  We consider a cooperative non-orthogonal multiple access (NOMA) network in
which a full-duplex (FD) multi-antenna relay assists transmission from a base
station (BS) to a set of far users with poor channel conditions, while at the
same time the BS transmits to a set of near users with strong channel
conditions. We assume imperfect self-interference (SI) cancellation at the FD
relay and imperfect inter-user interference cancellation at the near users. In
order to cancel the SI at the relay a zero-forcing based beamforming scheme is
used and the corresponding outage probability analysis of two user selection
strategies, namely random near user and random far user (RNRF), and nearest
near user and nearest far user (NNNF), are derived. Our finding suggests that
significant performance improvement can be achieved by using the FD
multi-antenna relay compared to the counterpart system with a half-duplex
relay. The achieved performance gain depends on network parameters such as the
user density, user zones, path loss and the strength of the inter-user
interference in case of near users. We also show that the NNNF strategy
exhibits a superior outage performance compared to the RNRF strategy,
especially in the case of near
