The Slotted-LBT: A RFID Reader Medium Access Scheme in Dense Reader Environments

RFID technology as a core technology for realizing ubiquitous environment is emerged. Although it was developed rapidly in the past few years, the read rate is still a concern in the RFID technology adoption. At the same time it is also a technical issue which must be resolved. In order to increase the read rate, a number of researches have focused on the air protocol method and the medium access method. In this paper, we propose a distributed Slotted-LBT method to increase the number of readers which can read tags simultaneously, to provide a stable channel access time, and to reduce the interference among readers by using a channel zone. From the results in this research, compared with the existing normal LBT method, the proposed Slotted-LBT method shows that the coefficient of variation for the channel access time is reduced from 96% to 38% and the effect of interference is reduced by 28.48%. Besides, since each channel can be controlled separately, we can use categorized channels according to demanding features of manifold applications.