CSI Feedback Reduction Techniques for CellularDownlink with Coordinated Multi-Point Transmission

MIMO downlink with base station coordination in a cellular network is considered. In centralized coordinated transmission from a cluster of base stations, the channel stateinformation (CSI) of users needs to be sent to a central processor for precoding and resource allocation. Real time CSI feedback from the users to their home base station and from thebase stations to the central processor is a serious challenge from a practical point of view. CSI feedback schemes based onuser channel strength and distance of a user to its home base station are proposed that reduce feedback overhead whilehaving not much affect on system throughput. Numerical results show the effectiveness of the proposed schemes.