A Testing And Research Of Noise Correlation Coefficient In The Phase-Inversion Symmetric Modulation

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.