Sum-throughput maximization for UAV-aided energy-harvesting WBANs: Hovering altitude design, power control and time allocation

UAV-aided energy-harvesting WBANs where sensor nodes can harvest RF energy transmitted by a UAV have attracted considerable attention. However, how to maximize the sum-throughput of the sensor nodes with cross-tier interferences from satellite and cellular systems has not been addressed. In order to bridge this gap, we devote this paper to developing two schemes with the fixed or variable duration of the energy-harvesting phase. Specifically, we formulate two non-convex optimization problems corresponding to the two schemes, and transform them to tractable subproblems, and accordingly two algorithms are proposed named HA-PC-TA and UAVPC-TA. In particular, we derive the closed-form optimum transmit power and time allocation for the sensor nodes and obtain the optimum UAV's hovering altitude in HA-PC-TA. We reveal the relationship between the optimum parameters and the allowed maximum transmit power of the VAU in UAVPC-TA. Finally, the simulations are conducted to validate the effectiveness of our proposed solutions.