Selected mapping, Clipping and Differential Scaling for reduction of PAPR in OFDM system

In this paper, an SLM technique is introduced for the PAPR reduction of space-frequency-block-coded OFDM systems with Alamouti coding scheme. Selected mapping (SLM) is a well-known technique for peak to-average-power ratio (PAPR) reduction of Orthogonal Frequency Division Multiplexing (OFDM) systems. In this paper, we also introduced a simple technique for the reduction of high Peak to Average Power Ratio (PAPR), based on Clipping and Differential Scaling, in Orthogonal Frequency Division Multiplexing (OFDM) systems. In this technique, the amplitude of complex OFDM signal is clipped and then scaled in such a way that the PAPR is reduced without causing much degradation in bit error rate (BER). We have determined the threshold values for clipping and scaling using Monte Carlo Simulations. We have also compared the performance of SLM with the clipping scaling technique.