Tag loss probability evaluation for a continuous flow of tags in the EPC-global standard

This paper addresses the evaluation of a passive RFID system under a continuous flow of tag arrivals and departures, for instance, in a conveyor belt installation. In such configuration, the main operational variable is the Tag Loss Probability (TLP). Since tags stay in the coverage area of the reader for a finite amount of time, it is possible that some tags leave the area unidentified if many tags compete for being simultaneously identified. A suitable configuration of the system (flow speed, tags per block, time between blocks, etc.) must be selected to assure that TLP remains under a given operative threshold. In this paper we focus on the EPCglobal Class-1 Gen-2 standard, which specifies an anti-collision protocol based on Framed Slotted Aloha. Our work is aimed at evaluating the TLP for the different configurations of such protocol, and selecting the right scenario configuration to guarantee a TLP below a given limit. This issue has not been studied yet, despite of its relevance in real-world scenarios based on assembly lines or other dynamic environments. Simulation results show that both anti-collision protocol operation mode and flow configuration heavily impacts in the performance. Additionally, real test have been conducted which confirm simulation results.