Research Of Anti-collision Algorithm In RFID System

Radio frequency identification (RFID) is a kind of data automatically collected technology, with no touch, by electromagnetic waves achieving the duplex communication between the reader and tags. RFID technology has a wide application prospect, now applied to the collection and processing of data applications, such as production, medical, carrying trade, traffic, anti-counterfeiting, tracking, the management of equipment and asset. With the development of LSI technology and printing technology, RFID application will be more and more widely.How to accurate quickly identify tags is one of the main problems and key technologys for anti-collision algorithm in the RFID system, influencing the cost of tag, the ability of reader and difficulty of algorithm implementation, even the compatibility of RFID system. To solve the problem of tags collision in RFID system, Anti-collision algorithm based on collision-bit tracking in RFID system is proposed to improve identification efficiency. Meanwhile, considering the different of cost requirement and application environment, we get two improved algorithms on this algorithm. They are anti-collision algorithm based on parallel processing in RFID system and anti-collision algorithm based on flood diversion measures in RFID system.Anti-collision algorithm based on collision-bit tracking in RFID system is proposed based on analysising classical binary-search algorithms. In order to reduce query frequency and data transmission and data interchange in the collision processing, the new algorithm adopts the technique of stack storage, back strategy and collision-bit tracking, etc. Performance analysis shows that this algorithm is significantly superior to the classical binary algorithms in reducing query frequency, data transmission and data interchange. The new algorithm is simple, practical and suitable for few tags.Anti-collision algorithm based on parallel processing in RFID system adds the queue and parallel processing technology compared with the front first algorithm, for suiting to the specific environment of large tags. The time of collision processing is shortened by collisions parallel processing between two modules. The algorithm makes both read-write operations and processing collision work simultaneously, thus read-write time is left out. The reader has the parallel processing modules. Performance analysis shows that this algorithm is significantly superior to the classical binary algorithms in reducing data interchange, query frequency, data transmission, the number of sending order and invalid command. The algorithm has a ability of parallel processing between two modules to improve the performance.Anti-collision algorithm based on flood diversion measures in RFID system is proposed based on the advantages of aloha algorithms and classical binary-search algorithms. Combining with the anti-collision algorithm based on parallel processing in RFID system, we add tags estimate and flood diversion measures technology. The algorithm estimates the number of tags, according to estimation, deals with tags by parallel processing like flood diversion measures, and makes the system have has muti-modules processor by using flood diversion measures, whatever the number of tags more or less, reader can quickly identify tags. Performance analysis shows that this algorithm is significantly superior to the classical binary algorithms in reducing data interchange, query frequency and recognition time.