Constellation optimization under the ergodic VLC channel based on generalized spatial modulation.

Wang, Fubin; Yang, Fang; Song, Jian

When the generalized spatial modulation (GSM) is applied to visible light communication (VLC), radio frequency (RF) technologies, such as constellation designs, should be modified for the ergodic VLC channel, which is different from that in typical RF environments. In this paper, constellations of amplitude-phase modulation (APM) symbols are optimized for GSM-based VLC systems in which optical signals must be real-valued and non-negative, while the ergodic VLC channel and the random characteristic of receiver locations are also considered. The algorithm of statistically convergent gradient descent (SCGD) is adopted for the maximization of coded modulation average mutual information (CM-AMI), and superior performances of optimal constellations are verified by numerical simulations.