碩士 / 國立臺灣海洋大學 / 電機工程學系 / 98 / Underwater channels posses the characteristics of very limited bandwidth, Doppler spread and multipath fading, thus requiring advanced signal processing techniques to increase data transmission rate and reliability.
Multiple transmit and receive hydrophones can be used to form multiple-input multiple output (MIMO) channels to increase the system capacity and reliability. If combined with the space-time block coding (STBC) scheme, the resultant system can provide spatial diversity gain to improve reliability. On the other hand, orthogonal frequency division multiplexing (OFDM) technique can cope with frequency-selective fading, thus reducing the intersymbol interference (ISI) caused by multipath delay. Therefore, in this thesis, we adopt STBC-based MIMO-OFDM scheme and propose a multiuser detector based on the widely linearly constrained minimum variance (W-LCMV) principle for underwater acoustic communications. The proposed W-LCMV detector on the basis of MIMO-OFDM is capable of suppressing multiple access interference (MAI) as well as co-channel interference (CCI) to reduce symbol error rate, thus increasing number of users allowed to communicate in a network. Except for the interference cancellation capability, W-LCMV detector is a linear detector with low complexity of operations. Computer simulation results show that W-LCMV detector outperforms LCMV detector and still possesses very good detection performance, even when the system is fully or overly loaded.
| Identifer | oai:union.ndltd.org:TW/098NTOU5442058 |
| Date | January 2011 |
| Creators | Chih-Chun Ho, 何至軍 |
| Contributors | Hsien-Sen Hung, 洪賢昇 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 50 |
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