Ricerc@Sapienza

This letter proposes a modulation scheme that combines both pulse slots and amplitudes in a flexible manner to obtain a desired level of flicker-free dimming while efficiently conveying information for visible light communication. The scheme is referred to as energy-constrained slot-amplitude modulation (ECSAM). Specifically, the total energy for every macro-symbol, containing multiple pulse slots, is fixed at a level that depends on the requested dimming target by adjusting the number of active slots and their amplitude levels.

In this paper, we propose a modified generalized spatial modulation (MGSM) scheme with dimming support for indoor optical wireless communication (OWC) systems. The spatial indices of the active LEDs and their transmitted optical power levels are utilized to modulate data in MGSM. The key property of the signal waveforms in MGSM is that it provides the same amount of optical power emitted at any time instant that corresponds to the dimming level requested.