A Counter-Based RFID Anti-Collision Protocol Using Parallel Splitting

In an RFID system, a reader identifies tags by interrogating them through a shared wireless communication channel. Collisions occur when multiple tags transmit their IDs to the reader simultaneously, degrading the performance of tag identification. How to reduce tag collisions to speed up the identification is thus important. There are several anti-collision protocols proposed for dealing with tag collisions. They can be categorized into two classes: ALOHA-based protocols and tree-based protocols that include deterministic tree-based and probabilistic counter-based subclasses of protocols. The ALOHA-based protocol has the tag starvation problem that a tag may never be successfully identified; the deterministic tree-based protocol has the problem that its performance is influenced by the tag ID length and/or distribution. On the contrary, the probabilistic counter-based protocol has no such problems. In this paper, we propose a probabilistic counter-based anti-collision protocol using the idea of parallel splitting to speed up RFID tag identification. The proposed protocol also utilizes an adaptive identification-tree height adjustment mechanism to fine tune the effect of parallel splitting. We analyze and simulate the proposed protocol and compare it with the counter-based protocol adopted by the well known ISO/IEC 18000-6B standard to demonstrate its advantages.