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收集所有交通大學研究人員與學生個人或團體所發表之各項學術著作，涵蓋期刊論文、教師專書、學位論文等項。;;Collections of Publications of NCTU Researchers and Students Like Journal Papers and Thesis.

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🏛️國立陽明交通大學機構典藏

Access type: Metadata onlyAuthor: search.filters.author.Hsieh, MH

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Now showing 1 - 5 of 5
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    Channel estimation for OFDM systems based on comb-type pilot arrangement in frequency selective fading channels
    (1998-02-01)
    Hsieh, MH
    ;
    Wei, CH
    ;
    電子工程學系及電子研究所
    ;
    Department of Electronics Engineering and Institute of Electronics
    In this paper, the channel estimation methods for OFDM systems based on comb-type pilot sub-carrier arrangement are in vestigated. The channel estimation algorithm based on comb-type pilots is divided into pilot signal estimation and channel interpolation. The pilot signal estimation based on LS or MMSE criteria, together with channel interpolation based on piecewise-linear interpolation or piecewise second-order polynomial interpolation is studied. Owing to the MMSE estimate of pilot signals, the inter-carrier interference and additive white Gaussian noise are reduced considerably. The computational complexity of pilot signal estimation based on MMSE criterion can be reduced by using a simplified LMMSE estimator with low-rank approximation using singular value decomposition. Phase compensators before and after interpolation are also presented to combat the phase changes of subchannel symbols arising from the frame synchronization errors. Comparing to the transform-domain processing based channel estimation algorithm, the MMSE estimate of pilot signals together with phase compensated linear interpolation algorithm provides better performance and requires less computations.
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    A multialphabet arithmetic coding with weighted history model
    (1995)
    Hsieh, MH
    ;
    Wei, CH
    ;
    電子工程學系及電子研究所
    ;
    Department of Electronics Engineering and Institute of Electronics
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    A frequency acquisition scheme for OFDM systems
    (1996)
    Hsieh, MH
    ;
    Wei, CH
    ;
    交大名義發表
    ;
    電子工程學系及電子研究所
    ;
    National Chiao Tung University
    This paper derives a frequency acquisition algorithm for orthogonal frequency division multiplexing (OFDM) systems. This frequency acquisition algorithm is a modification of the frequency tracking algorithm introduced in [1], which uses a repeated data symbol and a maximum likelihood estimation (MLE) algorithm to estimate the frequency offset. The estimate is extremely accurate but the acquisition range is limited to +/-1/2 of the intercarrier spacing. With some modifications of the frequency tracking scheme and an assumption of the multipath channel introduced in this paper, the frequency acquisition can be converted to an analogous PN sequence acquisition problem. Therefore, a partial-sum correlator with an appropriate threshold can be used to acquire the frequency offset.
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    Narrow-band interference rejection in OFDM-CDMA transmission system
    (1998)
    Hsiao, HF
    ;
    Hsieh, MH
    ;
    Wei, CH
    ;
    電子工程學系及電子研究所
    ;
    Department of Electronics Engineering and Institute of Electronics
    In this paper, we present a new method called "differential threshold exciser (DTE)" to suppress narrow-band interference in OFDM-CDMA transmission system. Also, another threshold exciser, "over-through threshold exciser (OTTE)", is discussed. The two methods use different transform characteristics of the interference and information signal to suppress the narrow-band interference no matter the interference is stationary or nonstationary. The DTE algorithm has nearly the same performance as the OTTE algorithm with less computation complexity.
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    Improvement in light-output efficiency of near-ultraviolet InGaN-GaN LEDs fabricated on stripe patterned sapphire substrate
    (2005)
    Lee, YJ
    ;
    Hsu, TC
    ;
    Kuo, HC
    ;
    Wang, SC
    ;
    Yang, YL
    The output power of GaN-based near ultraviolet stripe patterned sapphire substrate (PSS) LEDs was 20% higher than that of the conventional LEDs. The possible mechanism of this enhancement will be discussed in this report.