On the interference avoidance method in two-tier LTE networks with femtocells

Femtocells are attractive candidates in the future cellular system such as long-term evolution (LTE). However, the interference introduced by femtocells may hinder the improved system performance in LTE networks. In this paper, we consider the challenging problem of interference management in LTE networks with femtocells, propose two frequency reuse patterns and a novel interference avoidance method with the frequency resources of the macrocell reused by femtocells. The key idea of the interference avoidance method is to identify the macrocell user equipments (MUEs) which are near femtocells with the help of spectrum sensing performed by femtocells and avoid MUEs and nearby femtocells using the same frequency resources through spectrum scheduling. Moreover, we conduct simulations to verify that our proposed method is successful in avoiding the potential interference and improving the network performance.