Abstract
In radio frequency identification (RFID) systems, the detection range and read rates will suffer from interference among high power reading devices. This problem grows severely and degrades system performance in dense RFID networks. Consequently, medium access protocols (MAC) protocols are needed for such networks to assess and provide access to the channel so that tags can be read accurately. In this paper, we investigate a suite of feasible power control schemes to ensure overall coverage area of the system while maintaining a desired read rate. The power control scheme and MAC protocol dynamically adjusts the RFID reader power output in response to the interference level seen during tag reading and acceptable signal-to-noise ratio (SNR). We present novel distributed adaptive power control (DAPC) and probabilistic power control (PPC) as two possible solutions. A suitable back off scheme is also added with DAPC to improve coverage. Both the methodology and implementation of the schemes are presented, simulated, compared, and discussed for further work.
Notes
1Research supported in part by Air Force Research Laboratory Grant (FA8650-04-C-704) and Intelligent Systems Center.
3. “FCC Code of Federal Regulations,” Title 47, vol. 1, Part 15, Sections 245–249. 47CFR15. October 1 2000.
7. “TR (Technical Report) on LBT (listen-before-talk) for adaptive frequency agile SRD's as implemented in the draft EN 302 288,” ETSI TR 102 378 V1.1., October 2005.
10. “EPC Radio-Frequency Identity Protocols Generation 2 Identity Tag (Class 1): Protocol for Communications at 860MHz-960MHz,” EPC Global Hardware Action Group (HAG), EPC Identity Tag (Class 1) Generation 2, Last-Call Working Draft Version 1.0.2, November 24 2003.