Analysis and comparison of clipping techniques for OFDM Peak-to-Average Power Ratio reduction

One of the main disadvantages of Orthogonal Frequency Division Multiplexing (OFDM) is its high Peak-to-Average Power Ratio (PAPR), which significantly reduces the efficiency of the High Power Amplifier (HPA). Due to the simplest way for PAPR reduction, clipping techniques are frequently used in practice for OFDM PAPR reduction. In this paper, Classical-Clipping (CC), Heavyside-Clipping (HC), Deep-Clipping (DC) and Smooth-Clipping (SC) are implemented for reducing the PAPR of an OFDM system. The effectiveness of these techniques in terms of PAPR-reduction, average power variation and total system degradation are evaluated. From the analysis and simulation results, it is very difficult to say which of these four is the best. But, because of its flexibility in PAPR reduction, in total system degradation and in average power variation, DC technique appears to be the best of the four.

1. INTRODUCTION

Orthogonal Frequency Division Multiplexing (OFDM) is currently attracting more attention in wireless communications to meet the ever-increasing demands arising from the explosive growth of internet, multimedia, and broadband services. OFDM-based systems are able to deliver high data rate, operate in the hostile multipath radio environment. OFDM has been adopted by Digital Audio Broadcasting (DAB), Digital Video Broadcasting-Terrestrial (DVB-T) and Wireless LAN (WLAN) systems [1]. Additionally, OFDM has been used in the mobility mode of IEEE 802.16 WiMAX. Furthermore, it is currently a working specification in 3GPP Long Term Evolution (LTE) downlink, and is the candidate access method for the IEEE 802.22 Wireless Regional Area Networks (WRAN).