Multipath fading channel simulators are essential components of wireless systems physical layer simulations. This white paper presents a MATLAB-based approach to multipath fading channel simulation.
Section II presents an overview of popular methodologies for the simulation of multipath fading channels. Two effects must be simulated: the time selectivity of the channel (Doppler spreading) due to motion, and the frequency selectivity (time spreading) due to resolvable multipath components. Simulation approaches are reviewed for both these tasks.

Section III presents an overview of the simulation methodology used in our channel simulator. The simulator employs an interpolated filtered Gaussian noise source to simulate the Doppler spreading, followed by a bandlimited channel transformation to efficiently simulate the multipath dispersion. Both Rayleigh and Rician processes can be generated, for a set of different Doppler spectra.

Section IV presents the application programming interface (API) of the Communications Toolbox's channel functions, along with channel object properties. Examples illustrate how to create channel objects, use them in a simulation, and visualize simulation quantities using the channel visualization tool.

Simulation examples are given in Section V. The statistical performance is evaluated in terms of the simulated fading processes' probability distributions, Doppler spectra and autocovariances.