%0 Journal Article
%T Low-Complexity Distortionless Techniques for Peak Power Reduction in OFDM Communication Systems
%A A. Ghassemi
%A T. A. Gulliver
%J Journal of Computer Networks and Communications
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/929763
%X A high peak-to-average power ratio (PAPR) is one of the major drawbacks to using orthogonal frequency division multiplexing (OFDM) modulation. The three most effective distortionless techniques for PAPR reduction are partial transmit sequence (PTS), selective mapping (SLM), and tone reservation (TR). However, the high computational complexity due to the inverse discrete Fourier transform (IDFT) is a problem with these approaches. Implementation of these techniques typically employ direct computation of the IDFT, which is not the most efficient solution. In this paper, we consider the development and performance analysis of these distortionless techniques in conjunction with low-complexity IFFT algorithms to reduce the PAPR of the OFDM signal. Recently, proposed IFFT-based techniques are shown to substantially reduce the computational complexity and improve PAPR performance. 1. Introduction Multicarrier modulation is a data transmission technique, which provides efficient bandwidth utilization and robustness against time dispersive channels. Examples of multicarrier modulation systems are digital audio broadcasting (DAB), digital video broadcasting (DVB), and wireless local and metropolitan area networks using orthogonal frequency division multiplexing (OFDM), and digital subscriber line (DSL) using discrete multitone (DMT) systems. OFDM is an effective transmission technique for wireless communications over frequency selective channels as it provides immunity to multipath fading. An inverse fast Fourier transform (IFFT) and a fast Fourier transform (FFT) are typically employed for baseband modulation and demodulation, respectively. Using an IFFT/FFT simplifies the design of the transceiver and eliminates the need for high speed equalizers, resulting in an efficient hardware implementation. In order to fully exploit the benefits provided by OFDM modulation, large envelope variations before the RF portion of an OFDM transmitter must be avoided. Signal peaks can lead to saturation in the power amplifier (PA), which in turn increases out-of-band radiation, creates in-band distortion, and reduces PA efficiency. The PA dominates the power consumption of the communication system. Thus this decrease in efficiency results in lower battery life in mobile (wireless) devices and the need for sophisticated heat dissipation techniques in base stations. To deal with this important issue, advanced signal processing techniques are required, which have low implementation complexity. Numerous techniques have appeared in the literature to reduce the PAPR [1]. They can
%U http://www.hindawi.com/journals/jcnc/2012/929763/