Adaptive Random Beamforming with Interference Suppression and Beam Selection in Cellular Networks

In this paper, we propose an adaptive random beamforming scheme with beam selection. In order to recover the orthogonality among beams, we adopt a minimum mean-square error (MMSE) interference suppression receiver for the orthogonal random beamforming (ORBF) scheme and find efficient power allocation strategies. Based on a proportional-fairness criterion, we propose a sub-optimal beam selection scheme and show that the random beam selection (or power randomization) scheme can outperform the conventional equal power allocation scheme, mitigating the burden of optimal beam selection. Therefore, the proposed ORBF/MMSE with beam selection scheme can improve the degraded performance in the interference-limited environment considering the feedback overhead and time selectivity of the wireless channel for practical cellular systems.