Average AoI in Pinching Antenna-Assisted WPCNs With Probabilistic LoS Blockage

This paper analyzes the age of information (AoI) for a pinching antenna (PA)-assisted wireless powered communication network (WPCN) with probabilistic line-of-sight (LoS) blockage. AoI is a key metric for evaluating the freshness of information, and its optimization is crucial for ensuring the performance of time-critical applications. To facilitate analysis and gain useful insights, we consider a representative scenario, where an IoT device harvests energy from a base station (BS) equipped with a PA and transmits data packets to it. In particular, a PA is deployed along the waveguide to achieve directional wireless power transmission (WPT) and wireless information transmission (WIT), thereby enhancing energy harvesting (EH) efficiency and communication reliability. A “harvest-then-transmit” protocol is designed for the IoT device. The IoT device harvests energy via the PA until its capacitor is fully charged, then transmits status updates using all stored energy. We derive closed-form expressions for the average AoI by analyzing the capacitor charging time, transmission success probability, and inter-arrival time of successful updates. To minimize the average AoI, we formulate an optimization problem of PA position, and propose a one-dimensional search to solve it. The simulation results show that the optimal PA position deviates from the position closest to the IoT device. Moreover, the PA-assisted systems significantly outperform the conventional fixed-antenna systems.