Geometric Constellation Shaping for MISO Optical Wireless Communication

Geometric constellation shaping for multiple-input single-output optical wireless communication is considered in this letter. We first characterize the optimal shaping region, whose shaping gain may serve as a performance baseline for multidimensional constellation designs. Then, to approach this maximum shaping gain, we propose a novel constellation design based on modified truncated cubic shaping and existing signaling algorithms. Numerical results show that the gap between the maximum shaping gain and the shaping gain of the modified truncated cubic shaping is small, and significant performance gains over the benchmark schemes can be obtained.