Study On The PAPR Reduction In Visible Light ACO-OFDM System

Nowadays, the visible light communication technology is growing very quickly, it has advantages of high rate, mass storage capacity, environmental protection and other features. Orthogonal Frequency Division Multiplexing(OFDM) technology has a wide application in high speed wireless communication system, its application in a visible light communication will generate unipolar OFDM method, such as Direct-Current-biased optical OFDM(DCO-OFDM) and Asymmetrically-Clipped Optical OFDM(ACO-OFDM). This technology can be effective against multi-path interference of radio channel, as well as has high spectral efficiency. But ACO-OFDM system is a multi-carrier modulation, Peak-to-Average Power Ratio(PAPR) is a big disadvantage of OFDM system, severely limits the further application of this technology.This paper analyzed for the big PAPR of ACO-OFDM system, studied the basic principles of OFDM system, the unipolar principles and methods. The influence of high PAPR, and the reasons of high PAPR performance.The two representatives algorithms of PAPR reduction are discussed, including the simulation of different methods performance. The two pre-coding improvement program system can effectively reduce PAPR. We can adjust the threshold size, and achieve the purpose of flexible balance between computational complexity and PAPR reduction performance. Another improved PAPR reduction algorithm combines the characteristics of ACO-OFDM system and PAM-DMT modulated side information transmission. The complexity and PAPR of the system are reduced, the algorithms increased the feasibility of ACO-OFDM program. The simulation analysis of new programs in performance and complexity have become more outstanding.