Research On Anti-collision Optimization Algorithm Of RFID Based On Query Tree Under Capture Effect

As the key technology of automatic identification technology,radio frequency technology is widely used in supply chain management,access control system and other fields because of its low cost,accurate and efficient identification,strong data storage and processing ability.The sharing of wireless channels between tags and readers makes the data transmitted at the same time impact each other and collide,which results in the multi-tag collision problem that the reader can't get the tag information completely,and makes the reader recognition inefficient,poor stability,increased delay and serious missed reading.The multi-tag collision problem can be alleviated by the anti-collision algorithm coordinating the communication between reader and tag.At present,the better anti-collision algorithm in the mainstream has a recognition efficiency of about 0.45-0.5.This paper mainly studies the deterministic anti-collision algorithm based on tree,and analyses the advantages and disadvantages of several representative algorithms based on tree.At Last,this paper improves these shortcomings and proposes GMQT algorithm and PR-GMQT algorithm.The simulation results also show that the proposed algorithm has the characteristics of high recognition efficiency,low transmission delay and high stability.In this paper,the following two algorithms are proposed.Because of the influence of capture effect in wireless network,tree anti-collision algorithm still has some problems such as tag omission in the process of identification,so it is very important to study anti-collision method 'based on anti-collision algorithm.1.This paper proposes group mapping query tree(GMQT)algorithm which defines a three-bit arbitration grouping method based on XOR operation,which divides tags into four groups for query,and effectively reduces collision in process.The group number mapping method and the collision bit inference method are designed to track the collision bit,and the query prefix is expanded precisely,which further eliminates the idle time slot and improves the recognition efficiency of the algorithm to 0.66.2.This paper proposes an anti-capture algorithm PR-GMQT based on GMQT algorithm.PR-GMQT algorithm retransmits the prefix by calculating the unique matching probability selectivity of the current prefix.At the end of a round of queries,empty queries are sent to detect whether the tags are missing.If the tags are missing,the query tree is reconstructed to query again.PR-GMQT algorithm can not only ensure that all tags are identified,not affected by capture effect,but also maintain the performance advantage.