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 Research Article Low-Complexity Estimation of CFO and Frequency Independent I/Q Mismatch for OFDM Systems | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2009 Article ID 542187 11 pages doi 2009 542187 Research Article Low-Complexity Estimation of CFO and Frequency Independent I Q Mismatch for OFDM Systems Ying Chen 1 2 Jian Andrew Zhang 1 2 and A. D. S. Jayalath3 1 Department of Information Engineering The Australian National University Canberra ACT 0200 Australia 2 Program of Networked Systems National ICT Australia NICTA Canberra ACT 2601 Australia 3 School of Engineering Systems Queensland University of Technology Queensland QLD 4001 Australia Correspondence should be addressed to Ying Chen Received 1 November 2008 Revised 20 February 2009 Accepted 27 April 2009 Recommended by Marc Moonen CFO and I Q mismatch could cause significant performance degradation to OFDM systems. Their estimation and compensation are generally difficult as they are entangled in the received signal. In this paper we propose some low-complexity estimation and compensation schemes in the receiver which are robust to various CFO and I Q mismatch values although the performance is slightly degraded for very small CFO. These schemes consist of three steps forming a cosine estimator free of I Q mismatch interference estimating I Q mismatch using the estimated cosine value and forming a sine estimator using samples after I Q mismatch compensation. These estimators are based on the perception that an estimate of cosine serves much better as the basis for I Q mismatch estimation than the estimate of CFO derived from the cosine function. Simulation results show that the proposed schemes can improve system performance significantly and they are robust to CFO and I Q mismatch. Copyright 2009 Ying Chen 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. .