Research On Rfid Air Interface Protocol In 2.45ghz

RFID technique becomes one of the most potential technologies for its advantages, such as non-contact and non-line-of-sight. Standard air interface protocol of RFID has played a key role on RFID market. Now China is on the stage of developing her own standards. So study of the RFID air interface protocol is of great strategic significance.The 2.45GHz air interface protocol proposed by ZTE-V was analyzed and simulated upon a detailed study of the international standard ISO/IEC18000-4 in this dissertation.The authors deeply studied binary search algorithm and ALOHA anti-collision algorithm, found 1) tags will be still identified even if "single bit collision" occurs in the binary search algorithm; 2) division of time slots in ALOHA algorithm can effectively control tag's response time. The authors proposed a new algorithm called a RFID anti-collision algorithm based on code distance inversion. New algorithm combined time slot mechanism with the Manchester encoding. In accordance with the principle of "x-dimensional code distance equals to x", tags will be accessed in the same timeslot. The transceiver analyzes all tags' ID (TIDs) through three factors (collision information, x-dimensional code distance and time slot table from sender and receiver). Three TIDs could be recognized at the same timeslot at least. In order to resolve the common phenomenon of many empty time slots that exist in ALOHA algorithm, the authors designed a slot reservation method to make timeslot reserved as necessary. So the timeslot table will be changed on time. Empty timeslot will be restrained completely. Access speed and efficiency will be greatly improved. Simulation results show that the new algorithm and time slot reservation method can not only increase the access rates, but also improve tag access efficiency to 400%.The authors made a simulation model which includes MAC and correlative modules by using MATLAB/SIMULINK. Finally, the authors integrate all parts together, and give interpretation and analysis according to the draft resolution proposed by ZTE-V Cor., Ltd.