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Turbo Equalization with Prediction and Iterative Estimation of Time-Varying Frequency-Selective Channels

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Abstract

Turbo equalization that cooperates with channel prediction and iterative channel estimation is investigated for mobile wireless communications. Frames of information bits are encoded, interleaved, and mapped to symbols for transmission over time-varying frequency-selective fading channels. At the receiver, the Turbo equalizer consists of a maximum a posteriori probability equalizer/demapper and a soft-input soft-output maximum a posteriori probability decoder. With initial channel estimates and sparse pilot insertion across a number of frames, the receiver predicts the channel of the current frame. The effect of error propagation of channel prediction is mitigated by the de-interleaver that is embedded in the Turbo equalizer. The predicted and interpolated channel is refined through a channel estimator that uses the soft estimates of data symbols at each Turbo iteration. Due to the bandlimiting feature of channel variation, the channel estimation error can be smoothed by low-pass filters that follow the channel estimator. Simulation results show that incorporating Turbo equalization with channel prediction and iterative channel estimation can combat time- and frequency-selective fading and improve reception performance.

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Authors and Affiliations

  1. Department of Electrical and Computer Engineering, Western Michigan University, Kalamazoo, MI, 49008, USA

    Liang Dong

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  1. Liang Dong
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Correspondence to Liang Dong.

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Dong, L. Turbo Equalization with Prediction and Iterative Estimation of Time-Varying Frequency-Selective Channels. Wireless Pers Commun 55, 631–644 (2010). https://doi.org/10.1007/s11277-009-9824-y

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  • DOI: https://doi.org/10.1007/s11277-009-9824-y

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