A Comparison Between Concentrated and Distributed Massive MIMO Channels at 26 GHz in a Large Indoor Environment Using Ray-Tracing

In this paper, a comparative analysis between concentrated and distributed massive multiple-input multiple-output channels (C-mMIMO and D-mMIMO respectively), in an indoor environment using ray-tracing (RT) in the 26 GHz band is presented. The comparison is carried out in a realistic scenario consisting of a floor of a large building. The simulations emulated the up-link channel in an indoor cell in the framework of a time division duplex (TDD) - orthogonal frequency division multiplexing (TDD-OFDM) system. Both base stations, concentrated and distributed, were equipped with an array consisting of 100 antennas, and the maximum number of 20 simultaneously active users is considered. The channels are simulated using a well-tested and rigorous RT software. Using RT channel modeling, this work characterizes the up-link channels with both technologies, estimating the coherence bandwidth of the channels and analyzing the achievable capacity, assuming perfect channel state information (CSI). The results show that the D-mMIMO channel outperforms the C-mMIMO one from the point of view of their behavior in broadband as well as in terms of the obtainable capacity.