  In this paper, we investigate the impact of user distribution on resource
allocation in visible light communication (VLC) systems, using a wavelength
division multiple access (WDMA) scheme. Two different room layouts are examined
in this study. Three 10-user scenarios are considered, while an optical angle
diversity receiver (ADR) with four faces is used. A mixed-integer linear
programming (MILP) model is utilized to identify the optimum wavelengths and
access point (AP) allocation in each scenario. The results show that a change
in user distribution can affect the level of channel bandwidth and SINR.
However, a uniform distribution of users in the room can provide a higher
channel bandwidth as well as high SINR above the threshold (15.6 dB) for all
users compared to clustered users, which is a scenario that has the lowest SINR
with supported data rate above 3.2 Gbps.
