Research Of Anti-Collision Algrithm In Rfid-Sensor Network

With the development of radio frequency identification network and wireless sensor network, RFID technology is widely used and there are more and more researches on WSN. As these two networks both belong to the technology on perception layer in the field of internet of things, the researchers are paying more attention on the combination of two technologies and many papers on it have been published.As a new kind of network, RFID sensor network has built its own structure on the basic of RFID and WSN. In the RFID sensor network, WSN can help expand the reading range of RFID and the structure can be more flexible. Besides, RFID can lift the reading speed of information in WSN and the new network will have a stronger anti-interference ability. The new network has the characteristic of strong capability of data collecting and processing, more flexible structure and meeting more complex demands. However, the RFID sensor network still uses some traditional algorithms from RFID and WSN to operate, some traditional problems still exist. The problem of anti-collsion problem is one of them. To meet the demand of large amouts of tag fast recognition, the traditional algorithm can not estimate the tag number exactly. With the number of tag increasing, the throughput of system will decline rapidly using the traditional algorithm which is called the "landslide problem". And the tag starvation problem still exists.To solve these problems, the BE-PDFSA algorithm and TCS algorithm are proposed in this paper. They are both built on the basic of DFSA and do some optimization on the existing problems. In BE-PDFSA, we introduced the Bayesian Estimation to solve the inaccuracy of tag estimation. The Bayesian Estimation can use a few samples to get a more accurate estimation. For the landslide problem, the mechanism of probablitiy respose is proposed to make the theoretical number of tags to respond be the same as the frame length to improve the efficiency of the system and save the source of the whole system. In the TCS algorithm, the "tag communication slot" is proposed to let tags communicate with each other before the process of recognition in order to make the useful information focus on fewer tags. The TCS algorithm can reduce the number of tag participating in the recognition process and improve the efficiency of the whole system.