Unified Approach to the Analytical Assessment of Multi-user Diversity with Imperfect Channel State Information

In this paper, we explore the combined use of spatial and multi-user diversity in a cellular system where the channel state information (CSI) available at the base station (BS) is subject to imperfections. To do that, we consider a general statistical approach to describe the degree of CSI imperfection. By doing so, performance assessment is conducted for the generalized case in terms of ergodic system capacity, for which closed-form expressions are derived. In order to gain some insight, practical examples are presented and spatial vs. multi-user diversity trade-offs are analytically assessed.