| 题名 | 水下扩频声通信系统研究 |
| 作者 | 孟达 |
| 学位类别 | 博士 |
| 答辩日期 | 2000 |
| 授予单位 | 中国科学院声学研究所 |
| 授予地点 | 中国科学院声学研究所 |
| 关键词 | 扩频序列 扩谱 多途效应 水声通信 码间干扰 |
| 中文摘要 | 最近几年，水声通信的应用领域越来越广泛，从军事领域已经扩展到商业领域。因此，水下通信系统的研究受到了更多的重视，同时得到了更快地发展。水声通信面临的最大困难是水声信道的多途径效应用问题。在存在严重多途干扰的情况下，扩频技术可以用在通信系统中获得很高的处理增益，此外，扩频技术还能够提供多址能力，在水下形成通信网络。本文首先介绍了水声通信的发展现状、声信道对水声通信的影响以及水声扩频通信的优点。在第二章中介绍了通信系统的基本问题，包括M序列的产生、扩频通信系统的组成以及扩频信号的解扩和解调原理。在第三章中详细介绍了扩频通信系统的方案，介绍M序列信号编码原理，抗多途干扰方法，以及多路乘累加与同步包络相乘的解码方法。在第四章重点介绍了多途信道的测量方法，并在不同信噪比的条件下，对不同信道进行仿真。在第五章，在不同信噪比、不同信道对第三章的扩频系统方案进行仿真研究。结果表明这种方案在信噪比很低的情况下仍有理想的结果，解调的方法对多途测量的误差不敏感。最后对信道均衡解码作了介绍。 |
| 英文摘要 | Underwater communication is required for diverse underwater operations such as the retrieval of data from bottom packages and real time transmission of signals from underwater sensors. In recent years, Acoustic UnderWater(AUW) communications have known a huge increase in research and development due to the growing needs of wireless transimisson systems. The applications have begun to broad form military context towards commercial one. Major difficulties are encountered due to the long times and the multipath propagation in the underwater channels. Spread spectrum methods can be used in hostile environments to provide processing gain in channels where the transimitted signal is distorted by multipath propagation, to provide multiple access capabilities in systems shared by many users. These merits are of interest to underwater communication systems. The first part of the thesis gives the backgound of the work in the field of underwater communication, and discuss the major obstacles of underwater communication. In the second part, several basic problems of spread spectrum system are discussed, including the generation of spreading sequences, the basic structure of spread spectrum systems. In the third part part an UWC system is introduced. The coding scheme、modulation and demodulation are investigated for application in fading multipath channels. The estimation of multipath is discussed in the fourth part, and some emulating results are also given in this part. The fifth part emulates the proposed system and the results are analyzed. |
| 语种 | 中文 |
| 公开日期 | 2011-05-07 |
| 页码 | 48 |
| 内容类型 | 学位论文 |
| 源URL | [http://159.226.59.140/handle/311008/682]  |
| 专题 | 声学研究所_声学所博硕士学位论文_1981-2009博硕士学位论文 |
| 推荐引用方式 GB/T 7714 | 孟达. 水下扩频声通信系统研究[D]. 中国科学院声学研究所. 中国科学院声学研究所. 2000. |
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