Performance of multiuser MIMO systems under realistic propagation conditions

Many studies investigate wireless communication systems with multiple antennas on both sides of the link (MIMO systems) for future high-speed mobile communications. With these systems, the spatial properties of the propagation channel can be exploited. This paper deals with the investigation of MIMO systems on system level for the downlink case. In this scenario multiuser interference affects the capacity of each user. The interference depends on the spatial characteristics of the propagation channel. It is spatially-colored. A necessary step towards realistic simulation results is to include the spatial dependencies between different users via directional information on the angle of arrival of the multiuser interference. A new multiuser double-directional channel model (MDDCM), which fulfils this constraint, is presented in this paper, ft is based on a geometry approach with fixed scatterers and includes line-of-sight areas, far clusters and new models for street guided and over rooftop propagation. Simulation results of a cellular multiuser MIMO system for the downlink case based on the MDDCM are presented. With this tool it becomes possible to evaluate the performance of multiuser MIMO systems under realistic propagation and interference conditions