A limited feedback user-location-aware network MIMO coordination scheme for cellular downlink

Abstract

MIMO downlink with base station coordination in a cellular network is considered. In centralized coordinated transmission from a cluster of base stations, the channel state information (CSI) of users needs to be sent to a central processor for user scheduling and resource allocation. Real time CSI feedback from the users to their home base station and from the base stations to the central processor is a serious challenge from a practical point of view. Using user location information and cell sectorization, a network MIMO scheme with reduced feedback requirement is proposed, which for the case of DPC and a network of uniformly distributed users requires about 50 % less CSI while maintaining almost the same level of average cell throughput compared to base station coordinated transmission with full CSI. The proposed location aware network MIMO scheme is applied to DPC, zero-forcing block diagonalization (ZF-BD) and limited feedback ZF-BD.