Int. J. Electron. Commun. (AEÜ) 68 (2014) 1165–1172 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 based on entropy wavelet transform for Sniffer Mobile Robot O. Daoud a,∗ , Qadri J. Hamarsheh b , Saleh Saraireh a a Communications and Electronics Engineering Department, Philadelphia University, Amman 19392, Jordan b Computer Engineering Department, Philadelphia University, Amman 19392, Jordan a r t i c l e i n f o Article history: Received 11 December 2013 Accepted 14 June 2014 Keywords: MIMO-OFDM SNFRbot-EWT Wavelet Entropy PAPR a b s t r a c t In this paper, the performance of wireless systems has been improved based on a proposition of a new peak detection algorithm based on the entropy of the wavelet transforms [1] and to be imposed to the Sniffer Mobile Robot (SNFRbot). This enhancement has been compared with a previously published work that uses a predistortion neural network (PDNN) architecture has been imposed to the SNFRbot. More- over, the proposed method in this work has been applied to combat the Orthogonal Frequency Division Multiplexing (OFDM) system’s drawback; namely peak-to-average power ratio (PAPR). Generally, the proposed algorithm consists of three stages; firstly, reconstruction based on wavelet transform, secondly, predetermined thresholding, and thirdly, imposing moving filter. This algorithm is called Multiple-Input Multiple-Output (MIMO)-OFDM system based entropy wavelet transform and to be imposed to SNFRbot work; SNFRbot-EWT. The performance of SNFRbot-EWT has been evaluated using a numerical analysis and a conducted simulation. The results have been compared with the our previously published work, SNFRbot-EWT gives an improvement reach to around 30% for the same bandwidth occupancy, which will reduce the cost and the complexity of the transceiver’s structure. © 2014 Elsevier GmbH. All rights reserved. 1. Introduction The high demand for the various wireless and cellular system’s applications has steer the researchers interest toward the discipline of using powerful techniques during the previous two decades. Orthogonal Frequency Division Multiplexing (OFDM) is one of them, where the whole modulation process has been improved to be parallel instead of series. This permits the data rates to exceed the 100 Mbps for the downlink process and 30 Mbps for the uplink [2–4]. Not only has the support of high data rates as a significant advantages over the conventional ones, but also the robustness to multipath fading and a greater simplification of channel equaliza- tion. Therefore, the OFDM is preferable in many systems. It has been adopted in wireless and wired applications in recent years, such as wireless networking (IEEE 802.11), digital terrestrial tele- vision broadcasting and Broadband Radio Access Network (BRAN) [5–8]. ∗ Corresponding author. Tel.: +962 785053646. E-mail addresses: oamr1462004@yahoo.com, odaoud@philadelphia.edu.jo (O. Daoud). Moreover, the ubiquitous robots [9,10] have been used due to the rapid growth of wireless communication services. Further- more and to have the probability of achieving extraordinary data rates even in a rich scattering environment [6,11] multiple anten- nas techniques have been employed at both ends; namely MIMO technology. Such technology is known as spatial multiplexing or BLAST and allows an increase in bit rate in a wireless radio link without additional power or bandwidth consumption [12]. In a time-varying frequency-selective fading channel, the BLAST system may suffer from severe performance degradation. The combination of these two powerful technologies; MIMO and OFDM, will pre- vent and overcome the system’s degradation that could be resulted in the previously published work; Sniffer Mobile Robot (SNFRbot) [13]. To achieve this result a modification has been made in this work on the way of detecting the peaks and overcome the effect of the high ones, whereas the high Peak to Average Power Ratio (PAPR) is considered as one of the main deficiencies. It distorts the signals when they passed through nonlinear components such as power amplifiers, mixers and converters; and causes some sig- nal deficiencies such as intermodulation in energy being generated at frequencies outside the allocated bandwidth, spectral spread- ing and changing in signal constellation. Average signal power must be kept low in order to prevent the transmitter amplifier http://dx.doi.org/10.1016/j.aeue.2014.06.005 1434-8411/© 2014 Elsevier GmbH. All rights reserved.