In most environments, wireless channels consist of multiple paths due to various propagation mechanisms such as diffraction, reflections and scattering. In mobile environments, paths of similar delay can combine to cause a time-varying fading gain. In this lab, we show how to model, simulate and measure these multi-path fading channels. For measuring the channel, we will build a simple channel sounder -- a basic device for measuring channel response between a TX and RX. The channel sounder will be built first in simulation and then on a simple SDR. The digital communications class covered a simpler version of the channel sounder with a static channel.
In doing this lab, you will learn to:
- Describe cluster-delay line (CDL) models
- Get parameters for 5G CDL models using the 5G MATLAB toolbox
- Represent antenna orientations using global and local frames of reference
- Compute directional gains on paths from the angles
- Simulate multi-path fading channels with directive antennas
- Perform simple time-frequency channel sounding
- Implement the channel sounding experiments on a simple USRP
The lab has the following files:
multiPathLab.mlx: Main file to run the labChanSounder.m: A class for performing the TX and RX functions of the channel sounderSIMOMPChan.m: A class for emulating the multi-path channel for a single-input single-output (i.e., one antenna)ElemWithAxes.m: A class for modeling the orientation of the antenna elements