Research On Anti-collision Algorithm Of RFID Tags

With the rapid development of the Internet of Things technology,the radio frequency identification technology RFID,which has the characteristics of fast recognition,high security,non-contact identification,and strong anti-interference,has been widely used in aquaculture,food safety,logistics,medical treatment,transportation and other fields.With increasing the number of tags and the dynamics of application scenarios,the RFID tag collision has become a key in practical applications.Therefore,it is important to study of RFID tag anti-collision algorithms.RFID tag anti-collision algorithms are mainly divided into three categories: deterministic anti-collision algorithms based on tree structure,random anti-collision algorithms based on ALOHA,and anti-collision algorithms that combine the two.In this paper we mainly analyze the advantages and disadvantages of the three deterministic and four random anti-collision algorithms,and optimize for the recognition of total time slots,low recognition efficiency,and dynamic environment so on.Three tags anti-collision algorithms are proposed and as follows.Firstly,based on the collision tree CT algorithm,a checking grouping tag anti-collision algorithm(CGCT)is proposed.The check bit reserved is used to estimate the characteristics of the collision bits when multiple tags respond simultaneously and collide.Then the tag information is determined.Thus,it reduces the number of reader queries and the amount of communication between the reader and the tag.Through calculation and analysis,the recognition efficiency of CGCT algorithm is about 50% higher than that of CT algorithm,and the traffic is about half lower.Secondly,based on the dynamic frame slot algorithm DFSA and combined with CGCT,Checking Group Dynamic Framed Slotted ALOHA algorithm is proposed.The algorithm uses the frame slot algorithm to identify the tags.When a collision occurs in a certain slot,the CGCT algorithm is used to identify the collision tags one by one.In a large-scale tag environment,this algorithm can avoid the deterministic algorithm query times,but also avoid the missing tags and hunger in the random algorithm.At the same time,considering the new tags being added constantly in the dynamic environment,the number of arrivals of new tags is estimated by analyzing the reading of tags in the first two frames,and the number of slots in the next frame is reasonably divided,so that the system recognition efficiency reaches excellent.Through calculation and analysis,the algorithm has certain advantages in recognition efficiency and traffic compared with CT,CGCT,and DFSA algorithms.And it is suitable for dynamic environments.Finally,considering the impact of the capture effect in wireless communication on the identification of RFID systems,according to above research,we propose a CCG-DFSA algorithm.The algorithm analyzes the recognition situation,uses the tag estimation algorithm to estimate the number of tags to be recognized,calculates the number of non-captured tags and the number of newly arrived tags,so as to reasonably divide the number of slots in the next frame so that the system throughput rate to achieve the best.Through analysis,the algorithm can maintain a throughput rate of more than 63% under the capture effect.The average communication complexity can be maintained below 123 bits.