Please cite this article in press as: Siddiq AI. PAPR reduction in OFDM systems using peak insertion. Int J Electron Commun (AEÜ) (2014), http://dx.doi.org/10.1016/j.aeue.2014.11.009 ARTICLE IN PRESS G Model AEUE-51326; No. of Pages 6 Int. J. Electron. Commun. (AEÜ) xxx (2014) xxx–xxx Contents lists available at ScienceDirect International Journal of Electronics and Communications (AEÜ) j ourna l h om epage: www.elsevier.com/locate/aeue PAPR reduction in OFDM systems using peak insertion Abdulrahman Ikram Siddiq ∗ Technical College, Kirkuk, Iraq a r t i c l e i n f o Article history: Received 1 September 2013 Accepted 16 November 2014 Keywords: PAPR reduction OFDM Peak insertion a b s t r a c t A technique for Peak-to-Average Power Ratio (PAPR) reduction of Orthogonal Frequency Division Multi- plexing (OFDM) signals by Peak Insertion (PI) is proposed in this paper. PI depends on the duality property of the DFT and PAPR duality of an impulse. A relatively high peak is inserted to the OFDM symbol in the frequency domain such that the PAPR of the transmitted time domain signal is reduced. PAPR reduction up to about 11 dB at PAPR CCDF of 10 -4 is achievable by PI, but at the expense of increased signal power, which can be reduced by scaling to the desired level without affecting its PAPR. Computer simulation tests show that a tradeoff can easily be made between BER and the PAPR of the transmitted signal to achieve a desired system performance. The PI technique does not require any sort of side information transmission, searching, optimization, and iterative or parallel application of IDFT. PI is faster, simpler, and capable of achieving greater PAPR reduction as compared with other similar techniques which result in transmitted power increase, and therefore, it seems to be suitable to be used for OFDM signal PAPR reduction. © 2014 Elsevier GmbH. All rights reserved. 1. Introduction Due to its high spectral efficiency, immunity to frequency selec- tive fading, and high data rate, Orthogonal Frequency Division Multiplexing (OFDM) became a popular modulation technique in digital communication systems [1–7]. OFDM is the modula- tion standard for the IEEE802.11a/g wireless LANs, World wide Interoperability for Microwave Access (WIMAX), Digital Audio Broadcasting (DAB), Digital Video Broadcasting (DVB), Asymmetric Digital Subscriber Line (ADSL), etc. [2–5,7–9]. OFDM systems suffer mainly from the sensitivity to frequency offset and high Peak-to-Average Power Ratio (PAPR) of the trans- mit signal [1,2,4,5,7–10]. The latter is the major drawback of OFDM systems. The PAPR of a signal x(n) is defined as a ratio by PAPR = max   x(n)   2 E[   x(n)   2 ] (1) where |x(n)| is the magnitude of x(n), and E[·] denotes the expecta- tion operation. High PAPR occurs due to the summation of many subcarrier- modulated signals and the manner in which their phases can align in the frequency domain. A high PAPR requires a wide dynamic range high power amplifier (HPA) at the transmitter [11]. That is, ∗ Tel.: +964 770 13 23 692. E-mail address: draisiddiq@gmail.com the power amplifier needs to be backed-off to accommodate high peaks. This results in significant reduction in transmission power which leads to a very low power efficiency. There are many techniques for PAPR reduction in OFDM sys- tems. The basic techniques include amplitude clipping, clipping and filtering, coding, tone reservation (TR), tone injection (TI), active constellation extension (ACE), partial transmit sequence (PTS), selective mapping (SLM), and interleaving [6,7,9,12]. In the literature, many approaches have been proposed to reduce PAPR depending on modifications and optimizations to these basic tech- niques. Amplitude clipping is the simplest technique for PAPR reduc- tion. It causes both in-band and out-of-band distortion. The former results in degradation in error performance [13] and it cannot be reduced by filtering. While out-of-band radiation reduces spectral efficiency, it can be reduced by filtering, but at the expense of a risk of some peak regrowth [12]. Repeated clipping and filtering operation can be used to reduce the overall peak regrowth [12,14]. The deleterious effects of amplitude clipping may be reduced when it is used together with other techniques. However, any gained advantages are at the expense of increased system complexity [15,16]. Coding can also be used to reduce PAPR. The idea is to select the code words that minimize the PAPR for transmission [9,12]. This approach suffers from data rate loss and from the need to perform an exhaustive search to find the best codes and store large lookup tables for encoding and decoding, especially for large number of subcarriers. http://dx.doi.org/10.1016/j.aeue.2014.11.009 1434-8411/© 2014 Elsevier GmbH. All rights reserved.