Introduction to Technical Seminar Presentation on Radio Propagation Models for Mobile Communication:
We need to design such system that will catch transmitted signal transmitted from the transmitter and in the way it is distorted due to dispersion effect on the channel, that will be decoded back to transmitted signal. Dispersion can also be though indoor walls, when electromagnetic radiations fall on the wall the power of the radiation get less.
Ray tracing technique: it is generally based on the geometrical optics. According to the law ray follow shortest path between source and destination. When high frequency ray fall on the surface they produce reflection, refraction and diffraction. There are two types of ray-tracing methods, Image method and brute-force methods.
Image method: this technique generates the image of the source. They can be only used to handle simple environments. Rooftop rays are neglected. This image serves as secondary sources for point of reflection.
Brute force methods: they are used group of rays that may reach receiver or may not reach. In these methods rays are transmitted in different direction but with same vector angle. The original ray gets decomposed as an object penetrated rays.
FDTD model: this technique is accurate and but it consumes large computer memory. They are used transmitter and receivers are close to structures with complex material.
Moment method model: they are used when the building size is small and the precision required is higher.
Artificial neural network: it is used for fast evaluation as it is based on parallelism.
Ray tracing model: they have the capability to incorporate antenna radiations pattern.
VPR model: they use some virtual reflection points (VRF), that may be located at the intersection point of the land at the streets and the buildings walls. They do not consider the effects of traffic and movement of human.
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