PAPR Reduction for IRS-assisted OFDM Systems by PA-IPTS Technique

Intelligent Reflecting Surface (IRS) technology is a promising solution for improving signal propagation in B5G and 6G wireless communication systems. However, a significant challenge is their inherently high Peak-to-Average Power Ratio (PAPR), leading to inefficiencies in power amplifiers and increased signal distortion. We propose a two-stage approach to jointly reduce the PAPR named PA-IPTS algorithm. The initial stage employs a suboptimal iterative partial transmission sequence (IPTS) algorithm to reduce the PAPR of OFDM signals at the transmitter. In the second stage, we introduce the phase adjustment(PA) technique. The phase of the IRS reflection units is adjusted via the gradient descent method to further reduce the PAPR. Simulation results indicate that the PAPR of the proposed scheme can be reduced by approximately 5.2 dB and 5.8 dB at CCDF $10^{-3}$ for 16-QAM and 32-QAM signals, respectively. Consequently, the proposed algorithm emerges as an effective, low-complexity PAPR suppression in IRS-assisted OFDM systems.