Time-Constrained UAV-Aided Data Collection for IoT Networks with Energy Harvesting.

This work investigates the time-constrained unmanned aerial vehicle (UAV) aided data collection problem for Internet of Thing (IoT) networks, where multiple IoT devices (IoTDs) harvest the solar energy and send their sensed data to the UAV in the uplink by applying the time division multiple access (TDMA) method. Specifically, we propose to maximize the total number of served IoTDs in a finite data gathering period via optimizing the trajectory of UAV, the time allocation and transmitting power of IoTDs under the UAV's maximum flight speed constraint, and the energy harvesting neutralization constraint of every IoTD. To tackle this non-linear integer programming, we first convert it into an equivalent tractable problem by adding the deductive penalty into the target function, and develop the time-constrained UAV-assisted data collection algorithm (TCDCA) to achieve a sub-optimal solution by exploiting the alternating optimization, successive convex approximation (SCA) and quadratic approximation methods. Subsequently, abundant simulations results are provided to confirm that the TCDCA is able to notably enhance the total number of served IoTDs compared to the conventional scheme with constant trajectory or constant time allocation.