Theoretical and Experimental Analysis of Asymmetrically Clipped-FSK VLC System

Abstract

In this article, energy efficient asymmetrically clipped frequency-shift keying (AC-FSK) based visible light communication (VLC) system is theoretically and experimentally demonstrated. In order to facilitate straightforward comparison with the experimental results, theoretical expression for bit error probability, based on the Euclidean distance analysis of AC-FSK symbols, is provided. The VLC setup is based on commercial off-the-shelf components and software defined radio. The bit error rate (BER) performance of AC-FSK is evaluated considering maximum likelihood (ML) receiver, 1-tap discrete cosine transform (DCT) based receiver and frequency-domain harmonic receiver. Simulation and experimental results reveal that the performance of harmonic and ML receivers is almost identical. On the other hand, considering harmonic receiver for both AC-FSK and state-of-the-art unipolar (U)-FSK, we also gather that the BER performance of both schemes is almost the same. However, the harmonic receiver complexity of AC-FSK is 41.6% and 33.3% less compared to that of U-FSK for modulation order <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$M = 16$</tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$M = 128$</tex-math></inline-formula> , respectively. This is because unlike U-FSK, AC-FSK requires limited number of harmonics for its optimal operation.