【作者】 李通；

【导师】 萧宝瑾；

【作者基本信息】 太原理工大学 ， 信号与信息处理， 2008， 硕士

【摘要】 随着无线通信技术的发展,无线信道中人为噪声已成了主要噪声源。如何利用人为噪声的相关性来提高信噪比,逐渐引起了人们的重视。反相对称法(Phase-Inversion Symmetric Modulation,PISM)就是利用噪声的相关性来抑制噪声的一种方法,它能从强噪声中提取出弱信号,大大提高信噪比,因此近年来受到国内外同行的关注,而对带限噪声相关性的研究也将会成为信息与通信领域中的一个新的研究热点。本文仅对带限噪声的相关性做了一些研究,主要工作如下:一.探讨了当前通信环境改变的原因,并对国内外噪声处理方法进行了分析比较。二.阐述了PISM利用噪声的相关性提高通信系统信噪比的基本原理,并在此基础上,讨论了PISM与香农定理的关系以及PISM的适用范围。三.噪声相关系数的大小是PISM的关键。本文重点研究了时域、频域和空间域中噪声相关系数的大小以及影响它们的因素。1.在时域方面:本文分析了时域PISM的基本原理和抗噪声性能,并用Matlab和System-View对相邻时隙噪声的相关性进行了计算和仿真验证。2.在频域方面:对音频噪声和带限高斯噪声进行了大量的实际测试和仿真分析,得出了相邻频带噪声的相关系数随着带宽的增加而减小的结论。3.在空域方面:用数字存储示波器对当前空间电磁场的相对场强进行了大量测试,证实了人为噪声比自然噪声的功率大得多,同时证实了空间电磁噪声是宽平稳的随机过程。并通过分析和计算,得出了相邻空间噪声的相关系数随距离的增大而减小的结论。四.总结与展望:制作时域PISM通信系统并对时域PISM的相关系数进行实测;在频域方面继续对更高频率的噪声相关系数进行测试与研究;在空域方面进一步改善测试条件,提高测试精度。更多还原

【Abstract】 With the development of Wireless Communication Technology, the artificial noise in the wireless channel has become the main noise fountain. How to use noise correlation to enhance SNR has gradually attracts more attention. PISM (Phase-Inversion Symmetric Modulation, PISM) is a method which can effectively inhibit man-made noises by using the noise correlation. In this theory, weak signals can be extracted from strong noises therefore the SNR can be increased greatly. So it catches much attention of the counterparts’ at home and abroad in recent years, and the research of band-limited noise relevance will become a new focus in information and communication field.In this paper, only some research of the limited noise has been done, the main work is as followed:At first, this paper introduces the reasons of changes in the current communications environment, and makes analysis and comparisons for the methods of dealing with noise at home and abroad.Second, this paper discusses the relationship between PISM and Shannon theorem as well as the application scale of PISM. All the research above is on the basic of PISM law which enhance the SNR by using the noise correlation.Third, the key of PISM is the value of noise correlation. This paper focuses the value of noise correlation and the influencing factors in time-domain, frequency domain and space domain. 1. In the time domain, this paper first analyses the basic theory of PISM and its anti-noise performance in time domain, and gives the calculation and simulation of the noise correlation coefficient with system-view and matlab software in time-domain.2. In the frequency domain, a large number of experiments and simulations about the audio noise and Gaussian limited noise have been done, which get the conclusion that the noise correlation coefficient between the frequency bands will reduce with the increase of the Bandwidth.3. In the airspace, the paper first measures the electromagnetic environment of the current space with the digital oscilloscope which proves that the power of man-made noise is much larger than the natural noise, and a large number of space experiments show that electromagnetic noise is a random process of smooth width. Besides, analysis and calculation of the adjacent space show that the noise of the correlation coefficient decreases with the increase of the distance.Finally, the paper shows the summaries of the study and the prospects of the PISM. The next step is to structure the PISM communication systems in time domain and to test its correlation coefficients; In the frequency domain the measures and tests of the noise correlation coefficient in higher frequencies will be continue; In airspace the conditions of the test will be improved for a more accurate test and more detailed measurements.更多还原