Design Of UHF RFID Reader Based On Software-defined Radio

Radio Frequency Identification(RFID)is a new kind of non-contact automatic Identification technology,which has been widely applied in transportation,identification,logistics industry,security and public safety areas.Due to the existence of a variety of RFID standards,different standards of readers and tags can not be universal,and Software Defined Radio(SDR)technology can solve the problem.The core of SDR is to run different software codes on a unified and programmable hardware platform so as to communicate under different frequency bands and different protocols.The RFID reader based on SDR is more convenient for identifying many different standard electronic tags.This paper firstly introduces the development and research status of RFID technology and software radio technology.Then the basic structure,working frequency band and standard of RFID system are analyzed.The ISO/IEC 18000-6 Type C standard is studied emphatically,the communication process,coding method and modulation mode of reader and electronic tag are analyzed.Then introduced the software architecture and development mode of the GNU Radio open software Radio platform,and the RFID reader was designed according to the ISO/IEC 18000-6 Type C standard.The three signal processing modules of RFID reader are designed using C++,which are used for signal filtering,reader decoding and component reader command.By using python to write a flow graph,the various signal processing modules are connected together to become a complete system.Next test the design of the reader,each module of reader is simulated,and the correctness of each module is verified.Connection hardware platform for the reader system of the whole test,the test results show that the reader successfully implement the operation which ISO/IEC 18000-6 Type C standard definition,also has realized the reader according to software code are working under different frequency bands.After,the analysis of RFID anti-collision algorithm proves that the optimal frame length is the same as the tags number in the dynamic frame time-gap ALOHA algorithm.Based on the lower bound algorithm,an improved tags estimation algorithm is proposed.Finally,in order to apply the improved tag valuation algorithm to the reader,a new reader command was designed and the command was implemented using SDR technology in the reader.