Integrity Of Data Transmission, Radio Frequency Identification System

RFID (Radio Frequency Identification) system is an automatic identification technology that has been developed since 1980s. Compared with barcode system, optical character recognition technology, biometric identification technology, integrated circuit card, RFID system has particular contactless, anti-interference and environmental adaptability characters, so it becomes one of the most excellent automatic identification procedures that are applied in many fields.We introduce principium, configuration, characteristics and some relatively basic theory about RFID system, and analyze the key technologies that are data integrity and data security. For data integrity, it exists in two problems, external interference and collisions that multi-tags occupying a single channel and transmitting their data lead into at the same time. We use data check and anti-collision algorithms to resolve those two problems respectively. Using fumy cipher, transmission data are kept secret that can prevent others from reading or writing data without permit. It can ensure data security.Especially, we complete thorough research the collisions problem. When multiple tags are transmitting data simultaneity within reader's scope, that will occurs a collision. In order to resole this problem, we must use multiple access protocols. Due to the data transmission characteristics between tags and reader, space division multiple access (SDMA), frequency division multiple access (FDMA) and code division multiple access (CDMA) are applied in a limited way in RFID system. Therefore, time division multiple (TDMA) has been generally accepted. According to TDMA, there are ALOHA protocol, S-ALOHA, Binary-tree Protocol, Clipped Binary-Tree Protocol and others. And we analyze those features and disadvantages.In this thesis, the innovation is development of Dynamic Binary-Tree algorithm on base of Clipped Binary-Tree Protocol. Combining with each tag exclusive EPC (Electronic Product Code), we inspect collisions by bits, and form this algorithm principle, prove and validate it by simulation. Finally, conclusions are that thealgorithm's efficency of utilization is higher, requires much less slots, and veracity is better than others. So it can resolve those collisions much better that multiple tags are transmitting data at the same time within reader's scope. It can promote RFID applications in more fields.