Strong Interference Alignment

Interference alignment (IA) adjusts signaling scheme such that all interfering signals are squeezed in interference subspace, and obtains the maximum degrees of freedom in an interference channel. However, IA mostly achieves its performance via infinite extension of the channel, which is a major challenge in practical systems. In this paper, we schedule part of interference to be strong and achieve perfect IA within limited number of channel extensions. A single-hop 3 user single antenna interference channel (IFC) is considered and it is shown that one of the interfering signal streams needs to be strong so that perfect IA is feasible. Practical implementation of the proposed scheme is discussed in detail for the case of two extensions of the 3 user single antenna IFC.