  In this paper, we investigate downlink power control in massive
multiple-input multiple-output (MIMO) networks with distributed antenna arrays.
The base station (BS) in each cell consists of multiple antenna arrays, which
are deployed in arbitrary locations within the cell. Due to the spatial
separation between antenna arrays, the large-scale propagation effect is
different from a user to different antenna arrays in a cell, which makes power
control a challenging problem as compared to conventional massive MIMO. We
assume that the BS in each cell obtains the channel estimates via uplink
pilots. Based on the channel estimates, the BSs perform maximum ratio
transmission for the downlink. We then derive a closed-form spectral efficiency
(SE) expression, where the channels are subject to correlated fading. Utilizing
the derived expression, we propose a max-min power control algorithm to ensure
that each user in the network receives a uniform quality of service. Numerical
results demonstrate that, for the network considered in this work, optimizing
for max-min SE through the max-min power control improves the sum SE of the
network as compared to equal power allocation.
