Phase-Inversion Symmetric Spread Spectrum Technology Research

Phase-Inversion Symmetric Method (PISM) is a kind of method of communication which uses relativity of adjacent channels noises to restrain noise. Our research achieved a great step forward in this item since it funded by the Natural Science Foundation of China. The research results are applied in some communication systems. My task is research of the "Phase-Inversion Symmetric Spread Spectrum Technology" in the item group. Under my teachers and classmates' help, I finally complete my mission through the efforts of more than a year. This paper is written on the basis of it.Principle of PISM is to transmit two signals of phase-inversed in the adjacent channels, and make these two signals to subtract in the receiver. Noise will be restrained when the two noises are relativity. So whether the noises have relativity became the key issue of the item. Traditional theory considers that noises are not relative. With the theoretical analysis and the actual test with other classmates in my group, however, we find that no matter in adjacent time interval or adjacent channel or adjacent space, correlation coefficient of noise is greater than 0, especially man-made noise correlation coefficient is more than 0.9.During the process of research, I focus on the theoretical analysis and system simulation within time-domain PISM, and use PISM in spread spectrum communication system. I validate relativity of adjacent time interval noise by simulation software, the simulation results about conformed to the theoretical value. On this basis, combined PISM with spread spectrum communication technology, I propose a new method of spread spectrum communication, which goes through the simulation and experimental verification, finally make systemic model. Theory and practice both show that, in the same transmission conditions, capability of phase-inversion symmetric spread spectrum technology is superior to the general spread spectrum technology.We will continue research, and use it in actual communication system, making it become technological achievements of Chinese self-determination intellectual property rights.