Performance Analysis of DCO-OFDM and ACO-OFDM for Visible Light Communication System

摘要

Electromagnetic spectrum utilization for communication is increasing. Visible Light Communication (VLC) with a bandwidth up to 390 THz is expected to be an alternative technology for a wireless communication system. VLC comprises light emitting diodes (LEDs) on the transmitter and photodiode on the receiver side, where LEDs can be modulated at high speed so that allows high-speed wireless communication. One of the most potential modulation techniques for VLC is orthogonal frequency division multiplexing (OFDM), but the challenge is the output signal must be real and positive. Therefore OFDM needs to be modified, by adding DC-bias called direct current-biased optical OFDM (DCO-OFDM) or by signal clipping called asymmetrically clipped optical OFDM (ACO-OFDM). In this paper, we explain the implementation of DCO-OFDM and ACO-OFDM systems that have been realized in the Simulink System Generator. Verification is conducted by examining three main subsystems i.e. symbol mapping, OFDM, and reverse subsystem for 6 (six) requirements. The result shows DCO-OFDM system 100% meets all requirements, while ACO-OFDM is only able to meet 83.3% even though it does not affect the interpretation of signal received.