  In order to overcome the inherent latency in multi-user unmanned aerial
vehicle (UAV) networks with orthogonal multiple access (OMA). In this paper, we
investigate the UAV enabled uplink non-orthogonal multiple access (NOMA)
network, where a UAV is deployed to collect the messages transmitted by ground
users. In order to maximize the sum rate of all users and to meet the quality
of service (QoS) requirement, we formulate an optimization problem, in which
the UAV deployment position and the power control are jointly optimized. This
problem is non-convex and some variables are binary, and thus it is a typical
NP hard problem. In this paper, an iterative algorithm is proposed with the
assistance of successive convex approximate (SCA) technique and the penalty
function method. In order to reduce the high computational complexity of the
iterative algorithm, a low complexity approximation algorithm is then proposed,
which can achieve a similar performance compared to the iterative algorithm.
Compared with OMA scheme and conventional NOMA scheme, numerical results show
that our proposed algorithms can efficiently improve the sum rate.
