  We propose a cell-edge-aware (CEA) zero forcing (ZF) precoder that exploits
the excess spatial degrees of freedom provided by a large number of base
station (BS) antennas to suppress inter-cell interference at the most
vulnerable user equipments (UEs). We evaluate the downlink performance of
CEA-ZF, as well as that of a conventional cell-edge-unaware (CEU) ZF precoder
in a network with random base station topology. Our analysis and simulations
show that the proposed CEA-ZF precoder outperforms CEU-ZF precoding in terms of
(i) aggregate per-cell data rate, (ii) coverage probability, and (iii)
95%-likely, or edge user, rate. In particular, when both perfect channel state
information and a large number of antennas N are available at the BSs, we
demonstrate that the outage probability under CEA-ZF and CEU-ZF decay as 1/N^2
and 1/N, respectively. This result identifies CEA-ZF as a more effective
precoding scheme for massive MIMO cellular networks. Our framework also reveals
the importance of scheduling the optimal number of UEs per BS, and confirms the
necessity to control the amount of pilot contamination received during the
channel estimation phase.
