A Novel Capacity Outer Bound for the MIMO Gaussian Interference Channel and Application to Relay-Assisted Communications

A novel Genie-aided capacity outer bound is provided for MIMO Gaussian interference channels. Rather than requiring each side-informed receiver to cancel the interference from its received signal, it is suggested that each receiver views the interference as the useful signal undergoing a different channel, which we call an equivalent channel representation. Reflections on the existence and capacity enhancement of such equivalent channel representation are made. Subsequently, an application to relay-assisted communications is provided for which an achievable capacity region is determined. Finally, numerical examples are provided to demonstrate an increase of capacity owing to the proposed interference processing method.