Research On Multi-targets Quick Recognition Technology Base On RFID

RFID(Radio Frequency Identification) is a non-contact automatic identificationtechnology. Because of its non-contact, long identifying distance and muti-objectrecognition, this technology is currently commonly used in many fields. Owning to theability of identifying muti-object at the same time makes RFID technology stand outfrom the other automatic identification technologies. The anti-collision algorithm is thekey to fulfill muti-object recognition; this paper’s focus is all on anti-collisionalgorithm.The paper first illustrates the background of this paper, include the following parts:Firstly, The advantage and components of a RFID system; Secondly the domestic andforeign standards and the practical use of RFID technology; thirdly the core parts of thispaper—the domestic and foreign research status of anti-collision algorithm.The paper mainly focuses on the following parts:The probabilistic tag anti-collision algorithm—this paper puts forward aDTJ(Devalue Threshold Judgment)-ALOHA algorithm based on EPC G1G2globalagreement. DTJ algorithm change Q value, based on the devalue of idle slot andcollision slot instead of C value. DTJ algorithm is stable to the number of tags ischangeable. The simulations reveal that the throughput rate of DPT algorithm is betterthan EPC G1G2algorithm.The deterministic tag anti-collision algorithm—this paper puts forward a DPT–BBS algorithm based on BBS(Back Binary Search) algorithm. This algorithm rulesthat when collision occurs, tag will calculate the k bit UID from the highest collisionposition and send it to reader. This data contains the specific value correctly even aftercollision. This paper through the comparison of simulation and other improved binaryalgorithm, this algorithm proves to be efficient at search instructions and time in reader.The reader consist of main control chip MSP430and RFID chip TRF7960, thispaper has fulfilled the anti-collision algorithm, based on ISO14443A standard and DPTrules, at13.5MHZ frequency bands in the mentioned reader. This paper introducesprogramming process through pseudo-code. Finally, the test of this paper proved the following things:fistly the basic functionof communication is good; Secondly The ISO14443A and DPT anti-collision can run onthe reader well; Thirdly The DPT anti-collision algorithm is better than ISO14443Aalgorithm in paging times of reader. In a word, the test result shows that the algorithmcan recognition at most8cards at the same time, affected by the antenna covering range.It also proved that the DPT algorithm has practical value.