Enhancing Physical Layer Security in WPCNs With IRS and Controlled Jamming for 6G IoT Applications

This paper investigates the integration of an intelligent reflecting surface (IRS) and a jammer controlled interference to enhance the physical layer security (PLS) of wireless powered communication networks (WPCNs). In 6G networks, where low-power Internet of Things (IoT) devices are prevalent, security and energy efficiency are critical. While existing studies primarily focus on IRS-assisted methods to improve PLS by manipulating signal reflections, such approaches may not fully degrade the reception of eavesdroppers. We address this limitation by proposing an approach that combines IRS-assisted signal reflection with controlled jamming to further degrade the reception of eavesdroppers. Specifically, we jointly optimize the downlink/uplink time allocation, IRS phase shift matrices, and jamming interference to maximize the sum secrecy throughput. To address the non-convex nature of the problem, we develop an alternating optimization algorithm that decouples the problem into subproblems, ensuring efficient convergence to a locally optimal solution. Through detailed performance analysis, we demonstrate the superiority of our proposed scheme in terms of secrecy throughput and energy efficiency. Numerical results reveal that, compared to traditional IRS-assisted or non-jamming schemes, our approach yields substantial performance gains. This highlights the potential of integrating IRS and jamming to provide more secure and energy-efficient communication solutions for WPCNs, particularly in the context of 6G IoT applications.