阐述了一种三维电波传播模型来预测城市环境下的传播损耗．该模型建立在几何光学理论和几何绕射理论的基础上，模型考虑了地面和墙壁的反射，建筑物墙角和屋顶的绕射，计算出非视距区域的路径传播损耗 A three-dimensional radio propagation model is presented to predict the propagation loss in an urban environment. The model is based on the geometrical optics theory and the theory of geometrical diffraction. The model considers the reflection of the ground and the wall, the corner of the building and the diffraction of the roof, and calculates the path propagation loss in the NLOS area