Fractional frequency reuse for irregular cell geometry OFDMA systems

Future cellular systems are targeting aggressive frequency reuse to meet the ever increasing demands for capacity and throughput. However, aggressive frequency reuse results in high inter cell interference (ICI) especially at the cell edges. Fractional Frequency Reuse (FFR) has recently emerged as an attractive interference management approach in OFDMA cellular systems. In literature, FFR is studied mostly for regular cell geometry models and very limited work exists for irregular cell geometry models. In this paper we investigate the performance of FFR for cellular network based on irregular cell geometry. Furthermore, full frequency reuse is achieved by sectoring the cell edge users. Applying regular sub-bands of equal size to the irregular sectors of the cell-edge region leads to suboptimal performance. Therefore, a low complexity FFR scheme with optimal sub-carrier allocation is proposed for multicellular network and the capacity of the system is evaluated. It is shown that the proposed FFR scheme outperform the conventional frequency allocation schemes in term of cell edge throughput.