Achieving multiuser diversity under hard fairness constraints

Abstract

The focus of this study is the concept of multiuser diversity in the context of a single-cell multiuser channel. The primary result of this work is that using proper dynamic resource allocation strategies on Rayleigh fading channels can yield a non-negligible power boost which can be as high as 5 or 6 dB, for a moderate number of users employing a joint resource allocation policy. This gain grows logarithmically with the number of users. The main practical issue arising from these results is fairness. Users must wait (or the base station in the case of the broadcast channel) until their channel conditions are favourable enough to transmit. We show in this work that multiuser diversity can still be achieved in a multi-carrier system using simple orthogonal multiplexing even under the constraint that each user receives the same constant bandwidth resource at any time instant.