A Novel RFID Anti-Collision Algorithm Based on SDMA

In a multi-tag environment, RFID system performance is limited by the tag collision badly. Most of the existing anti-collision algorithm are based on TDMA (time division multiple access) and the space distributing characteristic of tags is not considered. In order to identify numerous dense tags in the read reign quickly and accurately, we propose a novel anti-collision algorithm in this paper. We adopt SDMA (space division multiple access) technology among the beams and present the TDBF (twice digital beamforming) strategy to solve the reader collision in the overlapping area between adjacent beams. Avoiding the tag collision within every beam, the inner anti-collision algorithm based on TDMA is adopted. The simulation results show that an improvement of more than 40% in identification time can be achieved.