共查询到17条相似文献,搜索用时 140 毫秒
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雨衰减严重影响第5代(the 5th Generation,5G)移动通信系统性能.在路径长度小于1 km的短距离链路情况下,现有雨衰减预测模型调整因子大于1,导致预测雨衰减随路径变短而增大,无法支撑毫米波短距离链路系统设计.通过分析国际电信联盟无线电通信部(Radiocommunication Sector of International Telecommunication Union,ITU-R)短距离链路雨衰减试验数据,发现湿天线衰减与路径雨衰减相当,得到毫米波短距离链路必须考虑湿天线衰减的结论.建立了湿天线衰减与降雨率的关系模型,分频段对模型参数进行了拟合,拟合结果与实测数据吻合得较好.提出了考虑湿天线衰减的短距离雨衰减建模新思路,可解决短距离雨衰减预测问题.研究结果有助于提高5G毫米波系统余量设计的可靠性. 相似文献
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利用中国国内58个典型站点的参数.根据ITU-R地空路径雨衰预报模型,计算出58个站点地空路径上Ka频段的降雨衰减以及不同频率的衰减值之比,通过数值计算方法拟合得到Ka频段频率比例因子的表达式.本文得到的频率比例因子的计算结果优于ITU-R所推荐的频率比例因子的计算结果. 相似文献
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降雨高度是地-空路径雨衰减预测中最重要的参数之一。本文简要叙述了降雨情况下0℃等温层高度和温度剖面的分布特性,详细介绍了雨高模型,该模型是根据中国西部山区降雨期间高空测量数据得到的。最后将该模型和CCIR雨高模型作了比较。 相似文献
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Warren L. Stutzman 《International Journal of Satellite Communications and Networking》1989,7(1):37-45
This paper reviews the effects of precipitation on earth-space communication links operating the 10 to 35 GHz frequency range. Emphasis is on the quantitative prediction of rain attenuation and depolarization. Discussions centre on the models developed at Virginia Tech. Comments on other models are included as well as literature references to key works. Also included is the system level modelling for dual polarized communication systems with techniques for calculating antenna and propagation medium effects. Simple models for the calculation of average annual attenuation and cross-polarization discrimination (XPD) are presented. Calculation of worst month statistics are also presented. 相似文献
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雨滴的散射和吸收作用会严重增加地空链路上太赫兹波的传输损耗,降低无线通信的性能。为实现太赫兹波在地空链路上的传输应用,必须对太赫兹波在降雨环境中的传输特性进行深入研究。本文对原有的雨衰模型进行了修正,基于Mie理论,分析了降雨率的变化对地空链路上太赫兹波传输的影响,并与原有模型的计算结果进行了对比。结果表明:在整个太赫兹频段,雨衰减损耗会随降雨率的增加而增大,随频率的增加先增大后减小,且高频太赫兹波段相对0.1~1 THz频段范围的雨衰损耗更小;同时,当频率超过1 THz时,大气窗口越靠近10 THz,损耗越小,在降雨天气环境进行无线通信传输时将更具有通信优势,且频率越低,天顶角越大,模型修正前后的差异性更加明显。 相似文献
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Kheirallah H.N. Knight J.P. Olsen R.L. Mccormick K.S. Segal B. 《Electronics letters》1980,16(12):448-450
Theoretical and numerical results are presented which demonstrate that the effective path length commonly used in the prediction of rain attenuation statistics for earth-space paths is frequency dependent. Also presented is a method of translating effective path length measurements in frequency. 相似文献
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Athanasios D. Panagopoulos John D. Kanellopoulos 《International Journal of Satellite Communications and Networking》2003,21(6):595-611
Knowledge about the dynamic characteristics of rain attenuation is of utmost importance for many applications in terrestrial and satellite communication systems operating at frequencies above 10 GHz. Long‐term rain rate statistics and rain rate duration statistics are usually available from meteorological data. In this paper, a spatial–temporal analysis is employed in order to evaluate the rain attenuation power spectrum of a terrestrial/satellite path. The predicted power spectrum is compared with experimental data. Based on the spectral analysis of rainfall rate a method for converting rain rate duration statistics to link fade duration statistics is also proposed. Fade duration statistics are presented for terrestrial and satellite links and compared with available experimental data. The agreement between the predicted results and the experimental data has been found to be quite encouraging. Finally, numerical results are presented for various climatic zones, elevation angles and frequencies. Some very useful conclusions concerning the dynamic properties of rain attenuation for a microwave path are deduced. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
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Persinger R. Stutzman W. Castle R. Jr. Bostian C. 《Antennas and Propagation, IEEE Transactions on》1980,28(2):149-153
A piecewise uniform rain rate distribution model is introduced as a quasi-physical model of real rain along earth-space millimeter wave propagation paths. It permits calculation of the total attenuation from specific attenuation in a simple fashion. The model predications are verified by comparison with direct attenuation measurements for several frequencies, elevation angles, and locations. Also, coupled with the Rice-- Holmberg rain rate model, attenuation statistics are predicated from rainfall accumulation data. 相似文献
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The role of rain in satellite communications 总被引:1,自引:0,他引:1
《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1975,63(9):1308-1331
The most fundamental obstacle encountered in design of satellite communication systems at frequencies above 10 GHz is attenuation by rain. The microwave power radiated toward an earth station, being limited by factors such as available primary power and size of antenna on the satellite, is insufficient, with present technology, to overcome the large attenuation produced by intense rain cells on the earth-space path. The resultant loss of signal makes for unreliable transmission. In what follows, methods of measurement of this attenuation at various frequencies and a technique called path diversity that substantially improves the reliability are presented. Other degradations produced by rain, such as depolarization, interference, increase in earth-station noise, and deterioration of earth-station antenna performance, are also discussed. 相似文献