Multiuser scheduling with reduced channel state information feedback

The objective of this paper is to give an overview of switched-diversity scheduling for wireless net-works. This multiuser scheduling scheme is based on one-bit only for the channel information feedback. The reduced feedback causes a slight reduction in the achievable rate per resource unit. Nevertheless, the saved resources for the feedback channel can be used to support more data traffic. We introduce the principle concept of this scheduling scheme, and we point out the main contributions in the literature. Furthermore, we discuss how the feedback thresholds of the users are optimized to maximize the system performance, and we provide a numerical example of the achievable rate region in a two-user scenario. Additionally, we highlight two technical challenges which are centralized optimization and fairness, and we show how these can be completely solved be proper scheduler design to achieve proportional fairness among the users. Moreover, we give some comments on two alternative designs, namely the post-user selection strategy and the hybrid switched-selection diversity scheme. We provide additionally some numerical results to demonstrate that the switched-diversity scheduling scheme operates within 0.3 bits/sec/Hz from the ultimate network capacity of a full feedback scheduling scheme in Rayleigh fading conditions.