Fractional Frequency Reuse in DCO-OFDM-Based Optical Attocell Networks

In this paper a fractional frequency reuse (FFR) technique is considered in a direct-current optical orthogonal frequency-division multiplexing-based optical attocell network. An optical attocell network is proposed as a special type of visible light communication system that has the complete function of a cellular network. The cellular network is composed of many cells of extremely small size-the optical attocells. Two FFR schemes, strict fractional frequency reuse and soft frequency reuse, are considered. The signal-to-interference-plus-noise ratio (SINR) statistics and the spectral efficiency of the optical cellular system with FFR are analyzed. The performance of the systems with full frequency reuse and FFR is evaluated and compared. The results show that the FFR scheme can effectively achieve interference mitigation in an optical attocell network. The cell edge user SINR and spectral efficiency are significantly improved. Additionally, FFR provides improvements in average spectral efficiency. The effects of important parameters such as cell radius are also studied.