Novel adaptive Channel State Information feedback for multiuser MIMO in wireless broadband communications

The availability of Channel State Information (CSI) at the transmitter in Multi User -Multiple Input Multiple Output (MU-MIMO) has been a popular research topic in recent years. The CSI makes it possible to adapt transmissions to current channel conditions, which is crucial for achieving reliable communication with high data rates in multi antenna systems. Basically there are two methods that allow the transmitter to obtain CSI from the receiver. This paper highlights both of these mechanisms and presents the basis of a novel feedback mechanism that efficiently provides the transmitter with minimum CSI to allow knowledge of a rapidly changing channel at the transmitter end of a MU-MIMO system. Preliminary simulation results show that channel capacity in a 4 × 4 MIMO system increases by up to 20% with the availability of CSI at the transmitter.