A Collected Blocking Collision Tree Algorithm with Bit Tracking for RFID Tag Identification

In many radio frequency identification (RFID) applications, a RFID reader repeatedly identifies the tags in its scope. An anti-collision algorithm with blocking mechanism lets the staying tags and arriving tags reply in different time periods and the collisions between the staying and arriving tags are prevented. However, in the existing blocking algorithms, the reader can only identify two staying tags at most in a slot. As a result, when the number of staying tags is large, the reader still consumes many slots to identify the staying tags. Thus, this paper proposes a collected blocking collision tree algorithm (CBCT) in which a bit tracking technology is used to enhance the system efficiency. Two key mechanisms are adopted in CBCT which are collecting and refreshing. By using the collecting mechanism, the reader can identify many tags in a slot. The refreshing mechanism is used by the reader to keep the continuity of all the staying tags. Simulation results show that the proposed algorithm is superior to the existing blocking algorithms and the algorithms with bit tracking technology.