Anti-collision Research Of Mobile Tags In Dynamic RFID Systems

Radio Frequency Identification (RFID) is a kind of non-contact, high-speed, real-time automatic identification technology, worked by inductive coupling and electromagnetic propagation characteristics. With the development of the Internet of things and big data, RFID has been widely used and developed as an important part of the recognition layer in Internet of Things.The performance of the anti-collision protocol in RFID technology directly determines the efficiency of the RFID system tag identification. This thesis mainly introduces the related anti-collision protocols based on ALOHA, and analyzes the system throughput and the factors which affect the throughput. The important protocols in this thesis are simulated by MATLAB that shows the relationship between throughput and non-recognition tags. In frame slotted ALOHA algorithms, accurate estimation of unrecognized tag provides an important basis for the next time frame size and improves the system recognition rate. Therefore, the thesis analyzes the common tag estimation method. Based on the existing algorithms, combining the bit reservation proposes for CIFSA anti-collision protocol which is adapted to the dynamic environment. As the CIFSA protocol cancel the free time slot, under the same conditions, so that has a great improvement in the system throughput rate compared to the FSA protocol.This thesis analyzes the difference between static RFID systems and dynamic RFID systems and specially analysis the ideal tag mobile RFID system dynamic system which can achieve the state of dynamic equilibrium. And then CIFSA protocol is applied to the ideal tag mobile RFID system and compared with the traditional FSA protocol. Finally, this thesis gets the conclusion of the recognition rate of the CIFSA protocol that is better than that of the FSA protocol.Based on the analysis of the system identification rate under dynamic balance, the more close to the actual tag mobile RFID system is analyzed. Combined with the characteristics of the system, the thesis analyzes the phenomenon of the common random post identification in the dynamic RFID system identification, and expounds the work process of the first come first served mechanism to overcome the phenomenon of random recognition. Finally, the FCFS-CIFSA protocol is proposed to fit the actual tag mobile RFID system, which is based on the first come first served mechanism and the CIFSA protocol, and the analysis, from the label density, tag identification time and tag arrival rate, indicates the conclusion that FCFS-CIFSA protocol in the dynamic RFID system is better than the CIFSA and FSA protocol.