Performance evaluation of distributed multi-cell beamforming for MU-MIMO systems

Inter-cell interference (ICI) from nearby cells can substantially degrade the sum-rate in WLAN systems. To improve the sum-rate in actual WLAN systems, some papers have investigated distributed multi-cell beamforming to mitigate ICI by zero forcing beamforming. All most of these approaches consider single-user multiple input multiple output (SU-MIMO) systems. In this paper, we present three techniques for distributed multi-cell beamforming for multi-user MIMO (MU-MIMO) systems with the same total number of transmit and receive antennas. The first technique is distributed multi-cell beamforming using receiver selection. The second one is antenna selection at the receiver. The last one is an iterative technique in which transmitter weight is updated at the transmitter to correspond to receiver weight. The sum-rate of these techniques with imperfect channel state information at transmitter (CSIT) is evaluated. We clarify the effectiveness of these techniques for MU-MIMO systems.