The Technique Of Reducing The PAPR In OFDM System

Orthogonal frequency division multiplexing has been seen as one of the key technique of 4G for its high spectral efficiency and good performance in fading radio channels. However, the major drawback of OFDM system is that the OFDM signal can have high peak to average power ratio(PAPR).The Partial Transmitted Sequences(PTS) reduces the probability of the appearance of high peak value using a set of appropriate phase rotation vectors, so that the PAPR of OFDM signal can be reduced with no distortion of signal. The conventional PTS has large computational complexity, so reducing the complexity of conventional PTS is the key point of the PTS' practice with precondition of reducing the OFDM signals' PAPR effectively.In this paper, we discussed and compared the characteristic of kinds of improved PTS after we analyzed the basic woking principle of the traditional PTS. Then, we propose a general principle of finding appropriate phase rotation vectors by analyzing the rule of the appearance of peak value for OFDM signals. And based on the principle, we propose a novel method to reduce the complexity of PTS. By emulating with matlab software, this new method can reduce the OFDM signals' PAPR with less complexity than traditional PTS.