An anti-collision algorithm based on smart antenna in RFID system

In radio frequency identification (RFID) system, one of the problems we must solve is the collision between tags which lowers the efficiency of RFID system. Now, most of the popular anti-collision algorithms are based on time division multiple access (TDMA) and the space distributing characteristic of tags is not considered. In this paper, a novel algorithm based on smart antenna is proposed. Fast Fourier transform (FFT) algorithm is adopted to produce fixed equally spaced beams which divide the reader field into several sub- spaces. Tags in different sub-spaces can be distributed in the same time slot and frequency. This algorithm is fully compatible with other anti-collision algorithms and can be combined with them according to the specific application circumstances. The experiment results show that this algorithm is viable and cost- effective that an improvement of nearly 50 percent can be achieved.