A Modified PTS Method Using M Sequences For PAPR Reduction

As a Multi-Carrier Modulation technology, OFDM(Orthogonal Frequency DivisionMultiplexing) has been considered as one of the key techniques in4G mobile communicationsystems due to its high rate data transmission with high bandwidth efficiency and itsrobustness to multipath delay. However, it has a important disadvantage, that is,the highpeak-to-average-power ratio(PAPR). The linear range of the power amplifier at thetransmitting terminal is limited, so the signals with high PAPR are distorted when throughingthe power amplifier at the transmitting terminal. Therefore, universal application of OFDM inpractice is limited by its disadvantage.For the problem of high PAPR in OFDM system, this paper has particularly researchedon PAPR reduction. And the paper introduced the basic knowledge of OFDM, then analysedthe modulation principle in detail. In addition, the paper detailed the definition of PAPR,analysed the influence on the power amplifier from PAPR and the distribution of PAPR.On this basis，he paper introduced three kind of existing methods to reduce the PAPR ofOFDM signals, including signal pre-distortion，encoding and the probability technology. Eachkind was explained in detail, and simulated by software of matlab. the advantages anddisadvantages were also offered.Especially, the paper researched the PTS method in kind of probability technology,analysed the major factors that influence the performance of OFDM system by PTS method.For the disadvantages of traditional PTS method, the high complexity, an improved algorithmof PTS using m sequences is proposed. This method could obtain the phase factors includingfour phases, so it could not only reduce the PAPR greatly, but also reduce the complexity ofPTS system. It is very pratical.