Analysis and Comparison of PAPR Reduction Techniques inOFDM Systems

The destructive impact of fading environments and also bandwidthlimitations are two main challenges which communication is dealing withthem. These challenges can affect on the growth of wirelesscommunication and even cause reliable communications and high datarate to be prevented. Thus, OFDM (Orthogonal Frequency DivisionMultiplexing) modulation by using of fast calculation hardwares such asFFT, high ability for combating multipath fading and appropriate spectralefficiency has taken into consideration. However, we should know thatOFDM systems potentially have high Peak to Average Power Ratio(PAPR). This drawback drives the power amplifier into saturation leadingto higher distortions and also degrades BER performance. Sinceincreasing the dynamic range of power amplifier is not affordable,reduction of the PAPR is so important. In this paper, we investigate thePAPR and its reduction methods by using the theoretical and numericalanalysis. These techniques can be classified into two main categories,signal distortion techniques, multiple signaling and probabilistictechniques. The advantages and disadvantages of each technique arederived from different prospectives. Moreover, we compare thenumerical results of the techniques in the first classification from BERprospective which demonstrates that for changing the parameterscorresponding to each technique, its performance can be changed greatly.Hence, we are sure that a technique can not outperform the other ones inall cases. Finally, the computational complexity of the techniques in thesecond classification are compared to each other which their results showthat TR and TI techniques are much more complex than the other ones.

Keywords:

OFDM , PAPR , PAPR reduction methods