Discussion of physical models of wireless channels through some simplified examples, which reveal some key features of wireless channels.
Dates: Wed, Jan 10 - Wed, Jan 17
Learning Outcomes
Physical models of wireless channels
You know how to derive the physical model of wireless channels using the ray tracing method.
You understand the key features of a wireless channel: small-scaling fading, large-scale fading, Doppler shift, delay spread, coherence distance, coherence time, and coherence bandwidth.
You understand what factors result in these features (e.g., moving transmitter and/or receiver result in Doppler shift, multipath results in delay spread).
You can implement the ray tracing method in Python, and use numerical simulation to study more realistic wireless channels.
Readings
Roadmap of this module
Overview
Case 1: Fixed antennas in the free space
Two antennas in the space of nothingness
Case 2: Antennas start moving...
Moving antennas create Doppler shift
Case 3: A wall enters the space
Reflection creates delay spread
Case 4: Reflecting wall and moving antennas
Doppler spread and coherence time
Practical propagation environments
Complicating factors in practice
Experiential Learning
Coherence distance and coherence bandwidth
Simulation for fixed antennas with a reflecting wall
Doppler spread and coherence time
Simulation for moving antennas with a reflecting wall