Analytical Evaluation of Uplink Fractional Frequency Reuse

The design and evaluation of Inter-cell Interference Coordination (ICIC) techniques has been the focus of significant research as wireless networks are increasingly faced with the challenge of balancing fairness to users at the cell-edge with high spectral efficiency. This work considers the use of Fractional frequency reuse (FFR), in the cellular uplink, which is well-suited for modern cellular networks due to its low complexity and coordination requirements and resource allocation flexibility. These approaches have typically been modeled using deterministic grids for the base station deployments and analyzed through system-level simulations, which do not lead to fundamental insights or tractable expressions of relevant metrics of coverage probability or average rate for a typical user. Instead, this work utilizes Poisson point processes for the underlying spatial models for user and base station locations. From the derived expressions we quantify the coverage gains with Strict FFR relative to universal reuse and Soft Frequency Reuse (SFR), as well as the performance tradeoff SFR achieves for edge and inner users through greater bandwidth efficiency. We additionally illustrate how the analytical model can be directly related to traffic or coverage requirements and gives insight into selecting power control parameters and resource allocations under Strict FFR and SFR to achieve system capacity gains over universal frequency reuse.