  A novel approach that combines visible light communication (VLC) with
unmanned aerial vehicles (UAVs) to simultaneously provide flexible
communication and illumination is proposed. To minimize the power consumption,
the locations of UAVs and the cell associations are optimized under
illumination and communication constraints. An efficient sub-optimal solution
that divides the original problem into two sub-problems is proposed. The first
sub-problem is modeled as a classical smallest enclosing disk problem to obtain
the optimal locations of UAVs, given the cell association. Then, assuming fixed
UAV locations, the second sub-problem is modeled as a min-size clustering
problem to obtain the optimized cell association. In addition, the obtained UAV
locations and cell associations are iteratively optimized multiple times to
reduce the power consumption. Numerical results show that the proposed approach
can reduce the total transmit power consumption by at least 53.8% compared to
two baseline algorithms with fixed UAV locations.
