Comparative Analysis of Selected Mapping Algorithm with out Side Index,clipping and Differential Scaling in Sfbc Ofdm

In this paper, we propose a simple technique for the reduction of high Peak to Average Power Ratio (PAPR), based on Clipping and Differential Scaling, in Orthogonal FrequencyDivision Multiplexing (OFDM) systems. In this technique, the amplitude of complex OFDM signal is clippedand then scaled in such a way so that the PAPR is reduced without causingmuch degradation in bit error rate (BER). We have determined the threshold values for clipping and scaling usingMonte Carlo Simulations. We have presented PAPR and BER of the systemconsidered using simulations for QPSK constellation. We have also compared the performance of the proposedPAPR reduction technique with the performance of the Selected mapping (SLM) algorithm without side index it is a well-known technique for peak-toaverage-power ratio (PAPR) reduction of orthogonal frequency-division multiplexing (OFDM) systems. In this technique, different representations of OFDM symbols are generated by rotation of the original OFDM frame by different phase sequences, and the signal with minimum PAPR is selected and transmitted.