A Novel Coordinated Spectrum Assignment Scheme for Densely Deployed Enterprise LTE Femtocells

With the emergence of femtocells, the complexity and heterogeneity of the mobile radio networks have been dramatically increased, which lead to more operational tasks such as self-configuration and optimization of the new distributed wireless system. The allocation of spectrum and avoidance of inter-cell interference are some of the more urgent challenges that operators have to face before femtocells become widely deployed. However, considering the small cell radius and irregular coverage area of the femto BS, the typical ICIC (Inter-Cell Interference Coordination) technologies such as FFR (Fractional Frequency Reuse) in current LTE network are not suitable for femtocells. In this paper, a novel coordinated spectrum assignment scheme is proposed for inter-femtocell interference coordination of densely deployed enterprise LTE femtocells. The proposed scheme is mainly composed of an autonomous selection process of dedicated subband for basic connectivity and a cooperated allocation process of shared subband for high data capacity. It works in a distributed and localized manner, showing a high level of scalability and feasibility.