| Radio Frequency Identification(RFID)system is a communication technology,which uses wireless electromagnetic wave as a carrier.It can achieve the purposes such as data reading and target identification,etc.,without establishing a mechanical direct contact.Reader,as a key technology of the system,is the channel to transmit the data between the system and the tags.With the continuous improvement and enlargement of the function and application of RFID,the demand for the reader is also growing.With the expansion of the scope of application of RFID,people put forward higher requirements on the power consumption,integration and volume of the reader.Meanwhile,an expectation of further improvement of the overall performance of anti-collision algorithm took a breakthrough.To any information system,security is a key factor in determining the extent of the application.There is a security risk because RFID system uses wireless communication.To ensure the security of RFID system,it requires certain cryptographic authentication mechanism to ensure safe data communication between the reader and tags.The paper firstly establishes a transmission model of wireless signal and energy according to the electromagnetic wave theory and Maxwell equation,which lays a theoretical foundation for system analysis and construction of RFID system.At the same time,the paper briefly introduces the radio frequency identification system standard and tag chip structure.And it also analyzes the framework and working principle of the RFID system of tag chip,then it does researches and designs with basic theories on some main modules of tag chip.The researches mainly includes:studying the rectifier circuit theoretically;designing a rectifier circuit based on Dickson;researching reference work on the sub threshold region;and designing the reference voltage stabilizing circuit.Meanwhile,it does researches on the theory of ASK modulation and demodulation and designs the ASK UHF demodulator for RFID tag and clock production circuit based on ring oscillator.Besides,it achieves the power on reset circuit by using charge discharge principle and capacitance level comparison principle.Finally,using Cadence Spectre simulation software to simulate each circuit module.The results show that the circuit designed in this paper meets the design requirements.Second,in RFID communication algorithm,to solve the reader collision problem when reading tags,the paper proposes a tag dynamic grouping anti-collision algorithm in the analysis of the existing anti-collision algorithm based on adaptive time slot,introduces the density function and the Mahalanobis distance and solves the distribution of initial clustering center and the similarity problem of packet process.It effectively solves the problems of the label grouping and group label number only distribution by using the fuzzy c-means clustering algorithm.Therefore,it realizes the dynamic adjustment of the reader frame slot,which is compatible with the advantages of traditional algorithm.The algorithm is better than the traditional dynamic binary tree algorithm and dynamic ALOHA algorithm in the aspects of recognition success rate and algorithm.It enhances the slot anti-collision algorithm utilization.Third,in order to solve the problem of the RFID Security Protocol,the paper proposes a Montgomery curve of ECDSA based on generalized sign encryption algorithm,under which the paper also proposes a security protocol of RFID.It can meet the sender non repudiation on the foundation of effectively guarantee of anonymity.Meanwhile,it has safety features like a two-way authentication,confidentiality,and availability and effectively resists multiple attacks that RFID faces.In short,this paper provides a detailed study of the key technology of the RFID tag chip analog frontend circuit,and tests it from different angles.At the same time,it provides innovative theoretical results for the communication algorithm between reader and tag. |
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