Inter-Cell Interference Sub-Space Coordination for 5G Ultra-Dense Networks

In this paper, we present an inter-cell interference subspace coordination scheme for multiple-input multiple-output communications. The method relies on downlink precoding design for distributed multi-cell multi-user networks. In the proposed method, receivers benefit from minimum-mean square error structure. Each receiver separates the received signal space into desired/interference sub-spaces. The key idea in this contribution is to employ precoding algorithms at the transmission-end with the objective of jointly projecting transmitted signal over desired subspace and aligning most of the interference onto predefined interference subspaces at the interfered receiver end. This idea works with only local channel state information available at transmitter-side and benefits from low computational complexity. Simulation results show that the proposed method offers about 28\% throughput enhancements in networks with high dominant interference regimes.