tailieunhanh - Báo cáo hóa học: " Research Article Power Backoff Reduction Techniques for Generalized Multicarrier Waveforms"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Power Backoff Reduction Techniques for Generalized Multicarrier Waveforms | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2008 Article ID 437801 13 pages doi 2008 437801 Research Article Power Backoff Reduction Techniques for Generalized Multicarrier Waveforms F. Danilo-Lemoine 1 D. Falconer 1 . Lam 1 M. Sabbaghian 1 and K. Wesolowski2 1 Department of Systems and Computer Engineering Carleton University Ottawa Canada K1S 5B6 2 Institute of Electronics and Telecommunications Poznan University of Technology 60965 Poznan Poland Correspondence should be addressed to D. Falconer ddf@ Received 3 April 2007 Revised 31 July 2007 Accepted 18 October 2007 Recommended by Hikmet Sari Amplification of generalized multicarrier GMC signals by high-power amplifiers HPAs before transmission can result in undesirable out-of-band spectral components necessitating power backoff and low HPA efficiency. We evaluate variations of several peak-to-average power ratio PAPR reduction and HPA linearization techniques which were previously proposed for OFDM signals. Our main emphasis is on their applicability to the more general class of GMC signals including serial modulation and DFT-precoded OFDM. Required power backoff is shown to depend on the type of signal transmitted the specific HPA nonlinearity characteristic and the spectrum mask which is imposed to limit adjacent channel interference. PAPR reduction and HPA linearization techniques are shown to be very effective when combined. Copyright 2008 F. Danilo-Lemoine 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. 1. INTRODUCTION High-power amplifiers HPAs used in radio transmitters have nonlinear characteristics which can cause significant distortion to signals whose instantaneous power fluctuations come too close to the HPAs output saturation power. Even small amounts of