摘 要
本文分析了各气象因素对ka-波段地空链路衰减特性的影响，得出了链路综合衰减分布函数，利用闪烁预测模型计算了全国各参考站点的闪烁月平均标准偏差和月百分比时间平均衰减值。在对信道衰减特性研究的基础上，提出一种基于物理层和数据链路层的抗衰减对策。本文研究了物理层afcm的控制算法，提出一种衰减检测优化算法；研究了自适应资源共享的方案，给出了一套自适应tdma完整的解决办法；对数据链路层hdlc协议进行了扩展，使数据链路层也具有抗衰减的功能。论文最后提出了一种ka-波段衰减信道的仿真方法并得出了一些结论。
关键词：雨衰 　 闪烁　 自适应tdma　　 　 衰减检测　
物理层　 数据链路层　 hdlc协议　　 　　信道仿真



abstract
in this paper, effects of atmospheric factors to ka-band earth-space links are analyzed, and the total fade distribution function is derived. with the scintillation prediction model, monthly averaged standard deviations and monthly percentage time averaged fade of scintillations for some of referential earth stations of our country are computed. founded of the research of characters of fade for channels, a fade countermeasure based on physical layer and data link layer is put forth. physical afcm algorithm is studied on this paper, and a optimized fade dection algorithm is put forth. adaptive resource sharing scheme is also studied in this paper and an integral solution for adaptive tdma is proposed. data link layer acquires ability to counteract rain attenuation after takeing our extended hdlc protocal. a method of simulation of fade channels for ka-band satellite communication is studied and some useful conclusions are derived at the end of this paper.
keywords： rain attenuation, scintillation, adaptive tdma ,
fade detection, physical layer, data link layer,
hdlc protocal, channel simulation


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