Based on intensity modulation and direct detection(IM/DD) principle,with a combination of on-off keying modulation and non-return to zero coding(OOK-NRZ),an 18×1 W high power white LED lamp is utilized to realize the indoor simplex downlink visible light communication(VLC) system.A physical model of the LED under investigation was established,and both the ray-tracing simulation and the line-of-sight(LOS) analytical results were used to optimize the LED layout.A VLC system composed of 4 LED lamps...