LTE planning for Soft Frequency Reuse

Future 4G cellular systems will address the need of capacity increase for the support of diverse Internet services. This article deals with cell capacity issues and cell planning for LTE technology. The Soft Frequency Reuse (SFR) scheme is considered here as an interesting approach to efficiently utilize the bandwidth in LTE systems. With SFR, a cell is divided into two parts (the central part and the external part) using different reuse schemes. On the basis of a suitable path loss model, we have been able to characterize the Signal to Interference plus Noise Ratio (SINR) and the probability to use different transmission modes in a cell with SFR. This has allowed us to evaluate the capacity of a cell that can be achieved with SFR. Finally, a cell capacity optimization has been carried out by means of extensive numerical results in order to select both the radius of the cell-center region and the border-to-center power ratio of SFR.