  Due to the large power consumption in RF-circuitry of massive MIMO systems,
practically relevant performance measures such as energy efficiency or
bandwidth efficiency are neither necessarily monotonous functions of the total
transmit power nor the number of active antennas. Optimal antenna selection is
however computationally infeasible in these systems. In this paper, we propose
an iterative algorithm to optimize the transmit power and the subset of
selected antennas subject to non-monotonous performance measures in massive
multiuser MIMO settings. Numerical results are given for energy efficiency and
demonstrate that for several settings the optimal number of selected antennas
reported by the proposed algorithm is significantly smaller than the total
number of transmit antennas. This fact indicates that antenna selection in
several massive MIMO scenarios not only reduces the hardware complexity and
RF-costs, but also enhances the energy efficiency of the system.
