A collision and tag number detector for UHF RFID reader conforming to EPC Gen2 protocol

In this paper, a collision and tag number detector for Radio Frequency Identification (RFID) reader is introduced. In EPC Gen2 protocol, Frame Slotted Aloha (FSA) is applied for multi-tag anti-collision. In some state-of-the-art researches, collision recovery methods are developed to turn a collision slot into a successful slot. To reduce failing recovery, the reader needs to know if there is collision and the detail number of tags in the slot. A clustering method based on histogram is designed to detect collision and the number of tags in this work. The simulation result shows that the average accuracy of the method can be as high as 90%. The success ratio of collision recovery is promoted by over 10% and the accuracy of tag number estimation is improved.