tailieunhanh - Báo cáo hóa học: " Research Article On Adaptive Contention Resolution Schemes for IEEE 802.16 BWA Systems"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article On Adaptive Contention Resolution Schemes for IEEE BWA Systems | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2009 Article ID 205057 8 pages doi 2009 205057 Research Article On Adaptive Contention Resolution Schemes for IEEE BWA Systems Chih-Heng Ke1 and Der-Jiunn Deng2 1 Department of Computer Science and Information Engineering National Kinmen Institute of Technolgoy Taiwan 2 Department of Computer Science and Information Engineering National Changhua University of Education Taiwan Correspondence should be addressed to Der-Jiunn Deng djdeng@ Received 28 January 2009 Accepted 17 May 2009 Recommended by Dmitri Moltchanov According to the latest version of the IEEE standard the mandatory contention resolution method is the truncated binary exponential backoff with the initial window size and the maximum window size controlled by the base station. However the problem of choosing the right set of backoff parameters for the current network level remains unsolved and left as an open issue since this strategy might incur a high collision probability and the channel utilization could be degraded in congested scenario. In this paper we propose two pragmatic adaptive algorithms namely semi-dynamic and quasi-dynamic contention resolution schemes that allow the base station to adjust its backoff window size based on current channel status. By controlling the size of backoff window according to varying network conditions both schemes are able to achieve higher performance in comparison with the legacy IEEE standard. Copyright 2009 . Ke and . Deng. 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. 1. Introduction High-speed transmission fast deployment and cost saving have made Broadband Wireless Access BWA systems a rapidly emerging field of activity in computer networking .