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

In this paper we propose a multiuser scheduling algorithm that has the maximum average system spectral efficiency, but obtains a significant reduction in feedback load compared to full feedback by using a feedback threshold. An expression for the threshold value that minimizes the feedback load is found. Novel closed-form expressions are also found for the system spectral efficiency when using M-ary quadrature amplitude modulation. Finally, we analyze the impact of scheduling delay and outdated channel estimates. 1

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

<p/> <p>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 The first scenario is where the scheduling decision is based on outdated channel estimates, and the second scenario is where both the scheduling decision and the adaptive modulation are based on outdated channel estimates.</p