Peak to average power ratio reduction for improving the performance of OFDM system

Orthogonal Frequency Division Multiplexing (OFDM) has a high tolerance to multipath signals and is spectrally efficient making it a good candidate for future wireless communication systems. One disadvantage of OFDM is that the peak of the signal can be up to N times the average power (where N is the number of carriers). These large peaks increase the amount of intermodulation distortion resulting in an increase in the error rate. The average signal power must be kept low in order to prevent the transmitter amplifier limiting. Minimizing the PAPR allows a higher average power to be transmitted for a fixed peak power, improving the overall signal to noise ratio at the receiver. It is therefore important to minimize the PAPR. The PAPR of an OFDM signal can be reduced in several ways. In this paper, a technique is described for a better than 5 dB reduction in the Peak to Average Power Ratio (PAPR) of an OFDM signal. The optimal amplitude and phase of additional peak reduction carriers (PRC) is obtained using a code-book, which is obtained using a search of all possible signal combinations.