| With the rapid development of Internet of Things technology,Radio Frequency Identification(RFID)technology,as a core technology in the field of Io T,with its capacity to quickly and accurately identifying multiple targets has been widely used in various scenarios to meet different needs.At present,the Internet of Things terminal widely used in the market is still EPC Gen2 type RFID tag,whose uplink multiple access mode adopts time division multiplexing technology.The total throughput rate of a single reader is limited by the uplink communication rate,and multiple readers can coexist through frequency division multiplexing.With the continuous increase of Io T devices and applications,higher requirements are put forward for the terminal capacity and coverage of a single RFID reader,and frequency division multiplexing technology is an important technical approach to achieve this requirement.Based on the above research background,this thesis systematically analyzes the components,working principle,baseband signal structure and characteristics of the frequency division multiplexing UHF RFID system in the scenario of a single reader.Based on the research findings already available,the signal processing algorithm of frequency division multiplexing UHF RFID reader is studied,and the baseband signal processing digital circuit for frequency division multiplexing UHF RFID reader is designed and implemented.it can handle baseband sending signal processing and multichannel parallel receiving processing,which provides a reference for the development of high throughput frequency division multiplexing UHF RFID systems.The main work and achievements of this thesis are as follows:1.An analysis and summation of the current research background of UHF RFID technology and the research status both domestically and internationally is presented.Based on the current achievements in the field of UHF RFID,the composition,working principle,baseband signal structure and characteristics of the frequency division multiplexing UHF RFID system in the scenario of a single reader are systematically described.2.The baseband signal processing method of frequency division multiplexing UHF RFID reader is studied,the principle of harmonic interference suppression is derived and analyzed,and the harmonic interference suppression algorithm suitable for frequency division multiplexing UHF RFID reader is proposed,and the construction of a Matlab simulation environment are all undertaken.The simulation results demonstrate that the harmonic interference suppression effect can exceed 12 d B.3.Designed and implemented the baseband signal processing digital circuit of frequency division multiplexing UHF RFID reader using VHDL/Verilog language,developed the signal processing module design scheme,at the same time given the corresponding parameters,and the key circuit behavior simulation.4.The baseband circuit board and RF front-end circuit board based on XC7Z020 chip are used to build the test platform,and the baseband signal processing performance test of frequency division multiplexing UHF RFID reader is completed.Baseband signal sending and four-channel signal receiving can be completed,and the suppression effect of harmonic interference can reach more than 10 dB. |
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