Ka频段宽带卫星通信信道雨衰特性的研究

发布时间：2018-10-11 14:57

【摘要】：在现代卫星通信系统中，现存的可用频谱资源已十分有限，超宽带高速传输必然要采用更高频率传输。目前的宽带卫星通信业务基本是使用Ku频段，以至于Ku频段的应用已经十分拥挤，故近来的超宽带高速传输卫星通信基本是采用Ka频段。本文前部分首先阐述了研究Ka波段卫星通信系统的意义以及国内外发展现状，并对影响Ka波段卫星通信链路性能的因素进行了分析。研究了降水对Ka波段信号的影响以及对其的衰减作用。基于降雨衰减机理，利用雨介质的等效介电常数模型计算了降雨的特征衰减。根据地-空路径上ITU-R的雨衰减预报模型和等效雨介质模型，仿真了北京和广州地区的降雨损耗曲线。然后通过Ku/Ka频段下行链路降雨衰减值的转换得到长春地区降雨数据，结合长春地区降雨特性对Ka频段降雨衰减的仿真结果，利用最小二乘法对降雨曲线进行了拟合，验证了其预测的有效性。本文后半部分针对Ka波段卫星通信的特性，综合分析了几种Ka波段卫星通信信道的衰减因素，尤其是雨衰对卫星通信信道的影响，确定了Ka波段卫星通信信道模型的乘性干扰矢量，完成了Ka波段卫星通信信道的建模。并基于Ka波段信道的建模，建立了Ka波段卫星通信系统的仿真模型，分析了采用不同调制方式下，，雨衰对Ka波段卫星通信系统的影响，给出了数字通信系统误码率（BER）在各种情况下的比较。分别分析了受到幅度和相位因素影响时雨衰对卫星通信系统BER性能造成的变化。并通过对比发现相比于单载波调制，OFDM作为一种多载波调制方式不仅能够增加频带利用率，而且对系统性能有着更好的提升。本文的研究对卫星数字通信系统的发展具有一定的实际意义。
[Abstract]:In the modern satellite communication system, the available spectrum resources are very limited, UWB high-speed transmission must adopt higher frequency transmission. At present, the broadband satellite communication service basically uses the Ku frequency band, so the application of the Ku band is already very crowded, so the UWB high speed transmission satellite communication basically uses the Ka frequency band recently. In the first part of this paper, the significance of the research on Ka band satellite communication system and its development status at home and abroad are described, and the factors influencing the performance of Ka band satellite communication link are analyzed. The influence of precipitation on Ka band signal and its attenuation are studied. Based on the rainfall attenuation mechanism, the rainfall characteristic attenuation is calculated by using the equivalent dielectric constant model of rain medium. Based on the rainfall attenuation prediction model and equivalent rain medium model of ITU-R on the ground-air path, the rainfall loss curves in Beijing and Guangzhou are simulated. Then through the downlink rainfall attenuation value of Ku/Ka band conversion to the Changchun region rainfall data, combined with the Changchun region rainfall characteristics of the Ka frequency band rainfall attenuation simulation results, using the least square method to fit the rainfall curve. The validity of the prediction is verified. In the second part of this paper, according to the characteristics of Ka band satellite communication, the attenuation factors of several kinds of Ka band satellite communication channels, especially the influence of rain attenuation on satellite communication channels, are analyzed synthetically. The multiplicative interference vector of Ka band satellite communication channel model is determined, and the model of Ka band satellite communication channel is completed. Based on the modeling of Ka band channel, the simulation model of Ka band satellite communication system is established, and the influence of rain attenuation on Ka band satellite communication system under different modulation modes is analyzed. The comparison of bit error rate (BER) in digital communication system under various conditions is given. The effect of rain failure on BER performance of satellite communication system is analyzed respectively when it is affected by amplitude and phase factors. Compared with single carrier modulation, OFDM can not only increase the bandwidth efficiency, but also improve the performance of the system. The research in this paper has certain practical significance for the development of satellite digital communication system.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN927.2

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