A Contract-Based Mobile Charging Scheme for Wireless-Powered Sensors in Industrial Internet of Things Networks

Industrial Internet of Things (IIoT) has provided intelligent industrial operations by leveraging the ubiquity of radio-frequency identification (RFID) and sensor devices. However, a wide range of deployment of IIoT accounts for a considerable amount of energy consumption. Mobile charging is a promising approach to charge low-power IIoT sensors for energy replenishment. In this paper, we consider a mobile charging IIoT network consisting of multiple mobile chargers that can travel through preplanned paths to charge a set of target sensors in the monitoring area. In practice, the limited energy capacity of the mobile chargers constrains their travel time. Thus, the aim of the mobile chargers is to charge more sensors with as less energy as possible. Nonetheless, the mobile chargers might not be aware of the truthful energy demand of the sensors due to information asymmetry. E.g., even if the sensors have sufficient energy to perform their operations, they might report that their current energy level is low with a motivation to receive more energy from the chargers. Information asymmetry leads to other low-power sensors being undercharged and affects the network lifetime. Motivated by this, we develop a contract theory-based mobile charging scheme for the low-power sensors in IIoT network. The optimal contract is derived to maximize the mobile chargers’ utility while meeting the sensors’ interests. Simulation results indicate that our proposed scheme can significantly improve the charging utility than the other mobile charging scheme.