A modified VPPM algorithm of VLC systems suitable for fast dimming environment

As LED applications with fast dimming appears, it is required that the variable pulse position modulation (VPPM)-based visible light communications (VLC) scheme works in this environment also. With the previous VPPM scheme, however, transmission was made possible only in different dimming levels, not in the transition period. In this work, we propose a novel VPPM scheme to operate even in rapid brightness fluctuation environment. For this purpose, we adopt a stepwise brightness change at the LED and moving average correlation masks to cope with the changing brightness. The implemented VLC testbed demonstrates that the proposed scheme is appropriate for fast dimming environment.