• Title/Summary/Keyword: Orthogonal Decision-Feedback Detector

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Performance Analysis of Blind Adaptive Orthogonal-Decision-Feedback Multiuser Detector in Synchronous DS-CDMA (동기식 DS-CDMA에서 블라인드 적응형 부귀환 직교 다중사용자 검파기의 성능평가)

  • 김우성;곽경섭
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.3B
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    • pp.259-266
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    • 2002
  • In the CDMA system, the Multiple access interference(MAI) causes system performance and capacity degradation. One of the MAI cancel method is a feedback detector that orthogonal decision-feedback detector(ODFD) and Deocrrelating decision-feedback detector(DDFD) have been studied by now. In this paper, we propose a blind adaptive ODFD(BA-ODFD) with blind equalizer combined ODFD, Also we simulate the operation of BA-ODFD in AWGN channel and Rayleigh (tiding channel. and compare blind adaptive ODFD with blind adaptive DDFD.

Performance Analysis of Suboptimal Receiver Combining Adaptive Array Antenna and Orthogonal Decision-Feedback Detector for DS/CDMA System

  • Cho, Young-pil;Yoo, Sung-Kyun;Lee, Hyung-ki;Kwak, Kyung-sup
    • Proceedings of the IEEK Conference
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    • 2002.07b
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    • pp.1354-1357
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    • 2002
  • In this paper, we propose a suboptimal receiver combining adaptive array antenna and orthogonal decision-feedback detector in DS/CDMA system. Adaptive array antenna can cancel out undesired signal using beamforming scheme. However, if there are interfering signals from undesired users with the same incident angle as that of a desired user, an adaptive array antenna cannot suppress them. The proposed receiver can cancel out remaining interference from users having nearly the same beam pattern. And we employ Orthogonal Decision-Feedback Detector (ODFD) as multiuser detection. The ODFD performs as good as the decorrelating decision -feedback detector (DDD) with much less complexity. Simulation results show that the proposed system provides a significantly enhanced performance.

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Suboptimal Receiver Combining Adaptive Array Antenna and Orthogonal Decision-Feedback Detector (적응 배열 안테나에 부귀환 직교 다중사용자 검출기를 결합한 준 최적 수신기)

  • Jo, Yeong-Pil;Kim, Jong-Mun;Gwak, Gyeong-Seop
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.39 no.8
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    • pp.26-32
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    • 2002
  • In this paper, we propose a suboptimal receiver combining adaptive array antenna and orthogonal decision-feedback detector in DS/CDMA system. Adaptive way antenna can cancel out undesired signal using beamforming scheme. However, if there are interfering signals from undesired users with the same incident angle as that of a desired user, an adaptive array antenna cannot suppress them. The proposed receiver can cancel out remaining interference from users having nearly the same beam pattern. And we employ Orthogonal Decision-Feedback Detector (ODFD) as Multiuser detection. The ODFD performs as good as the decorrelating decision -feedback detector (DDFD) with much less complexity. Simulation results show that the proposed system provides a significantly enhanced performance.

Decision-Feedback Detector for Quasi-Orthogonal Space-Time Block Code over Time-Selective Channel (시간 선택 채널에서의 QO-STBC를 위한 피드백 결정 검출기)

  • Wang, Youxiang;Park, Yong-Wan
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.12A
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    • pp.933-940
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    • 2009
  • This paper proposes a robust detection scheme for quasi-orthogonal space-time block code over time-selective fading channels. The proposed detector performs interference cancellation and decision feedback equalization to remove the inter-antenna interference and inter-symbol interference when the channel varies from symbol to symbol. Cholesky factorization is used on the channel Gram matrix after performing interference cancellation to obtain feed forward equalizer and feedback equalizer. It is shown by simulations that the proposed detection scheme outperforms the conventional detection schemes and the exiting detection schemes to time-selectivity.

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.