  We characterize the rate achievable in a bidirectional quasi-static link
where several user equipments communicate with a massive multiple-input
multiple-output base station (BS). In the considered setup, the BS operates in
full-digital mode, the physical size of the antenna array is limited, and there
exists a rate constraint on the fronthaul interface connecting the (possibly
remote) radio head to the digital baseband processing unit. Our analysis
enables us to determine the optimal resolution of the analog-to-digital and
digital-to-analog converters as well as the optimal number of active antenna
elements to be used in order to maximize the transmission rate on the
bidirectional link, for a given constraint on the outage probability and on the
fronthaul rate. We investigate both the case in which perfect channel-state
information is available, and the case in which channel-state information is
acquired through pilot transmission, and is, hence, imperfect. For the second
case, we present a novel rate expression that relies on the generalized
mutual-information framework.
