Outage Performance Analysis of Multi-Antenna Full-Duplex NOMA Cellular Systems

We consider a full-duplex (FD) cellular network, where uplink (UL) and downlink (DL) transmissions are performed at the same time over the same frequency band by using the non-orthogonal multiple-access (NOMA) technique. By leveraging the zero-forcing (ZF) beamforming at the FD multi-antenna base station, self-interference is mitigated, and the instantaneous sum rate of the system is maximized. More specifically, we propose two ZF-based beamforming designs at the base station, namely receive ZF (RZF) and transmit ZF (TZF) scheme, which respectively utilize the receive and transmit antennas at the BS to cancel out the SI at the BS. We derive closed-form expression for the outage probability of the NOMA near and far users as a function of different system parameters. Finally, we examine the accuracy of the results by using extensive simulation results. Our numerical results show that for both TZF and RZF scheme, increasing the number of transmit and receive antenna is beneficial to improve the outage performance of the DL near user, while increasing the number of transmit and receive antenna significantly improve the outage performance of the DL far user with RZF scheme.