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Research Letters in Signal Processing
Volume 2009, Article ID 515797, 5 pages
Research Letter

Design of an Adaptive Predistorter for Solid State Power Amplifier in Wireless OFDM Systems

1Laboratory for Intelligent Signal Processing and Communications, Department of Electrical Engineering and Computer Science, University of California, Irvine, CA 92697-2625, USA
2Central R&D Laboratory, Korea Telecom (KT), Seoul 137-792, South Korea

Received 21 April 2009; Accepted 31 July 2009

Academic Editor: Paul Cristea

Copyright © 2009 Rui J. P. de Figueiredo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Orthogonal frequency division multiplexing (OFDM) is a powerful modulation choice for wideband wireless communication systems. However, its high peak-to-average power ratio greatly limits the high power amplifier (HPA) power efficiency. Here, we present the design of an adaptive predistorter to compensate the distortion caused by the HPA. Specifically, we deal with the implementation issue of the proposed predistorter in Lee and de Figueiredo's work (2006). The performance improvement by predistorter is verified by both floating-point simulation and fixed-point simulation, where the latter includes the distortion effects from the hardware. The bit widths for OFDM signals, ADC, and DAC are evaluated, and the bit width of 10 is shown to be sufficient for the hardware design.