On the optimal small cell deployment for energy-efficient heterogeneous cellular networks

Deploying small cells has been widely accepted as a viable solution to meet ever-growing demand of user traffic in cellular heterogeneous networks (HetNets). These small cells can be deterministically or randomly deployed. In this paper we consider a HetNet scenario where multiple small cells are randomly or deterministically overlaid with a macro cell. We use the hexagonal grid model for the deterministic deployment and the Poisson point process model for the random deployment. We analyze user rate and network energy efficiencies, and our numerical results show that deterministic deployment strategy is generally better than random deployment. We evaluate the performances of macro cell and small cell users separately and find that most benefits go to small cell users, not macro cell users. Our simulation results also suggest that deterministically deploying more small cells continues to boost network energy efficiency, while randomly deploying more small cells brings little gain.