User Scheduling for Network MIMO Systems With Successive Zero-Forcing Precoding

In this paper, the authors consider simplified greedy user scheduling algorithms for clustered network multiuser Multiple-Input Multiple-Output (MIMO) systems with successive Zero-Forcing (SZF) pre-coding. The optimal user scheduling involves an exhaustive search, which is very complex. Among various suboptimal but lower complexity algorithms, greedy algorithms with heuristic scheduling metrics have been shown to achieve performance close to the exhaustive search. In this paper, they propose two simplified algorithms: Interference-Aware Greedy User Scheduling (IA-GUS) and Interference-Whitening Greedy User Scheduling (IW-GUS). IA-GUS schedules the users based on the information on interference power of the selected users in surrounding cooperating clusters, and IW-GUS schedules the users based on the information on whitened channels of all users requesting the service in the cluster.