tailieunhanh - Báo cáo hóa học: " Research Article Throughput Gain Using Threshold-Based Multiuser Scheduling in WiMAX OFDMA"

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 Gain Using Threshold-Based Multiuser Scheduling in WiMAX OFDMA | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2011 Article ID 941350 7 pages doi 2011 941350 Research Article Throughput Gain Using Threshold-Based Multiuser Scheduling in WiMAX OFDMA Ahmed Iyanda Sulyman Department of Electrical Engineering College of Engineering King Saud University Riyadh 11421 Saudi Arabia Correspondence should be addressed to Ahmed Iyanda Sulyman asulyman@ Received 5 October 2010 Revised 13 January 2011 Accepted 18 February 2011 Academic Editor Stefan Kaiser Copyright 2011 Ahmed Iyanda Sulyman. 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. This paper presents the analysis of the throughput enhancement possible using threshold-based multiuser scheduling in WiMAX OFDMA. We consider a point-to-multipoint PMP WiMAX network where base station BS schedules downlink packets for simultaneous transmissions to multiple users using the WiMAX OFDMA system. WiMAX OFDMA standard specifies several subcarrier permutation options such as the partial usage of subcarriers PUSC full usage of subcarrier FUSC and the band adaptive modulation and coding band-AMC among others for mapping the physical subcarriers into logical subchannels assigned to users by the BS schedulers. In this paper we propose the use of threshold testing prior to the process of subchannel assignment to users by the BS scheduler as a means of throughput enhancement. In the proposed threshold-based multiuser scheduling scheme the BS scheduler selects at any time instant users whose channel gains in the available subchannels equal or exceed a predetermined energy threshold. Thus only users who can maximize BS throughput on the available subchannels are assigned data transmission opportunities which enhance the BS data rate albeit at the expense of fairness to users.