Spatial modulation (SM) as a multiple-input multiple-output (MIMO) technique is a solution suitable which offers, with low system complexity and cost, improved spectral efficiency compared to singleinput-single-output (SISO) systems. Moreover, the transmission chain is simplified which decreases energy consumption. This paper aims to analyze the SM system transmission under different line-of-sight/non-lineof-sight (LOS/NLOS) propagation scenarios. The analysis of the SM system performance is based on both simulations and experimental results and the bit error rate (BER) is tackled. Concerning the experimental results, two strategies are considered in order to configure the propagation channel. One method consists in constructing a controlled propagation environment. More precisely, the multipath channel's Rician K-factor is imposed by configuring the power levels of the LOS and of the NLOS components. The second method consists in performing over-the-air transmissions on a realistic propagation channel. A channel sounding method allows us to measure the channel characteristics. The experimental results are confronted with the system-level simulation results, good agreement between experimental and simulation results are obtained. The results show that the SM system can maintain the performance in multipath propagation in the presence of indirect paths for both two proposed propagation environments.