Reduction of OFDM peak power to average power ratio (PAPR) in visible light communications

Visible Light Communication (VLC) is a wireless communication technology that enables data transmission using light sources such as LEDs. In this thesis, various methods have been proposed to reduce the Peak-to-Average Power Ratio (PAPR) in VLC using the Orthogonal Frequency Division Multiplexing (OFDM) technique. Common PAPR reduction techniques originally developed for RF systems, including Selective Mapping (SLM), Partial Transmit Sequences (PTS), Discrete Cosine Transform (DCT) pre-coding, and μ-law data compression, have been adapted to VLC and their performances have been analyzed. Additionally, a novel method called the Multi-Point Constellation (MPC) technique has been developed as part of this study. It has also been demonstrated that Gaussian matrices can be utilized in pre-coding. According to the obtained results, while the proposed MPC method alone does not surpass the PAPR performance of the SLM technique, it achieves better PAPR performance when combined with SLM. The proposed Gaussian pre-coding method exhibits superior PAPR performance compared to both DCT pre-coding and μ-law data compression techniques. The MPC and Gaussian pre-coding methods, originally designed for VLC, can also be easily adapted to RF systems. The proposed methods reduce the likelihood of LED signal clipping, improve Bit Error Rate (BER) performance, lower energy consumption, and enhance communication quality. Key Words: OFDM, VLC, PTS, SLM, MPC, GM, DPSO, CCDF, Metaheuristic algorithms