Title: A low complexity selective mapping OFDM using multiple IFFT stages

Authors: A. Ghassemi, T. Aaron Gulliver

Addresses: Department of Electrical and Computer Engineering, University of Victoria, P.O. Box 3055, STN CSC, Victoria, BC V8W 3P6, Canada. ' Department of Electrical and Computer Engineering, University of Victoria, P.O. Box 3055, STN CSC, Victoria, BC V8W 3P6, Canada

Abstract: A low complexity Selective Mapping (SLM) technique for reducing the Peak-to-Average Power Ratio (PAPR) of an Orthogonal Frequency Division Multiplexing (OFDM) signal is introduced. The intermediate signals within an N-point IFFT using a radix Decimation In Time (DIT) or Decimation In Frequency (DIF) IFFT algorithm are used to generate the phase sequences. It is shown that DIF provides lower multiplicative complexity in generating the SLM sequences compared to DIT, with the same PAPR reduction. In addition, a high radix FFT algorithm provides better PAPR reduction performance per stage with less multiplicative complexity compared to a low radix algorithm. We further reduce the computational complexity by proposing a low computational complexity technique based on multiplying the phase sequences at multiple IFFT stages. This new technique greatly reduces the multiplicative complexity while providing similar PAPR reduction to Ordinary SLM (O-SLM). The additive complexity is also reduced.

Keywords: orthogonal frequency-division multiplexing; OFDM modulation; peak-to-average power ratio; PAPR; decimation in frequency; DIF; decimation in time; DIT; selective mapping; SLM sequences; inverse fast Fourier transforms; IFFT; wireless communications.

DOI: 10.1504/IJCNDS.2008.020257

International Journal of Communication Networks and Distributed Systems, 2008 Vol.1 No.2, pp.129 - 139

Published online: 10 Sep 2008 *

Full-text access for editors Access for subscribers Purchase this article Comment on this article