Design and Experimentation of a Low-cost Receiver for Visible Light Communications

Abstract

Visible light communication (VLC), an emerging field of research, requires the use of visible light, optical sensors, transimpedance amplifiers (TIA), and filtration circuitry. As processing is done with voltages, TIAs convert the current from the optical source into a voltage. In this paper, we propose a low-cost receiver for long-range visible light communications. The receiver is composed of a wide bandwidth TIA using an off the shelf operational amplifier (op-amp). The design process focuses on the calculations for feedback resistance and capacitance, and other op-amp stabilization techniques for the receiver. We test the proposed receiver along with the TIA using the National Instruments simulator tool Multisim to determine the optimum operational bandwidth. The proposed VLC system is developed and experimented on a testbed composed of the transmitter circuitry, designed receiver, and National Instrument's USB-6351 data acquisition board for analog-to-digital (ADC) and digital-to-analog (DAC) conversion operations. Random data bit stream at a bit rate of 50 kb/s is transmitted using on-off keying (OOK) modulation scheme. We study the bit-error rate (BER) performance for different transmitter and receiver distances up to 860 cm. The experimental results reveal that for a distance of 380 cm a BER of 9.76×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-5</sup> is achieved.