A Multiplier-Free Dual-Hadamard Architecture for Peak-to-Average Power Ratio Reduction in OFDM Systems

Orthogonal frequency division multiplexing (OFDM) is widely used in broadband wireless communication systems because of its high spectral efficiency, flexible subcarrier allocation, and robustness against frequency-selective fading. However, the high peak-to-average power ratio (PAPR) of OFDM signals reduces the power efficiency of high-power amplifiers and may introduce nonlinear distortion. To address this problem, this paper proposes a multiplier-free Dual-Hadamard PAPR-reduction architecture. The term multiplier-free refers to the additional precoding and phase-weighting operations introduced by the proposed PAPR reduction module, excluding the common OFDM FFT/IFFT operations. Specifically, the proposed architecture combines fast Walsh–Hadamard transform (FWHT) precoding, interleaved partitioning (ILP), and Hadamard-based partial transmit sequence (H-PTS) weighting. Since the FWHT matrix and the H-PTS phase codebook contain only binary signs, the main additional operations are implemented by additions, subtractions, and sign inversions. Simulation results demonstrate that the proposed method reduces the PAPR relative to conventional OFDM without degrading the system’s bit error rate (BER) performance in an additive white Gaussian noise (AWGN) channel when the side information is recovered correctly.