RFID Tag Identification Algorithm For Low Collision Rate

Radio Frequency Identification is a kind of non-touching automatic identifying technology,it now has been widely used because it identifies the target through radio-frequency signal with advantages including many advantages of low cost,high accuracy,faster recognition speed and not being affected by severe environment.But there is a tag collision problem in the RFID system.Therefore,reducing the tag collision rate is very important to the effective application of RFID.We study the problem of RFID tag collision.The main work is as follows:1.An improving algorithm to estimating the number of tags is proposed.Using this algorithm can overcome the disadvantage which using too big or too small frame length will reduce the efficiency in the Frame Slot ALOHA algorithm.By using this algorithm,the system can make the sending frame length to be approximately equal to the number of tags,which can improve the algorithm efficiency.This algorithm has been compared with several existing estimation algorithm,the accuracy of these algorithms is tested by simulation.2.An improving low collision rate ALOHA algorithm is proposed.The hardware constraints cause the maximum frame length being only 256 in most RFID system,so this algorithm groups the tags by the number of tags,then identifies the tags in the group.This algorithm can improve the algorithm efficiency.This algorithm is analyzed and simulated in this dissertation.3.An low collision rate ALOHA algorithm based on dynamic grouping is proposed.In this dissertation,the conclusion is obtained by simulation analysis which the frame slot ALOHA algorithm can achieve higher throughput with fewer tags and optimization frame length.Combined with this conclusion,this algorithm dynamically determine the number ofgroups to make the number of tags less than 10.According to the simulation result,this algorithm can reduced collision rate and has good performance in terms of throughput.4.A RFID anti-collision algorithm based on tree collision detection is proposed.This algorithm overcomes a fault which there are too many idle slots in the anti-collision algorithm based on tree.Through the detection mode,this algorithm can get the value of collision bit,then combines the query mode to identify the tags.Through performance analysis and simulation experiment,it can be concluded that this algorithm can avoid the idle slot,reduce the collision rate and improve the tag identification efficiency.The results of this dissertation can be applied to RFID system,which can reduce the collision rate and improve the efficiency of tag recognition.