Adaptive Beam Deactivation for Coordinated Multi-cell System with Limited Feedback

Abstract

In this paper, we propose an adaptive beam deactivation scheme to mitigate inter-cell interference for a coordinated single-cell beamforming downlink transmission with limited feedback in a multi-cell multiple-input multiple-output wireless network. In the proposed scheme, each user feeds the indices of a desired beam and other undesired beams, and a certain channel quality indicator back to its home base station (BS). Based on the returned information, coordinating BSs assign each user to a serving BS by exploiting the proposed transmitting user set selection algorithm. Both exact and asymptotic sum rate analyses are done on the resulting system. Selected numerical examples are provided to show that the proposed scheme achieves noticeable sum rate gain compared to the conventional zero-forcing based coordinated multi-cell system with reduced feedback load.