Research On Data Transmission Protocols In Open RFID Systems

Following the computer and Internet,the Internet of Things(Io T)is treated as the third wave of the world's information industry and has become a strategic emerging industry in China.As one of the key supporting technologies of Io T,Radio Frequency Identification(RFID)technology uses electromagnetic coupling or backscatter to uniquely identify objects,which is widely used in a variety of applications due to its advantages of small size,low cost,passive perception(no power supply required),quick reading,and non-line-of-sight communication.The “2019 China RFID Industry Market Prospects Research Report” shows that China's RFID industry is entering a mature period of large-scale promotion.It is estimated that by 2022,the market size will exceed 150 billion yuan.As terminal equipment continues to increase and industry applications continue to deepen,large-scale open RFID systems are becoming increasingly popular.Unlike traditional systems,open RFID systems face new conditions such as large-scale,uncertainty,and privacy sensitivity,which pose severe challenges for the study of efficient RFID data transmission.Based on the different directions of RFID data flow,this thesis aims to achieve efficient and reliable reader-to-tag and tag-to-reader data transmissions in a large-scale,uncertain,privacy-sensitive scenario,which mainly includes the following three parts:(1)For the large-scale characteristics of an open RFID system,this work designs grouping protocols based on the collision reconciliation and data compression.In existing work,the reader transmits by one-to-one unicast,which is time-consuming and difficult to meet the real-time requirements of large-scale RFID systems.The paper proposes an efficient grouping protocol by jointly using the technologies of collisionreconciliation and data compression,which provides a guarantee for efficient data distribution of multicast.(2)For the uncertain characteristic of an open RFID system,this work proposes an unknown tag collision mechanism based on the Cuckoo filter.Uncertainty refers to the existence of unknown tags in an open RFID system that cannot be predicted in advance.These tags will interfere with the existing tags and cause false positives.The paper uses the methods of Cuckoo filter and tag fingerprint to quickly filter,separate,and identify unknown tags,which provides support for the reliability of upper-layer applications.(3)For the privacy-sensitive feature of an open RFID system,this work studies the missing-tag identification protocols resistant to irreconcilable tag collisions.To protect the privacy of RFID systems,blocking tags are usually used to protect target tags from being queried by illegal readers.However,blocking tags can cause irreconcilable tag collisions and thus failure of tag identification.Based on the idea of grouping,this paper is the first to propose a missing-tag identification protocol in a blocking RFID system,which paves the way for protocol design in a privacy-sensitive environment.