A Hybrid Anti-collision Algorithm For RFID System

Radio Frequency Identification (RFID) technology is a wireless communication technology.The development of the RFID technology in the future depends on tags read by the readers correctly.So the collision problems of RFID draw the attention of researchers. Generally, it is easier to solve the collision problems between readers than solving the collision problems of tags. There are two kinds of anti-collision algorithms to solve the collision problems which are named probabilistic algorithms and deterministic algorithms. Probabilistic algorithms are based on ALOHA algorithms while deterministic algorithms are based on binary search tree algorithms.According to the advantages and disadvantages of algorithms, this paper puts forward a new algorithm.The dynamic frame slotted algorithm can change the frame size to adapt to number of tags. But the frame size has upper limit. If the tags’ number is beyond the frame size’s range, DFSA will appear many collisions. The query tree algorithm can identify all tags if time is enough. Its identification efficiency will be very low if there are many tags in the reader’s range. Dynamic frame slotted ALOHA algorithm based on query tree with reversed IDs is a new algorithm which combine DFSA with QTR. Query tree with reversed IDs algorithm divides tags into groups and overcomes the problem of low matching efficiency. Then the dynamic frame slotted algorithm adjusts the best frame size for tags to identify all tags.The used slots of the improved algorithm are less than the slots used by the dynamic frame slotted algorithm while the throughput of the improved algorithm is better than the former algorithms through simulation of the MATLAB platform.