PAPR Reduction in OFDM Systems Using Selective Mapping Over Multipath Rayleigh Channel with M-QAM Modulation

This work presents a comprehensive simulation study of an Orthogonal Frequency Division Multiplexing (OFDM) system incorporating Selective Mapping (SLM) for Peak-to-Average Power Ratio (PAPR) reduction under realistic wireless channel conditions. The system employs M-QAM modulation schemes (4-QAM, 16-QAM, and 64-QAM) and considers both Additive White Gaussian Noise (AWGN) and multipath Rayleigh fading. Oversampling is implemented to accurately capture peak signal variations, and cyclic prefix is used to mitigate inter-symbol interference. The SLM technique is evaluated for multiple phase sequence sets (U = 1, 4, 8), where U = 1 represents the baseline OFDM system without PAPR reduction. Performance is analyzed in terms of Bit Error Rate (BER) versus Signal-to-Noise Ratio (SNR) and Complementary Cumulative Distribution Function (CCDF) of PAPR. Frequency-domain equalization is applied at the receiver using perfect channel knowledge. Results demonstrate that increasing the number of SLM phase candidates significantly reduces PAPR without degrading BER performance. However, marginal computational complexity increases are observed with higher U values. The study confirms that SLM is an effective distortion less technique for improving OFDM transmission efficiency in fading environments. The simulation framework and results are derived from a journalgrade implementation with reproducible parameters and statistical averaging.