Research And Implementation Technologies Of Communication Protocol For RFID Air Interface

Radio Frequency Identification (RFID) plays very important role in the processing of the construction and development of Internet of Thing (IOT) and has a huge market, which is the base and key technology on IOT. Now, the key technologies,standards and the core products mainly depend on developed countries, which needs to pay a great amount of money for patent and brings potential safe risk. To achieve the independence innovation on the RFID and to satisfy the requirement of the development of the RFID system in our country, it needs to solve a series of key technologies and to establish the RFID standard system which holds self-property right and self-controllable. This dissertation has a deep study on the data encoding, frame synchronization, anti-collision algorithm, information safety and the realization and validation of the air interface communication protocol, and then establishes the UHF RFID system air interface communication protocol. At the same time , the integrality, self-contained and practicable of the protocol are proved through several different algorithms and tools. The main contributions and innovations of the dissertation stress below:At first, some novel technologies are proposed at the physical layer of the UHF RFID system air interface communication protocol. These technologies include a forward encoding algorithm and two backward encoding algorithms and a frame synchronization algorithm. The forward encoding algorithm improves the energy supplying efficiency for the passive tag; and the two backward encoding algorithms can improve the spectrum character of the encoding signals. The frame synchronization algorithm is based on dual-Barker structure and can achieve better performance of synchronization. The forward encoding algorithm and the dual-Barker structure frame synchronization algorithm are applied in the air interface communication protocol successfully and achieve ideal effect.Secondly, five tag anti-collision algorithms are respectively proposed which aim at the competing condition with many tags and accord to the different application requirements and the different properties of the RFID systems with different frequency bandwidths. According to the ALOHA algorithm and the binary tree algorithm, a dynamic frame length slotted ALOHA algorithm based on tag grouping randomly is proposed. The algorithm can solve the sharp descend of the throughput as the estimate error of the number of tag is rather bigger. The two other anti-collision algorithms are proposed which are based on collision forecast and grouping preview. The two algorithms can effectively decrease the operation number applying to the free slot and the multi-tags slot, and can improve the identify efficiency. The fourth anti-collision algorithm is brought forward according to the properties of the binary tree algorithm and the multi-tree algorithm simultaneity, which can adjust the number of branch adaptively. Combining the property of the binary tree algorithm and ALOHA algorithm, the fifth anti-collision algorithm is proposed. According to the property of the passive UHF RFID system, the second anti-collision algorithm which is based on collision forecast and grouping preview is adopted in the UHF RFID air interface communication protocol.Thirdly, a new authentication protocol based on Hash function and key updating is proposed. The new protocol can meet the restriction of passive tag circuit which has limitation of the capacity of calculation and storage and the energy supplying, and can achieve the object with the low cost and the security and the dual-direction authentication. Experiment results show that the proposed authentication protocol can resist several possible attacks, including reply, counterfeiting, tracking, blocking and tampering attacks. Compared with other authentication protocols, the new protocol can decrease the calculation complexity and the storage complexity of the protocol.At last, based on the simulation of PC and the framework of the software define radio, the UHF RFID system air interface communication protocol has been realized and validated from several levels and algorithms, and the validation and the rationality of the key technologies have been demonstrated at the same time.The dissertation has made very important innovation in many aspects, such as data encoding method, anti-collision algorithm, information safety, frame synchronization, command sets and state machine, develop and validate the UHF RFID system air interface communication protocol based on the key technologies which have self-property right. The proposed protocol standard has very important academic significance and applicable value, which will be put in practice as military standard.