Channel Estimation and Carrier Frequency Offset Compensation in Orthogonal Frequency Division Multiplexing System Using Adaptive Filters in Wavelet Transform Domain

Document Type : Original Article

Authors

Department of Electrical Engineering, Islamic Azad University, Ahar Branch, Ahar, Iran

Abstract

In this paper, a combination of channel, receiver frequency-dependent IQ imbalance, and carrier frequency offset estimation under short cyclic prefix length is considered in orthogonal frequency division multiplexing system. An adaptive algorithm based on the set-membership filtering algorithm is used to compensate for these impairments. In short CP length, per-tone equalization structure is used to avoid inter-symbol interference. Due to CFO impairment and IQ imbalance in the receiver, we will expand the PTEQ structure to a two-branch structure. This structure has high computational complexity, so using the set-membership filtering idea with variable step size while reducing the average computation of the system can also increase the convergence speed of the estimates. On the other hand, applying wavelet transform on each branch of this structure before applying adaptive filters will increase the estimation speed. The proposed algorithm will be named SMF-WP-NLMS-PTEQ. The results of the simulations show better performance than the usual adaptive algorithms. Besides, estimation and compensation of channel effects, receiver IQ imbalance and carrier frequency offset under short CP can be easily accomplished by this algorithm.

Keywords


1. Murdas, I., “Quadrature amplitude modulation all optical orthogonal frequency division multiplexing-dense wavelength division multiplexing-optical wireless communication system under different weather conditions”, International Journal of Engineering - Transactions A: Basics, Vol. 30, No. 7, (2017), 988–994. doi: 10.5829/ije.2017.30.07a.08
2. Qiao, G., Babar, Z., Ma, L. and Ahmed, N., “Channel Estimation and Equalization of Underwater Acoustic MIMO-OFDM Systems: A Review Estimation du canal et l’égalisation des systèmes MEMS-MROF acoustiques sous-marins: une revue”, Canadian Journal of Electrical and Computer Engineering, Vol. 42, No. 4, (2019), 199–208. doi: 10.1109/CJECE.2019.2897587
3. Xie, H., Wang, Y., Andrieux, G. and Ren, X. “Efficient compressed sensing based non-sample spaced sparse channel estimation in OFDM system”, IEEE Access, Vol. 7, (2019), 133362–133370. doi: 10.1109/ACCESS.2019.2941152
4. Rodriguez-Avila, R., Nunez-Vega, G., Parra-Michel, R. and Mendez-Vazquez, A., “Frequency-selective joint Tx/Rx I/Q imbalance estimation using Golay complementary sequences”, IEEE Transactions on Wireless Communications, Vol. 12, No. 5, (2013), 2171–2179. doi: 10.1109/TWC.2013.040213.120622
5. Manasseh, E., Ohno, S. and Nakamoto, M., “Training symbol design for channel estimation and IQ imbalance compensation in OFDM systems”, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, Vol. 95, No. 11, (2012), 1963–1970. doi: 10.1109/VETECS.2012.6239897
6. Miyashita, H., Inamori, M., Sanada, Y. and Ide, T., “IQ imbalance estimation scheme with intercarrier interference self-cancellation pilot symbols in OFDM direct conversion receivers”, In 2012 IEEE 75th Vehicular Technology Conference (VTC Spring), IEEE, (2012), 1–5. doi: 10.1109/VETECS.2012.6239943
7. Nguyen, Q.D., Luu, T.T., Pham, L.H. and Nguyen, T.M., “Inter-Carrier Interference suppression combined with channel estimation for mobile OFDM system”, In 2016 Second Asian Conference on Defence Technology (ACDT), IEEE, (2016), 61–66. doi: 10.1109/ACDT.2016.7437644
8. Simon, E.P., Ros, L., Hijazi, H. and Ghogho, M. Simon, E. P., Ros, L., Hijazi, H. and Ghogho, M., “Joint carrier frequency offset and channel estimation for OFDM systems via the EM algorithm in the presence of very high mobility”, IEEE Transactions on Signal Processing, Vol. 60, No. 2, (2012), 754–765. doi: 10.1109/TSP.2011.2174053
9. Krishna, E. H., Sivani, K., and Reddy, K. A., “Empirical Mode Decomposition based Adaptive Filtering for Orthogonal Frequency Division Multiplexing Channel Estimation”, International Journal of Engineering (IJE), Vol. 30, No. 10, (2017), 1517–1525. doi: 10.5829/ije.2017.30.10a.13
10. Cheng, H., Xia, Y., Huang, Y., Yang, L. and Mandic, D.P., “Joint channel estimation and Tx/Rx I/Q imbalance compensation for GFDM systems”, IEEE Transactions on Wireless Communications, Vol. 18, No. 2, (2019), 1304–1317.
11. Cheng, H., Xia, Y., Huang, Y., Yang, L. and Mandic, D. P., “Joint Channel Estimation and Impulsive Noise Mitigation Method for OFDM Systems Using Sparse Bayesian Learning”, IEEE Access, Vol. 7, (2019), 74500–74510.