Basic Methods of Propagation
They have an impact on the wave propagation in a mobile communication system. The most important parameter, Received power is predicted by large scale propagation models based on the physics of reflection, diffraction and scattering
Three Basic Propagation Mechanisms:
Occurs when a signal is transmitted, some of the signal power may be reflected back to its origin rather than being carried all the way. When reflection occurs, it can be seen that the angle of incidence is equal to the angle of reflection for a conducting surface as would be expected for light. When a signal is reflected there is normally some loss of the signal, either through absorption, or as a result of some of the signal passing into the medium.
Figure 1.14 Sketch of three important prorogations Mechanism
Occurs through Large buildings, earth surface
The apparent bending of waves around small obstacles and the spreading out of waves past small openings.
Occur through Obstacles with dimensions in order of lambda
It Is a general physical process where light, sound, or moving particles, are forced to deviate from a straight trajectory, by one or more localized non-uniformities, in the medium through which they pass
Occur through Obstacles with size in the order of the wavelength of the signal or less
Foliage, lamp posts, street signs, walking pedestrian, etc.