| Satellite communication system has become the important means for worldwide individual communication and Internet air high-speed access due to its large coverage area, wide communication band and high capacity transmission. The Ku band satellite communication system has such merits:huge available bandwidth, small disturbance and small terminal equipment, it can offer better service for high speed satellite internet, interacting multimedia data transmission and other new communication services. Ku band has developed quickly after its emergence and has, so far, become one of important means for military wireless communications. However, in the process of satellite communication, in addition to having similar interference with other wireless transmission, the electric wave transmission is affected by many factors in the link of transmission, for example transmission attenuation, the attenuation of free space, rainfall and snowfall will lead to the attenuation of different degrees. The rainfall affects the signal more and will lead to the destroy of the link of the satellite communications. Especially to the Ku band satellite communication system, the destroy of rainfall has become a key impaction to the satellite communication quality because of the high frequency. Therefore, this article simulates major issues on the Ku-band interference—rain attenuation, researching the rain attenuation characteristics of the Ku band, and a effective compensation method for rain attenuation has played an significant role to improve the satellite communication system quality.The present work is the topological structure in the VSAT network, the typical design links, the standard line further defined, the sources of interference on the system carried out. The effect of rainfall on the electrical signal has been deeply analyzed, basing on the mathematical model for analyzing the physical mechanism of rainfall and rainfall characteristics. The design program of Ku-band communications satellite is determined, probably through the relationship between signal attenuation and rain attenuation of ku-band is given for the absorption of radio waves influence diagram. I depicted rain attenuation figures of china by MATLAB software. Then with changing some parameters, Respectively depicted the affection of all factors to rain attenuation under different latitude, different height, different antenna elevation conditions. Through analysis and comparison of several rain attenuation compensation method and theory, discusses the relationship with the characteristics of rainfall attenuation rate and the size of rainfall attenuation. So the rainfall attenuation rate with log-normal distribution and exponential distribution characteristics definited. were obtained the corresponding lines of the satellite digital communication method of the general design and main parameters of the communication. |
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