User selection strategies for multiuser MIMO systems with block diagonalization

Block diagonalization (BD) is an efficient precodingtechnique that eliminates inter-user interference in downlinkmultiple-input multiple-output (MIMO) systems. User selectionstrategies applied to multiuser MIMO systems with BD areinvestigated in this article. To enhance the capacity of multiuserMIMO systems, an equivalent capacity maximum (ECM) userselection strategy is proposed with low computational complexity.Considering both the factors of channel correlations andchannel conditions, the proposed strategy can select a group ofusers to serve for maximizing the total throughput. Simulationresults indicate that, for various channel conditions, proposedECM strategy gains a better performance compared withtraditional user selection strategies, and achieves a near optimalthroughput as the exhaustive search.