| Radio Frequency Identification (RFID) is a kind of non-contact data communication technology in wireless radio frequency way, in order to achieve the purpose of identifying the electronic tag and what it is stand for. RFID utilizes electromagnetic coupling to realize the data communication. RFID system has too many advantages, such as fast reading speed, high working efficiency, portability, security of data transmission, low production cost and so on. It has gradually replaced the traditional identification technology. In the public transportation, IOT and space location, RFID has also been gradually used. As an important part of the RFID system, RFID reader plays an important role in the data processing and system controlling. Baseband signal is the main processing object of the reader, so the research on the baseband has an important scientific significance.This paper firstly introduces the basic working principle of RFID system, components and functions of each component, mainly introduces three different types of communication system structure and technical parameters under ISO18000-6.Based on the understanding of the digital coder and modulation, this paper uses the software of Simulink to build a simulation model and carry out timing analysis for the two different communication structure of Type A/B, and also uses Simulink to simulate the receiving module. Then this paper makes use of the hardware description language Verilog-HDL to design some communication modules including Manchester encoder and decoder, FMO decoder, CRC error check, serial to parallel/parallel to serial converter and UART.As an important factor which decides the reader efficiency, the algorithm of anti-collision is also an important part of the design. Firstly, this paper discusses the principle of the traditional ALOHA and slotted ALOHA algorithms, then compares the working efficiency of the two algorithms. Secondly, this paper designs a dynamic binary tree anti-collision algorithm that conform to Type B. Comprehensively utilizes the modules of Manchester decoder, LIFO stack, reader and tag controllers which are based on state machine. All the above parts are designed and simulated in Quartus Ⅱ. At last, this paper comes up with a new idea of dynamic multi-binary anti-collision algorithm. |
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