An Analytical Framework for Multilayer Partial Frequency Reuse Scheme Design in Mobile Communication Systems

Partial frequency reuse (PFR) is one of the key techniques to improving max-min fairness for cell-edge user equipment in the fourth generation of mobile communication systems. Recently, multilayer PFR schemes have been proposed, which are considered to be a promising evolution of this technique. In this paper, we propose an analytical framework for multilayer PFR scheme design, which uses a triplet to completely describe a given PFR scheme. Then, closed-form expressions of the average spatial capacities of certain typical regions of a cell are derived. Based on a comprehensive analysis using this framework, a novel multilayer PFR scheme is designed, which divides each cell into inner, middle, and outer layers, with two homolographic sublayers for the middle layer. Reuse factors for the three layers are 1, 3/2, and 3, respectively, and an orthogonal division of the spectrum among different layers is guaranteed. Based on our numerical results, this novel scheme outperforms the traditional two-layer PFR scheme in max-min fairness without degrading the average spatial capacity. Compared with several representative multilayer PFR schemes, it achieves a better tradeoff between these two metrics.