EURASIP Journal on Wireless Communications and Networking 
Volume 2006 (2006), Article ID 36424, 7 pages
doi:10.1155/WCN/2006/36424

Rate-Optimal Multiuser Scheduling with Reduced Feedback Load and Analysis of Delay Effects

Vegard Hassel,1 Mohamed-Slim Alouini,2 Geir E. Øien,1 and David Gesbert3

 1Department of Electronics and Telecommunications, Norwegian University of Science and Technology, Trondheim 7491, Norway
2Department of Electrical Engineering, Texas A&M University at Qatar (TAMUQ), Education City, P.O. Box 5825, Doha, Qatar
3Mobile Communications Department, Eurécom Institute, Sophia Antipolis 06904, France
Received 30 September 2005; Revised 13 March 2006; Accepted 26 May 2006

Abstract

We propose a feedback algorithm for wireless networks that always collects feedback from the user with the best channel conditions and has a significant reduction in feedback load compared to full feedback. The algorithm is based on a carrier-to-noise threshold, and closed-form expressions for the feedback load as well as the threshold value that minimizes the feedback load have been found. We analyze two delay scenarios. The first scenario is where the scheduling decision is based on outdated channel estimates, and the second scenario is where both the scheduling decision and the adaptive modulation are based on outdated channel estimates.