Design and simulation of anti-collision RFID system based on SDMA-OFDM

This paper discusses the implementation of an efficient anti-collision algorithm for RFID systems. Conventional TDMA methods do not show a high efficiency and speediness in collision detection and do not take into account the spatial characteristics of tags distribution. By combining the TDMA (Time Division Multiple Access) and SDMA (Space Division Multiple Access) algorithms, the proposed approach takes into account the characteristics of the tag position in the reading area of the reader. Knowing that the SDMA method is based on the principle of Digital Beam Forming (DBF), we used the FFT and IFFT blocks to form the different beams and the OFDM technique to meet the orthogonality condition. We then divided the space into two subsets of beams and applied the TDMA method to detect any collision. The developed RFID anti-collision SDMA system has been coded by VHDL and simulated using the ISE software for FPGA implementation.