Investigation of Channel Correlation in Indoor Wideband Massive MIMO Systems

This study investigates the channel correlation and the power delay profile (PDP) of the propagation channels in wideband massive MIMO networks through measurements on prototypes under certain circumstance. To this purpose, an antenna array for the base station (BS) and the single directional antenna for the user equipments (UE) are designed and fabricated. In the setting up for the measurement, the UEs are located at different locations in an office in order to produce various realistic channel propagation scenarios. The results show that the channel correlation is heavily related to the locations of the UEs and the propagation environment, for example, closely located UEs in line-of-sight (LOS) have strong channel correlations. On the other hand, when the UEs are far away or being in a non-line-of-sight (NLOS) situation, a low-level channel correlations are observed even with closely placed antenna elements at the BS array.