  In this paper, we present the delay-constrained performance analysis of a
multi-antenna-assisted multiuser non-orthogonal multiple access (NOMA) based
spectrum sharing system over Rayleigh fading channels. We derive analytical
expressions for the sum effective rate (ER) for the downlink NOMA system under
a peak interference constraint. In particular, we show the effect of the
availability of different levels of channel state information (instantaneous
and statistical) on the system performance. We also show the effect of
different parameters of interest, including the peak tolerable interference
power, the delay exponent, the number of antennas and the number of users, on
the sum ER of the system under consideration. An excellent agreement between
simulation and theoretical results confirms the accuracy of the analysis.
