Degrees of Freedom in Wireless Multiuser Spatial Multiplex Systems With Multiple Antennas

The emergence of multiuser transmission techniques for wireless multiantenna systems has opened up the possibility of allowing multiple users to access the base-station at the same frequency and at the same time. The design of such a multiuser Multiple-Input Multiple-Output (MIMO) system demands not only multiuser detection and multiuser precoding techniques at the signal-processing level, but also the implementation of multiuser scheduling algorithms at the system level. The focus of this paper is on the optimal structure of multiuser scheduling and power control in a multiantenna wireless system.