Nonlinear Distortion in Distributed Massive MIMO Systems: An Indoor Channel Measurement Analysis

In this paper, we experimentally analyze the spatial distribution of nonlinear distortion in massive MIMO systems with various array topologies and user locations. With an indoor channel measurement, we reveal the spatial distortion distribution of the in-band (IB) and out-of-band (OOB) power leakage in a real-life scenario. We further investigate the power leakage under different antenna array topologies: including uniform linear array (ULA), uniform rectangular array (URA), distributed linear subarrays (DIS). The impact of user location on the per antenna distortion is also visualized. The results indicate that the DIS array configuration achieves the lowest in-band and out-of-band power leakage, which renders the distributed array a potential to reduce the linearity requirement of PAs when scaling up a practical massive MIMO system.