Inter-cluster interference canceller for multiuser MIMO distributed antenna systems

We propose a co-channel inter-cluster interference canceller for distributed antenna systems (DAS) that utilize the multiuser Multiple Input Multiple Output (MU-MIMO) technique in the downlink. We first define the cluster as a virtual cell that consists of a few remote antennas and subscriber stations which communicate cooperatively by MU-MIMO. Multiuser beamforming is applied to each cluster, so the proposed method can decrease the computational complexity of spatial division multiplexing processes compared to MIMO systems with large number of antennas. Though clustering causes co-channel inter-cluster interference, it can be cancelled simply by linear processing of the downlink transmission signals. Computer simulations show that the proposed method enables denser cluster configurations. The method contributes to the practical realization of distributed antenna systems through its effective frequency reuse.