Research On RFID Active Tag Anti-Collision Algorithm

For RFID system, in order to meet the various requirements of applications, it needs to improve the read efficiency of the system, which is the focus of the study for anti-collision algorithm. Multiple tags simultaneously send data to reader may cause collisions, anti-collision algorithm is to reduce the conflict when reader reads the tag data in the process, so the readers can effectively to read the data in the shortest time. Active RFID tags have its uniqueness, which is active to sends it's information out and have a longer distance, it have more applications than passive tags. This paper is main research on the RFID active tag anti-collision algorithm, the algorithm is now mainly to use ALOHA algorithm, this paper studies on the basis of it's improvement to achieve greater efficiency and energy saving effect. The main contents are as follows:First of all, an introduction of RFID, including RFID composition, theory and application development, then describe and analysis the status of anti-collision algorithms. After that, introduce and comparative analysis the active and passive systems in the RFID system, then conclude that the active systems have more advantages. At last simple introduce the technical characteristics and applications of main RFID band, and compares the characteristics for active and passive tags. Conclude that the active tags have better prospects for development and choose the active tags for this research.Then, in the selected active tag band of 2.45G, an introduction to the band's tag is shown, It's describing this tag's technical characteristic, various functional module situation and the main technical specification. And carries on to introduce the software architecture and the detail flow of tag's data transmission, this flow contains anti-collision algorithm (time delay in article), the detail introduction is shown in the following anti-collision algorithm.After having analyzed above the basic situation, this article mainly conducts the research of anti-collision algorithm. The ALOHA algorithm's application is widespread, therefore the research is about it. Firstly, this article introduced ALOHA algorithm research at present situation, then comparing various algorithms. According to actual requirements, this article selects the time slot to improve based on the ALOHA algorithm. According to the characteristics of CSMA protocols, the algorithm has been improved, builds mathematical model and analysis, and finally draws the conclusion.Lastly, introduce the test software, we can use it to test the tag performance and read mode, to verify the feasibility of this algorithm.