PAPR Reduction by Symbol Nulling

Abstract

As a multicarrier signal can exhibit large peaks in the time domain, the amplifier used to transmit the multicarrier signal must be highly linear, and thus expensive, to avoid nonlinear signal distortion. To reduce the high peak-to-average power ratio, and hence to allow cheaper amplifiers, several techniques are described in the literature. However, the drawback of these techniques is that they cause non-linear in-band distortion and out-of-band radiation, reduce the system throughput or require side-information. To avoid these drawbacks, we propose a PAPR reduction technique that has none of the above mentioned disadvantages. In the proposed technique, we replace some of the transmitted data symbols by nulls, i.e we introduce errors in the transmitted signal. To counteract the effect of the introduced symbol errors, the transmitted information is encoded. At the receiver, an iterative decoder is used to correct the transmitter and channel errors. The performance of the proposed technique is compared with the clipping technique. Although the clipping technique slightly outperforms the proposed technique with respect to the obtainable PAPR reduction and corresponding BER degradation, the proposed technique does not suffer from non-linear in-band distortion and out-of-band radiation.