In a fast-fading environment, e.g., high-speed railway communications, channel estimation and tracking require the availability of a number of pilot symbols that is at least as large as the number of independent channel parameters. Aiming at reducing the number of necessary pilot symbols, this work proposes a novel technique for joint channel tracking and decoding, which is based on the following three ideas. 1) Sparsity: While the total number of channel parameters to be estimated is large, the actual number of independent multipath components is generally small; 2) Long-term versus short-term channel parameters: Each multipath component is typically characterized by long-term parameters that slowly change with respect to the duration of a transmission time slot, such as delays or average power values, and by fast-varying fading amplitudes; and 3) Code-aided methods: Decision-feedback techniques can optimally leverage past, and partially reliable, decisions on the data symbols to obtain “virtual” pilots via the expectation–maximization (EM) algorithm. Numerical results show that the proposed code-aided EM algorithm is effective in performing joint channel tracking and decoding even for velocities as high as 350 km/h, as in high-speed railway communications, and with as few as four pilots per orthogonal frequency-division multiplexing data symbol, as in the IEEE 802.11a/n/p standards, outperforming existing schemes at the cost of larger computational complexity.


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    Titel :

    Code-Aided Channel Tracking and Decoding Over Sparse Fast-Fading Multipath Channels With an Application to Train Backbone Networks


    Beteiligte:
    Khalili, Shahrouz (Autor:in) / Feng, Jianghua (Autor:in) / Simeone, Osvaldo (Autor:in) / Tang, Jun (Autor:in) / Wen, Zheng (Autor:in) / Haimovich, Alexander M. (Autor:in) / Zhou, MengChu (Autor:in)


    Erscheinungsdatum :

    01.03.2017


    Format / Umfang :

    931482 byte




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Elektronische Ressource


    Sprache :

    Englisch