A new auto synchronization technique of unipolar MPAM signals for OFDM-based optical wireless communication systems

Optical wireless systems have attracted much attention, because they allow high speed transmission without electromagnetic interference. Orthogonal frequency division multiplexing (OFDM) can send multiple high speed signals by using orthogonal carrier frequencies. Recently, studies have focused on the optimal OFDM technique for optical wireless systems. When using OFDM, one important issue is the determination of the cyclic prefix and its removal from the frame before the receiver detects signals. In this paper, we propose a new auto synchronization technique for OFDM systems. This technique enables the removal of the cyclic prefix in any sample of the OFDM frame and valid only for unipolar MPAM signals. It is a candidate for 2 or 4-PAM OFDM. The results of mathematical analysis and simulations show that it can be used for optical wireless systems.