用射线跟踪法研究毫米波在微蜂窝中的传播特性

文中运用一种基于镜像理论的射线跟踪方法来预测工作频率为 62 .4GHz的微蜂窝信道的传播特性。该方法考虑了反射和绕射。预测结果表明当假设建筑物的表面是光滑并且忽略了大气中氧分子的吸收损耗时 ,预测的接收信号功率要比实际信号功率小 ,而考虑建筑物表面的粗糙度和氧分子的吸收损耗将改善预测精度。最大反射阶数为两阶并且忽略绕射射线的贡献就可以很好地预测微蜂窝的传播情况。当直射路径被阻挡时接收信号的强度会下降一个比较大的值 ,这种特性会影响微蜂窝的覆盖。

The Analysis of Millimeter-Wave Propogation Characteristics in Microcell Communications Ray-Tracing Method

Based on mirror image theory a ray-tracing method is employed to predict the propagation characteristics in 62.4 GHz microcell channels.It takes reflection and diffraction into account.The prediction results have shown that the predicated power of received signals is less than the practical one under the assumption of smooth building surfaces and the negligence of oxygen absorption whereas the prediction precision can be inproved taking into account of the coarseness of the building surfaces and oxygen absorption.While the maximam reflection coefficient up to the second order is found to be adequate to predicate microcell millimeter-wave propagation,the contribution of diffraction is negligible.If the direct path is blocked,the received signal level show a sharp drop.This will affect the radio coverage of microcells.