On Single-User Collaborative Random Beamforming

In recent years, multi-cell downlink (DL) collaborative multi-input multi-output (MIMO) transmission has drawn a lot of attentions due to its potential benefits in system throughput. However, the requirements on training and feedback may hamper its practical applications. In this paper, we consider a single-user collaborative random beamforming (Co-RBF) scheme to ease the training and feedback burden in a multi-cell environment. The proposed single-user collaborative random beamforming system, either with and without additional transmitter phase adjustments, are described and analyzed from outage probability perspective. From analysis and numerical results, collaborative random beamforming schemes can provide macro diversity gain with little feedback. This implies its feasibility for limited feedback collaborative wireless systems.