Synchronization in Power-Efficient DST-based ACO-OFDM-VLC Systems

Abstract

In the recent times, Visible Light Communication (VLC) has evolved as a new communication standard due to its stunning notability to render ubiquitous connectivity by emerging as a prominent revolutionary to radio frequency (RF) based wireless communications. However, an orthogonal frequency division multiplexing (OFDM) based VLC system is susceptible to timing errors. Therefore, this work addresses the synchronization aspects in asymmetrically clipped optical OFDM (ACO-OFDM) system which is exploiting real trigonometric transform like discrete sine transform (DST). The striking notability is that without the necessity of Hermitian Symmetry criteria, this optical OFDM system takes the advantages of real signal processing transformation technique like DST. Thus, this technique reinforces the transmission of double the data symbols in comparison to conventional optical OFDM system which is based on standard Fourier signal processing. Besides, this work derives the elaborate mathematical expressions illustrating the deleterious effects of unreliable timing errors in DST-based ACO-OFDM system. In addition, this paper interprets as well as compares the performance of timing synchronization algorithms exploiting the periodicity property of the optical OFDM symbol with the training symbol based STO estimation algorithm in DST-based ACO-OFDM system. Moreover, this work validates the derived Cramer Rao Lower Bound (CRLB) and the simulated results infer that derived CRLB pertaining to the timing errors contributes the minimum mean square error (MSE) when compared with other STO estimation algorithms.