A RFID Anti-Collision Algorithm Based On Capture Effect

RFID is a more natural wireless data collection technology, whose application is very extensive, especially in the field of logistics, cargo, delivery, warehousing, and manufactur-ing industry, supply chain management. In the application process, which the RFID system often requires multiple tags to identify at the same time, the collision problem often occurs, impacting on system performance seriously.Based on the "RFID sensor network key issues" and the "RFID sensor networks and its application technology research" projects, this paper mainly made a research on multi-tag anti-collision algorithm for dense tag RFID systems, the main work is as following:(1) Stated theoretical knowledge of radio frequency identification system, including its composition, classification, working principle and data integrity, then focused on the ALO-HA class tag anti-collision algorithm in RFID system.(2) Researched the mainstream ALOHA anti-collision algorithm and the binary tree al-gorithm in deep, synthesized advantages of the two algorithms, and put forward a frame slot ALOHA anti-collision algorithm. Then introduced the improved algorithm for its the basic principles of the implementation process and system throughput performance, meanwhile demonstrated in the instance of the algorithm.(3) Combined with the capture effect exists in the identification process of the multi-tag RFID systems using the DTMC (Discrete-time Markov chain) model and SIR model of cap-ture probability theory to make a analysis on the frame size fixed (Q value of fixed) reader with the frame recognition of the long variable type (Q-value variable) reader. Compared with the anti-collision performance of the frame length fixed (Q value is fixed) and the frame length variable type (Q value variable) reader to prove the improvement.(4) According to the EPC C1G2standard, used OMNET++simulation and ALIEN8800reader to analyze the typical parameters configured in the reader, with considering capture effect exist in the system or not. Then proposed the optimal allocation of system pa-rameters to determine the frame size of the reader which could offer the best recognition performance with the corresponding Q value.Simulation and experimental results showed that the capture effect has a significant im-pact on the anti-collision performance of the RFID system. While Q=4, the average slots in the variable frame length reader reduced by37percent, as for frame-fixed readers, it will reduced the average frame slots by14.7%. For the variable frame length readers, we have also got a key conclusion:The reader need a Q optimization in each recognition cycle to get the maximum throughput. These results can help the manufacturer to configure the optimal parameters to enhance the performance of RFID anti-collision for the reader.