The dynamic characteristic of rain fade slope is one important factor in determining the availability of a communication system, and it is very useful in the design of fade countermeasures. In the literature, many models were proposed for rain fade slope for earth-to-satellite links. However, there are no models available for rain fade point to point terrestrial microwave links. This paper proposes a new model for the estimation of rain fade slope statistics for terrestrial microwave links in tropical regions. First, the ITU-R model for rain fade slope for earth-to-satellite link was compared with the corresponding statistics obtained from rain attenuation data measured from three terrestrial links in Malaysia. It is found that the expression of its distribution and its standard deviation should be modified. This leads to the derivation of the proposed rain fade slope model based on the statistics of one link. Then, it is tested using the remaining data and its results were very close to the measured statistics for all attenuation levels higher than 1 dB. Moreover, the model was validated using the chi-square goodness-of-fit test.

中文翻译：

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地面微波链路的雨衰斜率模型

雨衰斜率的动态特性是决定通信系统可用性的重要因素之一，在衰落对策的设计中非常有用。在文献中，提出了许多用于地对卫星链路的雨衰斜率的模型。但是，没有可用于雨衰点对点地面微波链路的模型。本文提出了一种新的热带地区地面微波链路雨衰斜率统计估计模型。首先，将地对卫星链路雨衰斜率的 ITU-R 模型与从马来西亚三个地面链路测量的雨衰数据中获得的相应统计数据进行了比较。发现需要修改其分布及其标准差的表达式。这导致基于一个链路的统计推导所提出的雨衰斜率模型。然后，使用剩余数据对其进行测试，其结果非常接近所有高于 1 dB 衰减水平的测量统计数据。此外，该模型使用卡方拟合优度检验进行了验证。