| Summary: | 碩士 === 國立臺北科技大學 === 電機工程系研究所 === 97 === This thesis is to investigate the solutions for inter-carrier interference (ICI) cancellation due to Doppler shifts caused by time-variant highly mobile channel in the OFDM system. In conventional OFDM receiver, the energy of each subcarrier will leak to adjacent subcarriers which destroys the orthogonality between subcarriers in time-variant channel. This will result in the increased bit-error rate (BER) and raised error floor as well. The approaches for ICI cancellation can be categorized into three types including frequency-domain equalizer, time-domain window algorithm, and self-cancellation. The pre-mapping algorithm is an improved ICI self-cancellation method with low complexity without loss of bandwidth efficiency. An ICI self-cancellation method based on pre-mapping algorithm was proposed in this thesis. By using new pre-mapping matrix, the proposed method can improve the system performance without increasing much system complexity. Computer simulation results show that the proposed method is good in system performance, complexity and bandwidth efficiency.
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