Uplink Rate Maximization for Pinching Antenna- Assisted Covert Backscatter Communication

Abstract: The emerging pinching antenna (PA) technology enables flexible antenna positioning for creating line-of-sight (LoS) links, thus offering substantial potential to facilitate ambient signal-based backscatter communication (BSC). This paper investigates PA-assisted BSC for enhanced communication and covertness in the presence of a randomly distributed eavesdropper. An optimization problem is formulated to maximize the uplink covert transmission rate by jointly optimizing the transmit power and antenna positions while satisfying both communication reliability and covertness constraints. An alternative optimization (AO)-based framework is proposed to solve this problem. Numerical results demonstrate that the proposed PA-BSC effectively mitigates the double near-far problem, where energy harvesting and backscatter transmission degrade simultaneously due to distance disparities, thereby improving downlink energy harvesting and uplink data transmission while maintaining covertness performance under practical deployment scenarios.