Research On RFID Anti-Collision Algorithms Based On Query Tree

RFID technology is a new non-contact automatic identification technology.Compared with traditional identification technologies,RFID technology has many advantages such as non-contact reading,fast identification,high security,waterproof and magnetic immunity and strong adaptability to the environment.RFID technology has a broad market prospect and now has been extensively used in many fields such as traffic,retail,healthcare,logistics warehousing and manufacturing.The tag collision problem has always been one of the key issues in RFID technology.Therefore,designing an efficient and stable anti-collision algorithm is crucial to the further development of RFID technology.The anti-collision algorithm can be mainly divided into two major categories,ALOHA-based anti-collision algorithm and tree-based anti-collision algorithm.In this paper,the tree-based algorithm is discussed,and several representative algorithms are introduced in detail.By analyzing their advantages and disadvantages,we propose improvements focusing on the excessive number of queries,collision time slots,and large amount of transmission data.Two improved algorithms are proposed on the basis of the query tree,which are IGAQT algorithm and GIGAQT algorithm.The IGAQT algorithm mainly uses parity and prefix code to group the tags,depressing the probability of collision by reducing the number of tags.In addition,when the number of bifurcations is chosen adaptively,the prefix is determined by the prefix code,so the quad-tree is pruned to reduce the idle slot.The GIGAQT algorithm introduces an anti-capture mechanism based on IGAQT algorithm and use the prefix retransmission and tag prefix feedback mechanism.The tag performs a bitwise AND operation from the highest bit except prefix,until the result is 0,and then,the operation sequence is replied to determine the new prefix.In this way,a lot of useless prefixes are reduced.The experimental results show that the improved two algorithms have fewer query times,higher recognition efficiency and better performance.Using the improved algorithm to solve the multi-tag collision problem can effectively reduce the loss of tag data,reading errors and unnecessary energy waste caused by collisions,thereby improving the efficiency and performance of the RFID system and ensuring the reliability of the system.