A Improved Frame Slotted Aloha Protocol with Early End in Mobile RFID Systems

Frame slotted ALOHA (FSA) protocol is a classic tag anti-collision protocol. Similar to most existing anti-collision protocols, The FSA initially aims at tag identification of static scenarios, that is, all tags keep still during the tag identification process. However, in many real scenarios, tags generally move along a fixed path in the reader coverage area, that is, tags stay the coverage area only for a restricted time (sojourn time). Obviously, tag loss is inevitable in some mobile RFID scenarios. For example, tag quantity is too large or their moving speed is too high. Like almost existing tag identification protocols, FSA is not concerned with optimal management of lost tags. In this paper, we propose an improved FSA algorithm with early end which can decrease tag loss by early termining idle slots, collision slots and slots that are occupied by lost tag. Simulation results show that the proposed protocol can significantly reduce the numbers of lost tags in mobile RFID scenarios. The idea of the paper is beneficial for redesigning other existing tag anti-collision protocols so as to make these protocols adapt to mobile RFID systems. Copyright © 2013 IFSA.