TFDMA: A scheme to the RFID reader collision problem based on graph coloration

The reader collision problem occurs when multiple-RFID reader access tags concurrently. The system efficiency and system throughput will decrease greatly in multiple-reader environment. Most proposals in previous study use a single technique to solve the reader collision problem, thus their system throughput is not desirable. A scheme combining time division and frequency division, TFDMA, is proposed in this paper, which can solve both tag interference and frequency interference by means of graph coloration. According to the simulation and test results, the proposed scheme has better system throughput and system efficiency compared to the existing works.