Joint Probabilistic Shaping and Beamforming Scheme for MISO VLC Systems

We propose a joint probabilistic shaping and beamforming scheme to approach the channel capacity of multiple-input single-output (MISO) visible light communication (VLC) systems subject to both peak and average power constraints. In this scheme, unipolar pulse amplitude modulation (PAM) signals are probabilistically shaped according to the desired constellation distribution and assigned optical power levels according to beamforming weights. We present an iterative algorithm to obtain the optimal constellation distribution and beamforming vector by maximizing the mutual information. Numerical results demonstrate that the proposed scheme outperforms the conventional uniformly distributed PAM scheme and achieves mutual information very close to the capacity.