Volume 17, Number 1

Enhanced Papr Reduction in OFDM Systems using Adaptive Clipping with Dynamic Thresholds

  Authors

Fatma Ben Salah ¹, Abdelhakim Khlifi ², Marwa Rjili ¹, Amina Darghouthi ¹ and Belgacem Chibani ¹, ¹ University of Gabes, Tunisia, ² Sup’COM, University of Carthage, Tunisia

  Abstract

Orthogonal Frequency Division Multiplexing (OFDM) is a highly efficient multicarrier modulation method that is widely used in current high-speed wireless communication systems. It offers numerous benefits, including high capacity and resilience to multipath fading channels, when compared to other techniques. However, a significant drawback of OFDM is its high peak-to-average power ratio (PAPR), which can result in in-band distortion and out-of-band radiation due to the non-linearity of high power amplifiers. To address this issue, several techniques have been suggested, such as Selective Mapping (SLM), Partial Transmit Sequence (PTS), Clipping, and Nonlinear Compounding, which will be discussed later in the paper. The clipping technique, in particular, has been thoroughly analyzed as a simple and crucial method for reducing PAPR. However, an arbitrary choice of clipping threshold can result in significant signal distortion, degrading the transmission quality. Therefore, it is essential to find an optimum threshold that minimizes PAPR while preserving signal quality, which is a challenging task. The classical clipping scheme may not yield satisfactory results in this regard. This paper proposes a modified clipping scheme that estimates the dynamic range of a noisy OFDM signal. The estimated parameters are then used to determine the optimal threshold, which is more reliable than the previous technique that assumes an arbitrary dynamic value. Simulation results indicate that the proposed modified clipping scheme has achieved a PAPR reduction of 3.5 dB compared to the original OFDM.

  Keywords

OFDM; PAPR; Clipping; Threshold; Estimation; MUSIC; Eigen Decomposition