Design and Analysis of a New Massive MIMO Cell-Edge-Aware Precoding Scheme

In this paper, we propose cell-edge-aware (CEA) zero forcing (ZF) precoding for downlink massive MIMO cellular networks. The CEA-ZF precoder exploits the excess spatial degrees of freedom available at massive MIMO base stations (BSs) to suppress inter-cell interference at the most vulnerable neighboring users. We demonstrate that the CEA-ZF precoder outperforms a conventional cell-edge-unaware (CEU) ZF precoder in terms of (i) downlink data rate per cell, (ii) coverage probability, and (iii) 95%-likely rate. In a network with random topology, when both perfect channel state information and a large number of antennas N are available at the BSs, we find that the outage probability with CEA-ZF and CEU-ZF decay as 1/N^2 and 1/N, respectively. Our analysis and simulations also confirm the necessity to control the amount of pilot contamination received during the channel estimation phase.