Visible Light Communications: A Novel Indoor Network Planning Approach

We propose a Partition-based Visibility (PV) graph modeling to find the minimum number of Visible Light Communications (VLC) nodes and their locations for reliable indoor coverage. VLC network offers a low-cost technology on a license-free spectrum to complement the contemporary mobile network services offered on Radio Frequency (RF) bands. However, VLC suffers from propagation limits: Firstly, in presence of opaque obstacles such as walls, doors, and even curtains, strong link blockage is experienced as the power of reflections is much weaker than the power of the Line-of-Sight (LoS) link. Secondly, the received optical power at users drops as the angle of irradiance between a LED lamp and the user increases, imposing a range constraint on the VLC nodes. So, inspired by the Art Gallery Problem, we optimize the number and the locations of VLC nodes by characterizing the PV graph as a dual presentation of the floor plan and a Maximal Clique Clustering algorithm, which is able to solve not only the art gallery problem but also to extend the approach for the range constrained case.