Offloading Wireless Energy Harvesting for IoT Devices on Unlicensed Bands

Because the number of Internet of Things (IoT) devices has increased dramatically in both licensed and unlicensed band networks, wireless networks on licensed bands for the IoT, such as Long Term Evolution (LTE), are expected to become overloaded. Wireless energy harvesting in IoT networks also needs to be offloaded from existing licensed bands like LTE and onto unlicensed bands, such as wireless fidelity (WiFi). This paper proposes offloading channel resources from licensed bands to unlicensed bands for wireless IoT-device energy harvesting. Our proposed scheme is based on the licensed-assisted access protocol for transferring power packets as well as information. We propose a queueing model for energy storage in IoT devices and consumption behavior in batteries, and we propose a probability model of empty energy. Simulation proves that our proposed offloading scheme works properly for harvesting wireless energy through a 5-GHz unlicensed channel without affecting the performance of WiFi stations for IoT devices.