The Software Design Of Reader And Research On Anti-collision In RFID

Radio frequency identification technology,which has the largest advantage in automatic identification,is a kind of non-contact identification method(Radio).It uses the inductive(electromagnetic)coupling principle of the transmitted signal or the reflection characteristics of the signal to identify the target object.The advantages of this technolog lay in far transmission of the signal,large identification capacity,high security and strong penetration ability.Moreover,the multi-label is recognized at the same time.Therefore,it has been widely used in many aspects of our life,such as logistics warehouse,safe transportation,shopping malls and other fields.However,with the rapid development of RFID technology,it has gradually exposed some problems that need to be solved.When a number of readers have information exchange with a large number of electronic label in the region of RFID,the problem of signal interference may lead to the collision problem.To solve this problem,researchers have proposed RFID anti-collision algorithm.It is mainly to solve the problem of label collision in the process of communication and reduce the recognition time,improve the utilization efficiency of the channel and the throughput of the system.Electronic label anti-collision algorithm can solve the collision problem of many labels in the reader within the range of working.This thesis proposes a packet hybrid query anti-collision algorithm and HQT algorithm based on Frame-Slotted completes the in depth study of the binary search algorithm,ALOHA algorithm and other anti-collision algorithms software at the same time it design of the reader,and.The main contents of this paper include:(1)The software design of the reader is carried out.According to the standard protocol of our country,the software framework design of logic control unit is realized by 32 bit STM32F207.The underlying driver using SPI serial interface to achieve the communication between STM32F207 and FPGA.It is base on wireless communication and TCP/IP protocol transmission data than the baseband logic control unit and the host computer.The protocol layer is to take our own standard air interface protocol,realize communication state mechanism and protocol command for processing of the reader and the tag and the analysis,at the same time implementation of the interactive processing between the tag and the reader.(2)On the basis of the traditional binary search algorithm and QT algorithm,packet based hybrid query anti-collision algorithm is proposed.The number of bit sin the label when the collision bit more,the direct use of the multi tree algorithm will generate more queries.Overall,this thesis propose to use HQT algorithm to reduce the number of queries.The first algorithm using XOR block then using the combination information of the highest and second high collision bits of tag slot delay response,so as to stagger the collision of large Tags.The simulation results show that the new algorithm has obvious improvement compared with the HQT algorithm and the QT algorithm.Compared with the QT algorithm,the number of queries is significantly reduced,and the HQT algorithm is also reduced,the throughput system is increased significantly.(3)Based on the traditional ALOHA anti-collision algorithm and binary search anti-collision algorithm,this paper proposes a packet based Frame-Slotted HQT algorithm.Firstly,through the estimate the label number to decide whether to label into group,secondly reducing the collision probability to improve the efficiency of system identification;using multiple sets of random numbers in uncertainty algorithm,the algorithm reduce the idle time and then the time slot collision of the slot HQT anti-collision algorithm,which can improve the efficiency of system identification to reduce the amount of data transmitted and the number of empty slots.The simulation results show that compared with the dynamic Frame-Slotted ALOHA algorithm,the improved algorithm in the throughput of system is increased about from36% to 57%;with the increase of the number of slots in the electronic tag identification does not obvious,far less than the dynamic Frame-Slot ALOHA algorithm.