This paper presents the design of an 8×8 Multiple-Input Multiple-Output (MIMO) hardware simulator for time-varying propagation channels using heterogeneous systems (LTE-A and 802.11ac) with Visible Light Communications (VLC) signals. A new specific architecture of the simulator digital block is presented to characterize 5G scenarios. It is designed and implemented on a Xilinx Virtex-VII XC7VX690T Field Programmable Gate Array (FPGA). The simulator uses different impulse responses to cover many types of channels by merging TGn models, 3GPP-LTE models, outdoor-to-indoor measurements results and VLC models. The accuracy of the architecture, its FPGA occupation and latency are analyzed.