Effect of the Wavelength Reuse Pattern and Cell Size on the Performance of Indoor Cellular Visible Light Communication

The effects of the wavelength reuse pattern and cell size on the performance of indoor cellular visible light communication (VLC) systems are investigated in the present paper. A novel method for the evaluation of the intercell interference (ICI) and its impact on the performance of indoor cellular VLC is introduced and the numerical results are presented and discussed. A novel configuration is proposed for an indoor cellular VLC system employing wavelength division multiple access (WDMA) technique for serving multi-users, on-off keying OOK modulation for light signaling, and hexagonal-shaped cells for signal coverage and user mobility. The wavelength reuse patterns are employed to enhance the VLC system capacity. The cell radius and the size of the wavelength reuse pattern are the main design parameters that are concerned in the present work. The numerical results investigating the distribution of the signal strength, ICI, signal-to-ICI ratio (SICIR), and the resulting distribution of the bit-error rate (BER) over the area of a wide room are presented and discussed. It is shown that the intercell interference can be mitigated by increasing the cell radius and/or increasing the size of the wavelength reuse pattern. However, it has been shown that small cell radius is preferred to large cell radius as it produces more uniform signal strength distribution over the coverage area of the indoor VLC. Design curves for the proposed indoor cellular VLC system are provided in the present work to facilitate the design process by enabling the designer to determine the optimum cell radius and wavelength reuse pattern size to satisfy the VLC system design goals.