Treffer: PAPR Suppression in OFDM Systems Using a Combination of FWFT and Nonlinear Root-Based Exponential Companding with Minimum Complexity

The high peak-to-average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) system is a major drawback. To tackle this, we recommend a neoteric scheme which is associated with a combination of fast Walsh-Hadamard and Fourier transform (FWFT) of low computing complexity and nonlinear root-based exponential companding (REC). The FWF-transform is being obtained by cascading Walsh-Hadamard transform (WHT) and Fourier transform. The WHT is a linear precoder that distorts phase to somewhat mitigate PAPR. In addition to that, the REC scheme is introduced to further minimize PAPR by adjusting companding parameters. By knowing that conventional exponential companding (EC) increases the low amplitude signals and does not influence high peaks of OFDM signals appropriately. Though, REC scheme does not only compress high amplitudes but also enlarges low amplitudes of the OFDM system simultaneously. Correspondingly, PAPR of the OFDM system reduces. In comparison to any of the other existing schemes, our proposed scheme (FWFT-REC) preserves bit error rate (BER) performance over AWGN, AGWN with solid-state power amplifier (SSPA), and multipath Rayleigh fading channels at the same BER while suppressing PAPR up to 2.10 dB for QPSK at the same complementary cumulative distribution function (CCDF) = 10− 3.