In the previous module, we describe the physical model of the wireless channel. Now we can integrate the channel model into the system.

In particular, we will introduce the input/output model of the channel. In short, we can view the channel as a linear filter. Then the received signal, as the output of the filter, is the convolution of the input, namely the transmitted signal, and the channel impulse response.

Such a model is the foundation for the analysis. You will see this model in almost every research paper on wireless communications.