Opportunistic Beamforming with Single Beamforming Matrix for Virtual Antenna Arrays

In a multiuser wireless communication system (e. g., a cellular system), opportunistic beamforming is a promising technique for downlink transmissions to support multiple users at a time. In opportunistic beamforming, with limited feedback of channel state information (CSI), to minimize the impact of interference, the best beamforming matrix can be selected from a set of multiple beamforming matrices or a codebook. This approach may require excessive complexity due to the selection of a new beamforming matrix when a scheduler frequently updates the set of users to be supported. To avoid this problem, in this paper, we propose an opportunistic beamforming approach with single beamforming matrix. In addition, we show that the proposed approach suits for a virtual antenna array where multiple BS units form a transmit antenna array.