A novel spectrum allocation scheme in femtocell networks using improved graph theory

Abstract

In this paper, we propose a novel spectrum allocation scheme by using graph coloring and taking QoS thresholds into account. The goal of our proposed method is to reduce interference among femtocells deployed densely and improve spectral efficiency after reaching user’s QoS threshold. We design an interference-based graph model by detecting terminals’ transmit power between femtocell stations and classifying the interference levels according to the coloring algorithm. Spectrum resource is allocated based on the QoS requirement of each user in a centralized way. The simulation results show that when the scheme is deployed in femtocells with high density, it can effectively reduce the interference within same layer and improve system capacity along with spectrum efficiency.