【摘要】：在現(xiàn)代衛(wèi)星通信系統(tǒng)中，現(xiàn)存的可用頻譜資源已十分有限，超寬帶高速傳輸必然要采用更高頻率傳輸。目前的寬帶衛(wèi)星通信業(yè)務(wù)基本是使用Ku頻段，以至于Ku頻段的應(yīng)用已經(jīng)十分擁擠，故近來的超寬帶高速傳輸衛(wèi)星通信基本是采用Ka頻段。 本文前部分首先闡述了研究Ka波段衛(wèi)星通信系統(tǒng)的意義以及國內(nèi)外發(fā)展現(xiàn)狀，并對影響Ka波段衛(wèi)星通信鏈路性能的因素進行了分析。研究了降水對Ka波段信號的影響以及對其的衰減作用。基于降雨衰減機理，利用雨介質(zhì)的等效介電常數(shù)模型計算了降雨的特征衰減。根據(jù)地-空路徑上ITU-R的雨衰減預(yù)報模型和等效雨介質(zhì)模型，仿真了北京和廣州地區(qū)的降雨損耗曲線。然后通過Ku/Ka頻段下行鏈路降雨衰減值的轉(zhuǎn)換得到長春地區(qū)降雨數(shù)據(jù)，結(jié)合長春地區(qū)降雨特性對Ka頻段降雨衰減的仿真結(jié)果，利用最小二乘法對降雨曲線進行了擬合，驗證了其預(yù)測的有效性。 本文后半部分針對Ka波段衛(wèi)星通信的特性，綜合分析了幾種Ka波段衛(wèi)星通信信道的衰減因素，尤其是雨衰對衛(wèi)星通信信道的影響，確定了Ka波段衛(wèi)星通信信道模型的乘性干擾矢量，完成了Ka波段衛(wèi)星通信信道的建模。并基于Ka波段信道的建模，建立了Ka波段衛(wèi)星通信系統(tǒng)的仿真模型，分析了采用不同調(diào)制方式下，，雨衰對Ka波段衛(wèi)星通信系統(tǒng)的影響，給出了數(shù)字通信系統(tǒng)誤碼率（BER）在各種情況下的比較。分別分析了受到幅度和相位因素影響時雨衰對衛(wèi)星通信系統(tǒng)BER性能造成的變化。并通過對比發(fā)現(xiàn)相比于單載波調(diào)制，OFDM作為一種多載波調(diào)制方式不僅能夠增加頻帶利用率，而且對系統(tǒng)性能有著更好的提升。本文的研究對衛(wèi)星數(shù)字通信系統(tǒng)的發(fā)展具有一定的實際意義。
[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.
【學位授予單位】：吉林大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN927.2

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