Linear model of Adapting Frame Size in DFSA of Passive GEN2 RFID systems

Low costs of passive UHF RFID tags, as well as their simplicity makes them appropriate for the localization and tracking services in today’s fast-moving, information rich trading networks. However, a few disadvantages of passive RFID technology performances, as a reading range of passive tags and high collision rate during RFID reader-tag communication, still needs quality of service improvements. In order to maintain passive technology cheap, but to improve the disadvantages, it is important for tags not to include any additional electronic circuitry, and to maximize the efficiency of the actual hardware. So, it is necessary to develop the optimal algorithms in order to maximize the communication efficiency. In this paper we provide the analysis on MAC layer protocol of passive UHF-Gen 2 RFID standard. In the accordance with the standard, we provide the improvement for the frame size adaptation, which increases the throughput of RFID system and thus minimizes the time for tags identification. The algorithm for the improvement includes the estimate of the number of tags through the linear behavior model of number of Collisions (C), and Successful (S) slots within the frame. Estimated number of tags is used for adaptation of the frame size. For comparison, simulation results show that our approach provides better efficiency than Q-Selection algorithm from UHF-Class1-Gen 2 standard. Key-Words: Framed Slotted ALOHA, transmission control strategy, Q-selection Algorithm, RFID identification, Number of tags estimation