路径效应及分集接收 在无线通信系统中,地面对电波传播的影响主要表现在两个方面,一种是绕射效应,即电波传播空间的一部分或大部分被地面障碍物阻挡;一种是反射效应,即部分电波经过地面或地物反射后到达天线,因而形成电波的多径传播。这些地面的影响与路径的几何性质有直接的关系。 对于障碍路径,必须考虑可能出现的绕射衰减。对于由反射造成的多径衰落,唯一有效的办法就是在无线通信接收机中采用分集组合(diversity combining)技术。 Path effect and diversity reception In wireless communication system, the influence of the ground on the propagation of radio waves mainly in two aspects, one is the diffraction effect, that is, part or most of the radio wave propagation space is blocked by ground obstacles; one is The reflection effect, that is, part of the electric wave arrives at the antenna after being reflected by the ground or the ground object, thus forming a multipath propagation of the electric wave. The impact of these terrains is directly related to the geometric properties of the path. For obstacle paths, diffraction attenuation that may occur must be considered. For multipath fading caused by reflections, the only effective way is to adopt diversity combining techniques in wireless communication receivers.