A Cognitive Opportunistic Fractional Frequency Reuse Scheme for OFDMA Uplinks

Abstract

Inter Cell Interference (ICI) is an important issue to address in 4G Orthogonal Frequency Division Multiple Access (OFDMA) and beyond networks since it limits capacity. Fractional Frequency Reuse (FFR) scheme is one of the schemes suggested in the literature to mitigate ICI. However, it is important that the schemes should adapt to changing traffic load, otherwise, this will lead to spectrum underutilization and spectrum scarcity problems in cellular networks. We propose the cognitive based FFR for uplink that uses spectrum opportunistically. The proposed scheme allows the base stations to take the decisions autonomously while allocating spectrum to cell edge users hence the cell edge performance is improved. From the results, it is seen that the proposed scheme increases the spectral efficiency and blocking probability performance of cell edge users when compared against the existing FFR scheme for both realistic (irregular) and unrealistic (regular) cellular layouts.