Improved 4-ary Query Tree Algorithm for Anti-Collision in RFID System

In RFID system, because a collision occurs while a reader attempts to identify multiple tags at the same time, the anti-collision algorithm is necessary. This paper uses the tree based algorithm expressed in the form of a B-ary tree, in which the time required to indentify all tags varies according to the value of B(B≥2). An increase in the value of B will decrease the number of collision cycles, while increasing the number of idle cycles. In order to solve this problem in previous algorithms, an Improved 4-ary Query Tree Algorithm (I4QTA) is suggested. If a collision occurs, the I4QTA uses the Bits Change Method (BCM) to remove idle cycles by only detecting the tag IDs that actually exist. In other words, it can quickly identify all tags by reducing the number of query-responses.