Full-duplex versus half-duplex large scale antenna system

In this paper, we provide a unified framework for the study of multi-cell multi-user large-scale antenna system (LSAS) in both full-duplex (FD) and half-duplex (HD) modes of communications. Here, we employ the Poisson point process (PPP)-based abstraction model of massive-antenna base stations (BSs) and mobile terminals (MTs). The loop-back interference (LI) channels in FD mode are modeled using the Rician distribution with arbitrary statistics. All other channels are characterized using the unit-mean Rayleigh distribution, including the cross downlink (DL)-uplink (UL) interference (CI) in FD mode. The useful and interfering signals distributions under different linear conjugate-beamforming (CF) and zero-forcing (ZF) processes are derived. We develop analytical expressions for computing the LSAS DL and UL ergodic rates (ERs) and further study the performance gain of FD versus HD. The results highlight that the corresponding FD over HD ER gain increases logarithmically in the antenna array size. In addition, the anticipated two-fold improvement in ER is analytically shown to be only possible with an asymptotically large number of antennas.