The evaluation of physical layer concepts under realistic channel conditions is important for designing mobile communication systems. In this context the physical layer demonstrator UMICore has been developed which allows for the demonstration and visualization of any physical layer concept (e.g. HSPA, UMTS LTE or WiMAX). Apart from various statistical channel models, channel measurements can be used for even more realistic transmission. UMICore enables an interactive adaptation of physical layer parameters (e.g. code rate or modulation scheme) and channel settings. The transmission is visualized by live plots of signal constellations, bit error rate, throughput and channel impulse responses, amongst others.