The Research Of Anti-collision Problem For Multiple Readers In The RFID System

Radio Frequency Identification (RFID) technology is a kind of non-contactautomatic identification technology that has many useful properties. In recent years,with the rapid development of this technology, it has been widely used in a numberof areas. The Internet of Things system based on ultra high frequency RFID usuallyneeds multiple readers to work simultaneously in the same area. However, this mightcause multi-reader collision problem that seriously reduces the performance of thesystem. Thus, the research of reader collision in UHF RFID dense environment isvery important.This thesis aims to address the reader anti-collision problem and take UHFRFID reader anti-collision identification technology under intensive mode as ourresearch focus. The basic theory of reader anti-collision is discussed first. Then thenovel and improved algorithms are proposed:(1)A variety of domestic and foreign reader anti-collision algorithm areclassified and described in detail. And we point out the advantages and flaws ofthese algorithms.(2)Regarding the reader anti-collision algorithm based on scheduling, weproposed a more accurate range for coordinating through analysing the interferencerange of the reader and hidden terminal and exposed terminal problem in RFIDsystem. It contributes the design of a more effective anti-collision algorithm.(3)A new reader anti-collision algorithm is proposed based on multi-channelscheduling. It is called Distributed Adaptive Multi-Channel Anti-Collision Algorithmon RFID Readers (DAMC). The algorithm considers distributed readers, here ourdesign is suitable for reader network with mobile readers. Adjacent readers exchangecontrol information in the control channel. The double read mechanism can help torecognize tags that are left out.In order to solve the UHF RFID reader collision problem, this thesis designs anew reader anti-collision algorithm based on various anti-collision algorithm. Thenew algorithm uses frequency division multiplexing and distributed design.Simulation results demonstrate that our new algorithm can effectively alleviate the reader collision problem and the double read mechanism of readers can improve therate of identification. The throughput of our proposed algorithm is better than otherones.