The Research Of Tag Anti-collision Algorithm And Simulation In RFID System

RFID is a non-contacting automatic identification technology. It realizes data communication through the electromagnetic coupling or inductance coupling between reader and label which pastes on an object, in order to achieve automatic identification of label items.RIFD is widely applied in supply chain management, retail, air transport, library management etc, and has great potential of development and application.When RFID system is working, the domain of reader having two or more labels sending data, reader will appear conflict that is data collision, which lead to receiver of reader can not read data properly and timely thereby reducing the RFID system performance and efficiency. It is a fact that exists:if the reader read large number of labels at the same time, these labels need an anti-collision mechanism to protect each label which can read correct, the way of solving called tag anti-collision algorithm. It can archive right communication between reader and label, which determines the identification tag performance of speed and efficiency. So deeply research on RFID anti-collision mechanism, will help further enhance the RFID anti-collision technology.This paper is based on the RFID system anti-collision algorithm to research. Frist, it simply introduce the development course of RFID, classification, characteristics, research at home and abroad and development present status, current anti-collision algorithm status.on the basis of brief introduce the structure and working process, to discuss the one of key technologies focus. Summarizes the proposal to anti-collision, comparison and analysis the existing two categories.Further simulation analysis development of ALOHA algorithm and the algorithm, based on the existing random algorithm proposed based GLS of CDMA anti-collision algorithm which is CA-ALOHA algorithm, constructed the corresponding mathematical model, and deduced the algorithm in the stability of the transmission channel. This new algorithm chooses novel spreading code, shielding MAI in the channel successfully, expand one-dimension multiple access division of original ALHOA to two-dimension on time-frequency division, logical channels replace of real channels, which break the limitations of the channel division, existing before. The simulation indicates:under the same conditions, using GLS code in channel, the error rate of using GLS code channel performances better than traditional WALSH code under the same condition, and throughput of system of CA-ALOHA algorithm obviously precedes ALOHA and binary algorithm.