A channel model is an essential piece of a physical layer communication simulation. It is a mathematical representation of the effects of a communication channel through which wireless signals are propagated. The channel model is the impulse response of the channel medium in the time domain or its Fourier transform in the frequency domain. In general, the channel impulse response varies randomly over time.
Many factors are considered in building a channel model, such as carrier frequency, bandwidth, the locations of transmitter and receiver, Doppler frequency, medium type, RF polarization, weather conditions, and noise types. Selecting a channel model is a tradeoff between computational efficiency and model fidelity.
Communications System Toolbox™, WLAN System Toolbox™, LTE System Toolbox™, Phased Array System Toolbox™ and 5G Library offer a variety of channel models. These include AWGN, free space path loss, weather-related propagation models, Rayleigh, Rician, MIMO channel, generalized standard-compliant channels, WINNER II channel model, WLAN channels (TGn, TGac, and TGah), LTE multipath fading channel, and 5G channel. For example, using WINNER II channel model, you can model and simulate spatially defined channels for multi-user MIMO wireless systems.
The models can be parameterized by channel bandwidth, carrier frequency, Doppler frequency, fading channel profile, etc. The models are available as functions and System objects™ in MATLAB® and as blocks in Simulink®. These models can be used as a part of the design and simulation of your wireless communication systems. By using the right channel model in your design, you can optimize link performance, perform system architecture tradeoffs, and provide a realistic assessment of the overall system performance.
lteMovingChannel: Moving channel propagation conditions - Function
lteHSTChannel: High-speed train MIMO channel propagation conditions - Function