Optimal Fractional Frequency Reuse (FFR) in Multicellular OFDMA System

Abstract

This paper provides analysis of the inter cell interference coordination problem in multicell OFDMA systems. In order to reduce the interference without losing much frequency resources in each cell, cell users are partitioned into two classes, namely interior and exterior users. Frequency resources are universally used in all interior cells' areas whereas users of exterior zones have a frequency reuse factor strictly higher than 1. In this paper, we determine the optimal frequency reuse factor of the exterior users as well as the bandwidth to assign to both interior and exterior zones. The resource management and interference coordination are jointly formulated as an optimization problem. Results depicted in this paper allow determining the optimal configuration of the interior and exterior regions' dimensions as well as the optimal frequency reuse factor.