Objectives of the course
The content of the course is organized in a way that fits the actual position of a communication engineer. As a consequence the course does not have a too applicative planning (useful in practice, but limited and useless in the education) neither a too theoretical one (one can get to the bottom of a specific topic through the scientific literature). The result is a course where, first, the physic of the phenomena is duly introduced and, second, the theory behind them is addressed.
The electromagnetic spectrum: frequency bands and spectrum management.
Characterization of the radio channel in terms of single and multiple wave components: direct, reflected, diffracted and diffused waves; wave polarization.
Wave propagation in real environment. The ionosphere, the non-ionized atmosphere, and the ground. Physical characterization of the medium and electromagnetic description.
Propagation in the ionosphere and impact on Global Navigation Satellite Systems (GNSS). Refraction, attenuation, Faraday rotation, phase and group delay. The role of the Earth magnetic field.
Propagation in the presence of ground: the ground wave: direct, reflected, surface and evanescent wave components, knife edge diffraction.
Propagation in the non-ionized atmosphere (troposphere) and impact on radio relay links, and Earth to space (HAPs, LEO, MEO, GEO satellites, Deep Space probes) links. Clear air propagation: refraction, attenuation and scintillation. Propagation through clouds. Adverse weather disturbances: attenuation, depolarization, electromagnetic interference due to hydrometeors.
Effects of the ground: the ground wave: direct, reflected, surface and evanescent wave components, knife edge diffraction.
Atmospheric and extra-atmospheric noise sources. Impact on the signal detection.
Statistical characterization of the radio channel: the link budget. Fade mitigation techniques (i.e. site, frequency and time diversity, link power control)
Free space optical wave propagation: the optical channel, transmitters and receivers. Advantages and limitations of FSO. Impairments due to hydrometeors (fog and clouds), and to clear air (turbulence). Applications: ground links, Earth to space links.
Indoor applications: Visible Light Communication (VLC).