In recent decades, the world of telecommunications has experienced significant development, thanks to the success of 2G mobile communications systems and the widespread deployment of the Internet. The transition to 4G enables the integration of multiple services such as multimedia, packet switching and broadband radio access. In this context, MIMO (Multiple-Input Multiple-Output) technology is recognized as a good solution in the development of the next generations of broadband wireless networks. This technique is very attractive for digital communications, allowing increased data rates and/or improved system performance. The aim of this work is to highlight different aspects that concern the simulation and modeling of the propagation channel, which are particularly critical in the design of MIMO systems.