tailieunhanh - Báo cáo hóa học: " Research Article Towards Scalable MAC Design for High-Speed Wireless LANs"

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 Towards Scalable MAC Design for High-Speed Wireless LANs | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2007 Article ID 12597 14 pages doi 2007 12597 Research Article Towards Scalable MAC Design for High-Speed Wireless LANs Yuan Yuan 1 William A. Arbaugh 1 and Songwu Lu2 1 Department of Computer Science University of Maryland College Park MD 20742 USA 2 Computer Science Department University of California Los Angeles CA 90095 USA Received 29 July 2006 Revised 30 November 2006 Accepted 26 April 2007 Recommended by Huaiyu Dai The growing popularity of wireless LANs has spurred rapid evolution in physical-layer technologies and wide deployment in diverse environments. The ability ofprotocols in wireless data networks to cater to a large number of users equipped with high-speed wireless devices becomes ever critical. In this paper we propose a token-coordinated random access MAC TMAC framework that scales to various population sizes and a wide range of high physical-layer rates. TMAC takes a two-tier design approach employing centralized coarse-grained channel regulation and distributed fine-grained random access. The higher tier organizes stations into multiple token groups and permits only the stations in one group to contend for the channel at a time. This token mechanism effectively controls the maximum intensity of channel contention and gracefully scales to diverse population sizes. At the lower tier we propose an adaptive channel sharing model working with the distributed random access which largely reduces protocol overhead and exploits rate diversity among stations. Results from analysis and extensive simulations demonstrate that TMAC achieves a scalable network throughput as user size increases from 15 to over 300. At the same time TMAC improves the overall throughput of wireless LANs by approximately 100 at link capacity of 216 Mb s as compared with the widely adopted DCF scheme. Copyright 2007 Yuan Yuan et al. This is an open access article distributed .