A Hybrid Approach to Reduce the PAPR of OFDM Signals Using Clipping and Companding

Bo Tang,Haibo Mei,Kaiyu Qin

doi:10.1109/access.2020.2968560

Abstract

Orthogonal frequency division multiplexing (OFDM) is an important technology that has been widely used in broadband wireless communications. However OFDM has some drawbacks, one of which is the high peak-to-average power ratio (PAPR) problem. Many techniques for reducing PAPR thus have been proposed in the literatures, where clipping and companding are effective techniques and have gained a lot of research interest. Based on the study of clipping and companding, this paper proposes a hybrid approach to reduce the PAPR of OFDM signals. An iterative clipping and filtering (ICF) technique and an enhanced nonlinear companding (ENC) scheme are used as the typical clipping and companding techniques in this paper. The results of the analysis show that the computational complexity of the proposed method is slightly higher than that of ENC, but much lower than that of ICF. And the simulation results show that the proposed method has better performance on PAPR reduction and bit error rate (BER) in contrast to ICF. On the other hand, compared to ENC with equal PAPR reduction, the proposed method still achieves better performance on BER.

Highlights

Orthogonal frequency division multiplexing (OFDM) is one of the most popular technologies for broadband wireless communication and has been used in several widely used standards, such as Digital Video Broadcasting (DVB), Wireless Local Area Network (WLAN) and 4G-LTE [1]–[4]
iterative clipping and filtering (ICF) with 3 iterations is taken as the typical clipping based technique, and enhanced nonlinear companding (ENC) is taken as the companding based technique for conparison
The bit error rate (BER) comparison of ENC and the proposed method can be evaluated with the same shape factor and peakto-average power ratio (PAPR) reduction

Summary

INTRODUCTION

Orthogonal frequency division multiplexing (OFDM) is one of the most popular technologies for broadband wireless communication and has been used in several widely used standards, such as Digital Video Broadcasting (DVB), Wireless Local Area Network (WLAN) and 4G-LTE [1]–[4]. Apart from clipping, companding is an effective signal distortion technique to reduce the PAPR by compressing or expanding the amplitude of the OFDM signals [11], [26]. [33] proposed the enhanced nonlinear companding scheme (ENC) that can limit the signal to a desired power level and require no inverse operations at the receiver. This makes ENC an attractive approach to PAPR reduction. The ENC proposed in [33] does not require any additional operations of signal recovery in the receiver, and the simulation results show that it has provided better performance on PAPR reduction and bit error rate (BER) than other companding techniques.

BACKGROUND

THE PROPOSED METHOD

COMPUTATIONAL COMPLEXITY

SIMULATION RESULTS AND DISCUSSION

CONCLUSION