Energy-Efficient 8-PAM Optical DAC Design for Visible Light Communication Systems

This paper presents a cost-effective and energy-efficient optical digital-to-analog converter (ODAC) transmitter scheme for visible light communication (VLC) systems. The proposed ODAC transmitter enables data transmission while providing lighting, as desired in VLC systems, unlike existing ODAC structures in the literature, by switching power LEDs at high speeds with a MOSFET-based switching circuit design. This paper also discusses the ODAC design stages and presents the points to be considered in detail. In addition, by implementing the hardware design of an ODAC transmitter with a 3-bit resolution, that is, capable of generating 8-PAM signals, based on the proposed ODAC architecture, experimental studies are conducted for energy efficiency and communication performance results via the established VLC system using the designed ODAC. Experimental results demonstrate that the proposed ODAC transmitter achieves a data transmission rate of 18.75 Mbps with a bit error rate (BER) below the forward error correction (FEC) limit at a communication distance of 4 m, while also exhibiting a high power efficiency of 94%.