Visible light communication is a new frontier of communication allowing high data-rate Internet access specially in indoor environment. One of the key challenges is the limited modulation bandwidth of sources, that is typically around several MHz. As a room or coverage space would typically be illuminated by an array of Light Emitting Diode devices, there exists the potential for parallel data transmission. In this paper we investigate the use of multiple LEDs to perform a space-time block coding. By exploiting optical MIMO techniques, jointly with Pulse Position Modulation, we can achieve data rates of the order of hundreds of Mb/s (i.e., around 600 Mb/s) in indoor VLC systems, with no reduction of link reliability. Finally, the proposed approach has been compared to similar techniques, highlighting its effectiveness and robustness. © 2013 IEEE.