Analytical Evaluation of Throughput and Power Efficiency Using Fractional Frequency Reuse

Inter-Cell Interference (ICI) is always a key problem in Fractional Frequency Reuse (FFR) system to be focused on, which should be well resolved to pursue higher throughput and better power efficiency. In this paper, we investigate throughput and power efficiency of RR scheduling in FFR system by both closed-form expression and Monte Carlo trials method. We improve a previous throughput model by applying variable subcarrier distribution scheme and upgrading expression for the Cumulative Distribution Function (CDF) of SINR. Then we propose a new closed-form expression of average cell throughput. The fairness performance of this model is better than that using fixed subcarrier distribution scheme. Meanwhile, an optimal radius threshold is selected so as to achieve best throughput performance. Then we manage to explore the relationship between cell power efficiency and transmit power based on the optimal radius threshold. From both analytical and simulation results, it is shown that power efficiency is monotonically decreasing with transmit power. Hence operational power is introduced into power efficiency as energy consumption for base station. After that, the highest power efficiency can be reached by setting a proper and reasonable transmit power.