In this work we apply the spectral divergence to characterize the (dis-)similarity of different links in wide-band multi-user multiple-input multiple-output (MU-MIMO) channels. The spectral divergence measures the distance between strictly positive, non-normalized spectral densities, such as the power delay profile. The measurement data has been acquired using Eurecom’s MIMO Openair Sounder (EMOS). The EMOS can perform real-time MIMO channel measurements synchronously over multiple users. For this work we have used a line-of-sight measurement with two transmit antennas and two users with two antennas each. We compare the spectral divergence of different links with respect to the distance of the users. We find that the spectral divergence can be quite low when the users are close together. These findings are important for MU-MIMO precoding and scheduling algorithms.
