ARPA: An Arbitration Protocol Based on Advanced Channel Feedback for Radio Frequency Identification

This paper refers to a network scenario featuring a single RFID reader (interrogator) which aims at identifying a large number of objects geared with RFID tags, through multiple and sequential interrogations. Since several tags can answer to each interrogation, a problem of collisions arbitration at the reader arises. Classical previously proposed collisions arbitration protocols based on tree-search algorithms make use of channel feedback information on the outcome of the preceding transmissions either of binary type (collided/non collided), or ternary type (idle/successful/collided) achieving an average resolution time per object ranging between 2.1 and 2.8 interrogation cycles. In this paper, we show that the RFID transmission environment allows to obtain an enriched channel feedback information that can be leveraged to greatly improve the efficiency of the identification procedure. We further propose and analyze the arbitration protocol with advanced feedback (ARPA), able to asymptotically provide 100% efficiency. Finally, we show that the overhead needed to implement our protocol in practical RFID systems easily allows to achieve an average resolution time of about 1.4 interrogation cycles per object.