (QAM) signals are investigated for the MIMO systems according to the theoretical average mutual information (AMI) analysis. Compared with the Nyquist regular QAM MIMO systems in fast fading channel, the proposed PS scheme for MIMO systems with SSD can obtain shaping gain and diversity gain. The simulation results and AMI analysis show the reliability of the proposed scheme, which is suitable for the sixth generation (6G) communication systems.