Improving the time efficiency of QTA anti-collision algorithm

Radio frequency identification (RFID) suffers from collisions when multiple tags respond in the same time. This paper presents Query Tree ALOHA (QTA) anti collision algorithm, improved by using a new tag estimation technique based on signal strength. In addition, by using this technique it is possible to detect when two tags remain in the identification tree and hence acknowledge these tags without further frames or slots. These improvements result in significantly increased performance over the existing lower bound (LB) estimation technique used in the original proposal for QTA. The improvements in this paper are measured with respect to time efficiency, which provides more realistic results by taking into account the time used by frames and other overheads. The time efficiency is found to be 68%, compared to the original 53% with QTA-LB.