The impact of user spatial heterogeneity in heterogeneous cellular networks

The spatial distribution of users in cellular networks plays an important role on network performance. It is becoming increasingly common in the recent literature to model the user locations according to a homogeneous Poisson point process, yet users are often spatially clustered in reality. In this paper, we investigate the impact of user spatial heterogeneity in downlink cellular networks, including macro-only networks and small-cell enhanced heterogeneous cellular networks (HCNs). In the generic point process introduced in this paper, the degree of user spatial heterogeneity is scalable, smoothly controlled, and is measured by a non-negative real number. Numerical results show that the network performance deteriorates significantly when user distribution becomes more heterogeneous while remaining uncorrelated with the base station locations. However, by deploying small-cells in the centers of the user hot-spots found by cluster analysis on non-uniform user points, we show that HCNs can benefit from a certain degree of user spatial heterogeneity.