A CMOS Current Mirroring Integration Based Visible Light Receiver for Intelligent Transport Systems

Visible light communication (VLC) is gaining immense popularity for its inherent energy-efficient and freely available wide unlicensed spectrum in a range of applications that include indoor positioning, medical and navigational equipments and smart vehicular networks. In this paper, we present a current mirroring integration (CMI) based VLC receiver for intelligent transport systems. Polarization property of light is used to reject ambient light interference by sending and receiving differential data over adjacent channels. Each channel transmit and receive complimentary data through a set of linear polarizers. The receiver front-end is based on differential CMI topology which integrates the photocurrent over a pair of capacitors followed by a differential charge transfer amplifier (CTA) which performs amplification of differential optical signal and cancellation of background (DC) light up to 100 mu A. This is followed by a differential comparator with D-flip flop to make decision and latch the resultant data in digital format. Designed and simulated in 0.18 mu m CMOS process, the proposed VLC receiver front-end consumes 42 mu A current and achieve data rate of 5MHz with energy consumption of 15pJ/bit.