An improved Park timing synchronization combined with PN sequence for DCO-OFDM based visible light communication system

This paper presents a new method for timing synchronization of direct current-biased optical orthogonal frequency division multiplexing (DCO-OFDM) visible light communication (VLC) system. This improved method combines the modified Park's synchronization method with the pseudo-noise (PN) sequence. The synchronization performance of the proposed method is analyzed in details and compared with that of three traditional methods in DCO-OFDM system. It is demonstrated that the improved method can obtain only one narrow and accurate timing point, which increases the synchronization performance of DCO-OFDM VLC system. Furthermore, the simulated results reveal that the new method has higher timing accuracy and resolution than other conventional methods for different signal noise ratios (SNRs) and fast Fourier transform (FFT) block sizes. To further investigate the performance of time metric, experiment is employed and the results show that the proposed method outperforms the other methods.