• Title/Summary/Keyword: Multipath expansion model

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Joint Kalman Channel Estimation and Turbo Equalization for MIMO OFDM Systems over Fast Fading Channels

  • Chang, Yu-Kuan;Ueng, Fang-Biau;Shen, Ye-Shun;Liao, Chih-Yuan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.11
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    • pp.5394-5409
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    • 2019
  • The paper investigates a novel detector receiver with Kalman channel information estimator and iterative channel response equalization for MIMO (multi-input multi-output) OFDM (orthogonal frequency division multiplexing) communication systems in fast multipath fading environments. The performances of the existing linear equalizers (LE) are not good enough over most fast fading multipath channels. The existing adaptive equalizer with decision feedback structure (ADFE) can improve the performance of LE. But error-propagation effect seriously degrades the system performance of the ADFE, especially when operated in fast multipath fading environments. By considering the Kalman channel impulse response estimation for the fast fading multipath channels based on CE-BEM (complex exponential basis expansion) model, the paper proposes the iterative receiver with soft decision feedback equalization (SDFE) structure in the fast multipath fading environments. The proposed SDFE detector receiver combats the error-propagation effect for fast multipath fading channels and outperform the existing LE and ADFE. We demonstrate several simulations to confirm the ability of the proposed iterative receiver over the existing receivers.

Shallow Water High-frequency Reverberation Model (천해 고주파 잔향음 예측모델)

  • 최지웅;윤관섭;나정열;박정수;나영남
    • The Journal of the Acoustical Society of Korea
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    • v.21 no.8
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    • pp.671-678
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    • 2002
  • High-frequency monostatic reverberation model (HYREV: HanYang Univ. REVerberation model) suitable for shallow-water environment is presented. It is difficult to predict reverberation signals in shallow water due to scattering from sea surface and seafloor. The arrival times and transmission losses from the source to scatterers are obtained from the eigenrays. The composite roughness theory is used to predict the boundary scattering. The signals generated by the HYREV and the GSM were compared with the observed signals and it is showed that the HYREV model provided a closer fit to the observed signals than those obtained using the GSM.