A coloring-based resource allocation for OFDMA femtocell networks

In order to improve the spectrum efficiency in the femtocell network and mitigate the co-tier/cross-tier interference, we propose a novel graph-theoretic scheme based on coloring algorithm for self-adaptive spectrum resource allocation in femtocells. A dynamic orthogonal spectrum sharing between macrocell and femtocell is utilized in the proposed allocation scheme to reduce the cross-tier interference. In order to mitigate the cotier interference, a graph-based clustering resource allocation (GCRA) scheme is presented. The interference graph of the femto-tier is built first based on the measurement reports of femtocell user equipments (FUEs). Then a coloring algorithm is implemented in a distributed way to construct disjoint clusters in which the frequency band can be reused to improve the spectrum efficiency. Finally, a dynamic orthogonal resource allocation is performed to avoid the inter-cluster interference. The simulation results reveal that the GCRA approach enhances the spectrum efficiency of the femtocell network, while mitigating the co-tier/cross-tier interference of the heterogeneous network.