Research On Long Distance Radio Frequency Identification Technology

Radio frequency identification, based on the radio signal's features of space transmission or inductive and capacitive coupling, is a non-contact auto identification technology for both stationary and mobile objects. Short range radio frequency identification systems have been widely deployed around the world, however, long range systems with function distance of more than 10 meters or even more than 20 meters are still under researching. As for human and mobile object identification, the long range identification system shows a promising prospect for its advantages over the short rang ones concerning the system detection efficiency, mobile detection supporting ability, reader deployment convenience and system automating capacity.The project background of this thesis is to build a under mine long rang radio frequency identification system for human or equipment detection. This thesis covers four aspects of this system: physical layer design, MAC layer protocol design, MAC protocol research and MAC protocol software implementation.The theory and architecture of the radio frequency identification system is firstly introduced in this thesis. The system features and requirements of the project background are analyzed with the conclusion of five key technologies needed in this specific system. Based on the research of major consideration dimensions for the physical layer design by comparing different wireless communication approaches, diverse mature standards , important RF parameters and various MCU solutions, a reader/tag implementation using CC1010 working at 868MHZ is presented together with a PCB compact antenna design which is accomplished under the guidance of several reference documents and the experiment testing results from spectrum analyzer. The physical layer point to point communication test information is also provided in the thesis.MAC protocol plays an essential part in the wireless communication system for achieving high system efficiency. In according to the specific project background of this long rang radio frequency identification system, MAC protocols are designed including the frame definition, two types of MAC state machines design (SPY and Re-contention MAC, Sleep backoff MAC) and the time parameter limitation analyzing for each of these two state machines. A MATLAB based simulation platform for the SPY and Re-contention MAC is built and the formula representation of CW_optimal, which is an important parameter for the design of the SPY and Re-contention MAC, is given out after computer aided mathematical modeling. This formula representation of CW_optimal is validated by the MATLAB simulation platform, which paves the way for future improvement of the MAC protocols applying dynamic CW strategy.Finally, the thesis presents the software implementation frame for the reader and tag based on the CC1010 hardware, and interprets the primitive software codes for the SPY and Re-contention MAC. In addition, several suggestions are given out for the problems occurred in nowadays'system and future system ameliorating.