DoF achieving asymptotic interference alignment for two interfering 2 × 2 X channels

Abstract

We investigate the degrees of freedom (DoF) of a coexisting network composed by two interfering basic 2 × 2 X channels with single antenna at each node. Asymptotic interference alignment approach is used to obtain the lower bound on the based on symbol extension model. When n tends to infinity, the DoF lower bound achieves 2, which is proven to be the upper bound on DoF. Therefore, the bound on DoF is tight.