Hybrid Techniques for Reducing PAPR in OFDM Systems

Abstract

Orthogonal Frequency Division Multiplexing (OFDM) is a digital modulation technique which is widely applied in broadband communication systems. The concept of OFDM is to spliting a large data rate into low rate streams that are transmitted concurrently over a number of subcarriers. The disadvantage of OFDM is that the composite signal can shows a high Peak to Average Power Ratio (PAPR). PAPR is the proportion of maximal value of the signal to the mean value of the signal. At transmitter side, large peak values as input to high power amplifiers. this cause, high power amplifiers behave in non-linear section directing to nonlinear degradation. Greater PAPR appear in non-linearities in transmitting side, following to complicate operating. So, minimization of PAPR is compulsory for slighter difficulties, favourable effectiveness and significant constancy. Many methods have been suggested to diminish PAPR over the years. The prefered method can be minimize PAPR is effectively using precoding combined with new error function companding. The proposed technique is an excellent method for minimizing the PAPR of signals with acceptable BER compared to other systems.