MaMIMO User Grouping Strategies: How much does it matter?

In a Massive MIMO communication system, a large number of antennas increases the spectral efficiency; however, if this number is fixed, then the number and selection of users influence the performance of the system. In this work, an ultra-dense massive MIMO channel database is obtained for different antenna geometries, centralised and distributed scenarios, and propagation conditions. The greedy search selection of multiple users to form a group is analysed under capacity and simplified heuristic approximations. Experimental results show that the grouping strategy has a significant impact on the nLoS scenario only when a small number of users is served (multiplexing regime). However, in LoS cases, the distribution of the base station antennas has a higher impact on the system performance than the selection of the users.