  This paper studies unmanned aerial vehicle (UAV) aided wireless communication
systems where a UAV supports uplink communications of multiple ground nodes
(GNs) while flying over the area of the interest. In this system, the
propulsion energy consumption at the UAV is taken into account so that the
UAV's velocity and acceleration should not exceed a certain threshold. We
formulate the minimum average rate maximization problem and the energy
efficiency (EE) maximization problem by jointly optimizing the trajectory,
velocity, and acceleration of the UAV and the uplink transmit power at the GNs.
As these problems are non-convex in general, we employ the successive convex
approximation (SCA) techniques. To this end, proper convex approximations for
the non-convex constraints are derived, and iterative algorithms are proposed
which converge to a local optimal point. Numerical results demonstrate that the
proposed algorithms outperform baseline schemes for both problems. Especially
for the EE maximization problem, the proposed algorithm exhibits about 109 %
gain over the baseline scheme.
