RIS-Enhanced Wireless Powered MEC Networks: A Stackelberg Game-Based Energy Trading Framework

A reconfigurable intelligent surface (RIS) enhanced wireless powered mobile edge computing (MEC) network is considered, where an energy station (ES) first provides wireless charging to a passive Internet of Things device (IoTD), and then the IoTD leverages the collected energy for local computing and task offloading. We introduce an RIS to boost power transfer and task offloading efficiency by customizing an intelligent and controllable radio environment. A partial offloading (PO) scheme is proposed, where an energy trading framework is created based on Stackelberg game under the condition that the IoTD and ES are owned by two respective service suppliers. Specifically, the IoTD is required to provide payments to trade ES’s charging service, where the IoTD serves as a leader to maximize the difference between total computing bits’ revenues and charging payments, while the ES serves as a follower to maximize the difference between charging payments and charging costs. Through backward induction, the follower-level decision problem is first solved, and then the leader-level decision problem is processed via a block coordinate descent algorithm. Simulation results show that the proposed PO scheme obtains higher IoTD’s utilities than the full task offloading and full local computing schemes.