Energy Efficiency Optimization for Non-overlay Planning of Heterogeneous Cellular Networks

In this paper, we consider non-overlay planning of microcells in a heterogeneous cellular network. In this approach, in order to minimize overlaps between microcell and macrocell service areas, macrocells lower their common pilot channel power as the number of microcells around the hexagonal site edges increases. Under such a deployment assumption, we solve an energy efficiency optimization problem over certain parameters like the Inter Site Distance (ISD), the number of microcells per macrocell and the size of microcells. We assume coverage and spectral efficiency constraints and investigate the effect of user density on the optimization problem. The results show that the optimum number of microcells depends heavily on the user density and the target area spectral efficiency.