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
References
[1]
S. H. Han and J. H. Lee, “An overview of peak-to-average power ratio reduction techniques for multicarrier transmission,” IEEE Wireless Communications, vol. 12, no. 2, pp. 56–65, 2005.
[2]
X. Li and L. J. Cimini, “Effects of clipping and filtering on the performance of OFDM,” IEEE Communications Letters, vol. 2, no. 5, pp. 131–133, 1998.
[3]
D. Wulich, N. Dinur, and A. Glinowiecki, “Level clipped high-order OFDM,” IEEE Transactions on Communications, vol. 48, no. 6, pp. 928–930, 2000.
[4]
H. Ochiai and H. Imai, “Performance analysis of deliberately clipped OFDM signals,” IEEE Transactions on Communications, vol. 50, no. 1, pp. 89–101, 2002.
[5]
M. Sharif, M. Gharavi-Alkhansari, and B. H. Khalaj, “On the peak-to-average power of OFDM signals based on oversampling,” IEEE Transactions on Communications, vol. 51, no. 1, pp. 72–78, 2003.
[6]
R. Raich, H. Qian, and G. T. Zhou, “Optimization of SNDR for amplitude-limited nonlinearities,” IEEE Transactions on Communications, vol. 53, no. 11, pp. 1964–1972, 2005.
[7]
A. Gatherer and M. Polley, “Controlling clipping probability in DMT transmission,” in Proceedings of the 31st Asilomar Conference on Signals, Systems & Computers, pp. 578–584, November 1997.
[8]
J. Armstrong, “Peak-to-average power reduction for OFDM by repeated clipping and frequency domain filtering,” Electronics Letters, vol. 38, no. 5, pp. 246–247, 2002.
[9]
X. Huang, J. Lu, J. Zheng, J. Chuang, and J. Gu, “Reduction of peak-to-average power ratio of OFDM signals with companding transform,” Electronics Letters, vol. 37, no. 8, pp. 506–507, 2001.
[10]
X. Huang, J. Lu, J. Zheng, K. B. Letaief, and J. Gu, “Companding transform for reduction in peak-to-average power ratio of OFDM signals,” IEEE Transactions on Wireless Communications, vol. 3, no. 6, pp. 2030–2039, 2004.
[11]
T. A. Wilkinson and A. E. Jones, “Minimisation of the peak to mean envelope power ratio of multicarrier transmission schemes by block coding,” in Proceedings of the IEEE 45th Vehicular Technology Conference, pp. 825–829, July 1995.
[12]
J. A. Davis and J. Jedwab, “Peak-to-mean power control in OFDM, Golay complementary sequences, and Reed-Muller codes,” IEEE Transactions on Information Theory, vol. 45, no. 7, pp. 2397–2417, 1999.
[13]
D. Wulich, “Reduction of peak to mean ratio of multicarrier modulation using cyclic coding,” Electronics Letters, vol. 32, no. 5, pp. 432–433, 1996.
[14]
V. Tarokh and H. Jafarkhani, “On the computation and reduction of the peak-to-average power ratio in multicarrier communications,” IEEE Transactions on Communications, vol. 48, no. 1, pp. 37–44, 2000.
[15]
K. G. Paterson, “Generalized Reed-Muller codes and power control in OFDM modulation,” IEEE Transactions on Information Theory, vol. 46, no. 1, pp. 104–120, 2000.
[16]
J. Tellado, Peak to average power reduction for multicarrier modulation [Ph.D. thesis], Stanford University, 2000.
[17]
B. S. Krongold and D. L. Jones, “PAR reduction in OFDM via active constellation extension,” IEEE Transactions on Broadcasting, vol. 49, no. 3, pp. 258–268, 2003.
[18]
B. S. Krongold and D. L. Jones, “An active-set approach for OFDM PAR reduction via tone reservation,” IEEE Transactions on Signal Processing, vol. 52, no. 2, pp. 495–509, 2004.
[19]
S. H. Mueller and J. B. Huber, “Novel peak power reduction scheme for OFDM,” in Proceedings of the International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC '97), pp. 1090–1094, September 1997.
[20]
M. Breiling, S. H. Müller-Weinfurtner, and J. B. Huber, “SLM peak-power reduction without explicit side information,” IEEE Communications Letters, vol. 5, no. 6, pp. 239–241, 2001.
[21]
A. Alavi, C. Tellambura, and I. Fair, “PAPR reduction of OFDM signals using partial transmit sequence: an optimal approach using sphere decoding,” IEEE Communications Letters, vol. 9, no. 11, pp. 982–984, 2005.
[22]
N. Carson and T. A. Gulliver, “Peak-to-average power ratio reduction of OFDM using repeat-accumulate codes and selective mapping,” in Proceedings of the IEEE International Symposium on Information Theory, p. 244, July 2002.
[23]
A. D. S. Jayalath and C. Tellambura, “SLM and PTS peak-power reduction of OFDM signals without side information,” IEEE Transactions on Wireless Communications, vol. 4, no. 5, pp. 2006–2013, 2005.
[24]
L. Wang and C. Tellambura, “An adaptive-scaling tone reservation algorithm for PAR reduction in OFDM systems,” in Proceedings of the IEEE Global Telecommunications Conference (GLOBECOM '06), pp. 1–5, December 2006.
[25]
A. Ghassemi and T. A. Gulliver, “A low-complexity PTS-based radix FFT method for PAPR reduction in OFDM systems,” IEEE Transactions on Signal Processing, vol. 56, no. 3, pp. 1161–1166, 2008.
[26]
A. Ghassemi and A. T. Gulliver, “Partial selective mapping OFDM with low complexity IFFTs,” IEEE Communications Letters, vol. 12, no. 1, pp. 4–6, 2008.
[27]
A. Ghassemi and T. Gulliver, “PAPR reduction of OFDM using PTS and error-correcting code subblocking—transactions papers,” IEEE Transactions on Wireless Communications, vol. 9, no. 3, pp. 980–989, 2010.
[28]
A. Ghassemi and T. A. Gulliver, “A simplified suboptimal algorithm for tone reservation OFDM,” in Proceedings of the IEEE International Conference on Communications (ICC '09), pp. 1–5, June 2009.
[29]
C. C. Feng, C. Y. Wang, C. Y. Lin, and Y. H. Hung, “Protection and transmission of side information for peak-to-average power ratio reduction of an OFDM signal using partial transmit sequences,” in Proceedings of the IEEE 58th Vehicular Technology Conference (VTC '03), pp. 2461–2465, October 2003.
[30]
R. W. B？uml, R. F. H. Fischer, and J. B. Huber, “Reducing the peak-to-average power ratio of multicarrier modulation by selected mapping,” Electronics Letters, vol. 32, no. 22, pp. 2056–2057, 1996.
[31]
S. H. Muller and J. B. Huber, “Comparison of peak power reduction schemes for OFDM,” in Proceedings of the IEEE Global Telecommunications Mini-Conference, pp. 1–5, November 1997.
[32]
N. Ohkubo and T. Ohtsuki, “Design criteria for phase sequences in selected mapping,” in Proceedings of the 57th IEEE Semiannual Vehicular Technology Conference (VTC '03), pp. 373–377, April 2003.
[33]
D. W. Lim, S. J. Heo, J. S. No, and H. Chung, “A new PTS OFDM scheme with low complexity for PAPR reduction,” IEEE Transactions on Broadcasting, vol. 52, no. 1, pp. 77–82, 2006.
