Weitere Artikel dieser Ausgabe durch Wischen aufrufen
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.
Pollet T, Van Bladel M, Moeneclaey M: BER sensitivity of OFDM systems to carrier frequency offset and Wiener phase noise. IEEE Transactions on Communications 1995, 43(234):191-193. CrossRef
Moose P: A technique for orthogonal frequency division multiplexing frequency offset correction. IEEE Transactions on Communications 1994, 42: 2908-2914. 10.1109/26.328961 CrossRef
Li J, Liu G, Giannakis GB: Carrier frequency offset estimation for OFDM-based WLANs. IEEE Signal Processing Letters 2001, 8(3):80-82. 10.1109/97.905946 CrossRef
Ma V, Ylamurto T: Analysis of IQ imbalance on initial frequency offset estimation in direct down-conversion receivers. Proceedings of the 3rd IEEE Workshop on Signal Processing Advances in Wireless Communications (SPAWC '01), March 2001, Tauyuan, Taiwan 158-161.
Yu J-Y, Sun M-F, Hsu T-Y, Lee C-Y: A novel technique for I/Q imbalance and CFO compensation in OFDM systems. Proceedings of IEEE International Symposium on Circuits and Systems (ISCAS '05), May 2005, Kobe, Japan 6: 6030-6033.
Tubbax J, Fort A, Van der Perre L, et al.: Joint compensation of IQ imbalance and frequency offset in OFDM systems. Proceedings of IEEE Global Telecommunications Conference (GLOBECOM '03), December 2003, San Francisco, Calif, USA 4: 2365-2369. CrossRef
Fouladifard S, Shafiee H: Frequency offset estimation in OFDM systems in presence of IQ imbalance. Proceedings of the 8th International Conference on Communication Systems (ICCS '02), November 2002 1: 214-218.
Xing G, Shen M, Liu H: Frequency offset and I/Q imbalance compensation for direct-conversion receivers. IEEE Transactions on Wireless Communications 2005, 4(2):673-680. CrossRef
Yan F, Zhu W-P, Ahmad MO: Carrier frequency offest estimation for OFDM systems with I/Q imbalance. Proceedings of the 47th IEEE Midwest Symposium on Circuits and Systems (MWSCAS '04), July 2004, Cincinnati, Ohio, USA 2: 633-636.
De Rore S, Lopez-Estraviz E, Horlin F, Van der Perre L: Joint estimation of carrier frequency offset and IQ imbalance for 4G mobile wireless systems. Proceedings of IEEE International Conference on Communications (ICC '06), June 2006, Istanbul, Turkey 5: 2066-2071.
Yan F, Zhu W-P, Ahmad MO: Carrier frequency offset estimation and I/Q imbalance compensation for OFDM systems. EURASIP Journal on Advances in Signal Processing 2007, 2007:-11.
Horlin F, Bourdoux A, Lopez-Estraviz E, Van der Perre L: Low-complexity EM-based joint CFO and IQ imbalance acquisition. Proceedings of IEEE International Conference on Communications (ICC '07), June 2007, Glasgow, UK 2871-2876.
Chen Y, Jayalath ADS, Zhang J, Pollock T: Frequency offset estimation for OFDM systems in the presence of I/Q mismatch. Proceedings of the 18th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC '07), September 2007, Athens, Greece 1-5.
Channel models for hiperlan/2 in different indoor scenarios European Telecommunications Standards Institute, Norme ETSI, Sophia-Antipolis, Valbonne, France; 1998.
- Low-Complexity Estimation of CFO and Frequency Independent I/Q Mismatch for OFDM Systems
- Springer International Publishing
- EURASIP Journal on Wireless Communications and Networking
Elektronische ISSN: 1687-1499
Neuer Inhalt/© ITandMEDIA, Product Lifecycle Management/© Eisenhans | vege | Fotolia