Analysis And Research Of Tag Anti-collision Algorithms For UHF RFID System

Attached to the Internet,the Internet of Things has enabled to connect everything with the Internet.It effectively promote economic development and dive into the daily life of the people.In the realization of the Internet of Things,RFID technology is a key area.The UHF RFID system has many advantages,for example,high scanning speed,reusability,large storage capacity,and strong penetrability.With the widespread application and scale expansion of UHF RFID systems,the problem of multi-tag collision has seriously affected the speed of tag identification and restricted the development of UHF RFID technology.In this thesis,these below research based on the existing two types of anti-collision algorithms is carried out.(1)An improved binary tree anti-collision algorithm(IBS algorithm)is proposed.The main idea is to use the pre-processing strategy to extract the tag collision bit information to form a new ID,reduce the length of the reader query sequence number,and use the grouping strategy to use Parity grouping,XOR grouping,reducing collision bits;using "slot delay" strategy,no idle time slots will occur;quadtree algorithm is used to reduce the number of queries by converting the first two collision bits into decimal numbers.Matlab simulation found that this algorithm reduces the number of queries.When L=32,the system throughput rate reaches 0.76,and the overall performance of the system has improved.(2)An improved packet dynamic frame slot algorithm(IDFSA algorithm)is proposed.First,the DFSA algorithm is used to identify one frame to estimate the remaining labels,and the optimal number of packets is obtained according to the grouping coefficients.Finally,the labels in each group are identified by the IBS algorithm.This algorithm guarantees complete identification of all tags.Matlab simulation found that when L=254,the throughput of this algorithm is 0.542,which improves the overall performance of the system.(3)An improved adaptive query tree anti-collision algorithm(IGAQT algorithm)is proposed.First,the collision lock is performed,and the amount of data is reduced by operating only the collision bit.Secondly,the idea of grouping is proposed.The grouping method can reduce the number of identification tags at a time and reduce the probability of collisions.Then,in the adaptive branching,the idea of using the prefix grouping determines the possible prefix,and reduces the number of idle slots of the quadtree,thereby reducing the number of queries.Finally,using the self-identification idea,the sequence of only one bit of the collision bit is directly set to 0 and 1,and no additional two queries are performed,thereby reducing the number of queries.In this paper,the IGAQT algorithm is analyzed in terms of the number of queries,system throughput,transmission data volume and transmission delay.The simulation experiment is performed by Matlab.The algorithm identifies the average number of queries of a tag by 1.61 times.The rate is basically maintained at 62.6%,which is obviously better than AMS and QT algorithms.Furthermore,the performance advantages of the algorithm are verified.These three improved algorithms have significantly improved the anti-collision performance of UHF RFID systems based on previous researches,and have practical value and reference significance for the development of UHF RFID technology.