Multicell Collaborative Random Beamforming with Power Sharing and User Selection

We consider a multicell random beamforming scheme where a cooperative base station (BS) can simultaneously beamform to its served (local) user via utilizing perfect channel state information and randomly beamform to its neighboring users. The rationale behind this scheme is to curtail channel information feedback in a multicell MIMO system. By sharing antenna degree of freedom and transmit power at the collaborative BSs, user terminals (UT) can enjoy macro diversity gain and system spectrum efficiency (SE) is therefore improved. In this paper, the transmit power for a BS used for collaborative random beamforming (Co-RBF) is determined by the outage probability requirement of its served user. Besides, we propose a user selection scheme based on maximizing the incremental capacity comes from Co-RBF. The upper bound of the capacity increments in high signal-to-interference and noise ratio (SINR) regime is also derived. The proposed Co-RBF scheme shows its feasibility for multicell wireless applications due to its flexibility and lower feedback overhead.