A Figure-of-Merit for Evaluating the Overall Performance of OFDM PAPR Reduction Techniques in the Presence of High Power Amplifier

One of the major drawbacks of Orthogonal Frequency-Division Multiplexing (OFDM) is the large envelope fluctuations which either require an inefficient use of High Power Amplifiers (HPA) or decrease the system performance. Peak to-Average Power Ratio (PAPR) is a very well known measure of the envelope fluctuations and has become the cost function used to evaluate and design multicarrier systems. Several PAPR reduction techniques have been proposed with the aim to increase the system performance. Besides the fact that these techniques have varying PAPR-reduction performance, most previous studies haven't considered the loss of performance due to the average transmit power variation. In this paper, the Overall Performance (OP) due to PAPR reduction of clipping, Tone Reservation(TR) and Active Constellation Extension (ACE) techniques in the presence of a HPA is investigated by evaluating a figure of merit which takes account the PAPR-reduction performance, the average power variation and the in-band distortion. Based on this figure-of-merit OP, simulation results show that, TR is the best, followed by ACE and followed from afar by clipping.

I Introduction

Orthogonal Frequency-Division Multiplexing (OFDM) has recently attracted considerable attention since it has been shown to be an effective technique to combat delay spread or frequency selective fading of wireless or wireline channels. This approach has been adopted as the standards in several outdoor and indoor high-speed wireless and wireline data applications, including Wireless Local Area Networks (WLAN), Digital Audio and Video Broadcasting (DAB and DVB), and Digital Subscriber Line (DSL) modems [1]. OFDM transmission requires no equalizers, which makes it possible to combine with many advanced techniques to improve the capacity and enhance the performance of transmission.