Evaluation of Using Fast Walsh Hadamard Fourier Transforms (FWFT) in OFDM Systems

Abstract

Orthogonal frequency division multiplexing (OFDM) is a multicarrier modulation technology used in wireless communications to reduce inter-symbol interference (ISI) and transmit data at a high bit rate. However, the major negative effect of OFDM modulation is the high peak-to-average power ratio (PAPR) in the transmitter because of the subcarriers added by the inverse fast Fourier transform (IFFT), which results in an increased bit error rate (BER). Recently, several approaches for reducing PAPR have been proposed. In this study, we applied the fast Walsh-Hadamard-Fourier Transform (FWFT) to OFDM systems as a precoding technique based on the Walsh Hadamard transform (WHT) and Discrete Fourier transform (DFT) in a single fast transform to reduce the PAPR. In this paper, the order properties of (WHT) are used to achieve more PAPR reduction. Simulation results show that the proposed technique shows promise for obtaining reduced PAPR, higher BER performance, and low complexity.