Graph-based resource allocation scheme in interference-restricted two-tier OFDMA femtocell networks

With the increasing requirements for seamless coverage and high date rate for indoor users, femtocells are widely used as a compliment to macrocells. In this paper, we primarily address the OFDMA downlink co-tier interference resulting from "plug-and-play" by resource partitioning in two-tier femtocell networks. The main objective is to achieve the maximization of system throughput despite the harmful downlink interference. For this purpose, a novel resource allocation scheme based on interference graph with QoS ensured is proposed, which consists of three parts, i.e. triangulation, clique degree and dynamic resource reuse. The proposed algorithm identifies the interference of each user in a more accurate way by clique degree, which is an extension of degree in conventional graph theory. As shown in our simulation results, the aggregate and average throughput of femtocells are increased obviously with the consideration of fairness for femtocell users.