Research And Design On The Digital Baseband Of UHF RFID Reader Platform

The Ultra High Frequency(UHF)Radio Frequency Identification(RFID)technology characterized by fast identification,long transmission distance,resistance to harsh environments has been widely used in smart home,identification,public safety,and other fields.With the development of UHF RFID technology,new standards have implemented,which leads to the compatibility of reader platform to be solved.Therefore,it is significant to design and implement a reader verification platform which is easy to debug and system upgrade.Base on the software radio platform of National Instrument,a expandable reader platform is designed and implemented,and the hardware and software design of the reader is proposered.On basis of ISO/IEC 18000-6C protocol,the architecture of system,and state control of protocol layer is designed,especially,focused on the key technologies of digital baseband in readers.The state control,transmit and receive path of physical layer are achieved by Field Programmable Gate Array(FPGA)with high speed data throughput,which includes the generating,parsing command,encoding,decoding,framing,decoding frame,modulation,demodulation,system logical control and Cyclic Redundancy Check(CRC)redundancy check.In transmitting chain digital baseband design,The modeling filter combined with Hilbert filter is adopted to meet the demands of Radio Frequency(RF)signal envelop requirement,which can realize single sideband modulation,and improve bandwidth efficiency.During receicing chain digital baseband design,the system which combined with Cascaded Integrator-Comb Filter(CIC)filter,Half Band(HB)filter and Finite Impulse Response(FIR)filter is employed to meet the demands of data processing in multi-rate.Regard to different code rate data,regular oversampling which can lower hardware consumption and enhance the system aticexpansibility is used.According to test,The system has realized configurable hardware and protocol parameters in real time.Especially,the transmitting path has met the frequency regulations which protocol requires.It can handle 40 Kbps to 640 Kbps backward signal required by the protocol and realize 22% error tolerance.The test result shows that the reader platform can have a great inventory communication with business tag.