Research On Papr Reduction In OFDM System

Due to the excellent anti multi-path effect and the ability of the anti inter-symbol interference, orthogonal frequency division multiplexing (OFDM) technology has received more and more attention in the communication industry. However, one of the most obvious disadvantages of OFDM is that it possesses high peak-to-average power ratio. It can decrease performance of OFDM system. Therefore, it has become a hot topic to find out ways to reduce the peak-average power ratio of the OFDM system.This paper describes basic principles, components and the key technologies of OFDM system. This paper explains three basic methods to reduce the peak-to-average power ratio of OFDM signals, including the pre-distortion to coding technology and the probability technology. By analyzing the Partial Transmit Sequence (PTS) algorithm of the probability technology, this thesis suggests sub-optimal PTS algorithm, the adaptive sub-optimal PTS algorithm and the Dual Layered Phase Sequencing (DLPS) algorithm. The sub-optimal PTS algorithm vastly weakens the amount of computation of traditional PTS algorithm. The adaptive sub-optimal PTS algorithm is based on sub-optimal PTS algorithm by setting the right parameters. So it lessens the proportion of computation of the sub-optimal PTS. DLPS algorithm shows a hierarchical structure. The data is divided into two layers, in this way, it can achieve purpose of reducing the amount of computation. Finally, three algorithms will go through Matlab simulation, make comparison and summarize the advantages and disadvantages.