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An Improved Algorithm for PAPR
Reduction of OFDM Systems
Yazhen Li, Xinhui Zhou, and Jing Guan
Communication Engineering Department of
Northeastern University, Qinhuangdao
lyzlyz699@163.com
Abstract. To reduce peak-to-average power radio (PAPR) of orthogonal fre-
quency division multiplexing (OFDM) system, a hybrid algorithm is proposed. It
based on the DFT property of the time domain circular convolution (TCM) and a
linear companding transform (LCT) methods. The algorithm has reduced sys-
tem's PAPR through lower twice the PAPR of OFDM signal at the transmitter. A
number of simulation results demonstrate that the proposed algorithm can enjoy
an improved performance and has a low complexity cost.
Keywords: OFDM, PAPR, optimization.
1 Introduction
OFDM system has great advantages of having simple equalization and capability of
transmitting high data bit rates over frequency selective channels and has been widely
used modulation technique for wireless communication. One of its main drawbacks is
the large peak-to-average power ratio (PAPR) of the time-domain transmit signal. To
reduce the high PAPR of OFDM systems, many algorithms [1], [2] have been proposed
in recent years, such as clipping, scrambling and coding techniques. As a scrambling
technique, partial transmit sequence (PTS) is known to achieve high PAPR reduction
with a small amount of redundancy. However, PTS requires multiple inverse fast
Fourier transforms (IFFT), and the big issue of finding the optimal phase combination
for PTS sequence is complex and difficult when the number of subcarriers is increased,
which results in high computational complexity for practical system [3],[4]. In this
paper, a novel PAPR reduction algorithm is proposed by combining TCM [5] with LCT
[6] methods. The simulation results show that the algorithm has the better ability of
PAPR reduction than two algorithms.
2 Basic Idea of Hybrid Algorithm
Account for the shortage of the existing methods, based on the study of methods to
reduce PAPR, the proposed hybrid algorithm has been presented. The basic idea [7] is
as follows: Firstly, the OFDM signal is processed via TCM algorithm, and is selected
the sequence with the minimum PAPR for transmission in order to complete PAPR
 
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