Demonstration of a real-time vehicular visible light communication system with timing recovery

Abstract

Sampling clock offset (SCO) is a key factor affecting the transmission performance of a vehicular visible light communication (VLC) system. For the traditional on-off keying (OOK) scheme, timing recovery is required for mitigation of the SCO effect in a vehicular light-emitting diode (LED) based VLC system, which suffers nonlinearity. To investigate the impact of the LED nonlinearity on the performance of the timing recovery, a piecewise-parabolic interpolator-based timing recovery method with three different timing error detectors (TEDs) is used to evaluate the transmission performance of 25Mb/s OOK signal in a real-time vehicular VLC system with SCO. The impact of ambient light on the transmission performance is also investigated. It is shown that a SCO of up to ±1000ppm can be effectively compensated with the timing recovery with these TED schemes. A real-time 25Mb/s OOK system is successfully demonstrated over a VLC link up to 60m at a bit error ratio below 3 × 10−3.