tailieunhanh - Báo cáo: An Energy and Application Scenario Aware Active RFID Protocol

Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2010, Article ID 432938, 15 pages doi: Research Article An Energy and Application Scenario Aware Active RFID Protocol Bj¨ rn Nilsson,1, 2 Lars Bengtsson,1, 3 and Bertil Svensson1 o 1 Centre for Research on Embedded Systems (CERES), Halmstad University, 30118 Halmstad, Sweden Department, Free2move AB, 302 48 Halmstad, Sweden 3 Department of Computer Science and Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden 2 Research Correspondence should be addressed to Bj¨ rn Nilsson, bjni@ o Received 11 July 2010; Accepted 28 November 2010 Academic Editor: A. Vasilakos Copyright © 2010 Bj¨ rn Nilsson et. | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2010 Article ID 432938 15 pages doi 2010 432938 Research Article An Energy and Application Scenario Aware Active RFID Protocol Bjorn Nilsson 1 2 Lars Bengtsson 1 3 and Bertil Svensson1 1 Centre for Research on Embedded Systems CERES Halmstad University 30118 Halmstad Sweden 2Research Department Free2move AB 302 48 Halmstad Sweden 3 Department of Computer Science and Engineering Chalmers University of Technology 412 96 Gothenburg Sweden Correspondence should be addressed to Bjorn Nilsson bjni@ Received 11 July 2010 Accepted 28 November 2010 Academic Editor A. Vasilakos Copyright 2010 Bjorn Nilsson et al. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. The communication protocol used is a key issue in order to make the most of the advantages of active RFID technologies. In this paper we introduce a carrier sense medium access data communication protocol that dynamically adjusts its back-off algorithm to best suit the actual application at hand. Based on a simulation study of the effect on tag energy cost read-out delay and message throughput incurred by some typical back-off algorithms in a CSMA CA Carrier Sense Multiple Access Collision Avoidance active RFID protocol we conclude that by dynamic tuning of the initial contention window size and back-off interval coefficient tag energy consumption and read-out delay can be significantly lowered. We show that it is possible to decrease the energy consumption per tag payload delivery with more than 10 times resulting in a 50 increase in tag battery lifetime. We also discuss the advantage of being able to predict the number of tags present at the RFID-reader as well as ways of doing it. 1. Introduction . Background. Emerging technologies like printed .