Spatial overlapping index based joint beam selection for millimeter-wave multiuser MIMO systems

Abstract

In this paper, beam selection for millimeter-wave multiuser multi-input multi-output (MIMO) systems that employ zero-forcing based analog-digital hybrid processing is investigated. The existing approaches have tackled neither the joint beam selection at both sides of the communication system nor the strong interference imposed by the mobile stations (MSs) which share beams with some other MSs. Hence, by first assuming full channel state information, the problem of joint beam selection is formulated and the concept of spatial overlapping index (SOI) is proposed to deal with the strong interference imposed by the MSs which share beams with some other MSs. Furthermore, by considering the realistic scenario of having channel estimation, the joint beam selection is divided and integrated into the channel estimation process, and the SOI is redefined based on the channel estimates. Finally, our analysis and simulations show that the upper bound of the sum rate increases with the number of MSs and the number of base station antennas, the proposed approach outperforms the existing approaches, and the computational complexity of the proposed approach is close to or lower than that of the existing approaches.