Abstract:
In this paper, we present a novel framework to
maintain coverage continuity in a unmanned aerial vehicle
(UAV)-assisted wireless communication system, when a serving UAV runs out of energy. Service continuity is maintained
by launching another fully charged UAV to replace the
existing serving UAV. This replacement process must ensure
maximal coverage to all ground users. Our objective during
this replacement process is to maximize the achievable sum
rate of all ground users by jointly optimizing the threedimensional (3D) multi-UAVs trajectory and resource allocation to the users from the individual UAVs. This is carried
out in the presence of the UAV’s constraints on velocity,
collision avoidance, and energy availability while considering
a more practical and accurate probabilistic line-of-sight (LoS)
channel model. This results in a non-convex optimization
problem for which an efficient iterative algorithm based on
successive convex approximation and alternating optimization
is proposed. Numerical results are provided to obtain insights
on the UAV trajectories and the effectiveness of the proposed
scheme compared to the existing benchmark schemes is
shown
