UAV-assisted data collection for wireless sensor networks with dynamic working modes

Wireless Sensor Network (WSN) is a cornerstone of Internet of Things (IoT) and has rich application scenarios. In this work, we consider a heterogeneous WSN whose sensor nodes have a diversity in their Residual Energy (RE). In this work, to protect the sensor nodes with low RE, we investigate dynamic working modes for sensor nodes which are determined by their RE and an introduced energy threshold. Besides, we employ an Unmanned Aerial Vehicle (UAV) to collect the stored data from the heterogeneous WSN. We aim to jointly optimize the cluster head selection, energy threshold and sensor nodes' working mode to minimize the weighted sum of energy consumption from the WSN and UAV, subject to the data collection rate constraint. To this end, we propose an efficient search method to search for an optimal energy threshold, and develop a penalty-based successive convex approximation algorithm to select the cluster heads. Then we present a low-complexity iterative approach to solve the joint optimization problem and discuss the implementation procedure. Numerical results justify that our proposed approach is able to reduce the energy consumption of the sensor nodes with low RE significantly and also saves energy for the whole WSN.