Abstract
This paper proposes a frequency-domain iterative soft decision feedback equalization (SDFE) scheme for multiple-input–multiple-output orthogonal frequency division multiplexing communication systems in multi-path fading channels. Error propagation can seriously affect the performance of the adaptive decision feedback equalization. We propose an iterative SDFE to not only combat error propagation but also be suitable for multilevel modulation systems. Under a Gaussian approximation of the a priori information and the SDFE output, the output of an equivalent AWGN channel and expressions for the a posteriori log likelihood ratio (LLR) and the extrinsic LLR are derived for multilevel modulation. In addition, we also investigate the iterative receivers by employing irregular low-density parity check codes (LDPC) and turbo codes. The performance of the LDPC-coded iterative receiver is better than that of the turbo-coded iterative receiver. Some simulation examples are given to show the effectiveness and comparisons of the proposed receiver.
Similar content being viewed by others
References
Namboodiri, V., Liu, H., & Spasojevic, P. (2011). Low complexity turbo equalization for mobile MIMO OFDM systems. In Proceedings on International Conference on Communications and Signal Processing (pp. 255–260).
Douillard, C., Jézéquel, M., Berrou, C., Picart, A., Didier, P., & Glavieux, A. (1995). Iterative correction of intersymbol interference: Turbo equalization. European Transactions on Telecommunications, 6(5), 507–512.
Berrou, C., Glavieux, A., & Thitimajshima, P. (1993). Near Shannon limit error-correcting and decoding: Turbo codes. Proceedings on IEEE International Conference on Communications, 2, 1064–1070.
Lou, H., & Xiao, C. (2011). Soft decision feedback turbo equalization for multilevel modulations. IEEE Transactions on Signal Processing, 59(1), 186–195.
Lopes, R. R., & Barry, J. R. (2006). The soft-feedback equalizer for turbo equalization of highly dispersive channels. IEEE Transactions on Communications, 54(5), 783–788.
Talakoub, S., Sabeti, L., Shahrrava, B., & Ahmadi, M. (2007). An improved Max-Log-MAP algorithm for turbo decoding and turbo equalization. IEEE Transactions, 56(3), 1058–1063.
Lin, S., & Costello, D. J. (2004). Error control coding. Upper Saddle River: Pearson Prentice Hall.
Barhumi, I. (2012). Decision feedback turbo equalization for OFDM over doubly selective channel. In Proceedings on global communications conference (pp. 3801–3806).
Ahmed, S., Ratnarajah, T., Sellathurai, M., & Cowan, C. F. N. (2009). Iterative receivers for MIMO-OFDM and their convergence behavior. IEEE Transactions on Vehicular Technology, 58(1), 461–468.
Tüchler, M., Singer, A. C., & Koetter, R. (2002). Minimum mean square error equalization using a priori information. IEEE Transactions on Signal Processing, 50(3), 673–683.
Dejonghe, A., & Vanderdorpe, L. (2002). Turbo equalization for multilevel modulation: An efficient low-complexity scheme. Proceedings on IEEE International Conference on Communications, 3, 1863–1867.
Tüchler, M., Koetter, R., & Singer, A. C. (2002). Turbo equalization: Principles and new results. IEEE Transactions on Communications, 50(5), 754–767.
Vila, P. et al. (2000). Reduced-complexity M-ary decoders for turbo-equalization. In Presented at the 2nd international symposium on turbo codes related topics. Brest, France.
Lou, H., Xiao, C., & Rafati, A. (2011). Low-complexity soft-decision feedback turbo equalization for MIMO systems with multilevel modulations. IEEE Transactions on Vehicular Technology, 60(7), 3218–3227.
Lu, B., Yue, G., & Wang, X. (2004). Performance analysis and design optimization of LDPC-coded MIMO-OFDM systems. IEEE Transactions on Signal Processing, 52(2), 348–361.
ten Brink, S. (2001). Convergence behavior of iteratively decoded parallel concatenated codes. IEEE Transactions on Communications, 49(10), 1727–1737.
Wang, X., & Poor, H. V. (1999). Iterative (turbo) soft interference cancellation and decoding for coded CDMA. IEEE Transactions on Communications, 47(7), 1046–1061.
Proakis, J. G. (2001). Digital communications. New York: McGraw-Hill.
Ahmed, J., & Hamdi, K. (2013). Spectral efficiency of asynchronous MC-CDMA with frequency offset over correlated fading. IEEE Transactions on Vehicular Technology, 62(7), 3423–3429.
Rasadurai, V., & Kumaratharan, N. (2012). Performance enhancement of MC-CDMA system through turbo multi-user detection.In International conference on computer communication and informatics (pp. 1–7).
Panayirci, E., Senol, H., & Poor, H. V. (2010). Joint channel estimation, equalization, and data detection for OFDM systems in the presence of very high mobility. IEEE Transactions on Signal Processing, 58(8), 4225–4238.
Zhang, X., & Ryu, H.-G. (2010). Suppression of ICI and MAI in SC-FDMA communication system with carrier frequency offsets. IEEE Transactions on Consumer Electronics, 56(2), 359–365.
Li, Qinghua, Li, Guangjie, Lee, Wookbong, Lee, Moon-il, Mazzarese, David, Clerckx, Fruno, & Li, Zexian. (2010). MIMO Techniques in WiMAX and LTE: A feature overview. IEEE Communications Magazine, 48(5), 86–92.
Tomasoni, A., Siti, M., Ferrari, M., & Bellini, S. (2010). Low complexity, quasi-optimal MIMO detectors for iterative receivers. IEEE Transactions on Wireless Communications, 9(10), 3166–3177.
Song, S. H., Chen, G. L., & Letaief, K. B. (2011). Localized or interleaved? A tradeoff between diversity and CFO interference in multipath channels. IEEE Transactions on Wireless Communications, 10(9), 2829–2834.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Chung, CY., Ueng, FB. & Chang, YK. Frequency-Domain Iterative SDFE for MIMO-OFDM Systems. Wireless Pers Commun 86, 1121–1140 (2016). https://doi.org/10.1007/s11277-015-2978-x
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11277-015-2978-x