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OFDM Carrier Frequency Offset Estimation Methods With Improved Performance
Eu-Suk Shim,Sang-Tae Kim,Hyoung-Kyu Song,Young-Hwan You [Institute of Electrical and Electronics Engineers 2007 IEEE transactions on broadcasting Vol.53 No.2
<P>Orthogonal frequency division multiplexing (OFDM) systems are highly sensitive to carrier frequency offset and symbol timing error. This paper deals with estimation method of integer frequency offset (IFO) without the aid of pilot symbols. The proposed IFO estimator exploits two consecutive identical OFDM data symbols with only change of phase. In order to improve the accuracy of the IFO estimator, receive diversity is adopted. To demonstrate the efficiency of the proposed IFO estimators, comparisons are made with other existing estimators in terms of error performance, estimation range, and complexity.</P>
An Improved Integer Frequency Offset Estimation Scheme for OFDM systems
Eu-Suk Shim,Young-Hwan You 대한전자공학회 2009 ITC-CSCC :International Technical Conference on Ci Vol.2009 No.7
Orthogonal frequency division multiplexing (OFDM) systems are highly sensitive to carrier frequency offset. This paper deals with estimation method of integer frequency offset (IFO) with improved performance. The proposed IFO estimator exploits two consecutive identical OFDM data symbols with only change of phase. To demonstrate the efficiency of the proposed IFO estimators, comparisons are made with other existing estimator in terms of error performance.
Low-cost integer frequency offset estimation for OFDM-based DRM receiver
Eu-Suk Shim,Joonbeom Kim,Young-Hwan You IEEE 2010 IEEE transactions on consumer electronics Vol.56 No.4
<P>In this paper, we propose an improved and low-cost integer frequency offset (IFO) estimation method by partitioning pilot symbols effectively in an orthogonal frequency division multiplexing based digital radio mondiale (DRM) system. To this end, the time reference cell (TRC) symbol for frequency estimation is grouped into a number of pilot clusters, so that the TRC subcarriers in each cluster are closely spaced to show approximately frequency-nonselective characteristics. The performance of the proposed IFO estimator is compared with that of the conventional estimator, and shows that the proposed technique can effectively achieve lower estimation errors in frequency offset estimation as well as can be implemented with reduced computational complexity.</P>
Eu-Suk Shim,Hyoung-Kyu Song,Young-Hwan You IEEE 2010 IEEE transactions on broadcasting Vol.56 No.4
<P>Cyclic delay diversity (CDD) is a simple transmit diversity technique for coded OFDM systems with multiple transmit antennas. However, high frequency selectivity caused by CDD degrades the performance of post- FFT estimation, i.e., integer frequency offset (IFO). This paper suggests a simple way of improving the performance of the IFO estimator based on the pilot subset partitioning which is designed to reduce the effect of frequency selective fading by adopting the CDD. By partitioning uncorrelated pilot subcarriers into subsets to satisfy high correlation, and performing frequency estimation for each pilot subset, a robust IFO estimation scheme is derived. The simulation results show that the proposed method can provide benefit to the overall system performance .</P>
Low-Complexity Coarse Frequency Offset Estimation for OFDM Systems with Non-uniform Phased Pilots
SHIM, Eu-Suk,YOU, Young-Hwan The Institute of Electronics, Information and Comm 2011 IEICE transactions on fundamentals of electronics, Vol.ea94 No.2
<P>In this letter, we propose a low-complexity coarse frequency offset estimation scheme in an orthogonal frequency division multiplexing (OFDM) system using non-uniform phased pilot symbols. In our approach, the pilot symbol used for frequency estimation is grouped into a number of pilot subsets so that the phase of pilots in each subset is unique. We show via simulations that such a design achieves not only a low computational load but also comparable performance, when compared to the conventional estimator.</P>