Joint Estimation of Carrier Frequency Offset and I/Q Imbalance in the Presence of Time-Varying DC Offset

Due to the importance of maintaining the orthogonality among subcarriers, the estimation of carrier frequency offset (CFO) is a crucial issue in orthogonal frequency division multiplexing (OFDM) systems. The CFO estimation becomes complicated in OFDM direct-conversion receivers (DCRs), where additional analog impairments such as I/Q imbalance and time-varying DC offset (TV-DCO) exist. In this paper, we propose a novel joint estimation method for CFO and I/Q imbalance in the presence of TV-DCO. By using the linear property of the TV-DCO and employing a periodic pilot sequence, the desired estimates can be obtained in closed-form. Simulation results confirm the validity of the proposed method.

[1]  Donald C. Cox,et al.  Robust frequency and timing synchronization for OFDM , 1997, IEEE Trans. Commun..

[2]  Stefano Marsili.  DC offset estimation in OFDM based WLAN application , 2004, IEEE Global Telecommunications Conference, 2004. GLOBECOM '04..

[3]  Hamid Shafiee,et al.  Frequency offset estimation in OFDM systems in the presence of IQ imbalance , 2003, IEEE International Conference on Communications, 2003. ICC '03..

[4]  Hai Lin,et al.  A Low-Complexity Carrier Frequency Offset Estimator Independent of DC Offset , 2008, IEEE Communications Letters.

[5]  Teresa H. Y. Meng,et al.  Direct-conversion RF receiver design , 2001, IEEE Trans. Commun..

[6]  Behzad Razavi,et al.  Design considerations for direct-conversion receivers , 1997 .

[7]  Umberto Mengali,et al.  An improved frequency offset estimator for OFDM applications , 1999, IEEE Communications Letters.

[8]  Young-Hwan You,et al.  Frequency-offset synchronization and channel estimation for OFDM-based transmission , 2000, IEEE Commun. Lett..

[9]  Mamiko Inamori,et al.  Frequency Offset Estimation Scheme in the Presence of Time-Varying DC Offset and IQ Imbalance for OFDM Direct Conversion Receivers , 2007, 2007 IEEE 18th International Symposium on Personal, Indoor and Mobile Radio Communications.

[10]  Shoji Otaka,et al.  A Low Offset 1.9-GHz Direct Conversion Receiver IC with Spurious Free Dynamic Range of over 67 dB , 2001 .

[11]  Yong Hoon Lee,et al.  Joint ML estimation of carrier frequency, channel, I/Q mismatch, and DC offset in communication receivers , 2005, IEEE Transactions on Vehicular Technology.

[12]  Hai Lin,et al.  Pilot-Aided Low-Complexity CFO and I/Q Imbalance Compensation for OFDM Systems , 2008, 2008 IEEE International Conference on Communications.

[13]  Sumei Sun,et al.  Low complexity frequency offset estimation in the presence of DC offset , 2003, IEEE International Conference on Communications, 2003. ICC '03..

[14]  Liesbet Van der Perre,et al.  Joint estimation of carrier frequency offset and IQ imbalance for 4G mobile wireless systems , 2006, 2006 IEEE International Conference on Communications.

[15]  Paul H. Moose,et al.  A technique for orthogonal frequency division multiplexing frequency offset correction , 1994, IEEE Trans. Commun..

[16]  Hugo De Man,et al.  Joint compensation of IQ imbalance and frequency offset in OFDM systems , 2003, GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489).

[17]  Marc Moonen,et al.  Joint Adaptive Compensation of Transmitter and Receiver IQ Imbalance Under Carrier Frequency Offset in OFDM-Based Systems , 2007, IEEE Transactions on Signal Processing.

[18]  Mamiko Inamori,et al.  Frequency Offset Estimation Scheme in the Presence of Time-Varying DC Offset for OFDM Direct Conversion Receivers , 2007, IEICE Trans. Commun..