Reducing the peak-to-average power ration for NOMA waveform with diverse channel using micro genetic algorithm-based partial transmission sequence algorithm

This paper explores the efficiency of peak-to-average power ratio (PAPR) reduction methods in non-orthogonal multiple access (NOMA) systems under Rayleigh and Rician fading channels for various sub-carrier configurations. The μGA-PTS method improves PAPR performance with maintaining the bit error rate (BER) and power spectral density (PSD) performance in NOMA systems. The research explores complementary cumulative distribution function (CCDF) of PAPR under sub-carrier sizes from 256 to 4096. Traditional techniques including Clipping and Filtering (C&F), Selective Mapping (SLM), and Partial Transmit Sequence (PTS) offer fair performance against PAPR reduction. With an increase in the number of sub-carriers, their efficiency reduces because the dimensional complexity grows and phase diversity is limited. Compared to conventional methods, the newly proposed micro genetic algorithm-based PTS (μGA-PTS) method considerably outperforms others in all settings. For example, at a CCDF of 10−3, μGA-PTS attains maximum PAPR reductions of 16.4 dB and 7.7 dB for 4096 and 256 sub-carriers, respectively, in Rayleigh channels. Additionally, the μGA-PTS scheme shows high flexibility to Rician fading environments, attaining PAPR gains of up to 5.8 dB. Bit error rate (BER) analysis indicates that μGA-PTS also improves system performance with lower required SNR values (e.g., 5.9 dB and 8.0 dB for μGA-PTS V = 8 and V = 4, respectively, for BER = 10−3) than conventional approaches. The results validate the superior performance of μGA-PTS in efficiently exploring larger solution spaces and selecting optimal phase sequences, making it a promising candidate for high-capacity, power-efficient NOMA systems in 5G and future wireless networks. The technique notably reduces nonlinear distortion, improves signal integrity, and enhances overall transmission reliability under Rayleigh and Rician channels. By minimizing out-of-band radiation through optimized phase selection, it outperforms C&F, SLM, and PTS. It also provides up to 9.7 dB SNR gain at BER = 10−3, providing better signal quality.