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This dissertation, An Iterative Receiver With Pilot-aided Kalman Filter Based Channel Estimation for Wireless MC-CDMA Communication Systems by Tung-man, Law, 羅東文, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of the thesis entitled An Iterative Receiver with Pilot-Aided Kalman Filter based Channel Estimation for Wireless MC- CDMA Communication Systems submitted by Law Tung Man for the degree of Master of Philosophy at the University of Hong Kong in July 2007 Efficient channel estimation and multiuser detection techniques are required to overcome the deficiencies due to the multipath fading and multiuser access interference (MAI) in multicarrier code-division multiple-access (MC-CDMA) systems. In order to obtain further improvement, a turbo receiver using maximum a posteriori expectation-maximization (MAP-EM) demodulator with a soft low-density parity-check (LDPC) decoder is considered. In this thesis, we consider two main streams of channel estimation and multiuser detection for wireless MC-CDMA communications. First, a turbo receiver with pilot-aided Kalman filter-based channel tracking is developed to investigate the iiimportant role of channel estimation. The pilot-aided Kalman filter considerably simplifies the tracking of the time-varying channel, which helps to improve the performance of the MAP-EM demodulator and LDPC decoder in fast fading channels. Simulation results show that the proposed system gives a better BER performance than conventional turbo receiver, at the expense of a slightly lower data rate due to the use of pilot symbols. It is therefore an useful alternative to conventional approaches providing a different tradeoff between BER performance, implementation complexity, and transmission bandwidth. When some subcarriers in MC-CDMA system are contaminated by narrowband interfering signals, it was found that the performances of conventional least-squares (LS) channel estimators and multiuser detectors, and even the Kalman filter-based channel estimator, were significantly degraded. Therefore a turbo receiver with pilot- aided robust channel tracking and multiuser detection under time-varying narrowband interference (NBI) is developed. A new weighted least M-estimate (WLM) multiuser detector based on the M-estimation and weighted least square (WLS) algorithm is proposed to jointly suppress the MAI and time-varying NBI. To provide reliable channel estimation in NBI, a weighted recursive least M-estimate (WRLM) channel estimator is also employed to estimate time-varying frequency- selective fading channels. Simulation results show that the proposed WRLM channel estimator and WLM multiuser detector significantly outperform the conventional RLS channel estimator and linear decorrelator under NBI respectively. An abstract of exactly 307 words iii DOI: 10.5353/th_b3858166 Subjects: Signal detectionCode division multiple accessWireless communication systems

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