An Adaptive Ternary Query Splitting Based Tag Anti-Collision Protocol for Mobile RFID Systems

Tag collision occurs easily when the multiple tags respond to the same reader query simultaneously over a shared wireless channel. The solution of tag collision is a significant issue in the mobile RFID environment, because of the random mobility of tags. For the purpose of object tracking, locating and monitoring, the reader will repeatedly identify the same tags which still stay within its read range, which will waste a lot of resources and add some new collisions. To handle the above case well, we propose a tag anti-collision protocol based on adaptive ternary query splitting (ATQS), which can effectively avoid the collisions between the new arriving tags and the original staying tags by the blocking technique. Using the formula for the conversion of binary to ternary, the number and length of queries are simplified by a ternary query tree. Using the ternary resolution technique, the new processing procedure of tag identification is designed, in which the reader can use only one prefix of ID to identify at most three staying tags having the same prefix. From the simulation and performance analysis, it obtains that our protocol can effectively decrease the identification delay, which outperforms the previous protocols with the impacts of the staying ratio, the arriving radio and the number of tags.