An Improved Dynamic Framed Slotted ALOHA Using Posteriori Probability Tag Estimation Algorithm in the Mobile Radio Frequency Identification Systems

摘要

Chen protocol using posteriori probability tag estimation algorithm is a dynamic framed slotted ALOHA (DFSA) for tag anti-collision. It can very precisely estimate the number of tags according to the information of idle, collision, and successful transmission in static scenarios where all tags keep still during the tag identification process. However, the estimation algorithm generates many errors in mobile RFID systems, where tags move along a fixed path in the reader coverage area. The reason is that in mobile RFID systems, new arrival tags can result in tag estimation errors and thus low system performance. In this paper, we propose an improved dynamic framed slotted ALOHA using posteriori probability anti-collision protocol in mobile RFID systems. The protocol can eliminate the influence of new arrival tags on tag estimation and decrease the time wastage due to idle slots and lost tags. Simulation results show that the proposed protocol can significantly reduce the numbers of lost tags in mobile RFID systems. The idea of the paper is used in various existing DFSA variants so as to make these protocols adapt to mobile RFID systems.