Group optimal space-time MUD with beamforming

To improve the bandwidth efficiency of current and future generations of wireless cellular systems, several techniques exist such as beamforming (BF) and multiuser detection (MUD). To reduce the complexity of the MUD, it has been proposed to separate users within a cell into mutually exclusive groups and perform MUD independently in each group. Inter-group interference (IGI) is reduced by using beamforming. In this work, the group optimal MMSE linear receiver for BF based space-time multiuser detector (ST-MUD) receivers (BF-STMUD) is derived. The complexity of this structure is compared to that of the full ST-MUD. It is shown through computer simulations that with proper grouping, an important reduction in complexity can be achieved with almost insignificant loss of performance.