Massive MIMO-Enabled Full-Duplex Cellular Networks

We provide a theoretical framework for the study of massive multiple-input multiple-output (MIMO)-enabled fullduplex (FD) cellular networks in which the residual selfinterference (SI) channels follow the Rician distribution and other channels are Rayleigh distributed. In order to facilitate bi-directional wireless functionality, we adopt (i) in the downlink (DL), a linear zero-forcing with self-interference-nulling (ZFSIN) precoding scheme at the FD base stations (BSs), and (ii) in the uplink (UL), a self-interference-aware (SIA) fractional power control mechanism at the FD mobile terminals (MTs). Linear ZF receivers are further utilized for signal detection in the UL. The results indicate that the UL rate bottleneck in the FD baseline single-input single-output (SISO) system can be overcome via exploiting massive MIMO. On the other hand, the findings may be viewed as a reality-check, since we show that, under state-ofthe- art system parameters, the spectral efficiency (SE) gain of FD massive MIMO over its half-duplex (HD) counterpart is largely limited by the cross-mode interference (CI) between the DL and the UL. In point of fact, the anticipated two-fold increase in SE is shown to be only achievable when the number of antennas tends to be infinitely large.