Closed-Loop Beamspace MIMO Systems with Low Hardware Complexity

Multiple input-multiple output (MIMO) systems have drawn remarkable interest in recent years, since they are known to boost the spectral efficiency of wireless communication systems compared to single antenna architectures. However, the implementation cost and circuit complexity of such systems conflicts the guaranteed high performance gain. Recent research efforts focus on the investigation of cheaper and low complexity transceivers, introducing a novel beamspace MIMO (BS-MIMO) architecture. BS-MIMO systems have shown equivalent performance with the corresponding conventional systems, while they have been also evaluated in closed loop environments. In this paper we extend the closed loop BS MIMO approach presenting advanced limited feedback techniques which outperform predecessor feedback schemes.