System-Level Studies for Multi-User Interference Alignment in a Homogeneous Network

In this paper we study multi-user interference alignment at system level. Interference alignment (IA) is a quite recently proposed transmission strategy with varying precoding solutions. In IA, precoders and receivers are designed cooperatively between transmission points such that interference is aligned in a smaller vector space at each receiver than it would be without IA. One known problem for all IA schemes is that they are prone to external interference, interference from transmission points that are outside of the cooperation set. In this paper, we evaluate the system level performance of a multi-user IA scheme with a 3GPP LTE-Advanced compliant system level simulator. We found that IA is very prone to external interference and that a receiver that is cancelling also external interference is outperforming IA.