Exploiting multipath effects with ambient UHF RFID for intelligent shelf stock sensing

A critical challenge for physical retail stores is the frequent occurrence of out-of-stock (OOS) situations, which adversely affect both sales performance and the reputation of retail establishments. In this paper, we introduce an innovative methodology that exploits the multipath effect—typically considered a drawback in wireless communication—to estimate shelf availability without requiring item-level tagging or neatly arranged product placement, making it well-suited for cluttered or unstructured shelving conditions. By shifting the focus from tagging individual items to tagging the environment, this approach promises a substantial reduction in the overall costs associated with RFID hardware. The proposed system achieves a fill level prediction accuracy of up to 97.2% for metallic, plastic, and glass packaging. Moreover, our method can efficiently differentiate three products with 90.7% accuracy while addressing scalability and privacy concerns commonly associated with existing technologies.