A Complex-valued Vandermonde precoding technique for VLC-OFDM Systems

Abstract:

High peak-to-average power ratio is the main disadvantage of visible light communication-based orthogonal frequency division multiplexing (VLC-OFDM) systems. To address this problem, a novel precoding method is proposed in this letter. The complex-valued precoding matrix is constructed by a vandermonde matrix. The researched results show the proposed precoding scheme has better PAPR performance when compared to the conventional real-valued precoding methods. Moreover, a general closed-form expression of bit error rate (BER) for vandermonde precoded VLC-OFDM is derived for multi-path fading channel. The obtained BER formula shows that vandermonde precoding can improve the BER performance of VLC-OFDM over multi-path fading channel. This is verified by the simulation results. The researched results also show that different precoding schemes have the same BER performance and different PAPR performance.

Key words:visible light communications, orthogonal frequency division multiplexing (OFDM), peak-to-average power ratio (PAPR)