Downlink power setting for energy efficient Heterogeneous Cellular Networks

Heterogeneous Cellular Networks (HCNs) are aimed to provide high data rates to an user population which is non uniform in space in an energy efficient manner. However inter cell interference is a limiting factor that is exacerbated with the irregular locations of Base Stations (BSs) and heterogeneous nature of transmitted powers. Conventional deployments only apply power control in the uplink (UL) whereas BSs transmit with fixed power in the downlink (DL) with independence of each BS location. In this paper two power setting techniques are proposed for the DL of HCNs. These techniques adjust transmit power at each BS aiming to provide a target desired power ρ0 at the cell edge. Hence these schemes account for the interference that each BS transmission cause to users associated with neighboring cells, reducing unnecessary powerful transmissions for close BSs. It is shown through simulation that proposed schemes greatly increase the average energy efficiency of the network as well as the average binary rate or the fairness in the system.