Indoor Planning of Optical Wireless Networks for Line-of-Sight Condition in Access and Backhauling

Optical Wireless Communication (OWC) can complement wireless access services provided over Radio-Frequency (RF) bands by offering abundant additional unlicensed spectrum while enhancing privacy, security, and sustainability. This technology, however, requires Line-of-Sight (LoS) links with no obstructions between transmitter and receiver. In addition, the range of Visible Light Communication (VLC) for wireless access is limited to a few meters when using Light Emitting Diodes (LEDs). Hence, deploying VLC Access Points (APs) to prevent indoor coverage gaps is a challenging task. In this paper, we first characterize the VLC cell range in terms of the three-dimensional (3D) position, orientation, and parameters of the LEDs and the photodetector (PD). Secondly, we propose a graph model to represent the floor plan and, based on it, a clique clustering method that determines the minimum number of APs (and their locations) to ensure LoS coverage. Then, we transform this graph into a connectivity tree, such that the APs can communicate with each other via LoS infrared wireless. Based on our findings, the proposed deployment approach significantly outperforms conventional methods in terms of coverage area and required number of APs, improving the minimum/mean data rate of the VLC network when deployed to give service indoors.