Investigation And Implementation Of RFID Tags Anti-Collision Algorithm

Radio Frequency Identification (RFID) is a contactless automatic identification technology with the history of several dozen years. It’s widely used in logistics, transportation and production. The principle of RFID technology is complete the communication between reader and tags by the way of electromagnetic wave or inductive coupling,thus realizes the identification for the target objects. The RFID system mainly be composed by reader, tags and the data processing system. When there is massive tags in the reader’s scope, and all the tags sharing wireless communication channel, so it will produce aliasing between the signals, thus the tags will be conflict, and cause the reader wrong or leak to reads. Therefore, the effective anti-collision algorithm appears very important.The number of tags in the RFID system is big. So it requests the cost of tag to be very low. Therefore, the memory and computing ability of tag must be limited, and the anti-collision algorithm of the traditional network does not suitable for the RFID system. At present, most of the anti-collision algorithms based on the TDMA technology. It mainly has the ALOHA algorithm and the binary searching algorithm.This article introduced several methods of current RFID tags anti-collision algorithm(the ALOHA algorithm, the S-ALOHA algorithm and the binary searching algorithm). And analyzed the good or bad points of every algorithm. In view of the insufficiency of existing algorithms, this article gives a kind of new RFID tags anti-collision algorithm.At first, this article unified the TDMA technology and the CDMA technology, proposed a kind of RFID tags anti-collision algorithm, named as CMS-ALOHA algorithm.Second,this article made the theory inferential reasoning for the CMS-ALOHA algorithm, and with the matlab software,it made the simulation and analysis for the exiting algorithm and CMS-ALOHA algorithm.Third, this article used the C# language to simulate the CMS-ALOHA algorithm and the S-ALOHA algorithm, so it confirms the identification efficiency of RFID reader. Finally, this article introduced the circuit principle of RFID reader,and designed a RFID reader.The experiment indicated that the CMS-ALOHA algorithm met the actual need to a certain extent, and it surpassed the general anti-collision algorithm in the efficiency. When there are a lot of tags in the scope of the RFID reader, it can enhance the efficiency that the RFID reader identified the tags.