Issue No. 04 - April (2012 vol. 23)
DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/TPDS.2011.240
Lei Kang , The Hong Kong University of Science and Technology, Hong Kong
Jin Zhang , The Hong Kong University of Science and Technology, Hong Kong
Kaishun Wu , The Hong Kong University of Science and Technology, Hong Kong and Sun Yat-sen University, Guangzhou
Dian Zhang , Hong Kong University of Science and Technology, Hong Kong
Lionel M. Ni , The Hong Kong University of Science and Technology, Hong Kong
RFID tag identification is a crucial problem in UHF RFID systems. Traditional tag identification algorithms can be classified into two categories, ALOHA-based and tree-based. Both of them are inefficient due to the incidental high coordination cost. In this paper, we bring CSMA into UHF RFID systems to enhance tag read rate by reducing coordination cost. However, it is not straightforward due to the simple hardware design of passive RFID tags, which is unable to sense the transmissions or collisions of other tags. To tackle this challenge, we propose receiver-based CSMA (RCSMA) in this paper. In RCSMA, the reader notifies the tags channel condition. According to different sensing results of reader's notifications, the tags take corresponding actions, e.g., random back off. RCSMA does not require special RFID tag hardware design. An absorbing Markov chain model is presented to analyze the performance of RCSMA and shown to be consistent with the simulation results. Compared with optimized ALOHA-based algorithms and optimized tree-based algorithms, RCSMA can enhance the tag read rate by 30-70 percent under different reader and tag data rates.
RFID systems; CSMA; tag identification.
J. Zhang, D. Zhang, L. M. Ni, L. Kang and K. Wu, "RCSMA: Receiver-Based Carrier Sense Multiple Access in UHF RFID Systems," in IEEE Transactions on Parallel & Distributed Systems, vol. 23, no. , pp. 735-743, 2011.