The tag duplication problem in an integrated WSN for RFID-based item-level inventory monitoring

Radio Frequency Identification (RFID) technology has been adopted in various supply chain management applications because of its fast and low-cost ability to identify items uniquely. In this paper, we consider the integration of a Wireless Sensor Network (WSN) with RFID to provide item-level inventory monitoring in retail stores. First, we present a basic formulation for RFID-based item-level inventory monitoring applications. With the formulation, we illustrate that tag duplication problems can exist in the network layer due to tags' mobility and overlaps of RFID readers' interrogation zones. In order to prevent the tag duplication, we propose a tag-filtering scheme by utilizing multihop routing capability of an integrated WSN with RFID. Our proposed filtering scheme is implemented in the nesC programming language and is executed in the TOSSIM simulator to demonstrate its efficiency. Our preliminary results indicate that our filtering scheme improves network latency and tag check-out rate.