Understanding Mobile Radio Propogation-3 — Lesson 3

This lesson covers the intricate details of mobile radio propagation mechanisms. It delves into the free space propagation model, small scale propagation model, and large scale propagation model. The lesson also explores the Log-Distance Path Loss Model, which is crucial in urban areas, and the Log-Normal Shadowing model, a more realistic model. The lesson further explains the impact of various factors such as reflection, diffraction, and scattering on signal strength and propagation. It also discusses the importance of propagation models in determining the coverage area of a transmitter, optimizing cell life, and predicting appropriate modulation and coding schemes.

Video Highlights

01:17 - Introduction to mobile radio propagation mechanisms and their importance in urban areas
03:13 - Explanation of diffraction and scattering models
05:14 - Discussion on the impact of propagation model on modulation and coding schemes
09:14 - Discussion on the impact of distance on received power and path loss
20:16 - Introduction to large scale and small scale propagation models
33:13 - Explanation of the log distance path loss model and log normal shadowing
41:57 - Discussion on the impact of environment on path loss exponent
46:18 - Explanation of log normal shadowing and its role in path loss

Key Takeaways

- Free space propagation model is valid in many applications and forms the basis for other models.
- Small scale propagation model is used when the mobile moves over small distances, causing the instantaneous received signal to fluctuate rapidly.
- Large scale propagation model is used when the mobile moves away from the transmitter over a large distance, causing the local average of the received signal to gradually decrease.
- Log-Distance Path Loss Model is important in urban areas where the received signal power decreases logarithmically with distance.
- Log-Normal Shadowing model is a more realistic model that takes into account the shadowing effects due to cluttering on the propagation path.