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International Journal of Vehicular Technology
Volume 2009 (2009), Article ID 891367, 10 pages
Research Article

Suboptimal Rate Adaptive Resource Allocation for Downlink OFDMA Systems

Department of Electrical and Computer Engineering, WINCORE Lab, Ryerson University, Toronto, ON, Canada M5B 2K3

Received 11 January 2009; Revised 21 May 2009; Accepted 7 June 2009

Academic Editor: Ekram Hossain

Copyright © 2009 Sanam Sadr 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.


This paper aims to study the performance of low complexity adaptive resource allocation in the downlink of OFDMA systems with fixed or variable rate requirements (with fairness consideration). Two suboptimal resource allocation algorithms are proposed using the simplifying assumption of transmit power over the entire bandwidth. The objective of the first algorithm is to maximize the total throughput while maintaining rate proportionality among the users. The proposed suboptimal algorithm prioritizes the user with the highest sensitivity to the subcarrier allocation, and the variance over the subchannel gains is used to define the sensitivity of each user. The second algorithm concerns rate adaptive resource allocation in multiuser systems with fixed rate constraints. We propose a suboptimal joint subchannel and power allocation algorithm which prioritizes the users with the highest required data rates. The main feature of this algorithm is its low complexity while achieving the rate requirements.