The use of the low-frequency scattering coefficient leads to inaccurate receiving-power predictions in the millimeter-wave band. The inaccurate signal will hinder optimization of the base station location. In the millimeter waveband, a building surface becomes rougher in an urban environment. The scattering becomes increasingly significant and a non-negligible factor. In this article, the scattering characteristics of rough cement wall surfaces are studied to improve the scattering coefficients for millimeter waveband communications. The ray tracing method is adopted, and the lambertian and directive models are incorporated into this method, respectively. Moreover, the signal distributions of rough cement wall surfaces are acquired through an outdoor experiment at different incidence angles. The results reveal that the scatterings that are embedded into ray tracing are better than those which were not considered in the ray tracing, compared with the experiment. The directive model agrees more with the measurements than the lambertian model. The scattering coefficient S and exponent α_R of the directive model are 0.19 and 1 in the millimeter waveband, respectively, which disagree with the results at low frequencies. The scattering properties can be applied to simulate signal propagation in urban environments to improve the reliability of mobile telecommunication systems.

中文翻译：

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毫米波段城市环境水泥表面散射特性的测量与分析

低频散射系数的使用会导致毫米波段中的接收功率预测不准确。不准确的信号会阻碍基站位置的优化。在毫米波段，城市环境中的建筑物表面变得更加粗糙。散射变得越来越重要并且是不可忽略的因素。本文研究了粗糙水泥墙表面的散射特性，以提高毫米波段通信的散射系数。采用光线追踪法，将朗伯模型和定向模型分别纳入该方法。此外，通过室外实验获得了不同入射角下粗糙水泥墙面的信号分布。结果表明，与实验相比，嵌入射线追踪的散射优于未在射线追踪中考虑的散射。指令模型比朗伯模型更符合测量结果。散射系数指令模型的S和指数α _R在毫米波段分别为 0.19 和 1，与低频下的结果不一致。散射特性可用于模拟城市环境中的信号传播，以提高移动电信系统的可靠性。