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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 Throughput versus Fairness: Channel-Aware Scheduling in Multiple Antenna Downlink | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2009 Article ID 271540 13 pages doi 10.1155 2009 271540 Research Article Throughput versus Fairness Channel-Aware Scheduling in Multiple Antenna Downlink Eduard A. Jorswieck 1 Aydin Sezgin 2 and Xi Zhang3 1 Communications Laboratory Faculty of Electrical Engineering and Information Technology Dresden University of Technology D-01062 Dresden Germany 2 Department of Electrical Engineering Computer Science Henry Samueli School of Engineering University of California Irvine CA 92697 USA 3 ACCESS Linnaeus Center Royal Institute of Technology SE-100 44 Stockholm Sweden Correspondence should be addressed to Eduard A. Jorswieck jorswieck@ifn.et.tu-dresden.de Received 1 July 2008 Accepted 23 December 2008 Recommended by Alagan Anpalagan Channel aware and opportunistic scheduling algorithms exploit the channel knowledge and fading to increase the average throughput. Alternatively each user could be served equally in order to maximize fairness. Obviously there is a tradeoff between average throughput and fairness in the system. In this paper we study four representative schedulers namely the maximum throughput scheduler MTS the proportional fair scheduler PFS the relative opportunistic round robin scheduler ORS and the round robin scheduler RRS for a space-time coded multiple antenna downlink system. The system applies TDMA based scheduling and exploits the multiple antennas in terms of spatial diversity. We show that the average sum rate performance and the average worst-case delay depend strongly on the user distribution within the cell. MTS gains from asymmetrical distributed users whereas the other three schedulers suffer. On the other hand the average fairness of MTS and PFS decreases with asymmetrical user distribution. The key contribution of this paper is to put these tradeoffs and observations on a solid theoretical basis. Both the PFS and the ORS provide a reasonable .
