The Research On PAPR Reduction Techniques In OFDM Systems

Orthogonal Frequency Division Multiplexing (OFDM) is a special multi-carrier transmission technology. Because of its optimum spectrum efficiency and good performance on anti multi-path interference, OFDM is regarded as one of the key technology of 4G.. However, a major drawback of OFDM systems is its high Peak-to-Average Power Ratio (PAPR). This paper has mainly researched on the PAPR in OFDM system, and MATLAB is used to achieve simulation.Firstly, the principle, the advantages and disadvantages of OFDM technology are introduced. Then, the definition and distribution character of PAPR are analyzed. In this paper, three kinds of techniques to reduce the PAPR are summarized, which are clipping technique, coding technique and scrambling technique. The representative algorithm of every kind is particularly researched and simulated.In order to reduce the large computational complexity of PTS, IPTS(the suboptimal iterative PTS) and DLPS(the dual-layered PTS) are discussed and compared. Based on DLPS, an improved PTS method is proposed. This method searches the optimized phase factors in two layers. On the first layer, IPTS is used to get phase factor, and on the second layer, the subblocks are grouped into some divisions, and classical PTS algorithm is used for further PAPR reduction. The result of simulation shows that the proposed algorithm can get good performance of PAPR reduction with less complexity than classical PTS.