Improving fairness in multiuser diversity with capture

Abstract

In a wireless network, multiuser diversity can be exploited by allowing the mobile user with the best channel to use the channel. However, the overhead incurred in polling channel state information (CSI) can overshadow the multiuser diversity gain. In our previous work, we proposed a Multiuser Diversity with Capture (MDC) scheme to reduce the overhead by taking advantage of the fact that only the channel state information of the mobile station (MS) with the best channel is required to be available at the base station (BS). In this paper, we propose Fairer Multiuser Diversity with Capture (FMDC) to improve the fairness performance of MDC. We also develop a fairness measure for wireless systems that exploit multiuser diversity. By simulations, we evaluate the goodput and temporal fairness performance for FMDC, MDC and the Medium Access Diversity (MAD) schemes proposed in the literature. Our results show that with a small degradation in goodput performance, FMDC achieves much better fairness performance than MDC. Furthermore, FMDC achieves much better goodput performance than MAD, with comparable fairness performance.Index Terms-multiuser diversity, capture effect, IEEE 802.11a, channel state information, fairness