Research On RFID Multi-tag Anti-collision Recognition Technology

Radio Frequency Identification(RFID)technology plays an important role in data collection in the perception layer of the Internet of Things due to its advantages of fast identification speed,low cost,high security and strong anti-interference.It has been widely used in logistics,warehousing,medical treatment,transportation and other fields.The emergence of multi-tag collision problem has become an important challenge affecting the information collection of RFID system,so the research on efficient and stable tag anti-collision algorithm has important scientific significance and extensive engineering application value.Aiming at the shortcomings of the existing tag anti-collision algorithms,such as low system recognition efficiency,low slot utilization rate and high complexity,this paper studies the following three aspects:1.In order to solve the problems of long recognition time and high communication load in the existing Query Tree anti-collision algorithms,a Bit Query Based M-ary Tree(BQBMT)anti-collision algorithm was proposed on the basis of studying the mechanism of Bit Query and Bit string mapping.The algorithm uses the bit query to make the tag return a mapped bit string instead of the original ID sequence,eliminates the idle query,and at the same time can divide the collision label into more subsets and make full use of the collision bit information,and identify the tag quickly by the optimal switch between the bit query mode and the ID query mode.Theoretical analysis and experimental results show that the system efficiency of the proposed algorithm is as high as 89%,and it has good advantages in time slot number and communication load.2.In order to solve the problems of low slot utilization and long recognition time of existing DFSA algorithm in large-scale tag recognition environment,a Prefix Grouping DFSA(PG-DFSA)based on tag grouping and detection frame construction was proposed to solve a large number of collisions caused by too many tags.The algorithm uses the tag’s prefix to recognize the tag set,constructs the probe frame on the basis of the grouping,and uses the time slot statistics results of the probe frame to process the frames with a large number of idle and collision time slots.Experimental results show that when the number of tags is large,the system efficiency of the proposed algorithm is still close to the theoretical optimal throughput rate of DFSA algorithm 0.368.3.In order to address the problems of low Collision slot availability and high system overhead of the existing DFSA algorithm,a Dynamic Framed-Slotted ALOHA algorithm Based on Enhanced Collision Detection(ECD-DFSA)is proposed on the basis of studying the Enhanced Collision Detection mechanism.The algorithm uses pulse detection to detect collision time slot and idle time slot in advance.The idle time slot is skipped by the detection result and the collision time slot is processed by sub-frame mechanism.Theoretical analysis and experimental results show that the system efficiency of the proposed algorithm is up to 60%,which is significantly higher than the existing DFSA algorithm,and has good advantages in slot number and slot utilization.