Performance of femtocell access point deployments in user hot-spot scenarios

In this work, we investigate the impact of user clustering on the performance of femtocell-enhanced macrocellular networks. Various degrees of clustering are evaluated: A low degree corresponds to almost uniform user distributions, whereas a high degree relates to densly populated user hot-spots. Clustered user-scenarios are generated by applying a Poisson cluster process. We start out with a plain macrocellular network and cover an increasing amount of these clusters by femtocells. Expressions for the achieved Signal-to-Interference Ratio (SIR) of macrocell- and femtocell users are formulated and evaluated numerically. The efficiency of the femtocell enhancement is quantified by means of sum spectral efficiency and fairness.