Channel Nonlinear Effect Under The Complicated Electromagnetic Environment Research

With the gradual deepening of the exploiting of the earth’s space environment andthe rapid development of the navigation positioning technology and the mannedspaceflight technology, it becomes urgent to study the plasma increasingly. In practicalapplications, the various kinds of nonlinear effects, which are the main error sources ofwireless communication, are produced by the ionosphere plasma. On the other hand, itis effective method to solve the blackout problem by using the characteristics of thenonlinear effects of the plasma. Here, the blackout problem is produced by the re-entryprocess of the high-speed spacecraft.The wireless channel is the research object in this dissertation. Both the ionosphereplasma of the earth space and the plasma developed by the re-entry process of thespacecraft are the important parts of the wireless channel. Based on this, three aspects,which are the non-linear nature characteristic, the nonlinear effects characteristic of theplasma, and the application of nonlinear effects, are analyzed and simulated in detail.The simulation results show that the nonlinear effects of the plasma not only have harmpart, such as the breaking wave and the self-interaction wave, but also have benefit part,such as the blackout communication, which is solved by using the nonlinear effects ofthe plasma. The main achievement of the dissertation is as followed:1. The theory of the plasma. The structure and formative mechanism of theplasma, the influences of the complex electromagnetic environment for thespace plasma, the plasma oscillations and the Maxwell speed distribution areintroduced.2. The propagation characteristic of wave in the plasma. The dielectric constant ofthe plasma is educed in detail, and the nonlinear nature of the plasma isexpounded; The relationship of the attenuation constant of the electromagneticwave, the characteristic frequency of the plasma, the collision frequency, thefrequency of the electromagnetic wave are expounded and analyzed in detail,and the numerical simulation is showed; The reason of appearing blackoutphenomenon for the re-entry process of the spacecraft is analyzed and researched in detail, and the numerical simulation is given too.3. Two types of the nonlinear effects in the plasma, which are harm to thepropagation of the wave. The theory of two types of the nonlinear effects,which are the breaking wave and the self-interaction wave, is educed andanalyzed in detail. And the numerical simulation is given.4. The study of the interactional nonlinear effects of the wave in the plasma. Theinteractional process of three waves is educed and analyzed in detail. Themethod of solving the blackout communication by using this nonlinear processis educed and analyzed in detail, and the numerical simulation is given.