碩士 / 國立成功大學 / 系統及船舶機電工程學系 / 102 / The purpose of this study is to increase the quality of the underwater acoustic communication (UAC) and capable to transmitted the large amounts of data under multipath environment. The transmitted binary data is formatted by pattern time delay shift coding regime (PDS) and modulated by binary phase shift-keying (BPSK). At the receiving end, fast self-optimized least mean squares algorithm (FOLMS) of the equalizer and passive time reversal mirror (TRM) are used to recover the transmitted signal. Then, bit error rate (BER) is discussed with analyzed different coding regime from 1m to 50m UAC distance. The process of TRM is to reverse the time sequence of the received signal, then transmit it back to the signal source receiver in a virtual way, so the signal can focus on the original source location. Therefore, the signal to noise ratio (SNR) is increased and the multipath effect is minimized. The channel impulse response (CIR) of the sound path is estimated by use of FOLMS, which adapts its step size automatically of the typical least mean squares algorithm (LMS), and leads to much higher convergence speed. Through the algorithm of PDS, the UAC system can be more adaptable in changing UAC environment when the large amounts of data are transmitted. The UAC experiment is conducted in the 176m×8m×4m towing tank. A 64×64×8bit photo is transmitted, and the experimental result implies that the proposed combined algorithms can decrease BER under 5% even with a strong reverberation environment.
| Identifer | oai:union.ndltd.org:TW/102NCKU5345018 |
| Date | January 2014 |
| Creators | Hsi-HsunWang, 王錫旋 |
| Contributors | Gee-Pinn Too, 涂季平 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 80 |
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